Download PDF
ads:
UNIVERSIDADE FEDERAL DO RIO DE JANEIRO
Centro de Ciência da Saúde
Faculdade de Odontologia
Departamento de Odontopediatria e Ortodontia
Rio de Janeiro
2009
Ana Carolina Valinoti da Costa
POTENCIAL CARIOGÊNICO E EROSIVO DE
MEDICAMENTOS LÍQUIDOS PEDIÁTRICOS
ads:
Livros Grátis
http://www.livrosgratis.com.br
Milhares de livros grátis para download.
UNIVERSIDADE FEDERAL DO RIO DE JANEIRO
Centro de Ciência da Saúde
Faculdade de Odontologia
Departamento de Odontopediatria e Ortodontia
Rio de Janeiro
2009
Ana Carolina Valinoti da Costa
POTENCIAL CARIOGÊNICO E EROSIVO DE
MEDICAMENTOS LÍQUIDOS PEDIÁTRICOS
Dissertação de Mestrado apresentada ao Programa de
Pós-Graduação em Odontologia (Odontopediatria),
Faculdade de Odontologia, Universidade Federal do Rio
de Janeiro, como parte dos requisitos necessários à
obtenção do título de Mestre em Odontologia
(Odontopediatria).
Orientadora:
Prof. Dra. Lucianne Cople Maia
ads:
F
ICH A CAT ALOGRÁFICA
Costa, Ana Carolina Valinoti da
Potencial cariogênico e erosivo de medicamentos líquidos pediátricos / Ana
Carolina Valinoti da Costa. – Rio de Janeiro: UFRJ / Faculdade de
Odontologia, 2009.
xix, 100 f. : il. ; 31 cm
Orientadora: Lucianne Cople Maia
Dissertação (mestrado) – UFRJ / Faculdade de Odontologia, Programa de
Pós-graduação em Odontopediatria, 2009.
Referências bibliográficas: f. 92-100
1. Cárie dentária. 2. Erosão de dente. 3. Uso de medicamentos. 4. Acidez. 5.
Viscosidade. 6. Resinas Compostas - Tese. I. Maia, Lucianne Cople. II.
Universidade Federal do Rio de Janeiro, Faculdade de Odontologia,
Programa de Pós-Graduação em Odontologia (Odontopediatria). III. Título
iii
iv
D
EDI CATÓ RI A
A
O S M E U S Q U E R I D O S P A I S
L
U I Z
C
A R L O S E
S
O N I A
,
Obrigada pelo amor incondicional, por me apoiarem em cada uma das minhas
decisões e acima de tudo por acreditarem sempre em mim, muitas vezes abdicando
dos próprios sonhos para que eu pudesse realizar os meus.
Por serem os maiores exemplos e a maior inspiração para mim.
Vocês são o meu porto seguro e nada disso seria possível sem vocês.
A minha eterna gratidão por tornarem possível a realização deste sonho!
Dedico a vocês esta vitória!
O b r i g a d a p o r t ud o . A mo m u i t o v o c ê s !
v
A o s m e u s i r m ã o s L u i z C a r l o s J u n i o r e C a r l o s E d u ar d o ,
Obrigada por serem os meus maiores amigos, pelo incentivo, pela torcida e por
nunca deixarem que eu desanimasse, por mais difícil que tenha sido cada passo.
Ao Júnior, por ter me ajudado na análise dos dados e, em todas as horas do dia e da
noite, ter tirado as minhas dúvidas de computador e por ter me aconselhado e
escutado sempre que eu precisei.
Amo muito vocês!
vi
A
GRADECIMENTO
E
SPECIAL
A minha querida orientadora Lucianne Cople Maia, por toda a paciência, dedicação,
orientação e incentivo durante esses dois anos de mestrado. Muito obrigada por ter
ficado sempre ao meu lado e ajudado a superar cada um dos obstáculos, pelos
ensinamentos, por ter vibrado com cada vitória, mas também por todas as críticas
que com certeza também foram importantes para a minha formação. O meu eterno
agradecimento e admiração pelo exemplo de profissional que você é.
Muito obrigada!
vii
A
GRADECIMENTOS
A Deus por todas as oportunidades e pela força que foram muito importantes para
acreditar e trilhar os meus caminhos.
A toda a minha família por serem meus alicerces e por torcerem pelo meu sucesso.
As minhas queridas avós, Caridade e Yolanda, por todo o amor, carinho, exemplo e
proteção. Aos meus tios, Márcia, Alexandre, César e Débora por toda a torcida,
pela amizade e por todo amor. Aos meus queridos primos, em especial a Giovanna,
por ser esse anjinho lindo e carinhoso, por me fazer voltar a ser criança quando
estamos juntas, me ajudando a recarregar todas as minhas energias. Amo muito
vocês!
Ao meu namorado Rodrigo, por todo o amor, carinho, companheirismo que me
fizeram mais forte e mais feliz durante este período. Obrigada por acreditar em mim,
por estar ao meu lado nos momentos mais difíceis, por compreender as minhas
ausências e ainda por me encher de mimos nos momentos de desânimo e carência.
Te amo muito e pra sempre!
A todas as minhas queridas amigas: Carolina Roberty, Caroline Siqueira, Letícia
Loureiro, Letícia Camilher, Luciana, Renata e Tássia pelos momentos de
descontração, pelo ombro amigo, pela torcida e pelo entusiasmo com as minhas
vitórias. Por estarem acima de tudo sempre ao meu lado! Amigas, vocês são para
sempre! Amo muito vocês!
A amiga Carolina Roberty por estar sempre ao meu lado (por alguns momentos até
mesmo de longe), por me ouvir, apoiar e por me “emprestar” a sua família que
também sempre me apoiou. Meus sinceros agradecimentos ao Dudu, Carla e “tia”
Marilda por todo apoio e amizade.
As minhas queridas amigas de coração e de profissão, Dani e Aninha. Amigas que
eu conquistei na faculdade e vão ficar para a vida toda. Obrigada por tudo que
vivemos juntas e por estarem sempre ao meu lado, por me ouvirem, por me
viii
divertirem, por vibrarem com as minhas vitórias e por nunca terem me deixado
desanimar. Eu amo muito vocês!
As minhas queridas amigas de sempre Fernanda e Juliana. Apesar de não nos
vermos tanto quanto gostaríamos vocês moram no meu coração e agradeço por
tudo que fazem e já fizeram por mim! Amo vocês!
A minha querida cunhada, Fernanda. Obrigada por toda a amizade, carinho e por
sempre estar disposta a me ajudar. Saiba que eu te considero mais do que cunhada:
minha amiga! Até mesmo a sua mãe me ajudou e sou muito agradecida por isso.
A minha querida “co-orientadora” Viviane Pierro pela inestimável colaboração. Vivi,
não tenho palavras para agradecer! Obrigada por todos os ensinamentos,
conselhos, atenção, pelos sábados que deixou de estar com seu filho para me
ajudar e por todos os outros dias, dentre as suas inúmeras atividades. Admiro muito
você! Muito obrigada do fundo do coração!
A Profa. Ivete Pomarico pela disponibilidade, atenção e pela compreensão em
inúmeros momentos do mestrado.
A Profa. Glória Castro (Glorinha), uma professora e pessoa maravilhosa, muito
querida por mim. Obrigada por todos os ensinamentos ao longo do curso e por todos
os prazerosos momentos de aprendizado. Admiro e gosto muito de você!
Ao Prof. Marcelo Costa por todo o incentivo em diversos momentos, desde a
atualização até o fim do mestrado. Obrigada por ter feito parte do início da minha
história como odontopediatra e por ter estado sempre ao meu lado quando precisei.
Ao Prof. João Farinhas pela ajuda constante na clinica e por cada ensinamento.
Muito obrigada!
Ao Prof. Rogério Gleiser por todo o apoio e pelos agradáveis momentos de
aprendizagem ao longo deste período.
ix
Aos professores: Laura Primo, Maristela, Nena, Fátima, Rosana e Eduardo, pelos
ensinamentos transmitidos ao longo do curso.
A querida professora Áurea Simone (in memorian) por ser esse exemplo de
profissional e de vida, e que hoje é um anjinho a nos iluminar. Obrigada por tudo!
Você faz muita falta!
Aos meus queridos amigos de turma: Bárbara, Daniel, Érika, Patrícia, Raquel e
Senda. Cada um de vocês foi muito importante ao longo deste período. Obrigada
por todo apoio, amizade e por sempre terem estendido a o quando eu precisei.
Adoro muito vocês!
Aos amigos Rafael Pedro, Tatiana Kelly e Marina. Obrigada pela convivência e
amizade. Tati, muito obrigada pela amizade, pela ajuda de sempre, especialmente
no preparo das soluções. Marina, obrigada pela nossa amizade, pelos momentos de
desabafo, conselhos e descontração juntas! Adoro vocês!
Aos ex-alunos do Departamento que tive a oportunidade de conhecer e conviver,
Patrícia Dias, via Azeredo, Camilla, Fernanda Machado, Lizandra Ferrari,
Lúcia Helena, Viviane de Paula, Glaucia Athayde, Madeleine, e em especial à
Beatriz Neves por ter contribuído para este trabalho. Obrigada por tudo!
As alunas do Doutorado, Roberta Barcelos, Andréa, Ana Karla, Cristiana, Márcia
Alves, Luciana Pomarico e Carla Martins. Obrigada pelo convívio agradável e
oportunidade de aprendizado.
Aos funcionários do Departamento de Odontopediatria (FO/UFRJ), em especial
Gina, Kátia, Mere, Andréa, Luiza, Robson, Zezé, Bruna e Isabel. Meus eternos
agradecimentos, por todo apoio recebido durante o curso. Vocês foram
indispensáveis!
Ao João Carlos, que sempre com muita paciência e bom humor me ajudou nos
assuntos de informática. Obrigada de coração!
x
Ao Prof. Ronir Raggio pela ajuda de sempre nas análises estatísticas. Muito
obrigada!
Ao Prof. Eduardo Moreira da Silva (UFF) pela amizade, acolhida, disponibilidade
em todos os momentos que eu precisei e pela grande colaboração científica.
A Simone (Labiom-R / UFF) pela disponibilidade, colaboração e por ter sido um anjo
para mim quando eu não tinha experiência nenhuma em laboratório.
Ao Laboratório de Bioquímica Nutricional e de Alimentos (UFRJ) e a todos os
alunos que me ajudaram de alguma forma nas análises no HPLC, em especial à
doutoranda Aline Tocci. Meu sincero agradecimento à Profa Adriana Farah pela
acolhida, disponibilidade e prontidão em todos os momentos que precisei da sua
ajuda. Muito obrigada!
Ao Laboratório de Ensaios Mecânicos (IME) e especialmente ao Leonardo pelo
suporte nas análises de microdureza do esmalte.
Ao Laboratório de Microscopia Eletrônica (IME) e a toda atenção dada pelo Joel.
Ao Prof Jaime Cury, Profa Livia Tenuta e Waldomiro Vieira por todo o suporte e
atenção na realização das análises de fosfato e flúor (FOP - UNICAMP).
Ao Prof Delmo Santiago Vaitsman e Edna Lúcia Couto Oberosler pela
colaboração na análise de conteúdo de cálcio (Laboratório de Desenvolvimento
Analítico / Instituto de Química - UFRJ).
Ao Laboratório de Controle de Qualidade de Fármacos e Medicamentos (UFRJ),
em particular à Profa. Valéria Pereira de Sousa, pela paciência em me ensinar as
análises de acidez titulável.
Ao Instituto de Macromoléculas Profa Eloísa Mano (UFRJ), em especial à Profa.
Elizabete Lucas pela gentileza e atenção e a Lea Lopes pela realização das análises
de viscosidade.
xi
A CAPES pela bolsa de estudo concedida durante o curso de mestrado.
A CNPq (308029/2006-2) e a FAPERJ (E-26/171.241/2006) pelo apoio financeiro
para este projeto.
A todos que, direta ou indiretamente, contribuíram para a realização desta
dissertação, o meu sincero agradecimento!
xii
"Sonhe com aquilo que você quiser.
Vá para onde você queira ir.
Seja o que você quer ser, porque você possui apenas uma vida
e nela só temos uma chance de fazer aquilo que queremos.
Tenha felicidade bastante para fazê-la doce.
Dificuldades para fazê-la forte...
Tristeza para fazê-la humana...
E esperança suficiente para fazê-la feliz..."
Clarice Lispector
xiii
R
ES U MO
COSTA, Ana Carolina Valinoti da. Potencial cariogênico e erosivo de
medicamentos líquidos pediátricos. Rio de Janeiro, 2009. Dissertação (Mestrado
em Odontologia, área de concentração em Odontopediatria) Faculdade de
Odontologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 2009.
O presente estudo avaliou a concentração de açúcares, pH, acidez titulável e
viscosidade de 29 antibacterianos líquidos. Objetivou-se ainda avaliar o efeito de
medicamentos ácidos sobre o esmalte dental hígido (Klaricid
®
, Claritin
®
e Dimetapp
Elixir
®
) e sobre resinas compostas (Claritin
®
e Dimetapp Elixir
®
), sob condições de
ciclagem de pH in vitro. Para determinar a concentração de açúcares, utilizou-se a
cromatografia líquida de alta eficiência. A acidez titulável de cada medicamento foi
determinada através da adição gradual de 0,1N NaOH até alcançar o pH 7,0. O pH e
a viscosidade foram determinados utilizando pHmetro digital e viscosímetro,
respectivamente. Blocos de esmalte bovino (n=104) foram distribuídos em G1
(ciclagem de pH padrão) e G2 (ciclagem erosiva), que foram subdivididos (n=13) de
acordo com o meio de imersão (Klaricid
®
, Claritin
®
e Dimetapp Elixir
®
) e controle
(água deionizada). Além das viscosidades, os conteúdos de flúor (F), fósforo (P) e
cálcio (Ca) dos medicamentos e controle foram determinados. Espécimes (n=30)
dos compósitos resinosos TPH
®
, Concept
®
, Opallis
®
e Supreme
®
, foram divididos em
grupos (n=10) experimentais (Claritin
®
e Dimetapp Elixir
®
) e controle gua
deionizada). Rugosidade superficial e microscopia eletrônica de varredura (MEV)
foram avaliadas no esmalte e nos compósitos antes e após as condições
experimentais. Calculou-se também a porcentagem de perda de microdureza
superficial (%PDS) para o G1. As concentrações de sacarose variaram de 25,9g% a
77.46% em 19 antibacterianos. Quinze antibacterianos apresentaram pH abaixo do
crítico para a dissolução da hidroxiapatita. Viscosidade e acidez titulável variaram de
20 a 1780 cP e 0,26 a 40,48 ml, respectivamente. Verificou-se que a rugosidade
aumentou em G1 e G2, sendo mais acentuada em G2. Dimetapp Elixir
®
promoveu
maiores alterações na rugosidade, especialmente quando comparada ao Claritin
®
no
G1 e ao Klaricid
®
em ambos os grupos (p<0,008). A microdureza diminuiu em todos
os subgrupos de G1 (p<0,05). A análise por MEV mostrou padrões erosivos em
todos os subgrupos, mais pronunciados em G2, maior para o Dimetapp
®
e menor
para o Klaricid
®
em ambos os grupos. Klaricid
®
apresentou as maiores
concentrações de F, P e Ca e viscosidade. Quanto aos compósitos, houve aumento
significativo da rugosidade somente para TPH no grupo controle e TPH e Supreme
em Claritin
®
. Todas as resinas sofreram degradação superficial. A maioria dos
antibacterianos apresentou alta concentração de açúcares, alta acidez titulável, alta
viscosidade e baixo pH. A imersão de esmalte dental em medicamentos ácidos e
controle (água deionizada) promoveu padrões erosivos em todos os grupos, mais
acentuadamente em condições erosivas. A ciclagem de pH e a imersão em
medicamentos ácidos promoveram degradação superficial das resinas compostas,
sendo maior naquelas com partículas de carga maiores.
Palavras-chave: CÁRIE DENTÁRIA, EROSÃO DE DENTE, USO DE
MEDICAMENTOS, EDULCORANTES, ACIDEZ, VISCOSIDADE, RESINAS
COMPOSTAS.
xiv
A
BS TR AC T
COSTA, Ana Carolina Valinoti da. Potencial cariogênico e erosivo de
medicamentos líquidos pediátricos. Rio de Janeiro, 2009. Dissertação (Mestrado
em Odontologia, área de concentração em Odontopediatria) Faculdade de
Odontologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 2009.
The present study evaluated the concentration of sugars, pH, titratable acidity and
viscosity of 29 liquid antibiotics. The aim was also to evaluate the effect of acidic
medicines on sound dental enamel (Klaricid
®
, Claritin
®
e Dimetapp Elixir
®
) and on
composite resins (Claritin
®
e Dimetapp Elixir
®
), under in vitro pH-cycling conditions.
To assess the concentration of sugars, it was used a high performance liquid
chromatography (HPLC) with refractive index detector. Titratable acidity of each
medicine was assessed by gradual addition of 0.1N NaOH until reach pH 7.0 was
reached. The pH and viscosity were assessed using digital pHmeter and
viscosimeter, respectively. Enamel blocks (n=104) were distributed into G1 (standard
pH-cycling) and G2 (erosive cycling), which were subdivided (n=13) according to
media immersion (Klaricid
®
, Claritin
®
e Dimetapp Elixir
®
) and control (deionized
water). In addition to viscosity, the contents of fluoride (F), phosphorus (P) and
calcium (Ca) of medicines and control were determined. Specimens (n=30) of
composite resins TPH, Concept, Opallis and Supreme, were divided into (n=10)
experimental groups (Claritin
®
and Dimetapp Elixir
®
) and a control group (deionized
water). Surface roughness and scanning electron microscopy (SEM) were evaluated
in enamel and in composite resins before and after the experimental conditions.
Furthermore, the percentage of surface microhardness change (%SMC) was
calculated at group G1. Sucrose concentrations ranged from 25.9g% to 77.46% in 19
antibiotics. Fifteen antibiotics presented pH below the critical value for dissolution of
hydroxyapatite. Viscosity and titratable acidity ranged from 20 to 1780 cP, and from
0.26 to 40.48 ml, respectively. It was found that the roughness increased in G1 and
G2, being more pronounced in G2. Dimetapp Elixir
®
promoted greater changes in
surface roughness of enamel, especially when compared to Claritin
®
in G1 and to
Klaricid
®
in both groups (p<0.008). Microhardness decreased in all subgroups of G1
(p<0.05). SEM analysis showed erosive patterns of enamel in all subgroups, more
pronounced in G2, greater in Dimetapp Elixir
®
and lower in Klaricid
®
in both groups.
Klaricid
®
presented the highest concentrations of F, P and Ca and viscosity. With
regard to composites, there was a significant increase in roughness only for TPH in
the control group and TPH and Supreme in Claritin
®
. All resins presented surface
degradation. The most of the antibiotics showed high concentration of sugars, high
titratable acidity, high viscosity and low pH. The immersion of dental enamel in acidic
medicines and control (deionized water) promoted erosion patterns in all groups,
which was higher in erosive conditions. pH-cycling and acidic medicine’s immersion
promoted surface degradation of composite resins, which was higher in those with
larger filler particles.
Key words: DENTAL CARIES, TOOTH EROSION, DRUG UTILIZATION,
SWEETENING AGENTS, ACIDITY, VISCOSITY, COMPOSITE RESINS.
xv
L
IS T A D E
I
LU ST R A Ç ÕE S
ARTIGO 1
Figure 1: Performance frontier for sucrose and titratable acidty...............................30
Figure 2: Performance frontier for viscosity and titratable acidty..............................32
Figure 3: 3D visualization of the performance frontier according to titratable acidity,
viscosity and sucrose concentration..........................................................................33
ARTIGO 2
Figure 1: Schematic design of the experimental protocol.........................................53
Figure 2: Mean surface microhardness values (KHN) for the four subgroups
(Klaricid®; Claritin®, Dimetapp Elixir®, Control) from G1 before and after the
treatments .................................................................................................................55
Figure 3: Representative SEM photomicrographs of sound bovine enamel.............56
Figure 4: Representative SEM photomicrographs of bovine enamel after standard
pH-cycling and medicine’s immersion and Control:...................................................57
Figure 5: Representative SEM photomicrographs of bovine enamel after reverse pH-
cycling and medicine’s immersion and Control:.........................................................58
ARTIGO 3
Figure 1: Schematic design of the pH-cycling and medicine immersion...................75
Figure 2: Surface roughness before pH-cycling. Columns with the same letters do
not differ significantly (α = 0.05) ................................................................................76
Figure 3: Representative SEM micrographs of resin-based composites before pH-
cycling. ......................................................................................................................77
Figure 4: Representative SEM photomicrographs of resin-based composites after
pH-cycling and immersion in distilled water, control group........................................77
Figure 5: Representative SEM photomicrographs of resin-based composites after
pH-cycling and immersion in Claritin®.......................................................................78
Figure 6: Representative SEM photomicrographs of resin-based composites after
pH-cycling and immersion in Dimetapp®. .................................................................78
xvi
L
IS T A D E
T
AB EL AS
ARTIGO 1
Table 1. Brand names, manufacturers and active principles of all antibiotics analyzed
in the study................................................................................................................28
Table 2. Concentration of sucrose, pH, titratable acidity and viscosity of all analyzed
antibiotics. .................................................................................................................28
Table 3. Performance results (0-100%) of all analyzed antibiotics............................29
ARTIGO 2
Table 1: Chemical parameters of the acidic medicines and control used in the
present study.............................................................................................................52
Table 2: Descriptive statistics of the difference between the final and the initial
roughness values (Ra – µm), by pH-cycling conditions and media immersion..........54
Table 3: Means and standard deviations (SD) of surface microhardness (SMH) and
of percentage surface microhardness change (%SMHC) for enamel blocks from
standard pH-cycling (G1), according to media immersion (subgroups).....................55
ARTIGO 3
Table 1: Composition and specifications of composite resins used in this study ......74
Table 2: Characteristics of the acidic medicines used in the present study ..............74
Table 3: Results of paired t-test for surface roughness means (Ra; mm) before and
after pH-cycling .........................................................................................................76
xvii
L
IS T A D E AB R E VI AT U R AS
Al alumínio
ANVISA Agência Nacional de Vigilância Sanitária
Ba rio
BBC model modelo de Banker, Charnes e Cooper
Bis-EMA bisfenol A polietileno glicol dimetacrilato
Bis-GMA bisfenol-A glicidil metacrilato
°C Celsius
Ca íon cálcio
cP centipoise
DEA Data Envelopment Analysis
HPLC High Performance Liquid Chromatography
µL microlitro
µm micrometro
F flúor
g grama
g% grama/100grama
G1 Grupo 1
G2 Grupo 2
h hora
+H íon hidrogênio
KNH Knoop Hardness Number (unidade de dureza Knoop)
kV kilovoltagem
L litro
MEV Microscopia Eletrônica de Varredura
xviii
min minuto
mL microlitro
mm milímetro
mmol milimoles ou 10
-3
mol
N normal
NaOH hidróxido de sódio
P íon fósforo
PO
4
fosfato
pka potencial de ionização
ppm partes por milhão
pH potencial hidrogeniônico
Ra Rugosidade Superficial Média
s segundo
SEM Scanning Electron Microcospy
SPSS Statistical Analysis for Social Sciences
%SMC Surface Microhardness Change
SMH Surface Microhardness
TEGDMA trietileno glicoldimetacrilato
UDMA uretano dimetacrilato
UFRJ Universidade Federal do Rio de Janeiro
v/v volume/volume
Zr-Si Zircônia-Silica
xix
S
UM ÁR I O
1 INTRODUÇÃO .................................................................................................... 1
2 PROPOSIÇÃO .................................................................................................... 5
2.1 OBJETIVO
GERAL....................................................................................... 5
2.2 OBJETIVOS
ESPECÍFICOS......................................................................... 5
3 DELINEAMENTO DA PESQUISA ...................................................................... 6
4 ARTIGOS ............................................................................................................ 9
4.1 ARTIGO
1................................................................................................... 10
4.2 ARTIGO
2................................................................................................... 34
4.3 ARTIGO
3................................................................................................... 59
5 DISCUSSÃO ..................................................................................................... 79
6 CONCLUSÕES ................................................................................................. 79
REFERÊNCIAS BIBLIOGRÁFICAS ........................................................................ 92
1
1 I
N T R O D U Ç Ã O
O uso de medicamentos faz parte do cotidiano de muitas crianças que
apresentam problemas crônicos, principalmente em casos de alergias
respiratórias, asma, cardiopatias, e insuficiência renal crônica ou doenças
agudas recorrentes, como gripes e resfriados (Maguire, Baqir et al., 2007).
Na maioria das vezes, essas formulações farmacêuticas apresentam em sua
composição ingredientes inativos tais como a úcares e ácidos. Sacarose,
frutose e glicose apresentam função de aumentar a viscosidade,
palatabilidade e consequentemente, a aceitabilidade pelos pacientes, (Kenny
e Somaya, 1989) e ácidos, que funcionam como agentes tampões para
manter a estabilidade química, controlar a tonicidade ou garantir a
compatibilidade fisiológica, além de melhorar o sabor (Maguire, Baqir et al.,
2007).
A literatura revela que medicamentos com altas concentrações de
sacarose, baixo pH endógeno e alta acidez titulável apresentam tanto
potencial cariogênico (Shaw e Glenwright, 1989; Mackie, Worthington et al.,
1993; Mackie e Bentley, 1994; Maguire e Rugg-Gunn, 1994; Duward e Thou,
1997) quanto erosivo (Duward e Thou, 1997; Moss, 1998; Nunn, Ng et al.,
2001; Costa, Almeida et al., 2006; Da Costa, Almeida et al., 2006; Hellwig e
Lussi, 2006; Mcnally, Barbour et al., 2006; Maguire, Baqir et al., 2007; Babu,
Rai et al., 2008; Neves, Farah et al., 2009), uma vez que a sacarose presente
funciona como substrato para a fermentação da microbiota oral (Rekola,
1989), que em conjunto com o meio ácido leva à uma rápida queda do pH da
placa dental. Esse súbito descréscimo no pH pode permanecer por períodos
2
prolongados (Guedes, 1991; Duward e Thou, 1997;(Moss, 1998), o que pode
ser preocupante em relação à saúde oral.
Outros fatores podem contribuir para o desenvolvimento tanto da cárie
quanto da erosão dentária, tais como: a alta viscosidade desses
medicamentos líquidos (Feigal, Jensen et al., 1981; Duward e Thou, 1997), a
freqüência de utilização por crianças que apresentam doenças crônicas, e os
vários momentos de utilização diária, em especial, antes de dormir ou
durante o sono (Shaw e Glenwright, 1989; Mackie e Bentley, 1994; Maguire e
Rugg-Gunn, 1994; Durward e Thou, 1997).
Apesar da prevalência da carie dentária ter diminuído
significativamente nas ultimas décadas (Campus, Sacco et al., 2007), esta
ainda é a doença mais prevalente da cavidade bucal. Em contraste, a erosão
dentária aparentemente tem aumentado entre a população jovem nas últimas
décadas, especialmente em crianças e adolescentes (Nunn, Gordon et al.,
2003; Lussi e Jaeggi, 2006b). Esta doença de caráter multifatorial e complexo
é o resultado da perda de tecido dental que é quimicamente removido da
superfície dental devido à presença de elementos ácidos sem envolvimento
bacteriano (Ten Cate, 1996). A etiologia da erosão dentária tem sido
associada ao uso regular de produtos com baixo pH endógeno, alta acidez
titulável, e composições com baixas quantidades de íons cálcio, flúor, e
fosfato (Costa, Almeida et al., 2006). Dentre estes produtos, bebidas e
alimentos ácidos são considerados potencialmente erosivos (Linnett e Seow,
2001) além de medicamentos ácidos, especialmente se consumidos
frequentemente (Lussi, Jaeggi et al., 2004; Da Costa, Almeida et al., 2006;
Hellwig e Lussi, 2006; Lussi e Jaeggi, 2006a).
3
Estudos in vitro mostraram que medicamentos ácidos foram capazes
de reduzir a dureza de dentes decíduos (Costa, Almeida et al., 2006),
influenciar na rugosidade superficial (Pierro, Barcelos et al., 2004) e promover
alterações morfológicas no esmalte (Da Costa, Almeida et al., 2006; Babu,
Rai et al., 2008) e também induzir a degradação de materiais compósitos
(Valinoti, Neves et al., 2008). Entretanto pouco se sabe sobre o efeito in vitro
e in situ de medicamentos orais sobre o esmalte dental, sob condições
erosivas.
Vale ainda ressaltar que, no ambiente oral, muitos fatores, como as
variações no pH, constante presença de umidade, abrasão e condições
ásperas, induzem à solubilidade do esmalte, como também de materiais
restauradores podendo contribuir para a sua degradação (Soderholm, Zigan
et al., 1984). Materiais dentais restauradores têm mostrado degradação ao
longo do tempo sob condições ácidas (Gao, Matsuya et al., 1997; Sidhu,
Sherriff et al., 1997; Nicholson, Millar et al., 1999; Lussi e Jaeggi, 2006b;
Valinoti, Neves et al., 2008).
A biodegradação é um dos principais problemas que afetam a
durabilidade dos materiais restauradores e na boca parece ser um processo
complexo, envolvendo desintegração e dissolução na saliva e outros tipos de
degradação sico/química, desgaste e erosão causada por alimentos,
mastigação e atividade bacteriana (Oilo, 1992). Este processo pode
deteriorar as propriedades mecânicas dos materiais (Soderholm, Zigan et al.,
1984), reduzindo a vida clínica de restaurações compósitas resinosas. Além
disso, a desintegração superficial de resinas compostas pode aumentar o
desgaste e a retenção de placa, e consequentemente reduzindo a
4
longevidade das restaurações (De Witte, De Maeyer et al., 2003), e
aumentando potencialmente o risco de cáries secundárias.
Neste sentido, considerando que algumas crianças podem necessitar do
uso freqüente de medicamentos líquidos orais, a identificação de algumas
propriedades físico-químicas dessas formulações, bem como a avaliação do
comportamento do esmalte dental e de materiais restauradores adesivos
expostos a estes produtos constitui-se em uma importante ferramenta para a
odontologia.
5
2 P
R O P O S I Ç Ã O
2.1 OBJETIVO GERAL
Avaliar o potencial cariogênico e erosivo de medicamentos quidos
pediátricos e sua ação sobre a superfície dental e de materiais
restauradores adesivos submetidos a condições in vitro que simulem
condições bucais.
2.2 OBJETIVOS ESPECÍFICOS
2.2.1 Avaliar a concentração de carboidratos fermentáveis, o pH, a acidez
titulável e a viscosidade de antibióticos líquidos infantis presentes na lista de
medicamentos de referência da ANVISA;
2.2.2 Avaliar in vitro, sob condições de ciclagem de pH tradicional e sob um
modelo altamente erosivo, o efeito da utilização de medicamentos ácidos
(Klaricid
®
, Claritin
®
e Dimetapp
®
) no esmalte bovino.
2.2.3 Avaliar, sob condições de ciclagem de pH, os efeitos de medicamentos
ácidos (Claritin
®
e Dimetapp
®
) na superfície de materiais restauradores
resinosos.
6
3 D
E L I N E A M E N T O D A P E S Q U I S A
A proposta deste estudo foi avaliar as propriedades cariogênicas e
erosivas de medicamentos líquidos pediátricos e sua contribuição à
desmineralização do esmalte dental e à degradação superficial de materiais
restauradores.
Em 2006, Neves (Neves, 2006) analisou a concentração de açúcares,
pH, acidez titulável e viscosidade de xaropes infantis disponíveis no mercado
brasileiro. A amostra consistiu de antihistamínicos, antitussígenos,
broncodilatadores e mucolíticos. Em continuidade a este projeto, surgiu a
necessidade de avaliar a classe dos antibacterianos, medicamentos
amplamente utilizados por crianças. Dessa forma, o primeiro artigo deste
estudo consistiu em uma avaliação laboratorial de antibióticos líquidos
infantis (n=29) selecionados a partir da lista de medicamentos de referência
da ANVISA, considerados parâmetros de eficácia, segurança e qualidade
para os registros de medicamentos genéricos e similares. Esta lista é
constantemente atualizada e assim, este estudo baseou-se na lista disponível
on-line e atualizada em 18/06/07 (Brasil., 2007). Todos os antibióticos
infantis com sua forma de apresentação líquida foram selecionados para esta
etapa do estudo.
Estes medicamentos foram avaliados quanto à sua concentração de
carboidratos fermentáveis, pH, acidez titulável e viscosidade. Além disso,
todas as bulas dos antibióticos foram observadas, a fim de verificar se
mencionavam em sua composição a presença dos edulcorantes utilizados e
dos ácidos presentes. Em seguida, verificou-se o desempenho relativo de
7
cada antibiótico quanto ao seu potencial de desmineralização/ erosão do
esmalte através da metologia DEA (Data Envelopment Analysis).
O segundo artigo teve o propósito de avaliar o efeito in vitro de
medicamentos ácidos (Klaricid
®
50 mg/mL, Claritin
®
e Dimetapp
®
) sobre a
superfície do esmalte dental. Estes medicamentos foram selecionados a
partir de estudos prévios, que analisaram características físico-químicas que
podem contribuir para a desmineralização do esmalte dental (concentração
de açúcares, pH, acidez titulável e viscosidade). Os medicamentos Claritin
®
e
Dimetapp
®
foram selecionados com base no estudo de Neves (Neves, 2006) ,
por apresentarem os piores resultados no que diz respeito ao pH, acidez
titulável e viscosidade em conjunto. o antibiótico líquido Klaricid
®
50 mg /
mL foi selecionado com base em um estudo anterior (Valinoti, Neves et al.,
2008), por apresentar os piores resultados no que diz respeito ao pH, acidez
titulável, concentração de açúcar e viscosidade conjuntamente. Cento e
quatro blocos de esmalte foram distribuídos em dois grupos de acordo com
os modelos de ciclagem de pH utilizados, sendo um deles a fim de simular o
ambiente oral (G1 - ciclagem de pH tradicional) e o outro a fim de simular um
desafio altamente erosivo (G2). Cada grupo foi dividido em 4 subgrupos de
igual amostragem (n=13) de acordo com o meio de imersão: medicamentos
ácidos (Klaricid
®
50mg/mL, Claritin
®
e Dimetapp Elixir
®
) e controle (água
deionizada). Em seguida os espécimes foram submetidos às condições de
ciclagem de pH e a duas imersões diárias em medicamentos ácidos durante
12 dias. Alterações na superfície do esmalte foram analisadas através da
rugosidade superficial, microdureza superficial e microscopia eletrônica de
varredura (MEV).
8
O terceiro artigo objetivou avaliar os efeitos de medicamentos ácidos
(Claritin
®
e Dimetapp
®
), sob condições de ciclagem de pH, na degradação
superficial de compósitos resinosos, materiais restauradores amplamente
utilizados (microhíbrido: TPH, Concept, Opallis e nanoparticulado: Supreme).
Trinta espécimes de cada material foram aleatoriamente distribuídos em 3
grupos (n = 10): um controle e dois grupos experimentais, de acordo com os
medicamentos ácidos avaliados [E1 - Claritin
®
; E2 - Dimettap
®
and C
(controle) água deionizada]. Após os espécimes serem submetidos a um
regime de ciclagem de pH de 24 horas, durante 12 dias, as alterações
superficiais e morfológicas promovidas pela ciclagem de ph somadas a
imersão nos medicamentos e na água deionizada, foram avaliadas através
das análises de rugosidade superficial e através de microscopia eletrônica de
varredura (MEV).
9
4 A
R T I G O S
Artigo 1 - “CARIOGENIC AND EROSIVE POTENTIALS OF PEDIATRIC
ANTIBIOTICS”, será submetido ao periódico Pediatrics
Artigo 2 - “ALTERATIONS OF DENTAL ENAMEL SUBMITTED TO ACIDIC
MEDICINES AND pH-CYCLING”, será submetido ao periódico Pediatric
Dentistry
Artigo 3 - “SURFACE DEGRADATION OF COMPOSITE RESINS BY
ACIDIC MEDICINES AND pH-CYCLING”, Journal of Applied Oral Science
2008; 16(4):257-65
10
4.1. ARTIGO 1
ARE PEDIATRIC ANTIBIOTICS A THREAT TO DENTAL HEALTH?
Short title: CARIOGENIC AND EROSIVE POTENTIALS OF ANTIBIOTICS
Ana Carolina Valinoti, DDS
1
; Luiz Carlos da Costa Jr., MSc
2
; Adriana
Farah, PhD
3
; Valéria Pereira de Sousa, PhD
4
; Lucianne Cople Maia, PhD
5
1
MSc student, Department of Pediatric Dentistry and Orthodontics, School of
Dentistry, Federal University of Rio de Janeiro, RJ, Brazil;
2
PhD student, Systems
and Computing Engineering, COPPE/Federal University of Rio de Janeiro, RJ, Brazil;
3
Visiting Professor, Nutritional Biochemistry and Food Science Laboratory, Chemistry
Institute, Department of Biochemistry, Federal University of Rio de Janeiro, RJ,
Brazil;
4
Associate Professor, Quality Control of Drugs and Medicines Laboratory,
Department of Medicines, Federal University of Rio de Janeiro, RJ, Brazil;
5
Associate
Professor, Department of Pediatric Dentistry and Orthodontics, School of Dentistry,
Federal University of Rio de Janeiro, RJ, Brazil.
Adress correspondence to Dr. Lucianne Cople Maia
Rua Gastão Gonçalves, 47/501 – Santa Rosa
Niterói – RJ – Brasil
CEP: 24240-030
Telephone number: 00 55 21 2629.3738
Fax number: 00 55 21 2562.2098
11
Abstract
Objective: This in vitro study aimed to assess the cariogenic and erosive
potentials of 29 pediatric antibiotics.
Methods: Replicates of each antibiotic were analyzed for the concentration of
sugars (sucrose, glucose and fructose) and sorbitol by high performance
liquid chromatography (HPLC). The pH was determined by digital pHmeter.
Titratable acidity was determined in triplicate using the same pHmeter by
gradual addition of 0.1N sodium hydroxide (NaOH) until pH 7.0. Viscosity
measurements were carried out using a viscosimeter. In order to rank the
relative performance of each medicine, the DEA (Data Envelopment Analysis)
methodology was used.
Results: Sucrose concentrations ranged from 25.9g% to 77.46% in 19
antibiotics. Only one antibiotic contained sorbitol (66.9 g%). Twenty seven
antibiotics presented pH values ranging from 4.1 to 6.9 and most of them
(n=15) showed the pH below the critical value for dissolution of
hydroxyapatite. The values of titratable acidity and viscosity ranged from 0.26
to 40.48 ml and from 20 to 1780 cP, respectively. DEA methodology showed
that two medicines were distant from the performance frontier (Klaricid
®
50mg
and Zinnat
®
250mg), which means that these medicines showed the worst
performance and, therefore, greater potential for dissolution of dental enamel.
Conclusions: Many antibiotics presented high concentration of sugars, high
titratable acidity, pH below the critical value and high viscosity which can be
considered risk factors for dental caries and erosion, when consumed
frequently.
Key words: dental caries, tooth erosion, sweetening agents, Hydrogen-Ion
Concentration, viscosity, pharmaceutical preparations
12
INTRODUCTION
Liquid oral medicines contain in their formulation agents to improve
their appearance, bioavailability, stability, and palatability.
1
Sugars such as
sucrose, fructose and glucose are added to increase bulk, palatability and,
consequently, compliance.
2
. These sugars are widely used because they are
cheap, nonhygroscopic, and easy to process.
3
Acids are also added to
medicines and commonly act as buffering agents to maintain chemical
stability, control tonicity and/or to ensure physiological compatibility. In
addition, they may be used to improve flavour.
4
Because of these so called
“inactive ingredients”, many pediatric liquid medicines are characterized by
having a high concentration of sugars, high titratable acidity and low pH.
Because of these characteristics, various studies have pointed out the
possible relationship between dental caries and frequent intake of liquid oral
medicines.
3, 5-10, 11
The presence of sucrose in medicines leads to pH drop of
dental plaque, and also acts as substrate for fermentation of oral microbiota,
12
contributing to dental caries. Low endogenous pH and high titratable acidity
of these medicines also may favor dental erosion
4, 9, 11, 13-19
, especially when
the contact of the medicine with the tooth surface remains for a very long
time.
14
Besides, previous in vitro studies have also shown that acidic
medicines could reduce deciduous enamel hardness
13, 16
and cause
morphological enamel surface alterations
18
and surface degradation of
restorative materials.
20
Other concerning factors with regard to dental caries
and dental erosion are the high viscosity of liquid oral medication,
9, 21
lack of
oral hygiene after medicine’s intake
21
and its frequency of intake, especially in
13
children that present chronic diseases and need to make regular use of liquid
oral medicines.
3, 9
Considering that some medicines may be a threat to oral health
causing dental caries and erosion, the aim of this in vitro study was to
investigate some physico-chemical properties of liquid oral antibiotics, such as
pH, titratable acidity, sugar concentration and viscosity, which may contribute
significantly to their cariogenic and erosive potential.
METHODS
Twenty nine liquid antibiotics (Table 1) available in the Brazilian
market were selected for this study from a reference list registered in the
National Health Surveillance Agency. All of them were oral suspensions and
23 of them had their powders reconstituted with filtered water as
recommended by the manufacturers. The labels of each medicine were
examined in order to gather information on sugar and acid contents.
Sugar content analysis
Analysis of sugars (sucrose, fructose and glucose) and sorbitol were
performed using normal-phase HPLC-IR (High-Performance Liquid
Cromatography coupled to a Refration Index).
11, 22
One gram of each bottle
was diluted to 50 mL in a volumetric flask with MilliQ water (Milipore, USA).
The mixture was vigorously shaken and one aliquot of the supernatant (500
µL each) was diluted with pure acetronitrile in the proportion 1:1 (v/v). The
mixture was then centrifuged for 2 minutes (Beckman Microfuge E
TM
, USA)
14
and the supernatant was directly used for chromatography.
The concentrations were calculated using the peak heights of
commercial compounds standards of sucrose, fructose, glucose (Sigma
Aldrich, USA) and sorbitol (Vetec Química, Brazil). Results were average of
replicates from each bottle (sugars and sorbitol concentrations - g/100g - %).
Analysis of pH and titratable acidity
Antibiotics’ pH was determined at room temperature with an electrode
connected to a digital pHmeter (Digimed DM 20, USA). The electrode was
calibrated at the start of each session using standard buffers of pH 4.01 and
6.86 (Quimis, Diadema, SP, Brazil). Titratable acidity was measured in
triplicate for each antibiotic by using the same pHmeter and increments of
0.1N sodium hydroxide (NaOH) were titrated until neutrality (pH 7.0) was
reached.
11
A correction factor of 0.87 was obtained by factorizing 0.1 N NaOH
solution with potassium biphthalate. The total volume of 0.1 N NaOH solution
required to neutralize medicines multiplicated to correction factor of 0.87
corresponded to the titratable acidity value.
Viscosity
Viscosity measurements were carried out on a AR 2000 rheometer (TA
instrument, USA) using a parallel plate geometry of 25 mm diameter, at a
shear rate of 0.1 to 100 s
-1
and temperature of 40
o
C. Viscosity values were
obtained at 20s
-1
.
15
Data analysis
In order to verify how was the performance of each antibiotic in
comparison with the others, the DEA (Data Envelopment Analysis)
methodology has been used. DEA is a mathematical programming
methodology which evaluates the relative performance of list of units with
multiple attributes. It identifies a subset of performance "best-practice"
elements (benchmarks) and for remaining ones, the magnitude of their lack of
performance is measured by comparing to a piecewise frontier constructed
from the best elements, facilitating the interpretation of the results. It allowed
the evaluation of the relative performance of each antibiotic taking into
account the undesirable characteristics (high concentration of sugars, low pH,
high titratable acidity and high viscosity) and the desirable ones (absences of
sugars, high pH, low titratable acidity and low viscosity) in the sense of tooth
dissolution potential. In this analysis, the medicines with performance of 100%
are those which present better characteristics in comparison with the others
and, therefore, were less likely to harm the tooth enamel. On the other hand,
medicines with lower percentile values are those with the worst performance
and, in this way, have greater potential for dissolution of dental enamel.
The BCC model with input orientation and weight constraints was
applied. This analysis was carried out with the software IDEAL (Interactive
Data Envelopment Analysis Laboratory), developed by COPPE/UFRJ, which
allows the three-dimensional visualization of the performance frontier.
23
Pearson’s correlation coefficients were used to determine whether
there was any association among concentrations of sucrose, pH, titratable
16
acidity or viscosity, using the SPSS 13.0
®
software at a significance level of
5%.
RESULTS
The concentrations of sucrose, fructose, glucose and sorbitol as well as
pH, titratable acidity and viscosity of all antibiotics are presented as mean
values in Table 2. Table 3 and Figures 1, 2 and 3 show the performance of
the 29 antibiotics analyzed.
Sugar content
Out of the 29 formulations, sucrose concentrations ranged from
25.9g% to 77.46% in 19 antibiotics.However, according to the medicine’s
labels, only fifteen antibiotics (52%) presented sugars and only four of them
specified sugar concentration. None of the antibiotics contained glucose and
fructose. Among these antibiotics, five presented inconclusive data (Pen-ve-
oral
®
80.000UI/mL, Unasyn
®
250 mg/5mL, Zinnat
®
250 mg/5mL, Zitromax
®
600 mg and Zitromax
®
900 mg), despite of the presence of sucrose. Only five
antibiotics (17%) were sugar-free. Sorbitol was present in only one medicine
(3%), with concentration of 66.9g% and associated with sucrose (Table 2).
pH, titratable acidity and viscosity
Two antibiotics (11%) presented basic pH values of 9.7 and 10.8, while
the others presented pH values ranging from 4.1 to 6.9. Fifteen of the 29
analyzed antibiotics (52%) presented pH below the critical value for
17
dissolution of hydroxyapatite (pH 5.5). Values of titratable acidity and viscosity
ranged from 0.26 to 40.48 mL and from 20 to 1780 cP, respectively.
Pearson’s correlation coefficient’s showed that there was no correlation
between pH and titratable acidity (p>0.05) neither between sugar content and
viscosity (p>0.05).
Performance of Medicines (Software IDEAL)
The DEA methodology allowed the simultaneous evaluation of the
analyzed variables (concentration of sugars, pH, titratable acidity and
viscosity) and from the scores obtained, antibiotics were classified according
to their relative performance.
In order to facilitate the interpretation of the results, three figures of the
performance frontier were plotted (Figure 1, Figure 2 and Figure 3). Each
medicine was placed on its corresponding point, according to its attributes,
and can be identified by its corresponding number. Medicines placed in the
vertex points of each face are considered as references or benchmarks, have
100% performance and constitute the performance frontier.
Figure 1 shows the performance frontier for sucrose and titratable
acidty. It can be observed that medicines 14 (Clavulin
®
125mg), 15 (Clavulin
®
250mg), 16 (Clavulin
®
BD 200mg), 17 (Clavulin
®
BD 400mg) and 18 (Clavulin
ES
®
600mg) presented low levels of sucrose and titratable acidity and, for this
reason, are close to the frontier. On the other hand, the medicines 23
(Klaricid
®
25mg/5mL) and 24 (Klaricid
®
50mg/5mL) presented the worst
performance because of their high levels of sucrose and titratable acidity.
18
Figure 2 identifies the medicines with high levels of viscosity and
titratable acidity. Despite of their high viscosity, the medicines 7 (Bactrim
®
200mg/mL) and 8 (Bactrim F
®
400mg/5mL) showed low levels of titratable
acidity. Medicines with low viscosity and titratable acidity and close to the
performance frontier presented a better performance. Again, Klaricid
®
50mg/mL was distant from performance frontier because of their high levels of
titratable acidity and sacarose concentration, presenting the worst
performance (8%).
Finally, Figure 3 shows the 3D visualization of the performance frontier
and identifies the best and worst medicines (see also Table 3). Regions with
higher density of medicines show a group of medicines with an average
performance. Klaricid
®
50 mg/5mL was distant from the performance frontier,
which means that these medicines showed the worst performance and,
therefore, greater potential for dissolution of dental enamel.
DISCUSSION
Antibiotics, which were chosen for this study, as well as cough
medicines are the most common sugar-containing medicines regularly used
by young children.
24
Considering that they may still be used over relatively
long periods, it can be a concern for oral health. Moreover, these medicines
can present erosive potential due to presence of acids in their formulations,
low pH, high titratable acidity, presence of buffering agents and absence or
low concentrations of ions including those of calcium, fluoride, and phosphate
in their composition.
9, 13, 25, 26
19
Although the antibiotics analyzed in this study did not contain glucose
and fructose, the presence of high sucrose concentration in 83% of the
formulations, ranging from 26g% to about 77.46 g%, poses a real problem to
the young consumers. It may increase the caries risk, since sucrose is
considered the most cariogenic dietary carbohydrate, because it is
fermentable, and also serves as a substrate for the synthesis of extracellular
and intracellular polysaccharides in dental plaque.
27,28
. Others studies have
reported a predominant use of sucrose as a sweetener in medicines.
11, 29-31
On the other hand, there are controversial studies that show that despite of
the potentially high sucrose concentration in antibiotics, they work by reducing
the number of Streptococcus mutans and therefore are anticariogenic and
may counteract sucrose´s effect .
32, 33
It should be emphasized that in this
study five antibiotics (Pen-ve-oral
®
80.000UI/mL, Unasyn
®
250 mg/5mL,
Zinnat
®
250 mg/5mL, Zitromax
®
600 mg and Zitromax
®
900 mg) had
concentrations of sucrose with unaccepted values close to 100g% that was
considered inconclusive data and because of it theirs performance could not
be evaluated.
All sweetening agents identified in this study were in accordance with
the medicines’ labels. However, sugar concentrations were unspecified. In
relation to sugar-based medicines, most labels (93%) alerted that the product
should not be consumed by diabetic patients; however, none of them
mentioned its cariogenic potential, especially when used for long periods of
time.
Other factors analyzed in the present study were pH and titratable
acidity, and it is still generally accepted that titratable acidity is a better
20
indicator of erosive potential than pH alone.
34, 35
Titratable acidity is the
property of an acid solution of keeping its pH when neutralizing agents are
added, that is, the measure of its buffering capacity. In this way, a substance
with low titratable acidity is readily neutralized by oral fluids, the opposite
occurs with that characterized by high acidity, which causes prolonged drop in
pH and higher demineralization of the tooth structure.
34, 36
According
Jensdottir et al.,
37
teeth exposed to a limited volume of a drink with low pH
and high titratable acidity for a long time will result in erosive potential and
both qualities combined will result in the highest erosive potential. The liquid
oral antibiotics analyzed in this study had titratable acidic values ranging from
0.26 to 40.48 mL, but some of them proved to be discrepant in relation to
others, which can cause concern. It is now widely accepted that the total
titratable acidity is a more accurate measure of the total acid content of a
drink, and may, therefore, be a more realistic means of predicting erosive
potential. Although the mean endogenous pH for Klaricid
®
50mg/5mL and
Klaricid
®
25mg/5mL was 5.04 and 5.13, their mean titratable acidity was high
at 40.48 and 24.64 mL, respectively. It reflects the incorporation of acid in
excess in their formulation, which according medicine’s labels is citric acid.
Citric acid is considered the main acid used in prolonged oral clearance
medicines and as such, is a weak acid, dissociated in solutions with a higher
pH and able to act as a buffer over a range of pHs. However, it is a potent
erosive agent because of its ability to chelate calcium in hydroxyapatite, thus
increasing enamel’s rate of dissolution on exposure to the acid.
38
In the
present study, six of the twelve medicines which specified presence of acids
presented citric acid in their composition. Other acids presents were
21
clavulanic acid, succinic acid and estearic acid. Again, just as the sweeteners,
the real amount present in these products were not stated on the labels.
On the other hand, it is important to mention that the consumption of an
acidic drink will stimulate salivary flow.
39
It is possible, therefore, that a more
acidic drink may be either cleared from the mouth or neutralized more rapidly,
due to the increased salivary washing action and buffering capacity, and so
will spend less time in contact with the teeth. Clearance of a drink from the
mouth will also depend on the ability of a drink to adhere to the enamel.
40
It is necessary to highlight the real impact of the use of oral liquid
antibiotics in daily life of children. The amoxicillin, with or without association
of clavulanate, is a medicine widely used by children in the treatment of
infections. According to our study, despite of presenting a better performance
than a lot of medicines (Table 3), the group of amoxicillin (medicines 1 - 5)
presented pH values between 5.71 to 6.85 and high concentration of sugar
(36.77 to 49.97) which were worrying in relation to oral health. This fact was
also noted in medicines 14-18 that showed lower pH values ranging from 4.10
to 4.94 despite of being sugar free, which can favor to dental erosion. Other
medicines widely used in routine of immunocompromised patients to prevent
opportunistic infections are Bactrim
®
and Bactrim F
®
(medicines 7 and 8).
These medicines appeared distant from the performance frontier because of
their high concentrations of sucrose and high viscosity (Figure 3), despite of
their low titratable acidity (Figure 2).
It is also important to note the main factors that seem to increase the
likelihood of an individual suffering from dental erosion includes salivary flow
rate, pH, buffering capacity and pellicle formation.
41-43
All these factors added
22
to the properties of the drink itself, as well as associated factors relating to the
method of drinking, frequency of consumption, salivary parameters and dental
plaque play a role in the development of dental erosion. In addition, in
medically compromised children, many of these medicines may be taken at
times remote from food intakes or at night when salivary flow is reduced, and
these factors may add to the potential erosive challenge.
4
This fact is of concern because of the known relationship between
carbohydrates and dental caries, and it becomes even more alarming if one
considers that not all the pediatricians gave parents instructions about oral
hygiene after medicine’s intake. In a previous study,
44
pediatricians did not
perceive the correct relationship between the presence of acidity in medicines
and dental erosion; however, most of them presented a reasonable
awareness about the relationship between sugared pediatric medicines and
dental caries. Nevertheless, not all of them recommended oral hygiene after
their consumption (50.80%). Another study, verified that only 21.2% of the
guardians that associated the use of pediatric liquid medicines with the
development of dental caries performed the oral hygiene of their children. In
addition, 84.9% of those guardians had never received instructions of oral
hygiene after the intake of medicines.
45
In relation to oral hygiene immediately after acidic products, literature
has reported that eroded enamel is more susceptible to wear by tooth-
brushing and to toothpaste abrasion.
46, 47
In this way, after consuming acidic
foods or drinks, tooth-brushing should be delayed to allow the saliva to exert
its natural remineralizing action on the eroded enamel, thereby resulting in
increased resistance to abrasion.
47
Recommendation on immediate water
23
rinse and delayed tooth-brushing after syrup medicines’ ingestion could be
proposed at the time of prescription. Medicine’s labels also should alert in
relation to the possibility of cause dental caries and erosion because many
products could be consumed for prolonged periods, several times a day, at
bedtime, and without adequate oral hygiene, will certainly contribute to dental
caries and erosion.
CONCLUSION
Most of the analyzed antibiotics presented high sugar concentration,
titratable acidity and viscosity, and low pH which can be considered as risk
factors for dental caries and erosion when consumed frequently. We advise,
therefore, the use a warning about the medicine’s cariogenic potential in their
lables It is also necessary to recommend oral hygiene after the medicine’s
intake. Clinical studies are necessary to determine the real extension of the
problem.
ACKNOWLEDGEMENTS
The authors are grateful to Prof. Elizabete Lucas and Léa Lopes for
their support in the viscosity analysis at IMA (Instituto de Macromoléculas
Eloisa Mano), Federal University of Rio de Janeiro (UFRJ) and to Viviane
Pierro for her critical review of this manuscript.
24
REFERENCES
1. "Inactive" ingredients in pharmaceutical products: update (subject
review). American Academy of Pediatrics Committee on Drugs. Pediatrics.
Feb 1997;99(2):268-278.
2. Kenny DJ, Somaya P. Sugar load of oral liquid medications on
chronically ill children. J Can Dent Assoc. Jan 1989;55(1):43-46.
3. Bigeard L. The role of medication and sugars in pediatric dental
patients. Dent Clin North Am. Jul 2000;44(3):443-456.
4. Maguire A, Baqir W, Nunn JH. Are sugars-free medicines more erosive
than sugars-containing medicines? An in vitro study of paediatric medicines
with prolonged oral clearance used regularly and long-term by children. Int J
Paediatr Dent. Jul 2007;17(4):231-238.
5. Mackie IC, Bentley E. Sugar-containing or sugar-free paediatric
medicines: does it really matter? Dent Update. Jun 1994;21(5):192-194.
6. Mackie IC, Worthington HV, Hobson P. An investigation into sugar-
containing and sugar-free over-the-counter medicines stocked and
recommended by pharmacists in the north western region of England. Br Dent
J. Aug 7 1993;175(3):93-98.
7. Maguire A, Rugg-Gunn AJ. Prevalence of long-term use of liquid oral
medicines by children in the northern region, England. Community Dent
Health. Jun 1994;11(2):91-96.
8. Maguire A, Rugg-Gunn AJ, Butler TJ. Dental health of children taking
antimicrobial and non-antimicrobial liquid oral medication long-term. Caries
Res. 1996;30(1):16-21.
9. Duward C, Thou T. Dental caries and sugar containing liquid medicines
for children in New Zealand. N Z Dent J. 1997;93:124-129.
10. Shaw L, Glenwright HD. The role of medications in dental caries
formation: need for sugar-free medication for children. Pediatrician.
1989;16(3-4):153-155.
11. Neves BG, Farah A, Lucas E, Sousa VP, Maia LC. Are paediatric
medicines risk factors for dental caries and dental erosion? Community Dent
Health. 2009;in press.
12. Rekola M. In vivo acid production from medicines in syrup form. Caries
Res. 1989;23(6):412-416.
25
13. Costa CC, Almeida IC, Costa Filho LC. Erosive effect of an
antihistamine-containing syrup on primary enamel and its reduction by fluoride
dentifrice. Int J Paediatr Dent. May 2006;16(3):174-180.
14. Moss SJ. Dental erosion. Int Dent J. Dec 1998;48(6):529-539.
15. Nunn JH, Ng SK, Sharkey I, Coulthard M. The dental implications of
chronic use of acidic medicines in medically compromised children. Pharm
World Sci. Jun 2001;23(3):118-119.
16. da Costa CC, Almeida IC, da Costa Filho LC, Oshima HM. Morphology
evaluation of primary enamel exposed to antihistamine and fluoride dentifrice-
-an in vitro study. Gen Dent. Jan-Feb 2006;54(1):21-27.
17. McNally LM, Barbour ME, O'Sullivan DJ, Jagger DC. An in vitro
investigation of the effect of some analgesics on human enamel. J Oral
Rehabil. Jul 2006;33(7):529-532.
18. Babu KL, Rai K, Hedge AM. Pediatric liquid medicaments--do they
erode the teeth surface? An in vitro study: part I. J Clin Pediatr Dent. Spring
2008;32(3):189-194.
19. Hellwig E, Lussi A. Oral hygiene products and acidic medicines.
Monogr Oral Sci. 2006;20:112-118.
20. Valinoti AC, Neves BG, da Silva EM, Maia LC. Surface degradation of
composite resins by acidic medicines and pH-cycling. J Appl Oral Sci. Aug
2008;16(4):257-265.
21. Feigal RJ, Jensen ME, Mensing CA. Dental caries potential of liquid
medications. Pediatrics. Sep 1981;68(3):416-419.
22. Trugo LC, Farah A, Cabral L. Oligosaccharide distribution in Brazilian
soya bean cultivates. Food Chemistry. 1995;52:385-387.
23. Lins ME, Lobo MSC, Silva ACM, Fiszman R, Ribeiro VJP. The use of
Data Envelopment Analysis (DEA) for Brazilian teaching hospitals´ evaluation.
Ciência & Saúde Coletiva. 2007
12(4):985-998.
24. Mackie IC, Worthington HV, Hobson P. Paediatric sugar-free
medicines-stock and recommendations. Pharmaceutical Journal
1992;248(6686):621-622.
25. Lussi A, Jaeggi T, Zero D. The role of diet in the aetiology of dental
erosion. Caries Res. 2004;38 Suppl 1:34-44.
26
26. Featherstone JD, Rodgers BE. Effect of acetic, lactic and other organic
acids on the formation of artificial carious lesions. Caries Res.
1981;15(5):377-385.
27. Bowen WH. Do we need to be concerned about dental caries in the
coming millennium? Crit Rev Oral Biol Med. 2002;13(2):126-131.
28. Newbrun E. Sucrose, the arch criminal of dental caries. Odontol Revy.
1967;18(4):373-386.
29. Lima KT, Almeida ICS, Sena EL. Sweeteners and endogenous pH of
pediatric medicines [Abstract B-110]. J Dent Res. 2000;79:1130.
30. Pierro VS, Abdelnur JP, Maia LC, Trugo LC. Free sugar concentration
and pH of paediatric medicines in Brazil. Community Dent Health. Sep
2005;22(3):180-183.
31. Neiva A, Silva VS, Maia LC, Soares EL, Trugo LC. Análise in vitro da
concentração de sacarose e pH de antibacterianos de uso pediátrico.
Pesquisa Brasileira em Odontopediatria e Clínica Integrada. 2001;1:9-16.
32. Karjalainen S, Rekola M, Stahlberg MR. Long-term effects of syrup
medications for recurrent otitis media on the dental health of 6- to 8-year-old
children. Caries Res. 1992;26(4):310-314.
33. Paunio P, Rautava P, Helenius H, Alanen P, Sillanpaa M. The Finnish
Family Competence Study: the relationship between caries, dental health
habits and general health in 3-year-old Finnish children. Caries Res.
1993;27(2):154-160.
34. Edwards M, Creanor SL, Foye RH, Gilmour WH. Buffering capacities of
soft drinks: the potential influence on dental erosion. J Oral Rehabil. Dec
1999;26(12):923-927.
35. Grobler SR, Jenkins GN, Kotze D. The effects of the composition and
method of drinking of soft drinks on plaque pH. Br Dent J. Apr 20
1985;158(8):293-296.
36. Rytomaa I, Meurman JH, Koskinen J, Laakso T, Gharazi L, Turunen R.
In vitro erosion of bovine enamel caused by acidic drinks and other foodstuffs.
Scand J Dent Res. Aug 1988;96(4):324-333.
37. Jensdottir T, Bardow A, Holbrook P. Properties and modification of soft
drinks in relation to their erosive potential in vitro. J Dent. Aug 2005;33(7):569-
575.
38. Grenby TH, Phillips A, Desai T, Mistry M. Laboratory studies of the
dental properties of soft drinks. Br J Nutr. Sep 1989;62(2):451-464.
27
39. Sorvari R, Rytomaa I. Drinks and dental health. Proc Finn Dent Soc.
1991;87(4):621-631.
40. Ireland AJ, McGuinness N, Sherriff M. An investigation into the ability of
soft drinks to adhere to enamel. Caries Res. 1995;29(6):470-476.
41. Meurman JH, ten Cate JM. Pathogenesis and modifying factors of
dental erosion. Eur J Oral Sci. Apr 1996;104(2 ( Pt 2)):199-206.
42. Milosevic A. Sports drinks hazard to teeth. Br J Sports Med. Mar
1997;31(1):28-30.
43. Bevenius J, L'Estrange P. Chairside evaluation of salivary parameters
in patients with tooth surface loss: a pilot study. Aust Dent J. Jun
1990;35(3):219-221.
44. Neves BG, Pierro VS, Maia LC. Pediatricians' perceptions of the use of
sweetened medications related to oral health. J Clin Pediatr Dent. Winter
2008;32(2):133-137.
45. Neves BG, Pierro VS, Maia LC. Perceptions and attitudes among
parents and guardians on the use of pediatric medicines and their cariogenic
and erosive potential. Cien Saude Colet. Sep-Oct 2007;12(5):1295-1300.
46. Hooper S, West NX, Pickles MJ, Joiner A, Newcombe RG, Addy M.
Investigation of erosion and abrasion on enamel and dentine: a model in situ
using toothpastes of different abrasivity. J Clin Periodontol. Sep
2003;30(9):802-808.
47. Rios D, Honorio HM, Magalhaes AC, et al. Effect of salivary stimulation
on erosion of human and bovine enamel subjected or not to subsequent
abrasion: an in situ/ex vivo study. Caries Res. 2006;40(3):218-223.
28
Table 1. Brand names, manufacturers and active principles of all antibiotics
analyzed in the study.
Brand names
Manufacturers Active principles
1. Amoxil
®
125 mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin
2. Amoxil
®
250 mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin
3. Amoxil
®
500 mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin
4. Amoxil BD
®
200 mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin
5. Amoxil BD
®
400 mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin
6. Ampicilina
®
250 mg/5mL
EMS (S. B. do Campo, SP, Brazil)
Ampicillin
7. Bactrim
®
(200+40)mg/5mL
Roche (Rio de Janeiro, RJ, Brazil) Sulfamethoxazole + Trimethoprim
8. Bactrim F
®
(400+80)mg/5mL
Roche (Rio de Janeiro, RJ, Brazil)
Sulfamethoxazole + Trimethoprim
9. Ceclor
®
250 mg/5mL
Sigma Pharma (Hortolândia, SP, Brazil)
Cefaclor
10. Ceclor
®
375 mg/5mL
Sigma Pharma (Hortolândia, SP, Brazil)
Cefaclor
11. Cefamox
®
250 mg/5mL
Bristol-Myers Squibb (Barceloneta, Porto Rico)
Cefadroxil
12. Cefamox
®
500 mg/5mL
Bristol-Myers Squibb (Barceloneta, Porto Rico)
Cefadroxil
13. Cefzil
®
250 mg
Bristol-Myers Squibb (São Paulo, SP, Brazil)
Cefprozil
14. Clavulin
®
(125mg+31,25)mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin + Potassium Clavulanate
15.Clavulin
®
(250+62,5)mg/5mL
GlaxoSmithKline (Mexico)
Amoxicillin + Potassium Clavulanate
16. Clavulin BD
®
(200+28,5)mg/5mL
GlaxoSmithKline (Rio de Janeiro, RJ, Brazil)
Amoxicillin + Potassium Clavulanate
17. Clavulin BD
®
(400 mg+57)mg/5mL
GlaxoSmithKline (Worthing, England)
Amoxicillin + Potassium Clavulanate
18. Clavulin
®
ES (600+42,9)mg/5mL
GlaxoSmithKline (Col Romero de Terreros,
México)
Amoxicillin + Potassium Clavulanate
19. Eritrex
®
125 mg/5mL
Aché (Guarulhos, SP, Brazil) Erythromycin
20. Eritrex
®
250 mg/5mL
Aché (Guarulhos, SP, Brazil) Erythromycin
21. Keflex
®
250 mg/5mL
Lilly (São Paulo, SP, Brazil)
Cephalexin
22. Keflex
®
500 mg/5mL
Lilly (São Paulo, SP, Brazil)
Cephalexin
23. Klaricid
®
25 mg/mL
Abbott (Brazil)
Clarithromycin
24. Klaricid
®
50 mg/mL
Abbott (Brazil)
Clarithromycin
25. Pen-ve-oral
®
80.000UI/mL
Eurofarma (São Paulo, SP, Brazil)
Potassic Phenoxymethylpenicillin
26. Unasyn
®
250 mg/5mL
Pfizer (Latina, Italy)
Sultamicillin tosylate
27. Zinnat
®
250 mg/5mL
GlaxoSmithKline (England)
Cefuroxime Axetil
28. Zitromax
®
600 mg
Pfizer (Latina, Italy)
Azithromycin
29. Zitromax
®
900 mg
Pfizer (Latina, Italy)
Azithromycin
29
Table 2. Concentration of sucrose, pH, titratable acidity and viscosity of all analyzed antibiotics.
Antibiotics
Sucrose
a
Sorbitol
a
pH Vol NaOH (mL)
c
Viscosity (cP)
d
Label content
(sweeteners)
Label content (acids)
1. Amoxil
®
125 mg/5mL
49.97 ±1.64 ---- 5.71 ±0.02 1.38±0.05 30 Sucrose ----
2. Amoxil
®
250 mg/5mL
48.59 ±2.01 ---- 5.72 ±0.01 1.55±0.04 30 Sucrose ----
3. Amoxil
®
500 mg/5mL
36.77 ±2.46 ---- 5.74 ±0.01 2.23±0.10 90 Sucrose ----
4. Amoxil BD
®
200 mg/5mL
48.41 ±1.31 ---- 6.67 ±0.04 0.85 ±0.05 290 Sugar ----
5. Amoxil BD
®
400 mg/5mL
44.53 ±4.06 ---- 6.85 ±0.03 0.67 ±0.10 550 Sugar ----
6. Ampicilina
®
250 mg/5mL
36.43 ±1.9 ---- 6.16 ±0.04 2.73±0.00 40 Sodium cyclamate, Sodium saccharin, Sucrose
----
7. Bactrim
®
(200+40)mg/5mL
55.02 ±0.14 ---- 6.10 ±0.01 2.90 ±0.09 1350 Sugar ----
8. Bactrim F
®
(400+80)mg/5mL
59.02 ±8.01 66.90 5.69 ±0.02 4.55 ±0.22 1340 Sorbitol, Sodium saccharin ----
9. Ceclor
®
250 mg/5mL
58.86 ±0.26 ---- 4.34 ±0.02 3.78 ±0.26 300 Sucrose ----
10. Ceclor
®
375 mg/5mL
62.63 ±7.47 ---- 4.31 ±0.28 8.21 ±1.34 550 Sucrose ----
11. Cefamox
®
250 mg/5mL
58.03 ±4.41 ---- 5.12 ±0.02 2.76 ±0.13 20 Sugar ----
12. Cefamox
®
500 mg/5mL
61.01 ±2.70 ---- 4.86 ±0.06 5.54 ±0.53 180 Sucrose ----
13. Cefzil
®
250 mg
51.18 ±0.32 ---- 5.05 ±0.02 2.49 ±0.05 30 Sucrose, Aspartame Citric acid
14. Clavulin
®
(125mg+31,25)mg/5mL
ND ---- 4.32 ±0.01 1.23 ±0.09 170 Aspartame Clavulanic acid, Succinic acid
15.Clavulin
®
(250+62,5)mg/5mL
ND ---- 4.57 ±0.03 1.26 ±0.10 230 Aspartame Clavulanic acid, Succinic acid
16. Clavulin BD
®
(200+28,5)mg/5mL
ND ---- 4.10 ±0.00 0.97 ±0.00 120 Aspartame Clavulanic acid, Succinic acid
17. Clavulin BD
®
(400 mg+57)mg/5mL
ND ---- 4.45 ±0.01 1.20 ±0.05 190 Aspartame Clavulanic acid, Succinic acid
18. Clavulin
®
ES (600+42,9)mg/5mL
ND ---- 4.94 ±0.02 0.99 ±0.10 340 Aspartame Clavulanic acid
19. Eritrex
®
125 mg/5mL
68.53 ±1.03 ---- 5.33 ±0.00 6.83 ±0.22 530 Sugar Citric acid
20. Eritrex
®
250 mg/5mL
74.54 ±0.02 ---- 5.42 ±0.02 1.88 ±0.05 270 Sugar Citric acid
21. Keflex
®
250 mg/5mL
25.95 ±2.05 ---- 6.62 ±0.11 0.26 ±0,00 230 Sucrose ----
22. Keflex
®
500 mg/5mL
43.39 ±5.54 ---- 6.95 ±0.28 0.67 ±0,05 370 Sucrose ----
23. Klaricid
®
25 mg/mL
36.13 ±0.07 ---- 5.13 ±0.05 24.64 ±1.76 260 Sugar Citric acid
24. Klaricid
®
50 mg/mL
77.46 ±10.84 ---- 5.04 ±0.10 40.48 ±0.88 1660 Sugar Citric acid
25. Pen-ve-oral
®
80.000UI/mL
Inconclusive data ---- 5.94 ±0.01 0.26±0.00 170 Sugar, Sodium saccharin Citric acid
26. Unasyn
®
250 mg/5mL
Inconclusive data ---- 6.58 ±0.01 1.67±0.09 80 Sucrose ----
27. Zinnat
®
250 mg/5mL
Inconclusive data ---- 4.79 ±0.00 12.54±2.86 1780 Sucrose, aspartame Estearic acid
28. Zitromax
®
600 mg
Inconclusive data ---- 9.75±0.00 ------- 1130 Sucrose ----
29. Zitromax
®
900 mg
Inconclusive data ---- 10.08±0.00 ------- 420 Sucrose ----
a
Concentrations are expressed in g% (g/100g) (mean ± standard deviation);
b
ND= non-detected;
c
Volume of NaOH solution required to achieve the pH 7.0;
d
Viscosity values are presented at shear rate of 20s
(unit of viscosity: cP – centiPoise=millipascal second, mPa·s);
e
(----) = not mentioned in labels
30
Table 3. Performance results (0-100%) of all analyzed antibiotics.
Medicines Performance
Amoxil
®
125 mg, Clavulin
®
BD 200 mg, Keflex
®
250 mg
100%
Amoxil
®
250 mg,
98%
Ampicilina
®
250 mg, Cefamox
®
250 mg
95%
Clavulin
®
ES 600 mg
93%
Clavulin
®
125 mg, Clavulin
®
BD 400 mg
89%
Clavulin
®
250 mg
87%
Cefzil
®
250 mg
86%
Amoxil
®
500 mg
59%
Amoxil
®
BD 200 mg, Keflex
®
500 mg
54%
Amoxil
®
BD 400 mg
50%
Eritrex
®
250 mg
35%
Ceclor
®
250 mg
22%
Bactrim
®
200 mg
19%
Klaricid
®
25 mg
17%
Eritrex
®
125 mg
13%
Bactrim
®
F 400 mg
12%
Ceclor
®
375 mg
11%
Klaricid
®
50 mg
3%
31
Figure 1: Performance frontier for sucrose and titratable acidty.
Medicines 14 (Clavulin 125mg), 15 (Clavulin 250mg), 16 (Clavulin BD
200mg), 17 (Clavulin BD 400mg) and 18 (Clavulin ES 600mg) are close to the
frontier because their low levels of sucrose and titratable acidity, while
medicines 23 (Klaricid
®
25mg/5mL), 24 (Klaricid
®
50mg/5mL) and 27 (Zinnat
®
250mg/5mL) presented the worst performance because of their high levels of
sucrose and titratable acidity.
32
Figure 2: Performance frontier for viscosity and titratable acidty.
Medicines 7 (Bactrim
®
200mg/5mL), 8 (Bactrim F
®
400mg/5mL) and 27
(Zinnat
®
250mg/5mL) presented low levels of titratable acidity, despite of their
high titratable acidity. Klaricid
®
50mg/mL were distant from performance
frontier again, because of their high levels of titratable acidity and sacarose
concentration, presenting the worst performance.
33
Figure 3: 3D visualization of the performance frontier according to titratable
acidity, viscosity and sucrose concentration.
Grey area corresponds to the frontier where medicines with 100%
performance are included. Klaricid
®
50 mg/5mL and Zinnat
®
250 mg/5mL
were distant from the performance frontier, which means that these medicines
have the worst performance and, therefore, greater potential for dissolution of
dental enamel.
34
4.2 ARTIGO 2
“ALTERATIONS OF DENTAL ENAMEL SUBMITTED TO ACIDIC
MEDICINES AND pH-CYCLING”,
Running title: Medicines and dental erosion
Ana Carolina Valinoti, DDS
1
; Viviane dos Santos da Silva Pierro, DDS,
MSc
2
; Eduardo Moreira da Silva, DDS, MSc, PhD
3
; Lucianne Cople Maia,
DDS, MSc, PhD
4
1
MSc student, Department of Pediatric Dentistry and Orthodontics, School of
Dentistry, Federal University of Rio de Janeiro, RJ, Brazil;
2
PhD student, Department
of Pediatric Dentistry and Orthodontics, School of Dentistry, Federal University of Rio
de Janeiro, RJ, Brazil;
3
Associate Professor, Department of Restorative Dentistry,
Dental School, Federal Fluminense University, Niterói, RJ, Brazil;
4
Associate
Professor, Department of Pediatric Dentistry and Orthodontics, Dental School,
Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Adress correspondence to Dr. Lucianne Cople Maia
Rua Gastão Gonçalves, 47/501 – Santa Rosa
Niterói – RJ – Brasil
CEP: 24240-030
Telephone number: 00 55 21 2629.3738
Fax number: 00 55 21 2562.2098
35
Abstract
This study evaluated the effect of acidic medicines (Klaricid
®
50
mg/mL, Claritin
®
and Dimetapp
®
), on surface enamel, under in vitro
conditions. One hundred and four enamel blocks were randomly distributed
into two groups: G1 (standard pH cycling) and G2 (erosive conditions). Each
group consisted of 4 subgroups (n=13) according to the medicine’s immersion
and control (deionized water). Surface roughness and surface microhardness
were evaluated at baseline and after the specimens were submitted to in vitro
conditions and twice daily 30 min medicine’s immersion during 12 days. Three
specimens of each subgroup from G1 and G2 were analyzed by scanning
electron microscopy (SEM) after in vitro conditions. Percentage of surface
microhardness change (%SMC) was calculated by G1 group. Results showed
that surface roughness increased twenty-fold greater in G2. Dimetapp
®
showed the most pronounced enamel roughness alterations, especially when
compared to Claritin
®
at G1 group and to Klaricid
®
at both groups (P<.008).
Surface microhardness decreased in all subgroups at G1 (P<.05). SEM
analysis showed erosive patterns in all subgroups but it was greater to
Dimetapp
®
and lower to Klaricid
®
in both groups. In conclusion, the medicine
with lower pH and viscosity and Control showed erosive patterns more
pronouced. Furthermore, the medicine with the higher pH and viscosity
seemed to present an in vitro protector effect against acid attacks which could
be explained by its mineral contents and also by its viscosity.
Key-words: Pharmaceutical preparations,
Tooth erosion
, Viscosity, Hydrogen-
Ion Concentration, Hardness Tests
36
INTRODUCTION
Dental erosion is the result of a pathologic, chronic, localized loss of
dental hard tissue that is chemically etched away from the tooth surface by
acid and/or chelation without bacterial involvement.
1
The etiology of dental
erosion is complex and multi-factorial, being attributed to a wide range of
factors that may be either extrinsic or intrinsic.
2
Some intrinsic causes of
dental erosion include recurrent vomiting in psychological disorders such as
anorexia and bulimia and regurgitation of gastric contents due to
gastrointestinal problems.
3, 4
Extrinsic sources in children include the regular
use of products with low endogenous pH, high titratable acidity, and a
composition with a low quantity of calcium, fluoride, and phosphate ions.
5
Among these products are acidic foods and drinks,
3
and acidic medicines that
come in direct contact with teeth, especially if consumed frequently.
5-8
Liquid oral medicines are usually recommended for sick children for
short periods, except for chronic diseases when they consumed daily for
prolonged time. Acids are commonly used in medicines as buffering agents to
maintain chemical stability, control tonicity or to ensure physiologic
compatibility and to improve flavor,
9
and consequently enhancing patient
compliance.
In vitro studies have shown that acidic medicines could reduce
enamel hardness of primary teeth,
5
influence enamel roughness
10
and cause
morphological enamel alterations
11, 12
and also induce degradation of
composite materials.
13
However, little is known about the effect of oral
medicines on tooth surface under erosive conditions.
37
Therefore, considering that some children may require frequent use of
liquid oral medicines and in some cases, these children already present a
highly erosive diet by ingestion of acidic foods and drinks, the aim of this in
vitro study was to evaluate the acidic medicine’s contribution to enamel
demineralization in a standard pH cycling model and in an erosive model.
METHODS
Medicine selection, pH analysis, titratable acidity, concentrations of
fluoride, phosphate and calcium, and viscosity of the tested media
The pediatric syrup medicines chosen for this study (Claritin
®
,
Schering-Plough, Vila Olímpia, Brazil; and Dimetapp Elixir
®
, Wyeth, São
Paulo, Brazil) were selected based on a previous study,
14
which has pointed
out these medicines as presenting the worst results with regard to pH,
titratable acidity and viscosity taken together. The liquid antibiotic was
selected based on a previous study,
15
which highlighted that among 29
analyzed antibiotics, the Klaricid
®
50 mg/mL (Abbott, o Paulo, Brazil)
presented the worst results with regard to pH, titratable acidity, sugar
concentration and viscosity.
Chemical parameters considered important in the selected medicines
where also determined. Fluoride was analyzed using a combined electrode
Hach and TISAB III, pH 5.0 (containing 20 g NaOH/I), as a buffer. Phosphorus
was determined colorimetrical
16
and calcium was analyzed by atomic
absorption spectrophotometry using lanthanum to suppress phosphate
interference.
38
With regard to control, three deionized water samples of different pH
cycling days were analyzed and a mean of ionic contents obtained for each
sample used were calculated.
The characteristics of the acidic medicines and deionized water used in
this study are shown in Table 1.
Preparation of bovine enamel specimens
Two hundred and fifty enamel blocks (4 x 4 mm) were prepared from
one hundred twenty five sound bovine incisors stored in distilled water (pH
6.48 ± 0.12) at room temperature. Crowns were sectioned from the roots and
two enamel blocks were obtained from the labial surfaces using ISOMET Low
Speed Saw cutting machine (model 11-1280-170, Lake Bluff, IL, USA). All
enamel blocks were then embedded in acrylic resin, in PVC rings with labial
surfaces facing toward the ring base. After resin acrylic polymerization,
samples’ enamel labial surfaces were wet ground using 600, 800, 1200, 2500
(Norton, São Paulo, Brazil) and 4000-grit abrasive discs (Presi, Grenoble,
France) for 10 minutes each in a water-cooled grinding machine (Panambra
DPU-10, Struers; Copenhagen, Denmark) to produce an optically flat area of
enamel. After the polishing procedure, samples were viewed under an optical
microscope (Aus Jena, model 444181, with a 40 objective; Astro Optics
Division, Montpelier, USA) in order to check that surfaces were flat, polished,
and free of irregularities that could interfere with roughness evaluation.
39
Baseline Analysis
Baseline surface roughness of each enamel specimen (Ra - µm) was
measured using a surface roughness tester (Surftest SJ 201, Mitutoyo Co.,
Kawasaki, Japan). Three roughness measurements spaced at 60° were
recorded for each specimen (cut-off length of 0.25 mm). The mean value of
the three measurements was recorded as the surface roughness value for
each specimen. Forty enamel blocks were discarded after baseline surface
roughness determination because of their discrepant roughness values and a
total of 210 with surface roughness of 0.04-0.15 µm were selected to surface
microhardness evaluation.
To determine initial surface microhardness (SMH), a hardness tester
(Micromet 2003, model 1600-5300, Buehler, Lake Bluff, IL, USA) was
calibrated with a Knoop tip and load of 50g was applied for 15 s. Five
indentations spaced 100 µm from each other were made at the center of the
enamel surface and their average value was taken as equivalent to the
hardness value of the specimen. One hundred and seven enamel blocks with
surface microhardness ranging from 272 to 392.48 KNH were selected for the
experimental phase, as these were considered compatible with sound dental
bovine enamel. All the selected blocks were stored in 100% humidity
environment. Three enamel blocks were set aside for SEM evaluation in order
to assess surface’s topography at baseline.
Experimental protocols
After baseline analysis, enamel blocks were randomly distributed,
according to experimental protocols, in two different models (G1 and G2) of
40
daily pH changing conditions. Each group consisted of 4 subgroups (n=13)
according to media immersion: Klaricid
®
; Claritin
®
; Dimettap
®
and deionized
water (control).
The standard pH-cycling model
17
was performed in G1 to simulate
physiological oral conditions (02 hours in an acid solution, 21 hours in a
neutral solution and 01 hour in medicines’ or control’s immersion at 37ºC),
while an erosive pH-cycling model was employed in G2 to simulate an
erosive oral environment (16 hours in an acid solution, 07 hours in a neutral
solution and 01 hour in medicines’ or control’s immersion at 37ºC). The
experimental protocol is shown in Figure 1. The acid solution contained 3
mmol/L of calcium, 3 mmol/L of phosphate and 50 mL/L of acetic acid in a pH
adjusted to 4.5 with NaOH
18
, while the neutral solution was composed of 1.54
mmol/L of calcium, 1.54 mmol/L of phosphate, 20 mmol/L of acetic acid and
0.308 g of ammonium acetate with pH adjusted to 6.8 with potassium chloride
at 37°C
19
.
The amount of each medicine, deionized water, neutral and acid
solution for each group was 20 mL. The medicines and deionized water were
replaced by every immersion time and the solutions were daily changed. After
such medicines’ immersion, the specimens were rinsed with deionized water.
After the 12
th
day, surface roughness was reassessed, exactly as described
for baseline analysis. SMH was evaluated by making one row of five
indentations spaced at 100 µm on the side of the five baseline measurements,
and the percentage of surface microhardness change (%SMHC) was
calculated as follows: [%SMHC= (SMH after pH-cycling SMH
baseline)/SMH baseline] x 100.
41
Scanning Electronic Microscopy (SEM) Analysis
SEM analysis was performed to assess enamel surface’s topography
of three blocks from each subgroup of G1 and G2, which were randomly
selected after experimental procedures. Three additional enamel blocks were
set aside for SEM evaluation in order to assess surface’s topography at
baseline. These specimens were mounted on aluminum stubs, sputter-coated
with gold, and examined with a scanning electronic microscope (JEOL-JSM;
5800LV, Tokyo, Japan), with an acceleration voltage of 15kV. SEM
micrographs at 30, 850 and 5000 magnification were taken.
Statistical Analysis
The assumptions of equality of variances and normal distribution of
errors were checked for the tested response variables. Since the assumptions
were not satisfying, Kruskal-Wallis tests (α=0.05) were performed and Mann-
Whitney tests were carried out for statistical comparisons between subgroups.
In order to prevent an accumulation of errors from multiple comparisons,
Bonferroni correction was applied by dividing the significance level (α=0.05)
by the number of comparisons made. Then, the significance level was set at
0.8%. The SPSS software version 16.0 (SPSS Inc., Chicago, USA) was
applied for these purposes.
RESULTS
Mean differences between final and baseline roughness values showed
that all treatments increased the surface roughness of bovine enamel
considering both G1 and G2. Nevertheless, the roughness difference found in
42
G2 was about twenty-fold greater than the difference observed in G1.
Subsequent analysis showed that, in G1, Klaricid
®
and Claritin
®
promoted
enamel roughness alterations significantly lower than Dimetapp Elixir
®
’s –
P<.008. In G2, Dimetapp Elixir
®
showed, once more, the most pronounced
enamel roughness alterations, especially when compared to Klaricid
®
(subgroup A) P<.008. Descriptive statistics of the difference between the
final and the initial roughness values (R
a
µm) for all subgroups according to
the two different in vitro conditions are shown in Table 2.
Final surface microhardness determination was only performed for G1
because the highly erosive model was so destructive to enamel surface that it
prevented the final determination for G2. Table 3 and Figure 2 show that a
significant reduction in enamel surface microhardness occurred after pH-
cycling conditions for all subgroups in Group 1 (P<.05). Mann-Whitney tests
with Bonferroni correction showed that there was no statistical significant
difference (P>.008) only when Dimetapp Elixir
®
was compared with deionized
water. The highest percentage of surface microhardness change (%SMC)
was found for deionized water and the lowest for Klaricid
®
.
When compared to sound bovine enamel (Figure 3), qualitative
analysis of SEM images showed that all enamel specimens presented erosion
patterns after pH-cycling and immersion to acidic medicines and deionized
water (Figure 4 and 5). In Group 1, specimens exposed to Dimetapp Elixir
®
presented the most severe eroded areas, followed by those exposed to
Claritin
®
, Control and Klaricid
®
and to In Group 2, morphological changes
occurred in the following sequence according to their severity: Dimetapp
Elixir
®
> Claritin
®
> Control > Klaricid
®
.
43
DISCUSSION
It is well known that pH-cycling regimen is an efficient way to simulate
the oral environment in vitro, submitting test specimens to the alterations with
a pH that is commonly associated with this environment.
19
However, this in
vitro study aimed to verify if liquid oral medicines could contribute to dental
erosion not only in a normal oral environment (Group 1) but also when a
situation of high erosive challenge (Group 2), such as excessive intake of
acidic foods and drinks, is already installed.
Medicines selected for this study presented characteristics that may
increase their erosive potential, i.e., low endogenous pH and high titratable
acidity, probably due to the presence of citric acid.
5
It resulted in a substantial
loss of mineral from the enamel blocks after experimental conditions and
exposure to medicines and control (deionized water). The immersion of
enamel in a neutral solution for 20h daily, in Group 1, was not enough to
prevent the demineralization by two acid attacks (two 30-min immersions to
medicines and control). These findings are in accordance with the study of
Costa et al. (2006)
5
that showed a significant decrease in surface
microhardness of primary enamel after pH-cycling and three 5-min
immersions to an antihistamine-containing syrup and a nocturnal use of syrup,
corresponding to an 8-hour immersion. The nocturnal use of the antihistamine
Claritin D
®
showed a high surface microhardness change (SMHC), which was
similar to the surface’s microhardness decrease that occurred in all subgroups
of G1 (standard pH-cycling) in this study. In the present study, the nocturnal
use of medicines was not simulated. However, the twice daily 30-min
44
exposure time was overestimated. This overestimation probably led to a more
pronounced decrease on surface microhardness in G1.
Surface microhardness is, usually, the quantitative method employed
to verify dental erosion along with SEM observations,
20, 21
but roughness
analysis has already been used to evaluate the effect of acidic medicines,
under pH-cycling conditions, on the surface degradation of composite
resins.
13
In the present study, surface microhardness proved to be limited in
evaluating teeth submitted to a high erosive challenge because the
indentations could not be performed in Group 2 due to the significant surface
enamel loss. Surface roughness showed alterations in both groups, but it was
more pronounced in G2 where the roughness difference found was about
twenty-fold greater than the difference verified in G1.
Dental erosion may have resulted from some direct loss of the
superficial enamel layer, and in addition, may have softened the underlying
layer, resulting in lower microhardness
21-24
, as it was demonstrated,
respectively, by the surface roughness and surface microhardness analyses
here performed. Group 1 (standard pH-cycling) presented a lower variation in
surface roughness when compared to G2 (highly erosive pH-cycling).
However, its surface microhardness presented outstanding changes. This
finding could make us speculate that an alteration of innermost layer of
enamel could be the initial sign of dental erosion, suggesting an initial
subsurface loss not only for dental caries, but also for dental erosion. This
issue has already been described in a previous study, which demonstrated
that an eroded lesion was associated with an area of slight subsurface
mineral loss or softened enamel which has been shown to be
45
remineralizable.
25
The remineralization of eroded, etched and softened
enamel by precipitation of various calcium phosphates have also been
reported.
26, 27
In the present study, results of the control subgroups (deionized water)
from G1 and G2 could have been different if there was not an immersion
period in water. Deionized water was chosen to be the media immersion of
control groups because it would be inert to enamel and would not promote
structural alterations. However, probably, after the acid attacks and
subsequent loss of Ca
++
and PO
4
--
ions from the enamel, these ions have
been released to the deionized water because of its unsaturated condition
with respect to enamel, promoting surface alterations and softening, which
justifies the surface roughness and ultrastructural alterations viewed by SEM,
and the enamel softening, marked by low values of surface microhardness for
control groups. A previous in vitro study
28
has also shown similar results once
lower mineral loss and lesion depth were observed when bovine enamel was
immersed only in orange juice as compared with its immersion in orange juice
followed by water immersion.
The erosive effect of dietary acids on dental tissue can be influenced
by a number of factors, which include pH, pka, titratable acidity, temperature,
acid character, concentration and chelation potential. Furthermore, frequency
and timing of intake, time period in the mouth and the tooth to tooth variation
in structure, particularly with respect to the fluoride content and pellicle layer,
are thought to be of importance and compound the understanding of dietary
acid tooth erosion
29
. An increase of pH, often accompanied by addition of
calcium and/or phosphate salts, has been shown to reduce the erosive
46
potential of soft drinks in situ and in vitro
30-33
. Many studies have found the
erosive potential of drinks to be associated with their calcium and phosphate
concentrations
2, 32-34
. The addition of relatively small amounts of calcium to
citric acid solutions was found to reduce the loss of enamel and this effect
was observed progressively as the pH was increased
35
. Probably, the higher
pH and content of calcium, fluoride and phosphate of Klaricid
®
when
compared to the other tested medicines, promoted the lowest erosion pattern
observed in both subgroups (G1 A and G2 A).
It is also important to note that medicines evaluated presented high
values of viscosity, which were more pronounced in Klaricid
®
. In clinical
practice, viscous drinks are likely to adhere and will, therefore, be held in the
mouth for a longer period of time
36
and possibly penetrating into fissures and
proximal areas of tooth that are inaccessible to the toothbrush. In this way, a
high viscosity could increase their harmful effect. Although the specimens in
the present study were rinsed with deionized water after medicine’s
immersion, it could be hypothesized that Klaricid
®
, the most viscous medicine,
could be retained on the enamel’s surface providing a kind of pelliculle, which
may exhibit a protective effect against acid attacks of the acid solution. This
hypothesis could also account for Klaricid's lowest surface changes.
The difficulty in reproducing the clinical situation in in vitro studies
must be kept in mind. This is due to the complexity of the oral environment.
Therefore, this research may have overestimated the occurrence of erosive
demineralization because of the 30-min exposure time to medicines and
control that was greater than the time the human plaque remains acid in oral
environment. Also, the absence of buffering by saliva and of salivary pellicle
47
leading to media’s direct contact with the teeth are also aggravating factors
37,
38
. Nevertheless, some situations may also occur in the oral cavity, such as
the chronic use of medicines that besides being highly acidic, can also reduce
salivary flow, like the antihistamines here tested (Clarititin
®
and Dimetapp
Elixir
®
). With regard to Dimetapp Elixir
®
, there is even a label recommendation
for its use up to 6 times per day, which increases the chances of an erosive
challenge.
In this physicochemical model of remineralization and demineralization,
the presence of microorganisms and medicines’ sugar concentration were not
taken into consideration, but these factors could interfere in the effects of
these medicines in vivo. From a clinical point of view, it could be hypothesized
that these acidic medicines would, probably, lead to a drop in pH of dental
biofilm, increasing its acidogenicity. Some studies have already reported that
medicines with high concentrations of sucrose and low endogenous pH have
both cariogenic and erosive potentials
5, 12
, since they promote rapid drop in
oral pH, which remains low for longer periods of time. In situ studies to
evaluate the effect of acidic medicines on human enamel are suggested to
determine the real extension of the problem.
Besides, some studies reported that bovine enamel is more affected by
acid than is human enamel.
39, 40
In addition, removal of the outermost layer of
enamel during specimen preparation is thought to influence the severity of the
erosion process.
41
Therefore, the results here presented may be
overestimated when compared to those of human teeth in vivo.
From the experimental conditions adopted in this study, it could be
concluded that acidic medicine’s immersion and the simulation of oral
48
conditions promoted erosive patterns, which were more pronounced to
subgroups immersed to medicine with lower pH and viscosity and to Control.
Furthermore, the medicine with the higher pH and viscosity seemed to
present an in vitro protector effect against acid attacks which could be
explained by its mineral contents and also by its viscosity.
ACKNOWLEDGMENTS
The authors are grateful to Prof. Jaime Cury, Prof. Livia Tenuta and
Waldomiro Vieira for their support in the phosphate and fluoride content
analysis at School of Dentistry of Piracicaba, State University of Campinas
(UNICAMP) and to Prof. Delmo Santiago Vaitsman and Edna Lucia Couto
Oberosler for their support in the calcium content analysis at Chemical
Institute, Federal University of Rio de Janeiro (UFRJ).
The authors also would like to thank CNPq (Conselho Nacional de
Desenvolvimento Científico e Tecnológico) for the research grant
(308029/2006-2), and FAPERJ (Fundação Carlos Chagas de Amparo à
Pesquisa do Estado do Rio e Janeiro) (E-26/171.241/2006) for the financial
support.
RE FERENCE S
1. ten Cate JM, Imfeld T. Dental erosion, summary. Eur J Oral Sci
1996;104(2 ( Pt 2)):241-4.
2. Lussi A, Jaggi T, Scharer S. The influence of different factors on in vitro
enamel erosion. Caries Res 1993;27(5):387-93.
3. Linnett V, Seow WK. Dental erosion in children: a literature review.
Pediatr Dent 2001;23(1):37-43.
4. Knewitz JL, Drisko CL. Anorexia nervosa and bulimia: a review.
Compendium 1988;9(3):244-7.
5. Costa CC, Almeida IC, Costa Filho LC. Erosive effect of an
antihistamine-containing syrup on primary enamel and its reduction by fluoride
dentifrice. Int J Paediatr Dent 2006;16(3):174-80.
49
6. Lussi A, Jaeggi T. Chemical factors. Monogr Oral Sci 2006;20:77-87.
7. Hellwig E, Lussi A. Oral hygiene products and acidic medicines.
Monogr Oral Sci 2006;20:112-8.
8. Lussi A, Jaeggi T, Zero D. The role of diet in the aetiology of dental
erosion. Caries Res 2004;38 Suppl 1:34-44.
9. Maguire A, Baqir W, Nunn JH. Are sugars-free medicines more erosive
than sugars-containing medicines? An in vitro study of paediatric medicines
with prolonged oral clearance used regularly and long-term by children. Int J
Paediatr Dent 2007;17(4):231-8.
10. Pierro VSS, Maia LC, Silva EM. Effect of pediatric syrups on roughness
and erosion of enamel. Paper presented at: IADR 82nd General Session &
Exhibition, 2004; Honolulu.
11. Babu KL, Rai K, Hedge AM. Pediatric liquid medicaments--do they
erode the teeth surface? An in vitro study: part I. J Clin Pediatr Dent
2008;32(3):189-94.
12. da Costa CC, Almeida IC, da Costa Filho LC, Oshima HM. Morphology
evaluation of primary enamel exposed to antihistamine and fluoride dentifrice-
-an in vitro study. Gen Dent 2006;54(1):21-7.
13. Valinoti AC, Neves BG, da Silva EM, Maia LC. Surface degradation of
composite resins by acidic medicines and pH-cycling. J Appl Oral Sci
2008;16(4):257-65.
14. Neves BG, Farah A, Lucas E, Sousa VP, Maia LC. Are paediatric
medicines risk factors for dental caries and dental erosion? Community Dent
Health 2009;in press.
15. Valinoti AC, Farah A, Lopes L, Lucas EF, Sousa VP, Maia LC. Are
pediatric antibiotics risk factors for dental caries and erosion? Paper
presented at: IADR 87th General Session, 2009; Miami.
16. Fiske CM, Subbarow Y. The colorimetric determination of phosphorus.
. J. Biol Chem 1925;66(2):375-400.
17. White DJ. Reactivity of fluoride dentifrices with artificial caries. I. Effects
on early lesions: F uptake, surface hardening and remineralization. Caries
Res 1987;21(2):126-40.
18. Damato FA, Strang R, Stephen KW. Effect of fluoride concentration on
remineralization of carious enamel: an in vitro pH-cycling study. Caries Res
1990;24(3):174-80.
19. Lammers PC, Borggreven JM, Driessens FC. Acid-susceptibility of
lesions in bovine enamel after remineralization at different pH values and in
50
the presence of different fluoride concentrations. J Dent Res
1991;70(12):1486-90.
20. Magalhaes AC, Rios D, Honorio HM, Jorge AM, Jr., Delbem AC,
Buzalaf MA. Effect of 4% titanium tetrafluoride solution on dental erosion by a
soft drink: an in situ/ex vivo study. Arch Oral Biol 2008;53(5):399-404.
21. Rios D, Honorio HM, Magalhaes AC, Buzalaf MA, Palma-Dibb RG,
Machado MA, et al. Influence of toothbrushing on enamel softening and
abrasive wear of eroded bovine enamel: an in situ study. Braz Oral Res
2006;20(2):148-54.
22. Amaechi BT, Higham SM. Eroded enamel lesion remineralization by
saliva as a possible factor in the site-specificity of human dental erosion. Arch
Oral Biol 2001;46(8):697-703.
23. Imfeld T. Dental erosion. Definition, classification and links. Eur J Oral
Sci 1996;104(2 ( Pt 2)):151-5.
24. Moss SJ. Dental erosion. Int Dent J 1998;48(6):529-39.
25. Muhlemann HR, Lenz H, Rossinsky K. Electron Microscopy
appearance of rehardened enamel. Helv Odontol Acta 1964;8:108-11.
26. Mannerberg F. Saliva factors in cases of erosion. Odontol Revy
1963;14:155-66.
27. Collys K, Cleymaet R, Coomans D, Michotte Y, Slop D. Rehardening of
surface softened and surface etched enamel in vitro and by intraoral
exposure. Caries Res 1993;27(1):15-20.
28. Amaechi BT, Higham SM, Edgar WM. Techniques for the production of
dental eroded lesions in vitro. J Oral Rehabil 1999;26(2):97-102.
29. West NX, Hughes JA, Addy M. Erosion of dentine and enamel in vitro
by dietary acids: the effect of temperature, acid character, concentration and
exposure time. J Oral Rehabil 2000;27(10):875-80.
30. Tanaka M, Kadoma Y. Comparative reduction of enamel
demineralization by calcium and phosphate in vitro. Caries Res
2000;34(3):241-5.
31. Finke M, Jandt KD, Parker DM. The Early Stages of Native Enamel
Dissolution Studied with Atomic Force Microscopy. J Colloid Interface Sci
2000;232(1):156-64.
32. Hughes JA, West NX, Parker DM, Newcombe RG, Addy M.
Development and evaluation of a low erosive blackcurrant juice drink. 3. Final
drink and concentrate, formulae comparisons in situ and overview of the
concept. J Dent 1999;27(5):345-50.
51
33. West NX, Hughes JA, Parker DM, Newcombe RG, Addy M.
Development and evaluation of a low erosive blackcurrant juice drink. 2.
Comparison with a conventional blackcurrant juice drink and orange juice. J
Dent 1999;27(5):341-4.
34. Lussi A, Jaeggi T, Jaeggi-Scharer S. Prediction of the erosive potential
of some beverages. Caries Res 1995;29(5):349-54.
35. Hughes JA, West NX, Parker DM, van den Braak MH, Addy M. Effects
of pH and concentration of citric, malic and lactic acids on enamel, in vitro. J
Dent 2000;28(2):147-52.
36. Cairns AM, Watson M, Creanor SL, Foye RH. The pH and titratable
acidity of a range of diluting drinks and their potential effect on dental erosion.
J Dent 2002;30(7-8):313-7.
37. Hannig M, Balz M. Influence of in vivo formed salivary pellicle on
enamel erosion. Caries Res 1999;33(5):372-9.
38. Nekrashevych Y, Stosser L. Protective influence of experimentally
formed salivary pellicle on enamel erosion. An in vitro study. Caries Res
2003;37(3):225-31.
39. Amaechi BT, Higham SM, Edgar WM. Factors influencing the
development of dental erosion in vitro: enamel type, temperature and
exposure time. J Oral Rehabil 1999;26(8):624-30.
40. Featherstone JD, Mellberg JR. Relative rates of progress of artificial
carious lesions in bovine, ovine and human enamel. Caries Res
1981;15(1):109-14.
41. Meurman JH, Frank RM. Progression and surface ultrastructure of in
vitro caused erosive lesions in human and bovine enamel. Caries Res
1991;25(2):81-7.
52
Table 1: Chemical parameters of the acidic medicines and control used in the
present study
Characteristics
Klaricid
®
Claritin
®
Dimetapp Elixir
®
Deionized water
Batch number 640470-A
53425
801
-----
Active Principle Clarithromycin
Loratadine
Brompheniramine
and
Pseudoephdrine
-----
pH 5.04
2.80
2.70
5.60
Titratable acidity
(volume of 0.1 N
NaOH – ml)
40.02
14.59
11.96
0.10
Viscosity at 20s
-1
(cP)
1660
19.70
13.30
0.65
Presence of Citric
Acid
Yes
Yes
Yes
No
Calcium ( µg/ml ou
ppm)
11.16
10.98
9.82
<0.01
Phosphate ( µg/ml ou
ppm)
33.32
<1.5
<1.5
<1.5
Fluoride ( µg/ml ou
ppm)
0.17
<0.025
<0.025
<0.025
53
Figure 1: Schematic design of the experimental protocol
54
Table 2: Descriptive statistics of the difference between the final and the initial roughness values (Ra – µm), by pH-cycling
conditions and media immersion
Standard pH-cycling (G1)
Highly erosive pH-cycling (G2)
Descriptive
statistics
Klaricid
a
Claritin
a
Dimetapp Elixir
b
Deionized water
a,b
Klaricid
a
Claritin
a,b
Dimetapp Elixir
b
Deionized water
a,b
Mean
0.04 0.03 0.09 0.05
1.04 1.82 1.86 1.27
Standard
deviation
0.03 0.02 0.07 0.03
0.77 0.80 0.50 0.66
Minimum
0.00 0.00 0.02 0.00
0.17 0.55 1.11 0.03
1st quartile
0.01 0.01 0.29 0.03
0.31 1.15 1.44 0.81
Median
0.05 0.03 0.04 0.05
0.96 1.95 1.77 1.36
3rd quartile
0.06 0.04 0.08 0.07
1.50 2.48 2.43 1.90
Maximum
0.08 0.05 0.11 0.09
2.47 3.19 2.58 2.06
Results were analyzed with Kruskal-Wallis and Mann-Whitney tests for 2 independent samples. Subgroups marked by different superscript letters showed
significant differences (P < .008) within each group (G1 and G2). Subgroups marked by the same superscript letters did not show significant differences (P
> .008) within each group (G1 and G2).
55
Table 3: Means and standard deviations (SD) of surface microhardness (SMH) and
of percentage surface microhardness change (%SMHC) for enamel blocks from
standard pH-cycling (G1), according to media immersion (subgroups)
SMH (KHN ± SD)
Media Immersion
(subgroups)
Baseline
After pH-
cycling
%SMHC ± SD
Klaricid
®
331.44 ± 26.46 161.66 ± 13.01
50.92
a
± 5.67
Claritin
®
309.65 ± 25.45 87.40 ± 11.17
71.78
b
± 6.56
Dimetapp Elixir
®
320.16 ± 25.82 45.24 ± 39.74
85.99
c,d
± 6.56
Deionized water
311.55 ± 19.38 34.44 ± 10.93
88.92
d
± 3.62
Results were analyzed with Kruskal-Wallis and Mann-Whitney tests for 2 independent samples. Values in the same
column followed by different superscript letters indicate significant differences (Bonferroni correction, P<.008).
Figure 2: Mean surface microhardness values (KHN) for the four subgroups
(Klaricid®; Claritin®, Dimetapp Elixir®, Control) from G1 before and after the
treatments
Klarici
Clariti
Dimetap
Controle
0
50
100
150
200
250
300
350
Before
treatment
After
treatment
Mean Surface microhardness (KNH)
56
Figure 3: Representative SEM photomicrographs of sound bovine enamel.
(A) X30, (B) X850, (C) X5,000.
57
Figure 4: Representative SEM photomicrographs of bovine enamel after standard
pH-cycling and medicine’s immersion and Control:
(A), (B) e (C) - Klaricid® 50mg/mL; (D), (E) e (F) - Claritin®; (G), (H) e (I) - Dimetapp
Elixir®; (J), (K) e (L) - Control group
58
Figure 5: Representative SEM photomicrographs of bovine enamel after reverse pH-
cycling and medicine’s immersion and Control:
(A), (B) e (C) - Klaricid® 50mg/mL; (D), (E) e (F) - Claritin®; (G), (H) e (I) - Dimetapp
Elixir®; (J), (K) e (L) - Control group
59
4.3 ARTIGO 3
SURFACE DEGRADATION OF COMPOSITE RESINS BY ACIDIC MEDICINES
AND pH-CYCLING
Ana Carolina Valinoti
1
, Beatriz Gonçalves Neves
2
, Eduardo Moreira da Silva
3
,
Lucianne Cople Maia
4
1
DDS, Graduate student, Department of Pediatric Dentistry and Orthodontics, Dental School,
Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
2
DDS, MSc, Graduate student, Private Practice, Department of Pediatric Dentistry and
Orthodontics, Dental School, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
3
DDS, MSc, PhD, Associate Professor Department of Restorative Dentistry, Dental School,
Federal Fluminense University, Niterói, RJ, Brazil.
4
DDS, MSc, PhD, Associate Professor Department of Pediatric Dentistry and Orthodontics,
Dental School, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Corresponding address:
Dr. Eduardo Moreira da Silva
Universidade Federal Fluminense / Faculdade de Odontologia
Rua São Paulo, nº 28 - Campus Valonguinho, Centro, Niterói, RJ, Brasil - 24040-110
Phone: +55-21-2629-9832. Fax: +55-21-2622-5739
60
ABSTRACT
This study evaluated the effects of acidic medicines (Dimetapp
®
and Claritin
®
), under
pH-cycling conditions, on the surface degradation of four composite resins
(microhybrid: TPH, Concept, Opallis and Nanofilled: Supreme). Thirty disc-shaped
specimens = 5.0 mm / thickness = 2.0 mm) of each composite were randomly
assigned to 3 groups (n = 10): a control and two experimental groups, according to
the acidic medicines evaluated. The specimens were finished and polished with
aluminum oxide discs, and the surface roughness was measured by using a
profilometer. After the specimens were submitted to a pH-cycling regimen and
immersion in acidic medicines for 12 days, the surface roughness was measured
again. Two specimens for each material and group were analyzed by scanning
electron microscopy (SEM) before and after pH-cycling. Data were analyzed by the
Student’s-t test, ANOVA, Duncan’s multiple range test and paired t-test (α=0.05).
Significant increase in roughness was found only for TPH in the control group and
TPH and Supreme immersed in Claritin
®
(p<0.05). SEM analyses showed that the 4
composite resins underwent erosion and surface degradation after being subjected to
the experimental conditions. In conclusion, although the roughness was slightly
affected, the pH-cycling and acidic medicines caused surface degradation of the
composite resins evaluated. Titratable acidity seemed to play a more crucial role on
surface degradation of composite resins than pH.
Key Words: Composite resins. Surface degradation. pH-cycling. Acidic medicines.
Microscopy, Electron, Scanning.
61
INTRODUCTION
Composite resins are widely used in restorative and pediatric dentistry. Most of
the available composites contain a polymer matrix of dimethacrylate monomers, such
as Bis-GMA, UDMA, and TEGDMA, inorganic filler particles coated with a methyl
methacrylate-functional silane coupling agent to bond the filler to the organic matrix,
and a photoinitiator system to allow photoactivation by light units.
14,19,23
These
restorative materials are indicated for solving several problems, such as repairing
teeth damaged due to caries, restoring enamel lost by traumas and abrasion, and
also for esthetic reasons
1
.
Although the physical and mechanical properties of composite resins are
indicators that predict the behavior of composite restorations, other aspects, such as
material biodegradation, must be taken into account in the clinical performance of this
type of restorative procedure. The critical oral environment conditions, i.e., pH
changes and humidity, may increase resin composite biodegradation over time
27
.
This phenomenon is a complex process that may lead the composite polymer matrix
to collapse, causing several problems such as filler-polymer matrix debonding
26
,
release of residual monomers
22
, and wear and erosion caused by food, chewing and
bacterial activity
18
. This process may deteriorate the mechanical properties of the
material
27
, and reduce the clinical life of composite resin restorations. Furthermore,
surface disintegration of composite resins may increase wear and plaque retention,
thus decreasing the longevity of the restoration10, and potentially increasing the risk
of secondary caries.
Previously published studies have reported that acidic conditions show a
tendency to degrade glass ionômero cements, polyacid modified composite resins,
and composite resins
1,10,17,28
. Some medicines, considered acidic due to their low pH
62
and high titratable acidity, may act as extrinsic agents of dental erosion, especially if
consumed frequently
8
. These formulations are used on a regular basis and over long
periods, especially by adults and children that present chronic diseases, and may be
an example of potentially erosive agents of restorative materials. Up to now,
however, there are no studies on the effect of acidic medicines on these materials.
The purpose of this study was to evaluate the effects of acidic medicines,
under pH-cycling conditions, on the surface roughness and degradation of 4
composite resins. The tested null hypothesis was that pH-cycling and exposure to
acidic medicines would not influence the roughness and surface degradation of the
evaluated composite resins.
MATERIAL AND METHODS
Four composite resins were analyzed in this study: 3 microhybrid (TPH,
Concept Advanced Magic Kids, and Opallis) and 1 nanofilled composite (Supreme).
The material compositions and specifications are described in Table 1. The
characteristics of the acidic medicines used in this study are shown in Table 2. The
type and volume (mL) of acid present in each medicine was obtained by direct
contact with manufacturers. In addition, the medicines were analyzed with respect to
pH, titratable acidity and viscosity. The pH was measured with a pH meter (PM600,
Analion, Ribeirão Preto, SP, Brazil). The titratable acidity was determined in duplicate
by using the same pH meter. To detect the end point, 50 g of medicine solution was
dissolved in 200 mL of water and titrated with 0.1 N, using phenolphthalein. Claritin
presented pH 9.68 in the end point while Dimetapp presented pH 9.06. After that,
100 g of each medicine was dissolved in 150 mL of water to prepare new samples.
The titratable acidity of each medicine was measured following gradual addition of
63
0.05 N sodium hydroxide (NaOH) solution to the beaker until the end point. The
correction factor of 0.89 was obtained by factorizing 0.01 N NaOH solution with
potassium biphthalate (C
8
H
5
KO
4
). The total volume of NaOH solution required to
reach the end point multiplied by the correction factor of 0.89 corresponded to the
titratable acidity value
3
. Viscosity measurements were carried out on a viscosimeter
(HAAKE RheoStress 600 viscosimeter, Thermo Electron GmbH, Karlsruhe,
Germany) with a shear rate of 0.1-100 s
-1
at 35ºC. The viscosity values were
obtained at 20 s
-1
shear rate, at which the medicines presented a constant viscosity
value.
Specimen Preparation
Single increments of each composite resin were applied to an aluminum
mould (diameter = 5 mm and thickness = 2.2 mm), covered with a polyester strip and
a 0.1-mm-thick glass slide and light polymerized from the top for 20 s, with an
irradiance of 800 mW/cm
2
(Optilux 501, Kerr, Danbury, CT, USA). Thirty specimens
were prepared for each resin composite. After setting, the specimens were finished
and polished using medium, fine and superfine aluminum oxide abrasive disks
(Soflex; 3M/ESPE, St. Paul, MN, USA). A single operator, using a low-speed
handpiece without water cooling, performed this procedure.
Baseline Roughness Measurement
The surface roughness of each specimen (Ra - µm) was measured using a
profilometer (Surftest SJ 201, Mitutoyo Co, Kawasaki, Japan). Three roughness
measurements spaced at 60° were recorded for each specimen (cut-off length of
64
0.25 mm). The mean value of three measurements was recorded as the surface
roughness for each specimen.
pH-Cycling and Experimental Protocol
After the baseline roughness measurement, the 30 specimens of each
composite resin were randomly assigned to 3 groups (n=10) according to the
immersion medium [E1 - Claritin
®
; E2 - Dimettap
®
and C (control) deionized water]
and submitted to a 24-h pH-cycling regimen, using the model proposed by White30
(1987), and to acidic medicines. The experimental protocol is shown in Figure 1. The
compositions of the solutions were: demineralizing (3 mmol/L calcium, 3 mmol/L
phosphate and 50 mL acetic acid in a pH adjusted to 4.5 with NaOH)
9
and
remineralizing (1.54 mmol/L of calcium, 1.54 mmol/L of phosphate, 20 mmol/L of
acetic acid and 0.308 g of ammonium acetate with pH adjusted to 6.8 with potassium
chloride at 3C)
15
. The amount of each medicine, deionized water, remineralizing
and demineralizing solution for each group was 10 mL. The medicines and deionized
water were replaced at every immersion time and the solutions were changed daily.
After each immersion in medicines, the specimens were rinsed with 20 mL of
deionized water. These storage regimens were repeated uninterruptedly for 12 days.
After the 12th day, the surface roughness was measured again, exactly as described
for baseline.
Scanning Electronic Microscopy (SEM) Analysis
SEM analysis was performed to show the surface aspects of composite resins
before and after the experimental protocol. Two additional disc-shaped specimens of
each material were produced and set aside before pH-cycling, for later examination,
65
and one pair of each group was randomly selected after pH-cycling. These
specimens were mounted on aluminum stubs, sputter-coated with gold, and
examined with a scanning electronic microscope (JEOL-JSM; 6460LV, Tokyo,
Japan), with an acceleration voltage of 15kV. SEM micrographs at x 5,000
magnification were taken.
Statistical Analysis
Statistical analysis was performed using Statgraphics 5.1 Software
(Manugistics, Rockville, MD, USA). One-way ANOVA and Duncan’s multiple range
test were used to analyze the roughness data of the composite resins before pH-
cycling. Paired t-test was applied to check for differences between surface roughness
before and after pH-cycling. All statistical analyses were performed at a level of
significance of α = 0.05.
RESULTS
Surface Roughness
The results of surface roughness before pH-cycling are shown in Figure 2.
One-way ANOVA detected statistically significant differences among the composite
resins (p=0.0331). Duncan’s test showed that the roughness of TPH was statistically
similar to that of Supreme and significantly lower than that of Concept and Opallis
(p<0.05). Nevertheless, the roughness of Supreme, Opallis and Concept did not
differ significantly from each other (p>0.05). The results of paired t-test are shown in
Table 3. Only TPH and Supreme immersed in Claritin
®
, and TPH immersed in
66
deionized water (control) presented a significant increase in surface roughness
(p<0.05).
SEM Analysis
All composite resins showed a smooth surface before pH-cycling (Figure 3).
After pH-cycling, all materials presented some erosion (Figures 4-6). In the control
group, this aspect was more evident for TPH (Figure 4a), which presented more
accentuated matrix degradation. In general, specimens immersed in Claritin
®
(Figure
5) presented more structural defects than those immersed in Dimetapp
®
(Figure 6).
Damage on composite surface was more evident especially for TPH (Figure 5a), in
which several filler particles were observed protruding from the surface, as well as
voids suggestive of particle loss. TPH also showed a great deal of degradation when
immersed in Dimetapp
®
(Figure 6a). Irrespective of the acidic medicine, surface
degradation presented by Opallis and Concept was similar, with spaced pits
suggesting less matrix loss (Figures 5b, 5c, 6b and 6c). Supreme was the composite
that most resisted to the action of Dimetapp
®
(Figure 6d).
DISCUSSION
While only TPH and Supreme immersed in Claritin
®
and TPH immersed in
deionized water (control group) presented an increase in surface roughness, all
composite resins showed surface degradation after immersion in acidic medicines.
Thus, the null hypothesis of the present study was rejected. The widespread use of
resin-based restorative materials and their exposure to the harsh conditions of the
oral environment require them to be resistant to degradation
4
. However, under acidic
conditions, restorative materials, including the composite resins analyzed in this
67
study, may suffer degradation over time, which can be predicted by changes in
surface topography and roughness, decrease in hardness and wear resistance and
substance loss
11,12,17,24,25
. All these shortcomings will decrease the material’s
physicalmechanical properties as well as create a predisposing factor to bacterial
colonization, which could potentially increase the risk of oral diseases
25
.
The medicines selected for this study present characteristics that may
increase the erosive potential to teeth, i.e., low endogenous pH, high titratable acidity
and presence of citric acid
8,29
. Claritin
®
is an antihistamine frequently indicated for
chronic diseases, for example, allergies, and Dimetapp
®
elixir is indicated to relieve
symptoms of colds, upper respiratory infections and allergies. Published studies have
shown that acidic media produce surface alterations in resin restorative materials
28,31
.
In one of these studies, however, the materials were immersed in acid media for long
and uninterrupted periods of time
28
. This model probably overestimates the time in
which the human plaque remains acid. In the present study, the pH-cycling model
was used in an attempt to simulate the oral conditions as closely as possible, thus
allowing more realistic results about the behavior of the resin materials analyzed.
In the present study, the analysis of roughness data before pH-cycling showed
that TPH presented similar behavior to that of Supreme and lower roughness than
Concept and Opallis (Figure 2). After pH-cycling and immersion in distilled water and
Claritin
®
, however, TPH presented a significant increase in roughness (Table 3). This
finding could be due to the filler particle characteristics of this material. Previous
studies have shown that resin materials that have larger filler particles presented
greater surface micromorphology changes when submitted to acidulated phosphate
fluoride (APF) gel, i.e., a fluoride compound that has a low pH
5,29
. Among the resin
materials analyzed in this study, TPH presents the largest filler particles, 0.8 µm,
68
(Table 1), which has probably contributed to the increase of its roughness after pH-
cycling. Moreover, Supreme composite also showed an increase in roughness after
pH-cycling and immersion in Claritin
®
. The same rationale as for TPH behavior may
be used to explain this result. Although the primary particle size of Supreme is 20 nm,
it is reasonable to speculate that the Zr-Si cluster of 0.6-1.4 µm may have contributed
to the observed increase in roughness. Furthermore, the fact that Opallis and
Concept have a mean filler particle size close to the same value (Table 1) and did not
present significant changes in roughness after pH-cycling and immersion in the
evaluated medicines, reinforces the role that filler size plays on surface degradation
of resin-based restorative materials.
The SEM analysis showed that irrespective of immersion in acidic medicines,
all composite resins presented surface changes after pH-cycling, which could be
considered as a process of degradation and erosion of the polymer matrix. Several
protruding particles, voids and cracks were observed in all specimens analyzed
(Figures 4-6). These findings are in agreement with those of a previous study
28
,
which analyzed the changes in surface micromorphology of several resin-based
materials submitted to a pH-cycling regimen. This study
28
showed several filler
particles protruding from the surface of a microfilled composite, which was attributed
to polymer matrix degradation. Moreover, the polymer matrix of a hybrid composite
and a polyacid modified composite resin showed several voids, which were
associated with a possible degradation of the surrounding resin matrix or silane
coupling agent and loss of filler particles.
When comparing the roughness and SEM results, some interesting aspects
can be discussed. Figure 2 shows that, at baseline, TPH presented roughness similar
to that of Supreme and lower than that of Opallis and Concept. After pH-cycling,
69
however, only TPH and Supreme showed a significant increase in roughness (Table
3). Given that it has already been proved that composite materials with high
roughness values tend to show increased roughness after acid challenges, this result
was unexpected.30 Moreover, Figures 4 and 5 show that TPH and Supreme suffered
more degradation than Opallis and Concept. The only reasonable explanation for
these results could be the higher polymer matrix content in the compositions of TPH
and Supreme (Table 1). Wongkhantee, et al.
31
(2006) showed a greater reduction in
hardness after immersion in acidic drinks, for a microfilled composite when compared
to an universal hybrid composite, and claimed that this result was influenced by the
higher organic matrix content presented by microfilled composite. Since TPH and
Supreme present 10 and 7.5 vol% less polymer matrix, respectively than Opallis and
Concept (Table 1), the same rationale of the aforementioned study might be used to
explain the behavior of TPH and Supreme, as regards roughness, after pH-cycling
and acidic medicines immersion.
Comparing Figures 5 and 6, it can be seen that irrespective of changes in
roughness, Claritin
®
had a more aggressive effect than that of Dimetapp
®
. Since both
medicines have approximately the same pH (Table 2), it is may be assumed that this
finding is related to the titratable acidity.
6
The probable mechanism of acidity in
composite resin degradation may be explained by the hydrolysis of ester radicals
present in dimethacrylate monomers, i.e. Bis-GMA, Bis-EMA, UDMA and
TEGDMA
7,20
. Although previous studies assumed pH as a reliable indicator of the
acidity of drinks
21,31
, this parameter gives only the initial concentration of
+
H ions, and
does not represent the presence of undissociated acid in the medium. On the other
hand, titratable acidity can be considered as a more accurate measure of the total
acid content present in substances, and may represent their erosive effect more
70
realistically
6,16
. The values of citric acid presented in Table 2 (manufacturers’
information) agree with this assumption. Citric acid is an organic acid that may
produce high levels of tooth erosion, possibly due to its strong chelating properties
13
,
and some previous studies have shown that this acid may produce harmful effects on
resin restorative materials
7,20
.
From a clinical point of view, the higher viscosity presented by Claritin
®
(Table
2) may be considered as a crucial factor in composite resin degradation. It is
reasonable to suppose that a more viscous medicine will stay in contact with the
surface of composite restorations for a longer period, thus increasing its harmful
effect
6
. However, since the specimens in the present study were rinsed with distilled
water after immersion in the acidic medicines, their viscosity certainly did not interfere
on the composite resin degradation.
CONCLUSIONS
From the experimental conditions adopted in this study, it may be concluded that
although the roughness was only slightly affected, pH-cycling and immersion in acidic
medicines caused surface degradation of the tested composite resins. Titratable
acidity seemed to play a more crucial role on surface degradation of composite resins
than pH. Moreover, composite resins with large filler particles might be more
susceptible to degradation when submitted to acidic challenges.
ACKNOWLEDGEMENTS
The authors would like to thank CNPq (Brazilian National Council for Scientific and
Technological Development) for the research grant (308029/2006-2), FAPERJ (Rio
de Janeiro State Carlos Chagas Foundation for Research Funding) (E-
71
26/171.241/2006) and the Brazilian Government agency CAPES for the financial
support for this project.
REFERENCES
1- Aliping-Mckenzie M, Linden RWA, Nicholson JW. The effect of Coca-Cola and fruit
juices on the surface hardness of glass-ionomers and compomers. J Oral Rehabil.
2004;31:1046-52.
2- Asmussen E. Softening of BISGMA-based polymers by ethanol and by organic
acids of plaque. Scand J Dent Res. 1984;92:257-61.
3- Association of Official Analytical Chemist. Official methods of analysis. Sugars and
Sugar Products; 1966. p. 40.
4- Bagheri R, Tyas MJ, Burrow MF. Subsurface degradation of resinbased
composites. Dent Mater. 2007;23:944-51.
5- Benderli Y, Gökçe K, Kazak M. Effect of APF gel on micromorphology of resin
modified glass-ionomer cements and flowable compomers. J Oral Rehabil.
2005,32:669-75.
6- Cairns AM, Watson M, Creanor SL, Foye RH. The pH and titratable acidity of a
range of diluting drinks and their potential effect on dental erosion. J Dent.
2002;30:313-7.
7- Chadwick RG, McCabe JF, Walls AWG, Storer R. The effect of storage media
upon the surface microhardness and abrasion resistance of three composites. Dent
Mater. 1990;6:123-8.
8- Costa CC, Almeida ICS, Costa LC Filho. Erosive effect of antihistamine-containing
syrup on primary enamel and its reduction by fluoride dentifrice. Int J Paediatr Dent.
2006;16:174-80.
9- Damato FA, Strang R, Stephen KW. Effect of fluoride concentration on
remineralization of carious enamel: an in vitro pH-cycling study. Caries Res.
1990;24:174-80.
10- De Witte AMJC, De Maeyer EAP, Verbeeck RMH. Surface roughening of glass
ionomer cements by neutral NaF solutions. Biomaterials. 2003;24:1995-2000.
11- Gao F, Matsuya S, Ohta M, Zhang J. Erosion process of lightcured and
conventional glass ionomer cements in citrate buffer solution. Dent Mater J.
1997;16:170-9.
72
12- Jaeggi T, Gruninger A, Lussi A. Dental erosion. Monogr Oral Sci. 2006;20:200-
14.
13- Jarvinen VK, Rytomaa H, Heinonen OP. Risk factors in dental erosion. J Dent
Res. 1991;70:942-7.
14- Kalachandra S, Taylor DF, Mc Grath JE, Sankarapandian M, Shobha HK.
Structure- property relationships in dental composites based on polydimethacrylates.
Polymer Prepr. 1997;38:94-5.
15- Lammers PC, Borggreven JMPM, Briessens FCM. Acidsusceptibility of lesions in
bovine enamel after remineralization at different fluoride concentrations. J Dent Res.
1991;70:1486-90.
16- Larsen MJ, Nyvad B. Enamel erosion by some soft drinks and orange juices
relative to their pH, buffering effect and contents of calcium phosphate. Caries Res.
1999;33:81-7.
17- Nicholson JW, Millar BJ, Czarnecka H, Limanowska-Shaw H. Storage of
polyacid-modified resin composites (“compomers”) in lactic acid solution. Dent Mater.
1999;15:413-6.
18- Oilo G. Biodegradation of dental composites/glass ionômero cements. Adv Dent
Res. 1992;6:50-4.
19- Peutzfeldt A. Resin composites in dentistry: the monomer systems. Eur J Oral
Sci. 1997;105:97-116.
20- Prakki A, Cilli R, Mondelli RFL, Kalachandra S, Pereira JC. Influence of pH
environment on polymer based dental material properties. J Dent. 2005;33:91-8.
21- Rugg Gunn AJ, Maguire A, Gordon PH, McCabe JF, Stephenson G. Comparison
of erosion of dental enamel by four drinks using an intraoral appliance. Caries Res.
1998;32:337-43.
22- Ruyter IE. Physical and chemical aspects related to substances released from
polymer materials in an aqueous environment. Adv Dent Res. 1995;9:344-7.
23- Sideridou I, Tserki V, Papanastasiou G. Effect of chemical structure on degree of
conversion in light-cured dimethacrylate-based dental resins. Biomaterials.
2002;23:1819-29.
24- Sidhu SK, Sherriff M, Watson TF. In vivo changes in roughness of resin-modified
glass ionomer materials. Dent Mater. 1997;13:208-13.
25- Silva RC, Zuannon ACC. Surface roughness of glass ionômero cements
indicated for atraumatic restorative treatment. Braz Dent J. 2006;17:106-9.
73
26- Söderholm KJ, Mukherjee R, Longmate J. Filler leachability of composites stored
in distilled water or artificial saliva. J Dent Res. 1996;75:1692-9.
27- Söderholm KJ, Zigan M, Ragan M, Fischlschweiger W, Bergman M. Hydrolytic
degradation of dental composites. J Dent Res. 1984;63:1248-54.
28- Turssi CP, Hara AT, Serra MC, Rodrigues AL Jr. Effect of storage media upon
the surface micromorphology of resin-based restorative materials. J Oral Rehabil.
2002;29:864-71.
29- Turssi CP, Magalhães CS, Serra MC. Effect of fluoride gels on micromorphology
of resin-modified glass ionomer cements and polyacid-modified resin composites.
Quintessence Int. 2001;32:571-7.
30- White DJ. Reactivity of fluoride dentifrices with artificial caries. I. Effect on early
lesions: F uptake, surface hardening and remineralization. Caries Res. 1987;21:126-
40.
31- Wongkhantee S, Patanapiradej V, Maneenut C, Tantbirojn D. Effect of acidic food
and drinks on surface hardness of enamel, dentine, and tooth-colored filling
materials. J Dent. 2006;34:214-20.
74
Table 1: Composition and specifications of composite resins used in this study
Composite resins Composition Manufacturer
TPH Polymer matrix: Bis-GMA, Bis-EMA and TEGDMA
Filler: 57 vol% of Ba-Al-borosilicate glass and
colloidal silica with mean particle size of 0.8 µm
Denstply Ind. e Com. Ltda.,
Petrópolis, RJ, Brazil
Concept Advanced Magic
Kids
Polymer matrix: Bis-GMA,UDMA and Esther of
methacrylic acid
Filler: 67 vol% of Ba-Al-silicate glass with mean
particle size of 0.4 µm.
Vigodent, Rio de Janeiro,
RJ,
Brazil
Opallis Polymer matrix: BisGMA, BisEMA, and TEGDMA
Filler: 67 vol% Ba-Al silicate glass and silicon
dioxide with mean particle size of 0.5 µm.
FGM, Joinville, SC, Brazil
Supreme Polymer matrix: Bis-GMA, Bis-EMA, UDMA
TEGDMA
Filler: 59.5 vol% combination of aggregated
zirconia/silica cluster filler with primary particles
size of 5-20 nm, and non-agglomerated 20 nm
silica filler.
3M/ESPE, St. Paul, MN,
USA
*Bis-GMA= 2,2-bis[4-(2’-hydroxy-3’methacryloxypropoxy)phenyl]propane; TEGDMA= triethylene glycol dimethacrylate); UDMA= 1,6-
bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane; Bis-EMA= ethoxylated bisphenol A glycol, dimethacrylate.
Table 2: Characteristics of the acidic medicines used in the present study
Characteristics Medicines
Claritin
®
(E1)
(Schering-Plough, São Paulo, SP, Brazil)
Dimetapp Elixir
®
(E2)
(Wyeth-Whitehall, São Paulo, SP,
Brazil)
Batch Number 701 46139A
Active Principle Loratadine
Brompheniramine and
Pseudoephedrine
pH 2.57 2.51
Titratable acidity mean
volume of 0.05 N NaOH
(mL)
41.83 mL 36.31 mL
Viscosity at 20s
-1
19.7 13.3
Acid content according to
manufacturers (mg/mL)
Citric Acid
(8.8 mg/mL)
Citric Acid
(7.5 mg/mL)
75
Figure 1: Schematic design of the pH-cycling and medicine immersion
76
Figure 2: Surface roughness before pH-cycling. Columns with the same letters do
not differ significantly (α = 0.05)
Table 3: Results of paired t-test for surface roughness means (Ra; mm) before and
after pH-cycling
Before pH-cycling After pH-cycling P
Roughness variation
TPH E1 0.089 (0.012) 0.101 (0.012) 0.030* 0.0129
TPH E2 0.112 (0.020) 0.114 (0.020) 0.804 0.0023
TPH Control 0.096 (0.001) 0.117 (0.015) 0.003* 0.0213
Concept E1 0.116 (0.032) 0.124 (0.026) 0.554 0.008
Concept E2 0.119 (0.019) 0.130 (0.009) 0.109 0.0114
Concept Control 0.121(0.025) 0.114 (0.018) 0.589 -0.0054
Opallis E1 0.145 (0.083) 0.128 (0.023) 0.537 -0.0173
Opallis E2 0.110 (0.015) 0.110 (0.015) 0.932 -0.0006
Opallis Control 0.111 (0.016) 0.106 (0.019) 0.518 -0.0054
Supreme E1 0.091 (0.021) 0.117 (0.024) 0.025* 0.0253
Supreme E2 0.118 (0.061) 0.105 (0.024) 0.554 -0.0126
Supreme Control 0.101 (0.024) 0.101 (0.027) 0.985 -0.0002
77
Figure 3: Representative SEM micrographs of resin-based composites before pH-
cycling.
(a) TPH, (b) Concept, (c) Opallis and (d) Supreme
Figure 4: Representative SEM photomicrographs of resin-based composites after
pH-cycling and immersion in distilled water, control group.
(a) TPH, (b) Concept, (c) Opallis and (d) Supreme
78
Figure 5: Representative SEM photomicrographs of resin-based composites after
pH-cycling and immersion in Claritin®.
(a) TPH, (b) Concept, (c) Opallis and (d) Supreme
Figure 6: Representative SEM photomicrographs of resin-based composites after
pH-cycling and immersion in Dimetapp®.
(a) TPH, (b) Concept, (c) Opallis and (d) Supreme
79
5 D IS CUSS ÃO
Não há dúvida quanto à importância da composição de bebidas ácidas como
fator determinante da sua capacidade de produzir prejuízos à superfície do esmalte
dental (Meurman e Frank, 1991b) como a cárie e a erosão dentária. Considerando
que muitos medicamentos líquidos orais possuem componentes em suas
formulações que, associados ao seu uso freqüente e contínuo, podem trazer
prejuízos às estruturas dentais, o presente estudo in vitro inicialmente investigou as
propriedades físico-quimicas de medicamentos líquidos de uso pediátrico da classe
terapêutica dos antibacterianos.
Antibacterianos líquidos orais foram escolhidos, pois juntamente com os
antitussígenos, são os medicamentos açucarados mais comumente usados por
crianças (Mackie e Bentley, 1994) e, consequentemente, causam preocupação em
relação à cárie dentária. Além disso, a literatura relata que medicamentos quidos
orais apresentam potencial erosivo devido à presença de ácidos em suas
formulações, baixo pH, elevada acidez, presença de agentes tampões e baixa
concentração de íons, incluindo os de cálcio, flúor e fosfato em sua composição
(Featherstone e Mellberg, 1981; Duward e Thou, 1997; Lussi, Jaeggi et al., 2004;
Costa, Almeida et al., 2006).
Os resultados deste estudo mostraram que, apesar de glicose e frutose não
estarem presentes em nenhum dos medicamentos analisados, a maioria destes
(82,8%) apresentou sacarose, que é considerado o açúcar mais cariogênico
(Hobson, 1985), em sua composição. Estes resultados corroboraram estudos
prévios (Nicholson, Millar et al., 1999; Neiva, Silva et al., 2001; Pierro, Abdelnur et
80
al., 2005; Neves, Farah et al., 2009) que mostraram que a sacarose foi o principal
adoçante utilizado para a maioria dos medicamentos pediátricos analisados. Estudos
anteriores verificaram que a concentração deste carboidrato nos medicamentos
infantis variou de 3% a 85,9% (Kenny e Somaya, 1989; Neiva, Silva et al., 2001;
Pierro, Abdelnur et al., 2005; Neves, Farah et al., 2009) enquanto, no presente
estudo as concentrações de sacarose variaram de 26 g% a aproximadamente 77,46
g%, mostrando que estes podem ser uma ameaça à saúde bucal se consumidos
frequentemente e sem a higienização adequada. No entanto, esta questão é
controversa na literatura, uma vez que estudos indicam que antibacterianos orais
podem reduzir o número de Streptococcus mutans e, portanto, são anticariogênicos.
(Karjalainen, Rekola et al., 1992; Paunio, Rautava et al., 1993). Vale ainda lembrar
que todos os antibacterianos que apresentaram sacarose neste estudo tiveram
concentração maior que 10 g%, o que os caracteriza como acidogênicos (Lokken,
Birkeland et al., 1975), logo capazes de reduzir o pH do meio bucal, contribuindo
para a desmineralização dental.
Outro fator analisado neste estudo, a acidez, medida por pH e acidez titulável,
também é importante para mensurar o potencial erosivo e cariogênico dos
medicamentos. A acidez titulável é considerada uma medida mais acurada do
conteúdo total de ácido de uma bebida em relação à medição do pH e, portanto, a
forma mais realística de predizer o potencial erosivo (Grobler, Jenkins et al., 1985;
Edwards, Creanor et al., 1999). Dentes expostos a bebidas com baixo pH e elevada
acidez titulável por tempo prolongado irão resultar em um maior potencial erosivo
(Jensdottir, Bardow et al., 2005). A maioria dos antibacterianos (n = 27) apresentou-
se ácido, sendo que 51,7% (n = 15) apresentaram pH abaixo do valor crítico para a
dissolução do esmalte. Em relação aos valores de acidez titulável, variaram de 0,26
81
a 40,48 ml, o que pode causar preocupação quanto à saúde oral. Embora a média
de pH endógeno para Klaricid
®
50mg/5mL e Klaricid
®
25mg/5mL tenha sido de 5,04
e 5,13, pouco abaixo do pH crítico de 5,5, a sua dia de acidez titulável teve
valores altos de 40,48 mL e 24,64, respectivamente, o que reflete a incorporação de
ácido (cítrico) em excesso em sua formulação.
Além dos valores do pH e da capacidade tampão, o potencial erosivo de um
alimento é influenciado pelo tipo do ácido predominante em sua composição
(Larsen, 1975). O ácido cítrico por sua vez é um ácido fraco, dissociando em
soluções de alto pH e capaz de atuar como tampão sobre uma gama de pHs. No
entanto, é um potente agente erosivo devido à sua capacidade quelante ao cálcio da
hidroxiapatita, aumentando assim a taxa de dissolução do esmalte sobre a
exposição ao ácido (Grenby, Phillips et al., 1989). Porém, a quantificação de ácido
cítrico não foi proposta neste estudo.
A análise da viscosidade de medicamentos também é importante, já que um
líquido mais viscoso apresenta maiores chances de aderir à superfície dental,
portanto, permanecer na boca por mais tempo (Cairns, Watson et al., 2002). Apesar
de apresentar a água como um veículo da suspensão oral, a maior parte dos
antibacterianos líquidos analisados neste estudo mostraram valores de viscosidade
muito altos. Quando comparados com um estudo prévio, que analisou anti-
histamínicos, broncodilatadores e mucolíticos (Neves, Farah et al., 2009), os
antibacterianos do presente estudo apresentaram maior viscosidade, uma vez que
esta variou de 20 cP para 1780 cP, relativamente maior que os valores do estudo
citado anteriormente, onde a variação foi de 4,7 a 412,3 cP.
Todos estes fatores acrescentados às propriedades da bebida, bem como
fatores de risco relacionados com o modo de ingestão, a freqüência de consumo,
82
parâmetros salivares e placa dental, desempenham um papel no desenvolvimento
da cárie e da erosão dentária. Am disso, em crianças medicamente
comprometidas, muitos desses medicamentos podem ser ingeridos fora das
refeições ou à noite, quando o fluxo salivar é reduzido, e esses fatores podem
acrescentar um desafio ao potencial cariogênico e erosivo (Maguire, Baqir et al.,
2007).
Diante da dificuldade em se realizar estudos clínicos, avaliações in vitro
podem sugerir o efeito desses medicamentos na saúde bucal. Somando-se a essas
informações, procurou-se simular, in vitro, os efeitos de medicamentos ácidos
(Klaricid
®
, Claritin
®
e Dimetapp Elixir
®
) no esmalte dental submetido a condições que
simulassem os padrões normais de perdas e ganhos de mineral na cavidade bucal
(ciclagem de pH) e condições altamente erosivas (modelo erosivo). Considerando-se
ainda que, sob condições ácidas, materiais restauradores podem sofrer degradação
ao longo do tempo, que pode ser previsto por mudanças na topografia e rugosidade
superficial, diminuição da dureza e resistência ao desgaste e perda substancial
(Gao, Matsuya et al., 1997; Sidhu, Sherriff et al., 1997; Nicholson, Millar et al., 1999;
Da Silva e Zuanon, 2006; Jaeggi, Gruninger et al., 2006), procurou-se simular o
efeito da ingestão de medicamentos ácidos sobre a superfície de materiais
restauradores, sob condições de normalidade (ciclagem de pH). Modelos de
ciclagem de pH foram utilizados em uma tentativa de simular o mais próximo
possível as condições orais, permitindo, assim, resultados mais realistas sobre o
comportamento do esmalte bovino e dos materiais resinosos analisados.
Os medicamentos selecionados para este estudo apresentam
características que podem aumentar o potencial erosivo aos dentes (Klaricid
®
,
Claritin
®
e Dimetapp Elixir
®
), ou seja, baixo pH endógeno, elevada acidez titulável e
83
a presença de ácido cítrico (Turssi, De Magalhaes et al., 2001; Costa, Almeida et al.,
2006). Dentre eles, Claritin
®
e Dimetapp Elixir
®
são antihistamínicos, logo, além de
serem altamente ácidos, também podem reduzir o fluxo salivar. Além disso, o padrão
de ingestão do Dimetapp Elixir
®
aumenta as chance de desafios erosivos, uma vez
que as recomendações na bula indicam sua utilização até seis vezes ao dia.
Considerando que, um baixo fluxo salivar determina um risco de erosão dentária
cinco vezes maior do que aqueles com fluxo normal (Jarvinen, Rytomaa et al., 1991)
e que as crianças apresentam um fluxo e uma capacidade tampão da saliva
reduzidos em relação aos adultos (Johansson, Sorvari et al., 2001), pode-se sugerir
uma situação de maior risco à erosão dentária.
Em estudos para avaliar o comportamento do esmalte, dentes bovinos têm
sido utilizados, uma vez que estudos prévios mostraram que a sua estrutura
química, bem como sua resposta aos desafios erosivos, são comparáveis ao dente
humano (Davidson, Boom et al., 1973). No entanto, alguns estudos relataram que o
esmalte bovino é mais afetado por ácido do que o esmalte humano (Featherstone e
Mellberg, 1981; Amaechi, Higham et al., 1999a). Além disso, acredita-se que a
remoção da camada de esmalte mais externa do esmalte durante a preparação dos
espécimes possa influenciar na severidade do processo erosivo quando comparados
aos de dentes humanos, in vivo (Meurman e Frank, 1991a). Isso pode ter
superestimado os resultados de rugosidade superficial, microdureza superficial e as
alterações visualizadas microscopicamente do esmalte bovino submetido aos
medicamentos ácidos e controle, sob condições erosivas no presente estudo.
Sob os efeitos dos medicamentos e dos modelos de ciclagem, o esmalte
bovino apresentou alterações ultraestruturais com padrão de erosão no esmalte
visíveis por MEV, alterações na rugosidade superficial e na microdureza superficial,
84
enquanto que todas as resinas compostas apresentaram degradação superficial
após a imersão em medicamentos ácidos. Em relação às resinas, todas estas
deficiências irão diminuir as propriedades físico-mecânicas do material, bem como
criar um fator predisponente para a colonização bacteriana, o que poderia aumentar
potencialmente o risco de doenças bucais (Da Silva e Zuanon, 2006).
Os resultados mostram uma perda de mineral substancial dos blocos de
esmalte após a ciclagem de pH e exposição aos medicamentos e controle (água
deionizada) quando mensurada a microdureza superficial no Grupo 1, corroborando
com um estudo prévio (Costa, Almeida et al., 2006), uma vez que a imersão dos
blocos de esmalte em uma solução remineralizadora, com composição semelhante a
da saliva humana, durante 20h por dia não foi suficiente para evitar a
desmineralização por dois ataques ácidos (imersão em solução desmineralizante
com pH<4,5). O uso noturno do antihistamínico Claritin D
®
demonstrou ainda uma
grande alteração na microdureza superficial (SMH) (Costa, Almeida et al., 2006), que
foi semelhante à diminuição da microdureza superficial que ocorreu em todos os
subgrupos de Grupo 1 (ciclagem de pH padrão) no presente estudo. A acentuada
redução na microdureza superficial pode ser explicada pelo fato de as exposições
diárias de 30 minutos corresponderem a um tempo superestimado. Segundo outros
estudos, este aumento do tempo de exposição a produtos ácidos agrava a
ocorrência de erosão (Maupome, Diez-De-Bonilla et al., 1998; Hunter, West et al.,
2000b; 2000a; West, Hughes et al., 2000), assim como verificado no presente
estudo.
Apesar de a microdureza superficial ser, normalmente, o método quantitativo
empregado para verificar a erosão dentária, juntamente com observações através de
MEV (Turssi, De Magalhaes et al., 2001; Rios, Honorio et al., 2006), no presente
85
estudo, esta análise quantitativa revelou-se limitada na avaliação dos dentes
submetidos a um grande desafio erosivo, uma vez que as indentações não puderam
ser realizadas no Grupo 2, devido às significativas alterações superficiais do
esmalte. Este resultado é confirmado pela análise da rugosidade superficial, como
também pela avaliação através do MEV. Apesar de ambos os grupos terem
mostrado alterações na rugosidade superficial, esta se mostrou mais acentuada no
Grupo 2, uma vez que a diferença de rugosidade encontrada neste grupo foi cerca
de vinte vezes maior do que a diferença verificada no Grupo 1. Ao MEV, o Grupo 2
mostrou padrões erosivos com maior perda de estrutura e destruição do esmalte,
quando comparado ao Grupo 1.
A erosão dentária pode ser resultado de alguma perda direta da camada de
esmalte superficial, e, além disso, pode ter amolecido a camada subjacente,
resultando então em uma menor microdureza (Imfeld, 1996; Moss, 1998; Amaechi e
Higham, 2001; Rios, Honorio et al., 2006), como foi demonstrado, respectivamente,
pelas análises da rugosidade superficial e microdureza superficial aqui realizadas. O
Grupo 1 (ciclagem de pH padrão) apresentou uma menor variação na rugosidade
superficial quando comparado ao Grupo 2 (ciclagem de pH altamente erosiva).
Entretanto, sua microdureza superficial, apresentou alterações pronunciadas. Estes
resultados indicam um acentuado amolecimento do esmalte, o que poderia fazer-nos
especular que uma alteração da camada interna do esmalte pode ser o primeiro
sinal de erosão dentária, sugerindo uma perda subsuperficial inicial não só para a
cárie dentária, mas também para erosão dentária ou concomitante a esta,
caracterizando a presença simultânea dos dois fenômenos. Esta questão já foi
descrita em um estudo prévio, que demonstrou que a lesão erosada estava
86
associada com uma área de perda mineral subsuperficial discreta ou esmalte
amolecido (Muhlemann, Lenz et al., 1964).
Em relação aos resultados do grupo controle (Grupo 1 e Grupo 2 - água
deionizada), pode-se afirmar que poderiam ter sido diferentes se não houvesse um
período imersão em água. A água deionizada foi escolhida para ser o meio de
imersão dos grupos controle por ser inerte ao esmalte e não promover alterações
estruturais. No entanto, provavelmente, Ca
++
e PO4
-
do esmalte foram liberados
para a água deionizada, devido à sua condição subsaturada em relação à
hidroxiapatita, reduzindo, assim, seu conteúdo mineral e, conseqüentemente,
promovendo alterações superficiais e amolecimento, para que o equilíbrio nico
fosse alcançado. Isto justifica as alterações estruturais visualizadas no MEV e na
rugosidade superficial e, e os baixos valores de microdureza superficial do grupo
controle no Grupo 1. Um estudo in vitro prévio (Amaechi, Higham et al., 1999b)
também mostrou resultados semelhantes, pois menor perda mineral e profundidade
da lesão foram observadas quando o esmalte bovino foi imerso apenas em suco de
laranja em comparação com a sua imersão em suco de laranja seguido por imersão
em água.
O efeito erosivo dos ácidos da dieta sobre os tecidos dentais pode ser
influenciada por uma série de fatores, que incluem pH, pKa, acidez, temperatura,
característica do ácido, concentração e potencial de quelação. Além disso, a
freqüência e o período de ingestão, período de tempo na boca e as variações
estruturais individuais de cada dente, especialmente no que diz respeito ao teor de
flúor e camada da película, são considerados componentes para o entendimento da
erosão dentária pelos ácidos da dieta (Hooper, West et al., 2003). Um aumento do
pH, muitas vezes acompanhado por adição de cálcio e/ou sais de fosfato, tem
87
mostrado uma redução do potencial erosivo de bebidas in situ e in vitro (Hughes,
West et al., 1999; Finke, Jandt et al., 2000; Tanaka e Kadoma, 2000; Hooper, West
et al., 2003). Provavelmente, o maior pH e o conteúdo de cálcio, flúor e fosfato de
Klaricid
®
, quando comparado com os outros medicamentos testados, promoveram
um menor padrão erosivo observado no Grupo 1 e no Grupo 2.
Embora a boca seja o ambiente de teste definitivo para predizer o
comportamento de restaurações (Mair, Stolarski et al., 1996), devido à complexidade
e diversidade das condições intra-orais, modelos in vitro são muito importantes para
a compreensão dos mecanismos fundamentais para a biodegradação. No presente
estudo, após a ciclagem de pH e imersão em medicamentos ácidos (Claritin
®
e
Dimetapp Elixir
®
), todos os materiais resinosos apresentaram degradação
superficial, embora a rugosidade superficial tenha aumentado nos grupos TPH e
Supreme imersos em Claritin
®
e TPH imersos em água deionizada (grupo controle).
O aumento significativo na rugosidade pode ser explicado devido às
características das partículas de carga deste material. Estudos prévios mostraram
que os materiais resinosos que tenham partículas de carga maiores apresentaram
maiores alterações morfológicas superficiais quando submetidos ao gel de flúor
fosfato acidulado (APF), ou seja, um composto fluoretado que tem baixo pH (Turssi,
De Magalhaes et al., 2001; Benderli, Gokce et al., 2005). Entre os materiais
resinosos analisados neste estudo, TPH apresenta maiores partículas de carga, 0,8
µm, o que provavelmente contribuiu para o aumento de sua rugosidade após a
ciclagem de pH. O mesmo ocorreu com o compósito Supreme após a ciclagem de
pH e imersão em Claritin
®
e pode-se explicar pelo mesmo raciocínio. Embora a
dimensão das partículas primárias do Supreme seja de 20 nm, é razoável especular
que o agregado Zr-Si de 0,6-1,4 µm, pode ter contribuído para o aumento observado
88
na rugosidade. Além disso, o fato de que o Opallis e o Concept têm uma média de
partículas de carga de valores muito próximos e de não apresentarem alterações
significativas na rugosidade após a ciclagem de pH e a imersão nos medicamentos
avaliados, reforça o papel de que o tamanho das partículas desempenha na
degradação superficial de materiais restauradores resinosos.
Estudos publicados têm mostrado que meios ácidos produzem alterações na
superfície de materiais restauradores resinosos (Turssi, Hara et al., 2002;
Wongkhantee, Patanapiradej et al., 2006). Em um desses estudos, no entanto, os
materiais foram imersos em meio ácido por longos e ininterruptos períodos de tempo
(Turssi, Hara et al., 2002). Por outro lado, outro estudo avaliou o efeito erosivo de
uma imersão em refrigerante (5 min; 3x dia), alternada com saliva artificial, ou
somente imersão em saliva artificial, sobre a percentagem de alteração da
microdureza superficial (% SMH) e desgaste de diferentes materiais restauradores e
esmalte bovino com esses materiais, dentre eles resina composta. Resultados
mostraram um pequeno desgaste, que foi maior para os materiais submetidos aos
ataques erosivos. Para a % SMH, considerando os materiais e meios de imersão,
não houve diferenças significativas entre materiais e meio de imersão. Em contraste,
para as análises do esmalte, a ciclagem de pH associada à imersão em refrigerante
promoveu elevado desgaste e % SMH comparado à saliva.
De acordo com a literatura, o esmalte apresenta maior desgaste quando
comparado a materiais restauradores (Wongkhantee, Patanapiradej et al., 2006).
Considerando as análises do presente trabalho, pode-se dizer que este fato se
repetiu, uma vez que quando submetidos à ciclagem de pH e imersos em
medicamentos e controle (água deionizada), todos os materiais resinosos
apresentaram degradação superficial, porém a rugosidade superficial aumentou
89
nos grupos TPH e Supreme imersos em Claritin
®
e TPH imerso em água deionizada
(grupo controle). quando o experimento foi realizado com esmalte bovino, foram
observadas alterações ultraestruturais com padrão de erosão no esmalte visíveis por
MEV, alterações significativas na rugosidade superficial e na microdureza superficial
em todos os grupos e subgrupos.
O estudo de MEV mostrou que, independentemente de imersão em
medicamentos ácidos, todas as resinas compostas apresentaram alteração
superficial após a ciclagem de pH, o que poderia ser considerada como um processo
de degradação e erosão da matriz polimérica. Estes achados estão em concordância
com os de um estudo prévio (Turssi, De Magalhaes et al., 2001), em que analisaram
as mudanças na micromorfologia superficial de diversos materiais resinosos
submetidos a um regime de ciclagem de pH. Este estudo (Turssi, De Magalhaes et
al., 2001) mostrou várias partículas de carga projetadas da superfície de um
compósito microparticulado, que foi atribuída à degradação da matriz polimérica.
Além disso, a matriz polimérica de um compósito híbrido e uma resina composta
modificada por poliácido revelou várias lacunas, que estavam associadas a uma
possível degradação da matriz resinosa subjacente ou agente de união silano e
perda de partículas de carga.
Independentemente das mudanças na rugosidade, Claritin
®
teve um efeito
mais agressivo do que a de Dimetapp Elixir
®
sobre os materiais resinosos. Uma vez
que ambos os medicamentos têm aproximadamente o mesmo pH, é de se presumir
que este achado pode estar relacionado com a acidez titulável (Cairns, Watson et
al., 2002). O provável mecanismo da acidez na degradação das resinas compostas
pode ser explicado pela hidrólise dos radicais éster presentes nos monômeros
dimetacrilato, ou seja, Bis-GMA, Bis-EMA, UDMA e TEGDMA (Chadwick, Mccabe et
90
al., 1990; Prakki, Cilli et al., 2005). Os valores de ácido cítrico (informação dos
fabricantes) concordam com esta hipótese, e, segundo alguns estudos anteriores,
têm demonstrado que este ácido pode produzir efeitos nocivos sobre materiais
restauradores resinosos (Chadwick, Mccabe et al., 1990; Prakki, Cilli et al., 2005).
Em contraste, no presente estudo, o Dimetapp Elixir
®
apresentou um efeito
mais agressivo sobre o esmalte dental quando submetido à ação dos medicamentos
em ambos os grupos (Grupo 1 e Grupo 2), o que não seria esperado. No entanto,
pode-se dizer que o Claritin
®
por apresentar maior conteúdo iônico de Ca, F e PO
4
,
como mencionado, pode ter contribuído para algum ganho mineral, sendo
diminuído o efeito erosivo sobre o esmalte dental.
91
6 C
O N C L U S Õ E S
Com base na metodologia adotada e nos resultados obtidos, é lícito afirmar
que:
1- A maioria dos antibacterianos analisados apresenta alta
concentração de açucares, alta acidez titulável, baixo pH e alta
viscosidade, o que podem ser considerados fatores de risco para
cárie e erosão dentária.
2- A imersão de esmalte dental bovino em medicamentos ácidos e
controle (água deionizada) promoveu padrões erosivos em todos os
grupos, mais acentuado no desafio altamente erosivo e que pode ter
sido superesimado por ser bovino.
3- Embora a rugosidade tenha sido pouco afetada, a ciclagem de pH e
a imersão em medicamentos ácidos promoveram degradação
superficial das resinas compostas testadas, principalmente naquelas
com partículas de carga maiores.
92
R
E F E R Ê N C I A S
B
I B L I O G R Á F I C A S
Aliping-Mckenzie, M., R. W. Linden, et al. The effect of Coca-Cola and fruit juices on
the surface hardness of glass-ionomers and 'compomers'. J Oral Rehabil, v.31, n.11,
Nov, p.1046-52. 2004.
Amaechi, B. T. e S. M. Higham. Eroded enamel lesion remineralization by saliva as a
possible factor in the site-specificity of human dental erosion. Arch Oral Biol, v.46,
n.8, Aug, p.697-703. 2001.
Amaechi, B. T., S. M. Higham, et al. Factors influencing the development of dental
erosion in vitro: enamel type, temperature and exposure time. J Oral Rehabil, v.26,
n.8, Aug, p.624-30. 1999a.
Amaechi, B. T., S. M. Higham, et al. Techniques for the production of dental eroded
lesions in vitro. J Oral Rehabil, v.26, n.2, Feb, p.97-102. 1999b.
Asmussen, E. Softening of BISGMA-based polymers by ethanol and by organic acids
of plaque. Scand J Dent Res, v.92, n.3, Jun, p.257-61. 1984.
Association of Official Analytical Chemist. Official methods of analysis. Sugars and
Sugar Products. In: (Ed.), 1966. Association of Official Analytical Chemist. Official
methods of analysis. Sugars and Sugar Products, p.40
Babu, K. L., K. Rai, et al. Pediatric liquid medicaments--do they erode the teeth
surface? An in vitro study: part I. J Clin Pediatr Dent, v.32, n.3, Spring, p.189-94.
2008.
Bagheri, R., M. J. Tyas, et al. Subsurface degradation of resin-based composites.
Dent Mater, v.23, n.8, Aug, p.944-51. 2007.
Benderli, Y., K. Gokce, et al. Effect of APF gel on micromorphology of resin modified
glass-ionomer cements and flowable compomers. J Oral Rehabil, v.32, n.9, Sep,
p.669-75. 2005.
Bevenius, J. e P. L'estrange. Chairside evaluation of salivary parameters in patients
with tooth surface loss: a pilot study. Aust Dent J, v.35, n.3, Jun, p.219-21. 1990.
Bigeard, L. The role of medication and sugars in pediatric dental patients. Dent Clin
North Am, v.44, n.3, Jul, p.443-56. 2000.
Bowen, W. H. Do we need to be concerned about dental caries in the coming
millennium? Crit Rev Oral Biol Med, v.13, n.2, p.126-31. 2002.
Brasil. Ministério da Saúde, Agência Nacional de Vigilância Sanitária. Lista de
medicamentos de referência [Ministry oh Health, National Surveillance Agency. List
93
of reference medicines] 06/18/2007. Available at
http://www.anvisa.gov.br/medicamentos/referencia/lista.pdf. 2007.
Cairns, A. M., M. Watson, et al. The pH and titratable acidity of a range of diluting
drinks and their potential effect on dental erosion. J Dent, v.30, n.7-8, Sep-Nov,
p.313-7. 2002.
Campus, G., G. Sacco, et al. Changing trend of caries from 1989 to 2004 among 12-
year old Sardinian children. BMC Public Health, v.7, p.28. 2007.
Chadwick, R. G., J. F. Mccabe, et al. The effect of storage media upon the surface
microhardness and abrasion resistance of three composites. Dent Mater, v.6, n.2,
Apr, p.123-8. 1990.
Collys, K., R. Cleymaet, et al. Rehardening of surface softened and surface etched
enamel in vitro and by intraoral exposure. Caries Res, v.27, n.1, p.15-20. 1993.
Costa, C. C., I. C. Almeida, et al. Erosive effect of an antihistamine-containing syrup
on primary enamel and its reduction by fluoride dentifrice. Int J Paediatr Dent, v.16,
n.3, May, p.174-80. 2006.
Da Costa, C. C., I. C. Almeida, et al. Morphology evaluation of primary enamel
exposed to antihistamine and fluoride dentifrice--an in vitro study. Gen Dent, v.54,
n.1, Jan-Feb, p.21-7. 2006.
Da Silva, R. C. e A. C. Zuanon. Surface roughness of glass ionomer cements
indicated for atraumatic restorative treatment (ART). Braz Dent J, v.17, n.2, p.106-9.
2006.
Damato, F. A., R. Strang, et al. Effect of fluoride concentration on remineralization of
carious enamel: an in vitro pH-cycling study. Caries Res, v.24, n.3, p.174-80. 1990.
Davidson, C. L., G. Boom, et al. Calcium distribution in human and bovine surface
enamel. Caries Res, v.7, n.4, p.349-59. 1973.
De Witte, A. M., E. A. De Maeyer, et al. Surface roughening of glass ionomer
cements by neutral NaF solutions. Biomaterials, v.24, n.11, May, p.1995-2000. 2003.
Durward, C. e T. Thou. Dental caries and sugar-containing liquid medicines for
children in New Zealand. N Z Dent J, v.93, n.414, Dec, p.124-9. 1997.
Edwards, M., S. L. Creanor, et al. Buffering capacities of soft drinks: the potential
influence on dental erosion. J Oral Rehabil, v.26, n.12, Dec, p.923-7. 1999.
Featherstone, J. D. e J. R. Mellberg. Relative rates of progress of artificial carious
lesions in bovine, ovine and human enamel. Caries Res, v.15, n.1, p.109-14. 1981.
Featherstone, J. D. e B. E. Rodgers. Effect of acetic, lactic and other organic acids
on the formation of artificial carious lesions. Caries Res, v.15, n.5, p.377-85. 1981.
94
Feigal, R. J., M. E. Jensen, et al. Dental caries potential of liquid medications.
Pediatrics, v.68, n.3, Sep, p.416-9. 1981.
Finke, M., K. D. Jandt, et al. The Early Stages of Native Enamel Dissolution Studied
with Atomic Force Microscopy. J Colloid Interface Sci, v.232, n.1, Dec 1, p.156-164.
2000.
Fiske, C. M. e Y. Subbarow. The colorimetric determination of phosphorus. . J. Biol
Chem, v.66, n.2, p.375-400. 1925.
Gao, F., S. Matsuya, et al. Erosion process of light-cured and conventional glass
ionomer cements in citrate buffer solution. Dent Mater J, v.16, n.2, Dec, p.170-9.
1997.
Grenby, T. H., A. Phillips, et al. Laboratory studies of the dental properties of soft
drinks. Br J Nutr, v.62, n.2, Sep, p.451-64. 1989.
Grobler, S. R., G. N. Jenkins, et al. The effects of the composition and method of
drinking of soft drinks on plaque pH. Br Dent J, v.158, n.8, Apr 20, p.293-6. 1985.
Hannig, M. e M. Balz. Influence of in vivo formed salivary pellicle on enamel erosion.
Caries Res, v.33, n.5, Sep-Oct, p.372-9. 1999.
Hellwig, E. e A. Lussi. Oral hygiene products and acidic medicines. Monogr Oral Sci,
v.20, p.112-8. 2006.
Hobson, P. Sugar based medicines and dental disease. Community Dent Health, v.2,
n.1, Mar, p.57-62. 1985.
Hooper, S., N. X. West, et al. Investigation of erosion and abrasion on enamel and
dentine: a model in situ using toothpastes of different abrasivity. J Clin Periodontol,
v.30, n.9, Sep, p.802-8. 2003.
Hughes, J. A., N. X. West, et al. Development and evaluation of a low erosive
blackcurrant juice drink. 3. Final drink and concentrate, formulae comparisons in situ
and overview of the concept. J Dent, v.27, n.5, Jul, p.345-50. 1999.
Hughes, J. A., N. X. West, et al. Effects of pH and concentration of citric, malic and
lactic acids on enamel, in vitro. J Dent, v.28, n.2, Feb, p.147-52. 2000.
Hunter, M. L., N. X. West, et al. Relative susceptibility of deciduous and permanent
dental hard tissues to erosion by a low pH fruit drink in vitro. J Dent, v.28, n.4, May,
p.265-70. 2000.
Imfeld, T. Dental erosion. Definition, classification and links. Eur J Oral Sci, v.104, n.2
( Pt 2), Apr, p.151-5. 1996.
95
"Inactive" ingredients in pharmaceutical products: update (subject review). American
Academy of Pediatrics Committee on Drugs. Pediatrics, v.99, n.2, Feb, p.268-78.
1997.
Ireland, A. J., N. Mcguinness, et al. An investigation into the ability of soft drinks to
adhere to enamel. Caries Res, v.29, n.6, p.470-6. 1995.
Jaeggi, T., A. Gruninger, et al. Restorative therapy of erosion. Monogr Oral Sci, v.20,
p.200-14. 2006.
Jarvinen, V. K., Rytomaa, Ii, et al. Risk factors in dental erosion. J Dent Res, v.70,
n.6, Jun, p.942-7. 1991.
Jensdottir, T., A. Bardow, et al. Properties and modification of soft drinks in relation to
their erosive potential in vitro. J Dent, v.33, n.7, Aug, p.569-75. 2005.
Johansson, A. K., R. Sorvari, et al. Dental erosion in deciduous teeth--an in vivo and
in vitro study. J Dent, v.29, n.5, Jul, p.333-40. 2001.
Kalachandra, S., D. F. Taylor, et al. Structure- property relationships in dental
composites based on polydimethacrylates. Polymer Prepr, v.38, p.94-5. 1997.
Karjalainen, S., M. Rekola, et al. Long-term effects of syrup medications for recurrent
otitis media on the dental health of 6- to 8-year-old children. Caries Res, v.26, n.4,
p.310-4. 1992.
Kenny, D. J. e P. Somaya. Sugar load of oral liquid medications on chronically ill
children. J Can Dent Assoc, v.55, n.1, Jan, p.43-6. 1989.
Knewitz, J. L. e C. L. Drisko. Anorexia nervosa and bulimia: a review. Compendium,
v.9, n.3, Mar, p.244-7. 1988.
Lammers, P. C., J. M. Borggreven, et al. Acid-susceptibility of lesions in bovine
enamel after remineralization at different pH values and in the presence of different
fluoride concentrations. J Dent Res, v.70, n.12, Dec, p.1486-90. 1991.
Larsen, M. J. Degrees of saturation with respect to apatites in fruit juices and acidic
drinks. Scand J Dent Res, v.83, n.1, Jan, p.13-7. 1975.
Larsen, M. J. e B. Nyvad. Enamel erosion by some soft drinks and orange juices
relative to their pH, buffering effect and contents of calcium phosphate. Caries Res,
v.33, n.1, p.81-7. 1999.
Lima, K. T., I. C. S. Almeida, et al. Sweeteners and endogenous pH of pediatric
medicines [Abstract B-110]. J Dent Res, v.79, p.1130. 2000.
Linnett, V. e W. K. Seow. Dental erosion in children: a literature review. Pediatr Dent,
v.23, n.1, Jan-Feb, p.37-43. 2001.
96
Lins, M. E., M. S. C. Lobo, et al. The use of Data Envelopment Analysis (DEA) for
Brazilian teaching hospitals´ evaluation. Ciência & Saúde Coletiva, v.12, n.4, p.985-
998. 2007
Lokken, P., J. M. Birkeland, et al. pH changes in dental plaque caused by
sweetened, iron-containing liquid medicine. Scand J Dent Res, v.83, n.5, Sep, p.279-
83. 1975.
Lussi, A. e T. Jaeggi. Chemical factors. Monogr Oral Sci, v.20, p.77-87. 2006.
Lussi, A., T. Jaeggi, et al. Prediction of the erosive potential of some beverages.
Caries Res, v.29, n.5, p.349-54. 1995.
Lussi, A., T. Jaeggi, et al. The role of diet in the aetiology of dental erosion. Caries
Res, v.38 Suppl 1, p.34-44. 2004.
Lussi, A., T. Jaggi, et al. The influence of different factors on in vitro enamel erosion.
Caries Res, v.27, n.5, p.387-93. 1993.
Mackie, I. C. e E. Bentley. Sugar-containing or sugar-free paediatric medicines: does
it really matter? Dent Update, v.21, n.5, Jun, p.192-4. 1994.
Mackie, I. C., H. V. Worthington, et al. Paediatric sugar-free medicines-stock and
recommendations. Pharmaceutical Journal v.248, n.6686, p.621-622. 1992.
Mackie, I. C., H. V. Worthington, et al. An investigation into sugar-containing and
sugar-free over-the-counter medicines stocked and recommended by pharmacists in
the north western region of England. Br Dent J, v.175, n.3, Aug 7, p.93-8. 1993.
Magalhaes, A. C., D. Rios, et al. Effect of 4% titanium tetrafluoride solution on dental
erosion by a soft drink: an in situ/ex vivo study. Arch Oral Biol, v.53, n.5, May, p.399-
404. 2008.
Maguire, A. e W. Baqir. Prevalence of long-term use of medicines with prolonged oral
clearance in the elderly: a survey in north east England. Br Dent J, v.189, n.5, Sep 9,
p.267-72. 2000.
Maguire, A., W. Baqir, et al. Are sugars-free medicines more erosive than sugars-
containing medicines? An in vitro study of paediatric medicines with prolonged oral
clearance used regularly and long-term by children. Int J Paediatr Dent, v.17, n.4, Jul,
p.231-8. 2007.
Maguire, A. e A. J. Rugg-Gunn. Prevalence of long-term use of liquid oral medicines
by children in the northern region, England. Community Dent Health, v.11, n.2, Jun,
p.91-6. 1994.
Maguire, A., A. J. Rugg-Gunn, et al. Dental health of children taking antimicrobial and
non-antimicrobial liquid oral medication long-term. Caries Res, v.30, n.1, p.16-21.
1996.
97
Mair, L. H., T. A. Stolarski, et al. Wear: mechanisms, manifestations and
measurement. Report of a workshop. J Dent, v.24, n.1-2, Jan-Mar, p.141-8. 1996.
Mannerberg, F. Saliva factors in cases of erosion. Odontol Revy, v.14, p.155-166.
1963.
Maupome, G., J. Diez-De-Bonilla, et al. In vitro quantitative assessment of enamel
microhardness after exposure to eroding immersion in a cola drink. Caries Res, v.32,
n.2, p.148-53. 1998.
Mcnally, L. M., M. E. Barbour, et al. An in vitro investigation of the effect of some
analgesics on human enamel. J Oral Rehabil, v.33, n.7, Jul, p.529-32. 2006.
Meurman, J. H. e R. M. Frank. Progression and surface ultrastructure of in vitro
caused erosive lesions in human and bovine enamel. Caries Res, v.25, n.2, p.81-7.
1991a.
Meurman, J. H. e R. M. Frank. Scanning electron microscopic study of the effect of
salivary pellicle on enamel erosion. Caries Res, v.25, n.1, p.1-6. 1991b.
Meurman, J. H. e J. M. Ten Cate. Pathogenesis and modifying factors of dental
erosion. Eur J Oral Sci, v.104, n.2 ( Pt 2), Apr, p.199-206. 1996.
Milosevic, A. Sports drinks hazard to teeth. Br J Sports Med, v.31, n.1, Mar, p.28-30.
1997.
Moss, S. J. Dental erosion. Int Dent J, v.48, n.6, Dec, p.529-39. 1998.
Muhlemann, H. R., H. Lenz, et al. Electron Microscopy appearance of rehardened
enamel. Helv Odontol Acta, v.8, p.108-111. 1964.
Neiva, A., V. S. Silva, et al. Análise in vitro da concentração de sacarose e pH de
antibacterianos de uso pediátrico. Pesquisa Brasileira em Odontopediatria e Clínica
Integrada, v.1, p.9-16. 2001.
Nekrashevych, Y. e L. Stosser. Protective influence of experimentally formed salivary
pellicle on enamel erosion. An in vitro study. Caries Res, v.37, n.3, May-Jun, p.225-
31. 2003.
Neves, B. G. Avaliação dos fatores relacionados ao potencial cariogênico e erosivo
de medicamentos líquidos infantis. Departamento de Odontopediatria e Ortodontia,
Universidade Federal do Rio de Janeiro, Rio de Janeiro, 2006. 99 p.
Neves, B. G., A. Farah, et al. Are paediatric medicines risk factors for dental caries
and dental erosion? Community Dent Health, v.in press. 2009.
Neves, B. G., V. S. Pierro, et al. Perceptions and attitudes among parents and
guardians on the use of pediatric medicines and their cariogenic and erosive
potential. Cien Saude Colet, v.12, n.5, Sep-Oct, p.1295-300. 2007.
98
Neves, B. G., V. S. Pierro, et al. Pediatricians' perceptions of the use of sweetened
medications related to oral health. J Clin Pediatr Dent, v.32, n.2, Winter, p.133-7.
2008.
Newbrun, E. Sucrose, the arch criminal of dental caries. Odontol Revy, v.18, n.4,
p.373-86. 1967.
Nicholson, J. W., B. J. Millar, et al. Storage of polyacid-modified resin composites
("compomers") in lactic acid solution. Dent Mater, v.15, n.6, Nov, p.413-6. 1999.
Nunn, J. H., P. H. Gordon, et al. Dental erosion -- changing prevalence? A review of
British National childrens' surveys. Int J Paediatr Dent, v.13, n.2, Mar, p.98-105.
2003.
Nunn, J. H., S. K. Ng, et al. The dental implications of chronic use of acidic medicines
in medically compromised children. Pharm World Sci, v.23, n.3, Jun, p.118-9. 2001.
Oilo, G. Biodegradation of dental composites/glass-ionomer cements. Adv Dent Res,
v.6, Sep, p.50-4. 1992.
Paunio, P., P. Rautava, et al. The Finnish Family Competence Study: the relationship
between caries, dental health habits and general health in 3-year-old Finnish
children. Caries Res, v.27, n.2, p.154-60. 1993.
Peutzfeldt, A. Resin composites in dentistry: the monomer systems. Eur J Oral Sci,
v.105, n.2, Apr, p.97-116. 1997.
Pierro, V. S., J. P. Abdelnur, et al. Free sugar concentration and pH of paediatric
medicines in Brazil. Community Dent Health, v.22, n.3, Sep, p.180-3. 2005.
Pierro, V. S. S., L. C. Maia, et al. Effect of pediatric syrups on roughness and erosion
of enamel. IADR 82nd General Session & Exhibition. Honolulu, 2004. 0896-0896 p.
Prakki, A., R. Cilli, et al. Influence of pH environment on polymer based dental
material properties. J Dent, v.33, n.2, Feb, p.91-8. 2005.
Rekola, M. In vivo acid production from medicines in syrup form. Caries Res, v.23,
n.6, p.412-6. 1989.
Rios, D., H. M. Honorio, et al. Influence of toothbrushing on enamel softening and
abrasive wear of eroded bovine enamel: an in situ study. Braz Oral Res, v.20, n.2,
Apr-Jun, p.148-54. 2006.
Rios, D., H. M. Honorio, et al. Effect of salivary stimulation on erosion of human and
bovine enamel subjected or not to subsequent abrasion: an in situ/ex vivo study.
Caries Res, v.40, n.3, p.218-23. 2006.
Rugg-Gunn, A. J., A. Maguire, et al. Comparison of erosion of dental enamel by four
drinks using an intra-oral applicance. Caries Res, v.32, n.5, p.337-43. 1998.
99
Ruyter, I. E. Physical and chemical aspects related to substances released from
polymer materials in an aqueous environment. Adv Dent Res, v.9, p.344-7. 1995.
Rytomaa, I., J. H. Meurman, et al. In vitro erosion of bovine enamel caused by acidic
drinks and other foodstuffs. Scand J Dent Res, v.96, n.4, Aug, p.324-33. 1988.
Shaw, L. e H. D. Glenwright. The role of medications in dental caries formation: need
for sugar-free medication for children. Pediatrician, v.16, n.3-4, p.153-5. 1989.
Sideridou, I., V. Tserki, et al. Effect of chemical structure on degree of conversion in
light-cured dimethacrylate-based dental resins. Biomaterials, v.23, n.8, Apr, p.1819-
29. 2002.
Sidhu, S. K., M. Sherriff, et al. In vivo changes in roughness of resin-modified glass
ionomer materials. Dent Mater, v.13, n.3, May, p.208-13. 1997.
Soderholm, K. J., R. Mukherjee, et al. Filler leachability of composites stored in
distilled water or artificial saliva. J Dent Res, v.75, n.9, Sep, p.1692-9. 1996.
Soderholm, K. J., M. Zigan, et al. Hydrolytic degradation of dental composites. J Dent
Res, v.63, n.10, Oct, p.1248-54. 1984.
Sorvari, R. e I. Rytomaa. Drinks and dental health. Proc Finn Dent Soc, v.87, n.4,
p.621-31. 1991.
Tanaka, M. e Y. Kadoma. Comparative reduction of enamel demineralization by
calcium and phosphate in vitro. Caries Res, v.34, n.3, May-Jun, p.241-5. 2000.
Ten Cate, J. M. e T. Imfeld. Dental erosion, summary. Eur J Oral Sci, v.104, n.2 ( Pt
2), Apr, p.241-4. 1996.
Trugo, L. C., A. Farah, et al. Oligosaccharide distribution in Brazilian soya bean
cultivates. Food Chemistry, v.52, p.385-387. 1995.
Turssi, C. P., C. S. De Magalhaes, et al. Effect of fluoride gels on micromorphology of
resin-modified glass-ionomer cements and polyacid-modified resin composites.
Quintessence Int, v.32, n.7, Jul-Aug, p.571-7. 2001.
Turssi, C. P., A. T. Hara, et al. Effect of storage media upon the surface
micromorphology of resin-based restorative materials. J Oral Rehabil, v.29, n.9, Sep,
p.864-71. 2002.
Valinoti, A. C., A. Farah, et al. Are pediatric antibiotics risk factors for dental caries
and erosion? IADR 87th General Session. Miami: Journal of Dental Research, 2009.
p.
Valinoti, A. C., B. G. Neves, et al. Surface degradation of composite resins by acidic
medicines and pH-cycling. J Appl Oral Sci, v.16, n.4, Aug, p.257-65. 2008.
100
West, N. X., J. A. Hughes, et al. Erosion of dentine and enamel in vitro by dietary
acids: the effect of temperature, acid character, concentration and exposure time. J
Oral Rehabil, v.27, n.10, Oct, p.875-80. 2000.
West, N. X., J. A. Hughes, et al. Development and evaluation of a low erosive
blackcurrant juice drink. 2. Comparison with a conventional blackcurrant juice drink
and orange juice. J Dent, v.27, n.5, Jul, p.341-4. 1999.
White, D. J. Reactivity of fluoride dentifrices with artificial caries. I. Effects on early
lesions: F uptake, surface hardening and remineralization. Caries Res, v.21, n.2,
p.126-40. 1987.
Wongkhantee, S., V. Patanapiradej, et al. Effect of acidic food and drinks on surface
hardness of enamel, dentine, and tooth-coloured filling materials. J Dent, v.34, n.3,
Mar, p.214-20. 2006.
Livros Grátis
( http://www.livrosgratis.com.br )
Milhares de Livros para Download:
Baixar livros de Administração
Baixar livros de Agronomia
Baixar livros de Arquitetura
Baixar livros de Artes
Baixar livros de Astronomia
Baixar livros de Biologia Geral
Baixar livros de Ciência da Computação
Baixar livros de Ciência da Informação
Baixar livros de Ciência Política
Baixar livros de Ciências da Saúde
Baixar livros de Comunicação
Baixar livros do Conselho Nacional de Educação - CNE
Baixar livros de Defesa civil
Baixar livros de Direito
Baixar livros de Direitos humanos
Baixar livros de Economia
Baixar livros de Economia Doméstica
Baixar livros de Educação
Baixar livros de Educação - Trânsito
Baixar livros de Educação Física
Baixar livros de Engenharia Aeroespacial
Baixar livros de Farmácia
Baixar livros de Filosofia
Baixar livros de Física
Baixar livros de Geociências
Baixar livros de Geografia
Baixar livros de História
Baixar livros de Línguas
Baixar livros de Literatura
Baixar livros de Literatura de Cordel
Baixar livros de Literatura Infantil
Baixar livros de Matemática
Baixar livros de Medicina
Baixar livros de Medicina Veterinária
Baixar livros de Meio Ambiente
Baixar livros de Meteorologia
Baixar Monografias e TCC
Baixar livros Multidisciplinar
Baixar livros de Música
Baixar livros de Psicologia
Baixar livros de Química
Baixar livros de Saúde Coletiva
Baixar livros de Serviço Social
Baixar livros de Sociologia
Baixar livros de Teologia
Baixar livros de Trabalho
Baixar livros de Turismo