Faculdade de Odontologia de Piracicaba
Flávia Riqueto Gambareli Cirurgiã-dentista
“FUNÇÃO MASTIGATÓRIA EM CRIANÇAS APÓS A REABILITAÇÃO PROTÉTICA REMOVÍVEL BUCAL”
Dissertação apresentada à Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas como requisito para a obtenção do título de Mestre em Odontologia, Área de Odontopediatria.
Piracicaba 2006
Flávia Riqueto Gambareli Cirurgiã-dentista
“FUNÇÃO MASTIGATÓRIA EM CRIANÇAS APÓS A REABILITAÇÃO PROTÉTICA REMOVÍVEL BUCAL”
Dissertação apresentada à Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas como requisito para a obtenção do título de Mestre em Odontologia, Área de Odontopediatria.
Orientador: Profa. Dra. Maria Beatriz Duarte Gavião.
Banca examinadora:
Profa. Dra. Maria Beatriz Duarte Gavião. Prof. Dr. Francisco de Assis Mollo Junior. Prof. Dra. Regina Célia Rocha Peres.
Piracicaba 2006
FICHA CATALOGRÁFICA ELABORADA PELA
BIBLIOTECA DA FACULDADE DE ODONTOLOGIA DE PIRACICABA
Bibliotecário: Marilene Girello – CRB-8a. / 6159
G141f
Gambareli, Flávia Riqueto.
Função mastigatória em crianças após a reabilitação protética
removível bucal. / Flávia Riqueto Gambareli. -- Piracicaba, SP : [s.n.], 2006.
Orientador: Maria Beatriz Duarte Gavião
Dissertação (Mestrado) – Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba.
1. Eletromiografia. 2. Crianças. 3. Dentição mista. 4. Prótese dentária parcial removível. I. Gavião, Maria Beatriz Duarte. II. Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba. III. Título.
(mg/fop)
Título em inglês: Masticatory function in children after oral rehabilitation
Palavras-chave em inglês (Keywords): 1. Electromyography. 2. Children. 3. Dentition, mixed. 4. Denture, partial, removable
Área de concentração: Odontopediatria Titulação: Mestre em Odontologia
Banca examinadora: Maria Beatriz Duarte Gavião, Francisco de Assis Mollo Junior, Regina Célia Rocha Peres
Dedico este trabalho a meus pais Lázaro e Cida, que sempre me apoiaram em todos os momentos de minha vida, sonhando e lutando ao meu lado para que pudéssemos conquistar mais uma vitória, me dando forças para que não desistisse daquilo que eu queria e sabia ser melhor para mim.
Ainda lhes agradeço por compreenderem que não fui tão atenciosa e não estive presente nestes anos, em decorrência do muito que me foi pedido por conta de minhas escolhas acadêmicas e profissionais.
Agradeço a Deus pela vida e todas as possibilidades de crescimento e evolução pessoal.
À Universidade Estadual de Campinas, nas pessoas do Magnífico Reitor Prof. Dr. José Tadeu Jorge e vice-reitor Prof. Dr. Fernando Ferreira Costa.
À Direção da Faculdade de Odontologia de Piracicaba, da Universidade de Campinas, nas pessoas do Diretor Prof. Dr. Thales Rocha de Matos Filho e Diretor associado, Prof. Dr. Mário Fernando de Góes.
Ao Prof. Dr. Pedro Luiz Rosalen, coordenador geral dos cursos de Pós-Graduação.
Ao Prof. Dr. Francisco Groppo, coordenador do Programa de Pós-Graduação em Odontologia.
À Profa. Dra. Regina Maria Puppin Rontani, coordenadora da Área de Odontopediatria, pelo equilíbrio entre profissionalismo e amizade.
À Profa. Dra. Cecília Gatti Guirado, pelo carinho que sempre extrapolou as “frias” relações acadêmicas, mantendo seus braços amigos estendidos a todas as alunas da pós-graduação.
À Profa. Dra. Marinês Nobre dos Santos Uchôa, que com sua perspicácia nos ajudou a reforçar nossos critérios metodológicos e acadêmicos.
Aos Profs. Drs. Paulo Henrique F. Caria, Érico Barbosa Lima e Cecília Gatti Guirado pela significante contribuição apresentada na qualificação desta dissertação.
Aos professores do curso de Pós-Graduação em Odontologia, da Faculdade de Odontologia de Piracicaba, pelos ensinamentos recebidos.
À Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) pela bolsa de estudo concedida, pedra fundamental.
Às amigas do Mestrado da Área de Odontopediatria, Carolina Steiner Oliveira, Fernanda Miori Pascon, Kamila Rosamilia Kantovitz, Karlla Almeida Vieira, Márcia Diaz Serra e Milena Schaaf Teixeira. Obrigada pelo convívio amistoso e sincero, que tantas alegrias me trouxeram. Vocês foram importantes neste período para que percebesse o valor da amizade e companheirismo.
Agradeço em especial à Márcia Diaz Serra, com quem dividi o dia-a-dia desta pesquisa numa constante troca de conhecimentos e experiências, de modo que não apenas obtivemos dados juntas, mas dividimos todas as alegrias, conquistas e aflições, que se estendiam do laboratório à casa que dividimos estes anos.
Agradeço ainda aos meus amigos Luciano José Pereira, Leonardo Rigoldi Bonjardim e Paula Midori Castelo, alunos do doutorado que me ensinaram um pouco do que já tinham aprendido e também me proporcionaram um convívio agradável.
ajuda imprescindível.
Ás secretárias Maria Elisa dos Santos, Eliane Melo Franco, Marcela Cristina de Souza e Maria de Lourdes Gaspar Correa pela eficiente ajuda, e amabilidade com que trata todos os alunos.
Ao Marcelo Corrêa Maistro pela importante ajuda no laboratório de Odontopediatria.
Às crianças que participaram dessa pesquisa e seus respectivos responsáveis. Para nós foram mais que voluntários; foram alvo de nossos carinhos e preocupações ao longo deste período. Sem esta colaboração não seria possível a realização deste trabalho.
Ao Luís Fernando Batistella Spínola, por toda a experiência profissional transmitida, pelo incentivo ao estudo contínuo e por todo o apoio e compreensão durante esses anos. Você é uma pessoa incrível.
Ao Vagner da Silva, por toda colaboração e torcida nesses últimos meses que me ajudaram a superar momentos difíceis. Sua dedicação tem sido muito importante para mim.
A todos os demais amigos, que se não agradeço nominalmente, levo-os em meu coração. Como meus amigos da graduação da FOP, de minha e de outras turmas; meus amigos de Campinas, que sempre estiveram presentes e os companheiros de profissão de Vinhedo, que sempre me alegraram para que meus dias se encerrassem bem.
irmão Rodrigo e minha irmã Fernanda, não somente pelo apoio para o desenvolvimento deste trabalho, mas em todos os momentos, alegres e tristes. A ajuda e incentivo de vocês foram de grande importância para mim, pois nunca foi fácil estar longe de casa sem tal amor e amizade.
Agradeço em especial a Profa. Dra. Maria Beatriz Duarte Gavião, minha orientadora, pela possibilidade que me foi dada de realizar o curso de Mestrado, acontecimento de grande importância em minha formação profissional e acadêmica.
Agradeço ainda pelo acompanhamento constante no desenvolvimento deste trabalho, orientando-me em todos os momentos, transmitindo conhecimentos de valor não apenas acadêmicos, mas humanos. E também por sua prontidão, em sempre nos socorrer quando surgiam dificuldades.
“Tudo o que sabemos hoje aprendemos com os acertos e erros do passado, e cada vez que desistimos de alguma coisa por medo de errar estamos nos privando da possibilidade de evoluir e viver.”
RESUMO... 1 ABSTRACT ... 3 I - INTRODUÇÃO GERAL ... 5 II – PROPOSIÇÃO ... 9 III – CAPÍTULOS ... 11 CAPÍTULO 1 ... 13
Influence of measurement technique, test food, teeth and muscle force interactions in masticatory performance evaluation ... 13
CAPÍTULO 2 ... 33
Masticatory performance before and after oral rehabilitation in children ... 33
CAPÍTULO 3 ... 57
The influence of oral rehabilitation on muscle activity and chewing behavior in partially edentulous children... 57
IV – CONCLUSÃO GERAL ... 83 V – REFERÊNCIAS... 85 ANEXO 1... 89 ANEXO 2... 90 ANEXO 3... 91 ANEXO 4... 96
RESUMO
O objetivo deste trabalho foi avaliar a performance mastigatória, a atividade eletromiográfica dos músculos masseter e porção anterior do temporal e a mastigação de alimentos de diferentes consistências em crianças na fase de dentição mista, com perda precoce de dentes decíduos posteriores, antes e após reabilitação protética. Para tanto, o estudo foi composto por três capítulos. No capítulo 1, intitulado Influence of measurement technique, test food, teeth and
muscle force interactions in masticatory performance evaluation, realizou-se a
revisão de literatura sobre performance mastigatória e discorreu-se sobre as variáveis influenciadoras. A revisão mostrou que a performance mastigatória tem sido amplamente avaliada e associada às variáveis morfológicas e funcionais do sistema mastigatório. No capítulo 2, intitulado Masticatory performance before and
after oral rehabilitation in children, avaliou-se a performance mastigatória com
alimento teste artificial. No capítulo 3, intitulado The influence of oral rehabilitation
on muscle activity and chewing behavior in partially edentulous children, avaliou-se
a atividade eletromiográfica dos músculos masseter e porção anterior do temporal e o comportamento mastigatório com alimentos de diferentes consistências. Avaliou-se também as variáveis corporais, peso e altura em ambos os capítulos. A performance mastigatória foi avaliada através da mastigação de um material à base de silicona, utilizando o sistema de peneiragem fragmentada para determinar o tamanho das partículas após mastigação. Para o registro eletromiográfico, foram utilizados o sistema de aquisição de sinais (EMG System do Brasil Ltda.) e o software Aqdados – versão 5.0 da Lynx Eletrônica Ltda. O sinal eletromiográfico foi captado em contração voluntária máxima bilateral tendo o material Parafilm entre os molares e em mastigação habitual com alimento teste artificial. Os alimentos utilizados para avaliação da mastigação foram: goma de mascar (Trident tutti fruit, Adams), cenoura crua, queijo polenghi, banana nanica, torrada industrializada.Na análise dos dados do segundo e terceiro capítulos utilizou-se o
teste de Shapiro-Wilk para verificação da normalidade da distribuição dos dados. Os Testes t pareado, Wilcoxon, Kruskal-Wallis e post hoc Dun, Correlação de Pearson e Spearman e regressão linear foram aplicados quando indicados, com nível de significância de 5%. Os resultados mostraram que não houve diferença estatística entre os sexos para nenhuma das variáveis (p>0.05). Houve um decréscimo significativo para o tamanho da partícula mediana antes e após 6 meses da instalação do aparelho protético (p<0,001). A atividade muscular foi significativamente maior na segunda avaliação durante a mastigação do alimento artificial (p<0,05). Considerando as variáveis corporais, houve correlação negativa significativa entre performance mastigatória, altura e peso na primeira sessão de exames (p<0,05), e não houve correspondentes correlações na segunda sessão de exames (p>0,05). Houve diferenças significativas no número de ciclos mastigatórios até a deglutição, duração da mastigação e a quantidade de alimento ingerida tanto para os alimentos duros quanto macios nas duas avaliações. A prótese parcial removível influenciou os aspectos funcionais dos músculos, determinando melhora da eficiência mastigatória e aumento da atividade muscular.
Palavras-chave: criança, dentição mista, prótese parcial removível, performance mastigatória, comportamento mastigatório, eletromiografia.
ABSTRACT
The aim of this study was to evaluate the masticatory performance, the electromyographic activity of the masseter and temporal anterior muscles and the chewing of foods of different consistency in children in the phase of mixed dentition, with early loss of posterior deciduous teeth, before and six months after oral rehabilitation with removable dental prosthesis. Three chapters compose the study. In chapter 1, entitled Influence of measurement technique, test food, teeth
and muscle force interactions in masticatory performance evaluation, a review of
the pertinent literature about masticatory performance was done, and the influencing variables were discussed. The review showed that masticatory performance has been widely evaluated and associated to the morphological and functional variables of the masticatory system. The second chapter entitled
Masticatory performance before and after oral rehabilitation in children evaluated
the masticatory efficiency with artificial test food. The third chapter entitled The
influence of oral rehabilitation on muscle activity and chewing behavior in partially edentulous children evaluated the electromyographic activities of the masseter and
temporal anterior muscles and the chewing of foods of different consistency. Also, it was evaluated the body variables, weight and height, in these two chapters. The masticatory performance was evaluated by the mastication of a silicone impression material, using the fragmented sieving system to determine the size of the chewed particles. For the electromyographic record, were used the system of acquisition of signs (EMG System of Brazil Ltd.) and software Aqdados-version 5.0 of Lynx Eletrônica Ltd. The electromyographic sign was captured in maximum bilateral voluntary contraction having the Parafilm material among the molars and in habitual mastication with artificial tests food. The foods for the chewing evaluation were: chewing gum raw carrot, polenghi cheese, banana and industrialized toast. For data analysis in the second and the third chapters, the normality of the distributions was assessed by the Shapiro-Wilks W-test. The t paired tests,
Wilcoxon, Kruskal-Wallis and pos hoc Dun, Pearson’s or Spearman’s Correlations and linear regression were applied as indicated, with significance level of 5%. The results showed no statistical differences between genders for any of the variables (p>0.05). There was a significant decrease in the median particle size from first to second evaluation (p=0.000). The muscle activity was significantly greater on the second evaluation during the chewing of the artificial food (p<0.05). Considering the body variables, there was a significant negative correlation between masticatory efficiency, body height and weight in the first session of exams. After 6 months of the placement of the prosthesis no significant correlations were found for these variables (p<0.05). It was observed significant differences in number of cycles until swallowing, chewing duration and amount of food ingested for the soft and hard foods, at the two evaluations. Within the limitations of this study, it can be concluded that the removable dental prosthesis influenced the function of the muscles, determining an increase in the masticatory efficiency and an increasing in the muscle activity. It was considered that the body alterations could have been consequences of the enhancement in the masticatory function determined by the oral rehabilitation.
Key words: children, mixed dentition, removable dental prosthesis, masticatory performance, chewing behavior, electromyography.
I - INTRODUÇÃO GERAL
A manutenção da integridade dos arcos dentários nas fases das dentições decídua e mista, tanto do ponto de vista morfológico quanto funcional, tem sido o objetivo da Odontopediatria, devido à influência exercida por tais aspectos no desenvolvimento da dentição permanente. Os padrões funcionais básicos da oclusão são estabelecidos antes da erupção dos dentes permanentes, fazendo com que estes primeiros estágios de desenvolvimento oclusal sejam de extrema importância (Thurow, 1977).
A mastigação tem como função a fragmentação dos alimentos para que ocorra a deglutição e digestão adequadas, proporcionando estímulo e função indispensáveis ao desenvolvimento normal da face. As condições da dentição como o número de dentes presentes, o número de dentes posteriores em contato, tamanho das áreas funcionais de contato, grau de maloclusão, influenciam a performance mastigatória (Omar et al., 1987; Wilding, 1993).
A avaliação da performance mastigatória consiste na mensuração do quão bem uma pessoa pode triturar o alimento e é quantificada pela tomada de uma amostra de alimento depois de ter sido mastigado sem ter ocorrido a deglutição. A performance mastigatória decresce com a perda dos dentes e em geral é menor nos pacientes com próteses totais (Slagter et al., 1993a). É interessante observar que quando as superfícies oclusais estão comprometidas, os pacientes não tendem a compensar mastigando mais, ao invés disso, deglutem partículas maiores (Omar et al., 1987; Wilding, 1993). O número de ciclos ou o tempo gasto na mastigação antes da deglutição voluntária pode ser o reflexo da performance do processo mastigatório, e a sua redução, associada à perda dentária é um dos fatores contribuintes para a escolha inadequada de alimentos, podendo resultar em alterações no estado nutricional (Postner, 1979, Wayler et al., 1984, Wilding, 1993). Usualmente indivíduos com perda extensa de dentes consomem preferencialmente alimentos macios, mais fáceis de mastigar, que nem sempre apresentam conteúdo nutritivo adequado (Chauncey et al., 1981). A manutenção
da performance mastigatória parece ser determinante crítico da habilidade individual para ingerir uma variedade de alimentos, que proporcione estado nutricional favorável (Wayler & Chauncey, 1983). Wilding (1993) considerou a performance mastigatória como a quebra do alimento com o mínimo de esforço e redução máxima do tamanho da partícula.
Para se avaliar a performance mastigatória, a natureza do material teste é de grande importância. Desde sua comprovação por Edlund & Lamm (1980), o Optosil® tem sido usado freqüentemente em pesquisas de avaliação da função mastigatória, uma vez que alimentos testes artificiais são preferidos aos naturais, devido suas propriedades físicas permitirem armazenamento por algumas semanas sem deformações relevantes, não se dissolver em água, entre outros fatores (Edlund & Lamm, 1980; Olthoff et al., 1984; Slagter et al., 1993b).
Em adultos, as ausências dentárias são normalmente substituídas por próteses fixas ou removíveis para melhorar a função mastigatória. van der Bilt et
al. (1994), buscando obter informações objetivas e subjetivas sobre a função
mastigatória em sujeitos parcialmente desdentados antes e depois da restauração protética, observaram que o número total de dentes posteriores em oclusão aumentava com a reabilitação protética, influenciando positivamente a função mastigatória no aspecto objetivo. A média da performance mastigatória subjetiva também apresentou melhora com a prótese. Entretanto, existem poucos estudos relacionando diretamente a influência do tratamento protético com a performance mastigatória. Em crianças poucos trabalhos avaliam o efeito da reabilitação bucal nos aspectos funcionais do sistema mastigatório, mas observou-se que mantenedores de espaço funcionais instalados precocemente no início da dentição mista, para substituição de elementos dentários extraídos precocemente, influenciaram positivamente o processo mastigatório (Jacinto-Gonçalves 2003)
A mastigação requer atividade muscular tanto para o movimento mandibular como para exercer a força necessária para cortar ou moer os alimentos. Durante a mastigação, diferentes músculos mastigatórios são recrutados, com variações na amplitude e nos momentos em que ocorre a
contração muscular (Bakke et al., 1993; Belser & Hannam, 1986; Blanksma & van Eijden, 1995). A amplitude da atividade eletromiográfica (EMG) depende da textura do alimento; maior atividade EMG é observada para alimentos mais duros (Ahlgren, 1966; Plesh et al., 1986; Horio & Kawamura, 1989; Slagter et al., 1993b). Aparentemente, uma pequena parte da atividade muscular observada durante a mastigação é necessária para os movimentos rítmicos básicos da mandíbula, e mais atividade muscular adicional é requerida para produzir a força necessária para que ocorra a mastigação.
A avaliação da atividade elétrica dos músculos mastigatórios vem se tornando cada vez mais útil ao clínico, contribuindo para o conhecimento do desempenho destes músculos na postura mandibular, nos movimentos dos reflexos reguladores e nas mudanças do padrão muscular. Portanto, a eletromiografia revela dados de quando e como um músculo é ativado e ainda permite determinar como se estabelece a ação de diferentes músculos envolvidos no movimento. A eletromiografia, na pesquisa clínica de várias especialidades, tem se constituído em um importante instrumento para a investigação das bases fisiológicas das alterações que acometem esta musculatura. Além disso, a eletromiografia representa atualmente, um meio não só de avaliação, como também de acompanhamento do tratamento (Tomé & Marchiori, 1999).
Baseado nos dados encontrados na literatura e devido aos escassos trabalhos publicados que abordam as variáveis que influenciam o processo mastigatório em crianças na dentição mista, torna-se de interesse o estudo do aspecto funcional da substituição de dentes decíduos precocemente perdidos por dentes artificiais na função mastigatória e, conseqüentemente, no desenvolvimento do sistema mastigatório, sendo que isso implica no conhecimento de valores normais e de fatores responsáveis pela sua variabilidade.
II – PROPOSIÇÃO
Os objetivos desse estudo foram:
- Revisar a literatura sobre a performance mastigatória e as variáveis influenciadoras;
- Verificar a influência da reabilitação bucal, por meio de prótese parcial removível temporária atuando como mantenedor de espaço funcional, sobre as alterações musculares e funcionais em crianças na fase da dentição mista, antes e após seis meses do tratamento reabilitador, avaliando:
1. a performance mastigatória;
2. a atividade eletromiográfica dos músculos masseter e porção anterior do temporal;
3. o comportamento mastigatório de alimentos com diferentes consistências.
III – CAPÍTULOS
Esta dissertação está baseada na Resolução CCPG/001/98/UNICAMP que regulamenta o formato alternativo para teses de Mestrado e Doutorado e permite a inserção de artigos científicos de autoria ou co-autoria do candidato (Anexo 1). Por se tratar de pesquisa envolvendo seres humanos, o projeto de pesquisa deste trabalho foi submetido à apreciação do Comitê de Ética em Pesquisa da Faculdade de Odontologia de Piracicaba, tendo sido aprovado (Anexos 2). Assim sendo, esta dissertação é composta de três capítulos contendo artigos em fase de redação, conforme descrito abaixo:
Capítulo 1
“Influence of measurement technique, test food, teeth and muscle force interactions in masticatory performance evaluation” Gambareli FR, Serra MD, Pereira LJ, Gavião MBD. Este artigo será submetido para publicação no periódico Journal of Texture Studies.
Capítulo 2
“Masticatory performance before and after oral rehabilitation in children.” Gambareli FR, Serra MD, Gavião MBD. Este artigo será submetido para publicação no periódico The International Journal of Prosthodontics.
Capítulo 3
“The influence of oral rehabilitation on muscle activity and chewing behavior in partially edentulous children.” Gambareli FR, Serra MD, Gavião MBD. Este artigo será submetido para publicação no periódico American Journal
CAPÍTULO 1
INFLUENCE OF MEASUREMENT TECHNIQUE, TEST FOOD, TEETH AND MUSCLE FORCE INTERACTIONS IN MASTICATORY PERFORMANCE
EVALUATION
Review Article
Flávia Riqueto Gambareli Márcia Diaz Serra
Luciano José Pereira
Maria Beatriz Duarte Gavião
*Department of Pediatric Dentistry, Piracicaba Dental School - State University of Campinas (FOP/UNICAMP), Piracicaba, SP, BR.
Piracicaba Dental School – State University of Campinas Piracicaba, SP, BRAZIL
Correspond,
Prof. Dr. Maria Beatriz Duarte Gavião - Faculdade de Odontologia de
Piracicaba/UNICAMP - Departamento de Odontologia Infantil – Área de Odontopediatria Av. Limeira 901 CEP 13414-903 Piracicaba – SP/Brasil Telephone – 55 19 3412
Abstract
Mastication is the first step of the digestive process. It results from patterns of rhythmic mandibular movements, food manipulation and the crushing of food between the teeth. The teeth and masticatory muscles are important in the process of mastication because they form together the mechanism where the food particles are fragmented. Masticatory performance is defined as the capacity to reduce natural or artificial test food during mastication, or by counting the number of masticatory strokes required to reduce food to a certain particle size reduction. This study presents an update and synopsis of masticatory performance methods and interactions with muscle force, number of teeth and test food diversity. Apparently, bite force is the main factor influencing masticatory performance and the sieving technique using artificial test foods are the methods of choice in the masticatory performance evaluation.
Introduction
Mastication is the first step of the digestive process. It results from patterns of rhythmic mandibular movements, food manipulation and the crushing of food between the teeth. Mechanical breaking of the food into smaller pieces increases its surface area facilitating enzymatic processing in the digestive system (Julien et
al., 1996).
Masticatory performance and efficiency are defined as the capacity to reduce food during mastication, or by counting the number of masticatory strokes required to reduce food to a certain particle size reduction, respectively (Bates et
al., 1976). Masticatory performance results from a complex interplay of direct and
indirect effects. The number of functional tooth units and muscle (bite) force are the key determinants of masticatory performance, which suggests that their maintenance may be of major importance for promoting healthful functional status (Hatch et al., 2000). Measurement of masticatory performance and maximal occlusal force may provide essential information that could make an appropriate diagnosis regarding masticatory function (Okyama et al., 2003).
Nevertheless, many investigators (Gunne, 1985; Heath, 1972; Carlsson, 1984) have suggested that masticatory efficiency does influence food choices. People with impaired chewing efficiency try to compensate for this by either swallowing larger particles or avoiding food requiring mastication (Manly & Braley, 1950; Yurkstas 1965; Bergman & Carlsson, 1972). Either action may lead to development of deficiency in certain nutrients (Heath, 1972; Österberg & Steen, 1982; Chen & Lowenstein, 1984).
The aim of this study was to present an update and synopsis of masticatory performance based on the increasing current knowledge in this field.
Masticatory function
Mastication is a process in which pieces of food are ground into fine state, mixed with saliva and brought to approximately body temperature in readiness for transfer to the stomach and intestines where most of digestion occurs (Bourne, 2004). Pulverization of food is the main function of mastication, but it also imparts enjoyable sensations that fill a basic human need.
Several factors potentially influence masticatory performance, including severity of malocclusion (Omar et al., 1987), occlusal contact area and body size (Julien et al., 1996), number of functional tooth units and bite force (Fontijn-Tekamp et al., 2000; Hatch et al., 2001). The surface area of the teeth, particularly the areas of contact between occluding teeth, determines the area available for shearing food during each chewing cycle (Julien et al., 1996). Nevertheless, differences in the movement of the jaw and in the bite force may have a greater influence on chewing efficiency than the occlusal contact areas (Fontijn-Tekamp et
al., 2000). The strength of the jaw muscles determines the amount of available
force to cut or crush the food and the patterns of jaw movements determine the speed and direction with which the shearing surfaces of the teeth come together during each cycle (Julien et al., 1996).
Dental status
The teeth are important in the masticatory system. They form the occlusal surface where the food particles are fragmented. This fragmentation depends on the total occlusal area and thus on the number of teeth (Dahlberg, 1942; Shiere & Manly, 1952; Lambrecht, 1965, van der Bilt, 2002) and, more importantly, the number of occluding pairs (Helkimo et al., 1977), which have been positively related to performance.
The effects of dentition on masticatory performance were studied previously in adults and children (Julien et al., 1996). Multiple regression showed that median particle size was most closely related (R=0.85) with weight and contact area. Together the two variables explained 72% of individual differences in performance. However, in a more recent study, the correlation between number of chewing strokes before swallowing and dental state was accomplished and the results showed that masticatory performance was significantly influenced by dentition, but not by age or gender (Fontijn-Tekamp et al., 2004). The number of occlusal units was a factor that affected the median particle size of masticatory performance and the swallowing threshold. Indeed, a clear relationship exists between dental state and masticatory performance as determined with a chewing test (Hatch et al., 2000; Carlsson, 1984; Julien et al., 1996; Luke & Lucas, 1985; Yurkstas, 1965). Nevertheless, a good determinant of masticatory function seems to be bite force, which alone explained 40% of the variation on chewing performance (Fontijn-Tekamp et al., 2000).
Subjects with a reduced dentition cannot pulverize their food to the same extent as subjects with more occlusal units, in a fixed number of chewing strokes. Someone with carious, painful teeth will unconsciously avoid those teeth during mastication, reducing their masticatory efficiency (Tate et al., 1994). People with impaired dentitions seem to have lower masticatory efficiency than those with good dentitions (Bates et al. 1976; Carlsson, 1984).
Patients with dental and skeletal malocclusions would be expected to have poor masticatory performance due to fewer occlusal contacts, as demonstrated by Tate et al., (1994) in preorthognathic surgery patients who presented poorer masticatory performance than controls and no correlations with estimated forces and muscle efficiency, suggesting that occlusal relationships and mechanical advantages contribute to a person’s ability to chew. In a study of masticatory efficiency and occlusal state, Omar et al. (1987) performed masticatory efficiency tests on fifty subjects using Optosil silicone material and found a correlation
between masticatory efficiency and occlusal state in subjects between 21 and 23 years of age, most of whom needed orthodontic treatment.
Masticatory performance has been also related directly to the quality of dentures (Neil & Phillips, 1970). Denture wearers reach only 25% of dentate chewing performance. Chewing efficiency has been proven to be significantly better in patients with overdentures and dental implants than in patients with full dentures. However, subjects with natural roots under their overdentures performed significantly better compared with subjects with dental implants. After implant treatment, bite force and chewing performance nearly doubled (van Kampen et al., 2002; van Kampen et al., 2004).Masticatory performance is an important outcome measure of occlusal therapy because it is directly influenced by the state of the dentition (Owens et al., 2002).
Test food
Various methods have been developed by researchers for evaluation of masticatory function (Manly & Braley, 1950; Helkimo et al., 1978; Edlund & Lamm, 1980; Gunne et al., 1983; Olthoff et al., 1984; Nakasima et al., 1989; Chong-Shan et al., 1990; Mowlana et al., 1994; Kato et al., 1995; Huggare et al., 1997; Al-Ali et al., 1999; Ohara et al., 2003; Okyama et al., 2003). In these methods, comminuted natural food or artificial materials, which enable investigator to standardize the property of test foods, were analyzed. Masticatory efficiency is one measure of function (Carlsson, 1984; Schneider, 1992; Gunne, 1983) and so, a material with uniform properties that can be reliably reproduced would provide an ideal test bolus for the scientific study of masticatory effectiveness (Compagnon et al., 1999). As test material, some type of natural food has usually been chosen, but only a few studies explain why they selected a particular test substance (Edlund & Lamm, 1980). Real foods previously used in masticatory studies, included carrots, peanuts and almonds (Yurkstas & Manly, 1950; Manly & Braley, 1950; Shiere & Manly,
1952; Yurkstas, 1965; Helkimo et al., 1978; Haraldson & Carlsson, 1979; Lundqvist & Haraldson, 1990). However, these foods have often been used without prior mechanical characterizations of the test food or assessment of the uniformity of the samples of the test food (rheologic evaluation) (Compagnon et al., 1999). Food substances with reproducible, constant physical properties are not found in nature. Researches have therefore started to use synthetic test substances whose physical properties are easier to control, such as formalin-hardened gelatine and silicone elastomers (Compagnon et al., 1999).
In the past, Dahlberg (1942) listed a number of requirements for an ideal test material that should be observed nowadays: (1) It should resemble ordinary food, i.e. not so easy to chew that it can be crushed by the alveolar ridges or so difficult that persons with a poor dentition cannot take part in the test. (2) It should not swell or dissolve in water or saliva and it should pulverize in such manner that the degree of pulverization can be clearly established. (3) It should not break along predetermined lines of cleavage or be tough or sticky. (4) It must be possible to standardize, be non-perishable and of good or at least indifferent taste.
Following demonstration of its suitability (Edlund & Lamm, 1980), Optosil® (a condensation silicone impression material now marketed as CutterSil) has become the test food of choice (Olthoff et al., 1984; van der Bilt et al., 1987, 1993a; Omar
et al., 1987; Slagter et al., 1992). Optosil® was chosen as a test material primarily on account of the advantages, from a physical point of vies, offered by a synthetic material (Edlund & Lamm, 1980). Furthermore, it is readily available and identical test portions can be produced under identical conditions all over the world (Edlund & Lamm, 1980). Standardized pieces of Optosil® are suitable as test portions in masticatory efficiency tests and well fill the generally accepted requirements of a test material (Edlund & Lamm, 1980).
However, Optosil® is an artificial test food with fracture strength too high in proportion to the maximum bite force of subjects with compromised oral conditions. Consequently, an experimental artificial test food (Optocal) was prepared, based on Optosil NF® (Version 1987)*. In a study of Slagter et al. (1993a), its
force-deformation properties were compared with those of Optosil® (version 1980). Optocal appeared to be much weaker, less elastic and less resistant to deformation. It appears to be an artificial test food well suited for measurements of masticatory performance in complete denture wearers as well as in dentate subjects. Optocal was much easier to chew than Optosil® in the experience of complete denture wearers and its texture was judged to be comparable to that of natural foods normally consumed by complete denture wearers.
The silicone samples fulfill all the criteria of a test material. Namely, the test material is stable, accurate, reproducible, and has mechanical properties that are comparable to those of natural food substances. The test materials do not dissolve in water or saliva and are able to be broken down during mastication. They do not break along predetermined fault lines and have no taste. They are standardized and can be stored without loss of their properties. The only constraint to their use is that the polymers cannot be digested and must not be swallowed. Therefore they could not be used in studies of the entire process of mastication from incising to swallowing. Otherwise, the silicone samples may be masticated in exactly the same way as a natural food.
Other materials have been developed for masticatory tests. Among these it can be mentioned the gummy jelly, which is an experimental food product. Quality control is much easier to achieve than in real food, such as peanuts, carrots or almonds (Slagter et al., 1992). In addition, gummy jelly is an edible product whose shape can remain the same while its hardness varies (Okyama et al., 2003).
Based on individual differences in occlusion, the health of the chewing apparatus is best assessed by performing a masticatory evaluation which involves the patient actually chewing a test food (Yamashita et al. 1999), this involves an analysis of particle size. Until future research can better understand human masticatory patterns, measures of performance using specific test foods remain the gold standard.
Masticatory performance methods
The most common technique used in the measurement of masticatory efficiency has been the weighing method associated with a sieve system (Mowlana
et al., 1995). Fractional sieving is a technique of separating the food after chewing
for a given time period that has been used since 1924 to determines the degree of the breakdown of the chewed food (Manly & Braley, 1950; Edlund & Lamm, 1980; Lucas & Luke, 1983; Olthoff et al., 1984; Jiffry, 1987) and is still considered to be a viable method (van der Bilt & Fontijn-Tekamp, 2004). The basic principle involved in this method is that the more efficient the mastication the higher the proportion of food that will pass through the smaller meshes (Mowlana et al., 1995). The weight of particles collected on each sieve is commonly expressed as a percentage of the total weight and used as indices of the efficiency of mastication (Manly & Braley, 1950; Helkimo et al., 1978; Edlund & Lamm, 1980; Jiffry, 1981; Lucas & Luke, 1983; Olthoff et al., 1984; Mowlana & Heath, 1991). Multiple-sieving methods (Edlund & Lamm, 1980; Olthoff et al., 1984) are more valid, reliable (Bates et al., 1976; Boretti et al., 1995) and sensitive than single-sieving methods in evaluating masticatory function (van der Bilt & Fontijn-Tekamp, 2004).
The projected dimensions of the comminuted food particles were measured using a video camera (Eliyas & Heath, 1989; van der Bilt et al., 1993b), determining the diameter of each food particle. The comparison of sizing particles with optical scanning and sieving almond particles suggests general confidence in both methods (Mowlana et al., 1994). The scanning has an obvious advantage where large particles are involved. Sieving may be better if the very small particles are important (Mowlana et al., 1994).
Methods utilizing gum (Liedberg & Owall, 1995; Matsui et al., 1996; Hayakawa et al., 1998; Prinz et al., 1999) have been developed in order to simplify the test procedures. Masticatory function with and without removable partial dentures was investigated using gum and found no significant difference between
the two groups (Liedberg et al. 1995). This suggests that the gum method might not be sensitive enough to detect changes in masticatory function.
Another test that used a cube made of paraffin wax dyed in two colours have been utilized (Sueda et al., 2003). This test is known as Mixing Ability Test, and the masticatory performance is obtained through the degree of colour mixing and deformation of the test food that were obtained from the digital image of the chewed material using image analyzer.
Asakawa et al. (2005) concluded that the masticatory function improved significantly when removable partial dentures in bad condition were replaced with new ones and that the Mixing Ability Test was sensitive enough to detect an improvement in masticatory function suggesting that the Mixing Ability Test can be applied for clinical use.
Masticatory Performance and Bite force
Another method of evaluating masticatory function is the measurement of bite force (Boretti et al., 1995). This is an indirect method and is based on the assumption that function correlates with bite force (Boretti et al., 1995). It is believed that someone who generates higher force during mastication might have better masticatory performance (Tate et al., 1994).
Correlations between bite force and masticatory performance have been studied. Bite force shows a positive relationship with masticatory performance (Fontijn-Tekamp et al., 2000; Okyama et al, 2003; Tate et al., 1994) and dietary selection (Okyama et al., 2003; Hiiemae et al., 1996), which is closely related to quality of life (Ikebe et al., 2005).
Previous studies have reported the associations between masticatory performance and maximal occlusal force (Tate et al., 1994; Fontijn-Tekamp et al., 2000; Okyama et al., 2003). Okiyama et al. (2003) found that maximal occlusal
force had a significant positive correlation to the masticatory performance both with soft gummy jelly and with hard gummy jelly.
In a study of Tate et al. (1994) it was reported that the correlation seen between maximum voluntary bite force and median particle size indicates that subjects who are able to generate higher maximum bite forces may be able to reduce a bolus of food more effectively than those who generate lower forces.
Recently, many researchers have noted that the increasing softness of foods is an environmental factor that might exert a strong influence on occlusal force (Maki et al., 2001), which was significantly lower in school age children who mainly ate soft diet than those who ate a more fibrous diet (Maeda et al., 1989).
Therefore, if there is a correlation between masticatory performance and bite forces, this measurement, could be used as a clinical indicator of masticatory performance (Tate et al., 1994).
Conclusion
Masticatory efficiency and performance can be measured to determine the capacity of the individual to comminute a natural or artificial test food. The teeth are important since they form the occlusal surface where the food particles are fragmented.
A material with uniform properties that can be reliably reproduced is essential to provide an ideal test bolus for the scientific study of masticatory effectiveness. Natural foods have often been used lately, however food substances with reproducible, constant physical properties are not found in nature. As a result, silicone samples were introduced because they fulfill all the criteria of a test material.
The most common technique used in the measurement of masticatory efficiency has been the weighing method associated with a sieve system. The measurement of the comminuted food particles using a video camera is a reliable
procedure as well. It is considered that the scanning has an obvious advantage where large particles are involved, whereas sieving may be better if the very small particles are important.
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CAPÍTULO 2
MASTICATORY PERFORMANCE BEFORE AND AFTER ORAL REHABILITATION IN CHILDREN
FLÁVIA RIQUETO GAMBARELI* MÁRCIA DIAZ SERRA*
MARIA BEATRIZ DUARTE GAVIÃO DDS, MS, PhD **
*Post-Graduate Students, Department of Pediatric Dentistry, Dental School of Piracicaba - State University of Campinas (FOP/UNICAMP), Piracicaba, SP, Brasil.
**Professor, Department of Pediatric Dentistry, Dental School of Piracicaba - State University of Campinas (FOP/UNICAMP), Piracicaba, SP, Brasil.
Flávia Riqueto Gambareli: Av. Limeira, 901, Piracicaba, SP - 13414-903, Brazil Márcia Diaz Serra: Av. Limeira, 901, Piracicaba, SP - 13414-903, Brazil
Correspond with:
Prof. Dr. Maria Beatriz Duarte Gavião
Faculdade de Odontologia de Piracicaba/UNICAMP – Departamento de Odontologia Infantil – Área de Odontopediatria
Av. Limeira 901, Piracicaba, SP. 13414-903, Brazil
Phone: #55-19-34125368/5287 Fax: #55-19-34125218
Abstract
There is a clear relation between dental state and objective masticatory function. However, there have been few studies determining the influence of prosthodontic treatment on masticatory function in children. Purpose: The aim of this study was to obtain information on the masticatory performance of partially edentulous children before and after completion of prosthetic rehabilitation. Methods: Twenty-five children were selected (12 female and 13 male) aged from 6 to 9 years. The subjects received treatment during which missing deciduous post-canine teeth were replaced by a removable partial denture that also functioned as a space maintainer. The masticatory function was determined objectively by chewing 17 cubes of artificial test food (3 cm3) during 20 chewing strokes. The degree of fragmentation of the chewed food portions was determined by the sieving method (median particle size and broadness of the distribution). Body variables, weight, height and the body mass index, as well as performance masticatory were assessed before and 6 months after the placement of the removable prosthesis. Results: There were no significant gender differences, either in the first or second session, for all variables. The masticatory performance improved significantly after 6 months of oral rehabilitation (p<0.001), as well as the weight and height (p<0.001). Conclusion: It was concluded that the removable prosthesis was adequate to replace the missing posterior primary teeth, giving the possibility to reestablish the function of the masticatory system, improving the masticatory performance.
Keys words: children, premature tooth loss, removable prosthesis, masticatory performance, artificial test food.
Introduction
The restoration of natural teeth or the replacement of missing teeth to achieve an acceptable masticatory function is one of the treatment goals in dentistry, being the basis for proper digestion and absorption of nutrients.1,2
There have been several objective measures providing essential information that could make an appropriate diagnosis regarding masticatory function, such as objective masticatory function, swallowing threshold and occlusal force.3 Objective masticatory function is defined as masticatory performance and has often been measured by determining an individual's capacity to grind or pulverize a test food. The rate of breakdown of food depends on many anatomical and physiological variables.
Indeed, a clear relation exists between dental state and masticatory function,4 since several factors have influence, including severity of the malocclusion,5 occlusal contact area, body size,6,7 number of functional tooth units and bite force.4,7 The areas of contact between occluding teeth determine the area available for shearing food during chewing cycles.8,9,10 Individuals with deteriorated dentition would be expected to have poor masticatory performance.7 The subjects’ capacity to comminute a test food was reduced significantly after loss of post-canine teeth,4 as for those ones wearing removable dentures.11 On the other hand, implant-supported prosthesis improve the oral function and satisfaction in edentulous patients.7,12,13
Therefore, the tooth loss often leads to disturbance of masticatory functions and alteration in the proper contact of the inclined planes of the teeth. Moreover, if a primary posterior tooth is lost, there will be a great possibility to occur space loss.14 In this way, the premature loss of primary teeth is an indicator for prosthetic provision in the form of space retainers or partial dentures to maintain or to reestablish the oral functional status, which is considered necessary for
undisturbed lower facial growth.15 Without prompt treatment, different acquired facial-occlusal defects may develop.16
In fact, the study of the comminution of solid food is of interest in revealing the relative importance of the influencing variables to masticatory performance.17 A wide variety of methods has been used to analyze chewing performance.18,19,20,21,22 However, fractional sieving has been widely used to determine the degree of breakdown of the chewed food,7,21,23,24 being the multiple-sieving more valid, reliable and sensitive than single-sieving.1,23,24,25,26
Natural and artificial foods have been used as test materials for measurements of masticatory performance, nevertheless the artificial foods may be preferred to natural ones because the physical properties, as well as the shape and size of their particles, are more reproducible.7,23,24,27,28
Although numerous studies have described normal masticatory performance in young adults and children,6,29 little comparative information has been show regarding the differences in mastication between dentate and edentulous subjects of similar age and with regard to rehabilitation after premature primary teeth lost.
The aim of this study was to evaluate the masticatory performance of partially edentulous children before and 6 months after completion of prosthetic restoration.
The null hypothesis of this study was that the removable prosthesis had no influence on the masticatory performance of children with premature primary tooth loss.
Material and Method
Sample: Two hundred and forty nine children from 6 to 9 years old, who
were to start dental treatment in the Department of Pediatric Dentistry, Piracicaba Dental School, State University of Campinas, Brazil, were scanned and 25 children
were selected, 12 female and 13 male. The written and verbal consent was obtained from each child’s parents and the research was approved by the Ethics Committee of that Dental School.
The children were in the mixed dentition. The criteria for inclusion were the presence of all first permanent molars in contact, the presence of primary or permanent incisors, and primary canines. All children had recently missing primary molars due to early loss, or necessity of extraction of them, indicated through clinical and radiographic examination. On the radiographies it was also assessed the conditions of the remaining teeth, the eruption process and degree of root formation in the permanent teeth. All the children had Angle’s Class I molar relation. After diagnosis, individual treatment plan was established, including, when indicated: detailed parental and child education and instructions in relation to feeding behavior and oral hygiene, fluoride therapy, extraction of teeth, restoration of the cavities and pulpal treatments. The children received a dental removable prosthesis, also functioning as a space maintainer, made with acrylic resin, artificial teeth (Fig. 1 and 2) and clasps. Artificial teeth were added to the acrylic part of the prosthesis to replace the missing teeth and to give back the aesthetic to the child.
Masticatory performance
Artificial test food: The material utilized was prepared as follows11: Opsotil NF® (version 1987) was mixed with toothpaste (Colgate®), Vaseline (Rioquímica®), powder of dental plaster (Herodent-SoliRock-Vigodent®), and alginate powder (Jeltrate®), in the respective percentages by weight: 58.3, 7.5, 11.5, 3, 10.2, and 4%. The putties were mixed with catalyst paste, using 20.8mg/g, and arranged in moulds, giving cubes with an edge size of 5.6mm (Fig. 3). After setting, the samples were stored in an electrical stove for 16h at 60ºC to ensure complete polymerization.
Chewing test: Children were instructed to chew 17 cubes (approximately
3cm³) and were trained before the experiment in relation to masticatory movements and mouth rinsing, so that they would chew correctly, did not swallow and were familiarized with the taste of the test material. During the chewing test they performed 20 strokes controlled by an examiner. The chewing was unrestricted and allowed to be performed uni – or bilaterally. The procedure was carried out twice. After the mastication each child spat out the sample into a plastic cup cover with a filter paper and their mouth was then rinsed with water. The child spat out the remaining mouth contents until all particles were removed. The mouth was verified to check that no test material particles remained. If any particle remained it was removed with a dental nipper. After washing and drying, the chewed particles were sieved through a stack of 10 sieves, with square apertures ranged from 5.6 decreasing to 0.5 mm, finishing in a bottom plate.11 The sieves were stacked on a mechanical shaker and the sample was vibrated for 20 minutes. Next, the amount of test food on each sieve and on the bottom plate was weighed to the nearest 0.0001g. The degree of fragmentation of the food (chewing performance) is given by the median particle size, X50, which is the aperture of a
theoretical sieve through which 50% of the weight of the comminuted food could pass. A large value of X50 indicates a poor masticatory performance.
The distribution of particle sizes by weight of the comminuted test food was mathematically described by a cumulative function (Rosin-Rammler equation).21,24
In which Qw is the weight fraction of particles with a size smaller than X. The median particle size, X50, which is the aperture of a theoretical sieve through
which 50% of the weight can pass, whereas the variable ‘‘b’’ represents the size spread of the distribution (broadness variable), reflecting the extent to which the particles are equally sized. Increasing values of “b” correspond to curves with steeper slopes and thus to distributions of particle sizes that are less broad. The
variables X50 and “b” were determined by curve-fitting the data to the equation with
nonlinear regression.21,24
Body Variables
Weight and height were determined through an anthropological commercial scale. The body mass index (BMI= Weight/Height2) was determined for each patient.
Before and six months after the children had been worn the prosthesis, the masticatory performance was evaluated, as well as the body weight and height. All the evaluations were made in the same daytime for each child in the first and the second evaluation. Each child was used as his/her own control.
Statistical analysis
The assumptions of equality of variances and normal distribution of errors were checked for all tested variables (Shapiro-Wilks W-test) and those that did not satisfy were transformed. When the data could not be transformed, they were analyzed by non-parametric tests. Thus, the values of the median particle sizes were log 10 transformed and compared between the two evaluations by paired t test, while for the broadness of the particle size distribution (b) the Wilcoxon test was applied, as well as for the body variables. The correlations among the variables were assessed by Spearman’s coefficients and adjusted different regression models to the data were applied in each significant correlation at the P < 0.05 level. All analyses were carried out using SPSS1 9.0 (1998; SPSS, Chicago, IL, USA).
Results
There was no statistical significant difference (p>0.05) among the variables for boys and girls, therefore the data were pooled. The resulting cumulative weight distributions were fitted according to the equation yielding values for the median particle size, X50, and the broadness variable, “b”. The mean values of the two
evaluations are demonstrated on Table 1. The null hypothesis was rejected. There was a significant decrease in the median particle size from first to second evaluation (p=0.000), but the broadness did not show significant difference (Fig. 4 and 5).
On comparing the body variables before and after the placement of the prosthesis, it was found that the weight and height had significantly difference between the sessions (p=0.0001, p=0.0000, respectively), showing that the subjects gained weight and grew up within the 6 months of treatment. Nevertheless, the body mass index did not show a statistically significant difference (p=0.0556) (Table 1).
The body weight and height were negatively correlated with masticatory performance (X50 value) at the first session of exams (Table 2), and the respective
determination coefficients were 19.75% and 31.43%, given by linear regression. After 6 months of the placement of the prosthesis no significant correlations were found for these variables (Table 3).
Discussion
Primary teeth play a critical role in the growth and development of a child. In addition to their role in esthetics, eating, speech, and to encourage normal function and resultant expected growth, the other main function of a primary tooth is to hold space for the permanent successor until it is ready to erupt.30 The
