UNIVERSIDADE ESTADUAL DE CAMPINAS
FACULDADE DE ODONTOLOGIA DE PIRACICABA
TALITA MALINI CARLETTI
INFLUÊNCIA DE PRÓTESES TOTAIS INFERIORES NA
MASTIGAÇÃO, ESPESSURA MUSCULAR E PERCEPÇÃO ORAL
INFLUENCE OF LOWER COMPLETE DENTURES ON
MASTICATION, MUSCLE THICKNESS, AND ORAL PERCEPTION
Piracicaba 2018
TALITA MALINI CARLETTI
INFLUÊNCIA DE PRÓTESES TOTAIS INFERIORES NA
MASTIGAÇÃO, ESPESSURA MUSCULAR E PERCEPÇÃO ORAL
INFLUENCE OF LOWER COMPLETE DENTURES ON
MASTICATION, MUSCLE THICKNESS, AND ORAL PERCEPTION
Dissertação apresentada à Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas como parte dos requisitos exigidos para obtenção do título de Mestra em Clínica Odontológica, na Área de Prótese Dental.
Dissertation presented to the Piracicaba Dental School of the University of Campinas in partial fulfillment of the requirements for the degree of Master in Clinica l Dentistry, in Prosthodontics area.
Orientadora: Profa. Dra. Renata Cunha Matheus Rodrigues Garcia
ESTE EXEMPLAR CORRESPONDE À VERSÃO FINAL DA DISSERTAÇÃO DEFENDIDA PELA ALUNA TALITA MALINI CARLETTI E ORIENTADA PELA PROFA. DRA. RENATA CUNHA MATHEUS RODRIGUES GARCIA.
Piracicaba 2018
Agência(s) de fomento e nº(s) de processo(s): FAPESP, 2015/21704-1; CNPq,
166610/2017-8
ORCID: https://orcid.org/0000-0002-1549-2621
Ficha catalográfica
Universidade Estadual de Campinas
Biblioteca da Faculdade de Odontologia de Piracicaba Marilene Girello - CRB 8/6159
Carletti, Talita Malini, 1993-
C193i Influência de próteses totais inferiores na mastigação, espessura muscular e percepção oral / Talita Malini Carletti. – Piracicaba, SP : [s.n.], 2018.
Orientador: Renata Cunha Matheus Rodrigues Garcia.
Dissertação (mestrado) – Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba.
Car1. Músculo masseter. 2. Mastigação. 3. Estereognose. 4. Sensação. 5. Língua. I. Rodrigues-Garcia, Renata Cunha Matheus, 1964-. II. Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba. III. Título.
Informações para Biblioteca Digital
Título em outro idioma: Influence of lower complete dentures on mastication, muscle
thickness, and oral perception
Palavras-chave em inglês: Masseter muscle Mastication Stereognosis Sensation Tongue
Área de concentração: Prótese Dental Titulação: Mestra em Clínica Odontológica Banca examinadora:
Renata Cunha Matheus Rodrigues Garcia [Orientador] Stefania Carvalho Kano
Thais Marques Simek Vega Gonçalves
Data de defesa: 01-03-2018
UNIVERSIDADE ESTADUAL DE CAMPINAS Faculdade de Odontologia de Piracicaba
A Comissão Julgadora dos trabalhos de Defesa de Dissertação de Mestrado, em sessão pública realizada em 01 de Março de 2018, considerou a candidata TALITA MALIN I CARLETTI aprovada.
PROFª. DRª. RENATA CUNHA MATHEUS RODRIGUES GARCIA
PROFª. DRª. THAIS MARQUES SIMEK VEGA GONÇALVES
PROFª. DRª. STEFANIA CARVALHO KANO
A Ata da defesa com as respectivas assinaturas dos membros encontra-se no processo de vida acadêmica do aluno.
DEDICATÓRIA
Dedico este trabalho aos meus pais, Lucimar Gomes Carletti e Carla Belmock Malini Carletti, e ao meu irmão, Lorenzo Malini Carletti, por me ensinarem a ser quem sou hoje e me permitirem, mesmo que distante, seguir minhas vontades e sonhos. Obrigada por me ajudarem sempre que preciso, sem hesitar. Vocês são as pessoas mais importantes que tenho na vida. Amo vocês! À toda minha família, tios, tias, primos e primas, por entenderem minha ausência e por torcerem sempre por mim. Ao Isaac Jordão de Souza Araújo, pelo companheirismo durante todo o meu Mestrado, por todo o incentivo para continuar na vida acadêmica e por me ensinar a ser um ser humano melhor a cada dia.
AGRADECIMENTO ESPECIAL
À minha orientadora, Profa. Dra. Renata Cunha Matheus Rodrigues Garcia, por acreditar no meu potencial desde o primeiro dia que entrei na FOP/UNICAMP, pelos ensinamentos, paciência, profissionalismo e ética com suas “filhas” mestrandas e doutorandas. Obrigada por orientar minha vida acadêmica sob tantos cuidados e preocupações.
AGRADECIMENTOS
Primeiramente agradeço a Deus, pois Ele nos deu o dom da vida e nos permitiu chegar até aqui para ajudar a cuidar de outras vidas. Nada é possível sem a Sua presença.
À Universidade Estadual de Campinas, por meio do seu Magnífico Reitor, Prof. Dr. Marcelo Knobel, e à Faculdade de Odontologia de Piracicaba (FOP/UNICAMP), nas pessoas do diretor Prof. Dr. Guilherme Elias Pessanha Henriques e do vice-diretor Prof. Dr. Francisco Haiter Neto.
À Coordenadora dos Programas de Pós-Graduação da Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas, Profa. Dra. Cinthia Pereira Machado Tabchoury e à Coordenadora do Programa de Pós-Graduação em Clínica Odontológica, Profa. Dra. Karina Gonzales Silverio Ruiz.
À Profa. Dra. Altair Antoninha Del Bel Cury, membro docente da Comissão do Programa de Pós-Graduação em Clínica Odontológica da Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas, pelo apoio e incentivo à pesquisa.
Aos docentes do Programa de Pós-Graduação em Clínica Odontológica da Faculdade de Odontologia de Piracicaba, em especial: Prof. Dra. Altair Antoninha Del Bel Cury, Prof. Dr. Wander José da Silva, Prof. Dr. Valentim Adelino Ricardo Barão, Prof. Dr. Marcelo Ferraz Mesquita, Prof. Dr. Mauro Antônio de Arruda Nóbilo, e Profa. Dra. Célia Marisa Rizatti Barbosa pelas aulas ministradas e experiências clínicas transmitidas em grupos de discussão e disciplinas. Obrigada por estimularem nossa criticidade e nosso crescimento pessoal e profissional todos os dias.
A todos os docentes do curso de Odontologia da Universidade Federal do Espírito Santo, que foram responsáveis pela minha formação como Cirurgiã-Dentista, minha admiração é eterna. Sou grata por todos os ensinamentos que recebi ao longo da graduação.
Às minhas eternas amigas de graduação: Dannyelle Loureiro Rocha, Gisele Gomes da Silva e Tarcila Batista, que, mesmo à distância, mantêm contato, apoiam minha jornada e estão sempre na torcida pelas conquistas.
À minha amiga Mariana Dias Flor Ribeiro, do laboratório da Dentística, obrigada pela amizade desde a época da graduação na Universidade Federal do Espírito Santo, incentivo em
realizar a prova do mestrado na Faculdade de Odontologia de Piracicaba e por me acolher em sua casa no primeiro dia que cheguei em Piracicaba.
Aos amigos e agregados que já passaram e permanecem na nossa república “Casa do Cavalo”: Thayla Hellen Nunes Gouveia, Rafaela Costa de Holanda, Jéssica Teobaldo, Guilherme Teobaldo, Michele Lima, Bruna Marin Fronza, Carolina Bosso, Aline Tavares Holanda e Lívia Nazareth Ferreira. Obrigada por compartilhar experiências e estimular incontáveis discussões sobre Prótese, Dentística, Materiais Dentários e Odontopediatria. Agradeço pelas risadas, caronas, conversas, almoços, jantares e mais importante, amizade e companheirismo.
Às amigas orientadas da Profa. Dra. Renata: Mayara Abreu Pinheiro, Olívia Maria Figueiredo, Mariana Barbosa Câmara de Souza, Ingrid Meira, Camilla Fraga do Amaral, Giselle Rodrigues Ribeiro, Camila Heitor Campos, Thaís Marques Simek Veiga Gonçalves, meus agradecimentos pela amizade, conversas, disponibilidade em ajudar e pelos momentos agradáveis.
Aos amigos de pós-graduação: Rafael Soares Gomes, Victor Ricardo Manuel Muñoz Lora, Giancarlo de la Torre Canales, Louise Morais Dornelas Bezerra, Raissa Micaella Marcello Machado, Raíra Brito, Bruna Ximenes, Caroline Dini, Bruna Egumi, Jairo, Heloisa, João Gabriel, Thaís Barbin, Marco Aurélio Carvalho, Priscila Cardoso Lazari, Edmara Tatiely Pedroso Bergamo, Diego Nóbrega, Ana Camila Medeiros, por toda amizade e aprendizado compartilhado nesse período.
Aos amigos do laboratório de Materiais Dentários da Faculdade de Odontologia de Piracicaba, obrigada por me acolherem como família e por me alegrarem na presença de vocês. É meu segundo laboratório preferido!
À técnica do Laboratório de Prótese Parcial Removível da Faculdade de Odontologia de Piracicaba, Sra. Gislaine Alves Pitton, nossa “Gi”, obrigada pelo carinho de mãe, conselhos e puxões de orelha! Nosso laboratório sem sua presença não funcionaria da mesma forma.
À secretária do Departamento de Prótese e Periodontia da Faculdade de Odontologia de Piracicaba, Sra. Eliete Aparecida Ferreira Marin, pelo carinho, amizade, dedicação, e por nos manter sempre organizados e atualizados com as programações da Faculdade.
Ao engenheiro técnico do Laboratório de Materiais Dentários, do Departamento de Odontologia Restauradora da Faculdade de Odontologia de Piracicaba, Sr. Marcos Cangiani,
o querido “Marcão”, pela paciência, sabedoria e disponibilidade em sempre nos ajudar com as pesquisas.
À Profa. Dra. Maria Beatriz Duarte Gavião, do Departamento de Odontologia Infantil da Faculdade de Odontologia de Piracicaba que prontamente disponibilizou a utilização do equipamento de ultrassom.
À Sra. Shirley Rosana Sbravatti Moreto secretária do Departamento de Odontologia Infantil da Faculdade de Odontologia de Piracicaba, que organizava o agendamento do equipamento de ultrassom.
Ao Eliseo Aparecido Bertti, técnico em Biblioteconomia, e Heloisa Maria Ceccotti, bibliotecária da Biblioteca da Faculdade de Odontologia de Piracicaba, agradeço ao auxílio com a busca de livros e artigos científicos.
Às funcionárias do Restaurante Universitário da Faculdade de Odontologia de Piracicaba, que trabalham diariamente para que nossa refeição seja bem servida.
Aos funcionários da manutenção e limpeza da Faculdade de Odontologia de Piracicaba, que tornam nossa Faculdade e laboratórios ambientes limpos e organizados todos os dias.
A todos os pacientes e pessoas que participaram direta ou indiretamente deste trabalho. À FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo, pelo Auxílio à Pesquisa concedido (processo número 2015/21704-1).
Ao CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnologia, pela concessão da Bolsa de Estudos (processo número 166610/2017-8).
RESUMO
O edentulismo total pode afetar a função mastigatória, levando à atrofia da musculatura facial devido à mudança no padrão alimentar, caracterizada pelo baixo consumo de alimentos consistentes e fibrosos. Nesse sentido, a ausência do uso de próteses totais (PT) inferiores, bem como a utilização de novas PT superior e inferior, por idosos totalmente edêntulos, poderia alterar a função mastigatória e a espessura do músculo masseter. Além disso, a habilidade sensorial oral de indivíduos desdentados também pode ser modificada, uma vez que a perda dental contribui para diminuição da propriocepção. Desta forma, no presente estudo avaliou- se como a não utilização de PT inferiores impacta a musculatura e consequentemente a função mastigatória desses indivíduos. Também foi avaliada, como essa função é restabelecida após a instalação e uso das novas PT duplas. A habilidade sensorial oral e a pressão máxima da língua também foram avaliadas. Segundo cálculo amostral prévio, foram selecionados 15 indivíd uos totalmente edêntulos em ambas as arcadas dentárias, que não faziam uso da PT inferior nos últimos 3 meses foram selecionados nas dependências da Faculdade de Odontologia de Piracicaba, Unicamp. As variáveis foram analisadas antes (baseline) e após (1, 3 e 6 meses) a adaptação às novas PT. A função mastigatória foi analisada por meio do cálculo da performance mastigatória, expressa pelo tamanho médio de partícula (X50) de Optocal, após trituração por 40 ciclos e análise do material pelo sistema de peneiras. A habilidade sensorial oral foi avaliada por meio de teste de estereognose oral. A espessura do músculo masseter em posição de relaxamento e máxima contração foi mensurada por meio de ultrassom. A pressão máxima da língua foi mensurada por meio de três sensores digitais posicionados na base da PT superior (dois localizados na região posterior e um na região anterior). Inicialmente, os dados foram submetidos ao teste de normalidade Shapiro-Wilk. Observada homogeneidade, os dados foram submetidos aos testes ANOVA para medidas repetidas e post-hoc Tukey-Kramer, para todas as variáveis. O nível de significância de 5% foi adotado. Os valores médios de X50 reduziram após um mês de utilização das novas próteses, evidenciando um aumento da performance mastigatória (P < 0.05) se comparado ao período baseline. Além disso, a espessura do músculo masseter (P < 0.05) aumentou durante o estado de relaxamento após 3 meses de uso das novas PT duplas, enquanto para o estado de contração muscular, a espessura aumentou logo após 1 mês de adaptação às novas PT. Não houve diferença para a habilidade sensorial oral (P > 0.05). Os valores de pressão máxima de língua reduziram 1 mês após a instalação das novas próteses (P <0.05). Não houve correlação entre a estereognose oral e pressão máxima da língua (r =.08;
P = 0.57). Conclui-se que o uso de novas PT superior e inferior melhoram consideravelme nte
a função mastigatória de idosos desdentados que não utiliza vam as PT inferiores, evidenciado pelo aumento da espessura muscular, melhora da performance mastigatória e redução da pressão máxima da língua.
Palavras-Chave: espessura do masseter, performance mastigatória, estereognose oral, função sensorial oral, força da língua.
ABSTRACT
Total edentulism can affect the masticatory function, leading to facial muscle atrophy due to changes in food pattern, characterized by the low consumption of consistent and fibrous foods. In this sense, the absence of use of lower complete dentures (CD) and the use of new upper and lower CD by completely edentulous elderly can alter masticatory function and masseter muscle thickness. In addition, the oral sensory ability of edentulous individuals is also deficient, since the dental loss contributes to decreased proprioception. Thus, in the present study, the non-use of the lower CD impacts musculature and consequently masticatory function of these subjects. It was assessed how this function is re-established after installation and use of new upper and lower CD. The oral sensory ability and maximum tongue pressure were also evaluated. According to a previous sample calculation, 15 completely edentulous elderly in both denta l arches, which did not use the lower CD in the last 3 months were selected at Piracicaba Dental School - Unicamp. All variables were analyzed before (baseline) and after (1, 3 and 6 months) the adaptation to the new CD. The masticatory function was analyzed by means of masticator y performance calculation (X50), performed after the Optocal grinding for 40 cycles and analys is of the material by the sieving system. The oral sensory ability was evaluated by oral stereognosis test. The thickness of masseter muscles in the position of relaxation and maxima l voluntary contraction was measured by ultrasound. The maximum tongue pressure was measured using three digital sensors positioned on the base of the upper CD (two located in the posterior region and one in the anterior region). Initially, the data were submitted to the Shapiro -Wilk normality test. Observed homogeneity, the data were submitted to repeated measures ANOVA and Tukey-Kramer post-hoc tests, for all variables. A significance level of 5% was adopted. The X50 values decreased after 1 month of new CD use, evidencing a rise on masticatory performance (P < 0.05), if compared to baseline assessments. Besides, masseter thickness (P < 0.05) increased during relaxed states after 3 months using the new CD, while for maximum voluntary contraction, the thickness raised just after 1 month after adaptation of the new dentures. after the insertion of the new CD. No differences were found for the oral sensory ability (P > 0.05). Maximum tongue pressure values were reduced 1 month after the installa t io n of the new prostheses (P < 0.05). No correlations were observed between oral stereognosis and maximum tongue pressure (r =0.08; P = 0.57). It is concluded that the use of new upper and lower CD considerably improves the masticatory function of edentulous elderly who did not
use the lower CD, once it increases the masseter thickness, improves masticatory performance and reduces the maximum tongue pressure.
Keywords: masseter thickness; masticatory performance; oral stereognosis; oral sensory function; tongue force.
SUMÁRIO
1 INTRODUÇÃO 15
2 ARTIGO: Influence of lower complete dentures use on masseter muscle and masticatory
function: a longitudinal study 21
CONCLUSÃO 45
REFERÊNCIAS 46
ANEXOS 50
ANEXO 1 – Certificado de aprovação do Comitê de Ética em Pesquisa da Faculdade de Odontologia de Piracicaba 50
ANEXO 2 – Mini-exame do estado mental (MEEM) 51
ANEXO 3 – Figuras 52
15
1 INTRODUÇÃO
A mastigação é um processo complexo, onde diversas estruturas do sistema estomatognático, incluindo dentes, músculos, língua e o próprio sistema gastrointestinal, atuam em harmonia e equilíbrio com objetivo de triturar adequadamente os alimentos e formar o bolo alimentar apto a ser deglutido (van der Bilt et al., 2006). Assim, as partículas de alime nto trituradas facilitam a ação das enzimas digestivas, contribuindo para a absorção dos nutrientes pelo organismo e consequente manutenção da homeostase (N’Gom e Woda, 2002).
Em se tratando da alimentação de indivíduos idosos, os processos fisiológicos inerentes ao envelhecimento, bem como fatores patológicos, que exercem influência no padrão alimentar desses indivíduos, devem ser considerados. Estas alterações, que ocorrem em nível celular e molecular no corpo humano, ao longo do tempo, explicam o aumento do número de doenças crônicas e comorbidades que mais acometem essa faixa etária. Doenças neurodegenerati vas, depressão, doenças articulares, renais, hepáticas, câncer, hipertensão arterial e diabetes, são algumas das condições mais comuns (Hillen et al., 2017; Chowdhury et al., 2017).
Como consequência da presença de doenças, e na impossibilidade de executar tarefas diárias independentemente, muitos idosos alteram seus hábitos cotidianos. Essas mudanças podem envolver, inclusive, alterações nos hábitos alimentares, fator este que eleva significativamente o risco de má nutrição e perda de peso, ampliando a necessidade de assistência aos idosos principalmente durante a alimentação, em decorrência da falta de apetite, disfagia e até dificuldades na deglutição (Favaro-Moreira et al., 2016).
Ainda, a desnutrição em idosos está relacionada à presença de dentes na arcada dentária, já que a ausência destes interfere não só no tipo de alimento selecionado e consumido, mas também no processo mastigatório (N’Gom e Woda, 2002; Fueki et al., 2011). Na ausência de dentes, além do aumento no consumo de alimentos macios e ricos em carboidratos e gorduras, notavelmente menos nutritivos (Muller et al., 2008; Nakata, 1998; N’Gom e Woda 2002), as partículas de alimento são trituradas de forma deficiente e, por consequência pouco absorvidas
16
no trato gastrointestinal, levando à carência de nutrientes e minerais (Han e Kim, 2016; N’Gom e Woda, 2002; Kido, 2015). Além disso, o padrão alimentar alterado de idosos desdentados totais requer menor esforço da musculatura mastigatória (Farias-Neto et al., 2012).
A redução da atividade muscular causada pela ausência de suporte oclusal posterior afeta os músculos da mastigação, principalmente o músculo masseter, um dos principa is músculos da atividade mastigatória, que se atrofia (Farias-Neto et al., 2012) em razão da redução no tamanho das fibras musculares (Tsai et al., 2012). Além disso, a diminuição da espessura desse músculo provoca alterações na força de mordida (Yamashita et al., 2000; Fontijn-Tekamp et al., 2000; Helkimo et al., 1977) e na performance mastigatória do indivíd uo (Fontijn-Tekamp et al., 2000; Slagter et al., 1993).
Considerando a importância do suporte oclusal posterior sobre o processo mastigatór io de idosos desdentados, e para reverter as consequências relacionadas à nutrição deficiente, uma das opções é a reabilitação protética das arcadas dentárias por meio de próteses totais (PT) convencionais (Han e Kim, 2016). Esse tipo de reabilitação parece ter papel importante na manutenção da musculatura mastigatória, prevenindo a atrofia do músculo masseter (Tetsuka et al., 2012). Em um estudo realizado em cadáveres (Tetsuka et al., 2012), usuários de PT apresentam maior espessura do masseter quando comparados aos indivíduos edêntulos que não utilizam próteses, uma vez que mantêm o suporte oclusal e estabilizam a posição mandibular, permitindo assim que os músculos mastigatórios atuem de forma adequada e harmônica. No entanto, este estudo não fornece informações consistentes acerca dos efeitos morfológicos que o uso de PT convencionais poderia acarretar na recuperação muscular.
Ainda neste contexto, um estudo piloto (Bhoyar et al., 2012) revelou resultados promissores em relação ao tratamento reabilitador, pois a substituição de PT antigas levou ao aumento significativo na espessura do músculo masseter após três meses de uso das novas próteses. Além disso, Schimmel et al. (2010) confirmou em um relato de caso, um ganho
17
significativo na espessura deste músculo por meio da utilização de overdenture suportada por dois implantes. Não obstante, o músculo masseter também foi avaliado em grupos de indivíd uos totalmente dentados e desdentados totais que utilizavam overdentures, próteses fixas sobre implantes e PT convencionais. (Muller et al., 2012) Apesar do design transversal deste estudo, o aumento da espessura do músculo masseter foi confirmado em todos os grupos de indivíd uos desdentados reabilitados com próteses, ainda que não tenha sido superior aos valores obtidos para o grupo de indivíduos dentados. Esses resultados demonstram a importância da reabilitação protética e o impacto, quase que imediato, destas próteses sobre a muscula t ura mastigatória revertendo assim, a atrofia muscular por desuso. Entretanto, estudos pareados, com maior tempo de acompanhamento são necessários para confirmar esses resultados, uma vez que a relação causa e efeito pode ser melhor observada.
Além de recuperar a estrutura muscular, a reabilitação por meio de PT convencio na is apresenta boa previsibilidade, custo-benefício favorável e grande importância no que se refere à melhora, ainda que parcial, da função mastigatória e nutrição de pacientes totalmente edêntulos (N’Gom e Woda, 2002; Fontijn-Tekamp et al., 2000; Slagter et al., 1993b; Nakata, 1998; Han e Kim, 2016; Fitzpatrick, 2006). Em adição, devido à melhora na habilidade mastigatória, idosos usuários de PT convencionais superior e inferior aumentam a ingestão de alimentos considerados saudáveis, como frutas e vegetais, levando à diminuição consideráve l nos problemas relacionados à deglutição, quando comparados à sua condição inicial de edentulismo (Han e Kim, 2016).
Todavia, ainda é comum observar idosos totalmente edêntulos que não utilizam as próteses totais inferiores. Isso ocorre principalmente devido à problemas protéticos, relacionados à falta de retenção e estabilidade da prótese, (Berg, 1993) visto em alguns casos, em função da baixa disponibilidade de osso alveolar na arcada dentária, decorrente da reabsorção provocado pela ausência dentária (Gonçalves et al., 2014). Contudo, outros aspectos
18
relacionados à dor e desconforto provocados por próteses antigas e/ou mal adaptadas, problemas fonéticos, hiperssalivação e, até mesmo, fatores socioeconômicos estão associados à aceitação quanto ao uso de PT (Berg, 1993). Todos esses fatores contribuem para que a força de mordida e a função mastigatória do indivíduo seja reduzida (Gonçalves et al., 2014). Assim, pode-se hipotetizar que a ausência de uso das PT, principalmente da arcada dentária inferior, poderia acarretar alterações na arquitetura da musculatura mastigatória, e até mesmo levar a atrofia destes músculos, o que explicaria a redução na função muscular. Apesar da importância do tema, apenas um estudo piloto (Bhoyar et al., 2012) foi realizado com pacientes totalmente edêntulos, reabilitados com próteses totais convencionais duplas, em que a espessura do músculo masseter foi avaliada. Porém, neste estudo (Bhoyar et al., 2012) os pacientes edêntulos utilizavam PT antigas e foram reabilitados com novas PT duplas, não sendo possível avaliar o impacto do não uso das PT inferiores individualmente. Foi encontrado na literatura apenas um relato de caso (Schimmel et al., 2010) que avaliou as possíveis consequências da não utilização de próteses totais inferiores sobre a função mastigatória e sobre a espessura do masseter.
Além de influenciar os fatores acima citados, pesquisas (Müller et al., 1995; Meenakshi et al., 2014)indicam que a perda de dentes altera a habilidade sensorial oral dos indivíduos. Isto pode ser explicado pela complexidade do sistema neurossensorial que, na ausência do ligamento periodontal, o qual garante a propriocepção (Meenakshi et al., 2014; Mantecchini et al., 1998), torna deficiente a transmissão nervosa de informações periféricas do que ocorre no ambiente intraoral (van der Bilt et al., 2006).
A habilidade sensorial oral também é um fator que contribui para a aceitação e adaptação do paciente ao uso das próteses reabilitadoras (Müller et al., 1995). Quando a percepção intraoral é alta, possíveis imperfeições ou irregularidades na prótese, inerentes ao próprio processo de confecção, influenciam sua utilização (Berg, 1993; Müller et al., 1995; Meenakshi
19
et al., 2014). Não obstante, a habilidade sensorial oral foi relacionada à percepção do tamanho das partículas de alimentos trituradas durante os ciclos mastigatórios aptas a serem deglut idas (Engelen et al., 2004).
Apesar disso, estudos afirmam que a presença de PT melhora a habilidade sensorial oral (Meenakshi et al., 2014) e a função mastigatória (Hirano et al., 2004). Entretanto, nestes estudos, foram avaliados pacientes totalmente dentados (Hirano et al., 2004; Ladha e Verma, 2011), ou que nunca fizeram uso de PT (Müller et al., 1995),ou ainda que não tiveram suas próteses antigas substituídas (Ikebe et al., 2007). Além disso, a habilidade sensorial foi avaliada após duas a três semanas de uso das próteses (Müller et al., 1995) ou apenas um mês após instalação de novas próteses totais (Meenakshi et al., 2014). Portanto, o uso de PT convencionais bem planejadas, executadas e adaptadas são importantes na manutenção da habilidade do paciente em manipular objetos intraoralmente (Mantecchini et al., 1998).
A habilidade sensorial oral também envolve uma atividade motora, e a língua desempenha uma função essencial durante o processo mastigatório (Steele et al., 2014). Tarefas sensoriais de identificação intraoral de formas, como os testes de estereognose oral (Meenakshi et al., 2014; Mantecchini et al., 1998; Hirano et al., 2004; Ladha e Verma, 2011; Ikebe et al., 2007), requerem comportamentos motores da língua, no que diz respeito à exploração e manipulação do objeto (Steele et al., 2014). Os músculos da língua não apenas manipula m, preparam e transformam as partículas de alimento em bolo alimentar, mas são também responsáveis por sua transferência à orofaringe durante a deglutição (van der Bilt et al., 2006). Não obstante, a cinética do movimento da língua, incluindo a força lingual, depende do trabalho em conjunto com outros elementos do aparelho estomatognático, como o rebordo alveolar, os dentes, a mucosa jugal e os lábios (N’Gom e Woda, 2002), a fim de que a informação sensorial seja percebida, e o córtex cerebral sintetize a função motora adequada (Meenakshi et al., 2014). Portanto, a língua deve exercer força suficiente para a execução
20
eficiente das principais funções fisiológicas, como mastigação, deglutição, respiração, sucção e articulação da fala. No que diz respeito à fase de deglutição, principalmente em se tratando de indivíduos idosos, com ausência total de dentes e que não utilizam PT (Yamamoto et al., 2013), ocorre um aumentado risco de disfagia. Na ausência das PT, durante o movime nto fisiológico de deglutição do bolo alimentar, o contato entre a língua e o palato diminui significativamente (Kondoh et al., 2015), contribuindo para elevar as chances de pneumonia por aspiração (Langmore et al., 1998), uma vez que os resíduos alimentares permanecem por mais tempo na orofaringe, antes de serem totalmente deglutidos. Sabe-se que o tratamento reabilitador com PT é essencial no restabelecimento do contato entre língua e palato, favorecendo a deglutição adequada do bolo alimentar (Kondoh et al., 2015).
Além dos problemas acarretados pela perda dos dentes e o não uso das PT inferiores na função mastigatória e percepção intraoral dos idosos, é importante investigar o quanto a instalação e utilização de próteses novas poderia auxiliar na restauração da espessura muscular, e sua influência sobre a função mastigatória, habilidade sensorial oral e força da língua. Assim, o presente estudo se propõe a:
(1) Avaliar as possíveis consequências da não utilização de PT inferiores por pacientes idosos totalmente edêntulos sobre a espessura do músculo masseter e função mastigatória.
(2) Esclarecer se a instalação de novas PT auxilia na restauração da espessura muscular, na função mastigatória e sensorial oral de indivíduos desdentados.
(3) Verificar se há correlação entre a habilidade sensorial oral e a pressão máxima da língua.
21
2 ARTIGO: Influence of lower complete dentures use on masseter muscle and masticatory
function: a longitudinal study
Talita Malini Carletti, DDSa
Mayara Abreu Pinheiro, DDS, MSa
Thais Marques Simek Vega Gonçalves, Ph.Db Renata Cunha Matheus Rodrigues Garcia Ph.Dc.
a Graduate Student, Department of Prosthodontics and Periodontology Piracicaba Dental School, University of Campinas
Avenida Limeira, 901; Piracicaba, São Paulo – Brazil – 13414-903
b Associate Professor, Departament of Prosthodontics Federal University of Santa Catarina
Campus Reitor João David Ferreira Lima, s/n; Trindade, Florianópolis – Brazil - 88040-900
c Professor
Department of Prosthodontics and Periodontology Piracicaba Dental School, University of Campinas
Avenida Limeira, 901; Piracicaba, São Paulo – Brazil – 13414-903
Corresponding author:
Renata Cunha Matheus Rodrigues Garcia
Av. Limeira, no 901, Bairro Areião, Piracicaba, SP, Brazil, CEP: 13414-903 Phone Number: +55 19 210652-40/ Fax Number: +55 19 210652-11
22
Abstract
Aims: The aim of this study was to verify if the absence of lower complete dentures (CD) use would significantly affect mastication and oral perceptions of edentulous elderly before and after the rehabilitation with both upper and lower CD. Methods: Fifteen edentulous elderly who wore only the upper CD were selected and received new upper and lower CD. Volunteers were evaluated at baseline before CD installation and after 1, 3 and 6 months of new prosthesis use. Masticatory performance (MP) was assessed by the sieving method and expressed as the median particle size (X50 values). Masseter thickness (MT) was evaluated by ultrasonograp hy during rest and maximum voluntary contraction. Oral sensorial ability (OSA) was assessed by oral stereognosis test and maximum tongue pressure (MTP) was verified by pressure sensors on the upper CD base. Data were submitted to repeated measures ANOVA and Tukey-Kramer posthoc tests (α = .05). Correlation analysis between OSA and MTP values was verified by Person’s correlation test. Results: X50 and MTP values decreased (P < 0.05) after 1 month using new CD and remained stable (P > 0.05) for next assessments, showing chewing improveme n ts and efficiency of the tongue force. After 3 months, MT in rest position was also increased (P < 0.05), while during maximum voluntary contraction 1 month was enough to increase MT (P < 0.05). No differences were found for OSA test (P > 0.05) and no correlation was found between OSA and MTP. Conclusion: The rehabilitation with new upper and lower CD considerably improves masticatory functions of elderly who do not use lower CD.
Keywords: masseter thickness; masticatory performance; oral stereognosis; oral sensory function; tongue force.
23
Introduction
After the advent of dental implants, complete dentures (CD) are not the primary elective rehabilitation treatment for edentulous.1,2 In spite of that, CD are still used for patients who cannot undergo invasive surgical procedures, whether for medical or personal reasons or when dental implants are not financially viable, as the resorption of alveolar ridge requires the placement of grafts.3 Besides, although CD can restore aesthetics and masticatory function,4 – 7 it is common to find people who do not use a CD, especially on the lower arch. This non-use is attributed to loss of retention and stability, pain or discomfort of maladapted prostheses.8
It is known that the loss of teeth can interfere with occlusal support, reducing chewing capacity, as mandible changes the position to stabilize the grinding path.4,9 As a consequence, edentulous subjects enhance cooking time as an attempt to reduce food consistency and the particle size, weaken the diet quality.6,7 They also raise the consumption of carbohydrates and fats,6,7 which are easier to chew than fiber foods. Indeed, denture wearers present difficult ies concerning mastication process once masticatory muscle activity and masticatory performance are reduced.4,5,10
Evidently, for CD wearers, a pasty food pattern requires less effort of masticator y muscles and explains their reduced electrical activity.11 Besides, a study conducted in cadavers12 showed that the loss of occlusal support is also associated with facial muscula t ure atrophy, mainly of the masseter muscles. Other authors performed an in vivo study with rats,13 to verify whether the reduction of the diet consistency and quality has influence on masticator y muscles and affects craniofacial growth. They observed that the altered food pattern indirect ly contributed to deteriorate masticatory muscles function and induced to changes of skull forms.1 3 Thus, it becomes evident the importance of occlusal support on chewing process, nutrition and, consequently, elderly quality of life.
24
Prosthetic rehabilitation seems to present a crucial role in maintenance of masticator y function, preventing the muscle atrophy.12,14,15 Tetsuka et al. (2012)12 reported in a cadaver study that CD wearers have greater masseter muscle thickness when compared to edentulous subjects who do not use CD. According to them, the use of existing CD keeps the occlusal support and stabilize the mandible position.12 Still, a research14 revealed that the replacement of old CD increased masseter muscle thickness after 3 months of new CD use. These studies12,14,15 establish the importance of prosthetic rehabilitation and its impact on masticator y muscles to revert the muscular atrophy.
Besides muscular changes, edentulism can occasionally imply an altered oral sensory ability (OSA),16,17 due to the loss of dental proprioception. Some authors16,17 have verified that the use of new CD improves OSA once patients have adapted to their prosthesis. The tongue plays a considerable role in the intraoral detection of shapes,18 being considered the most important sites of this perception. In addition, the tongue contributes to preparing food bolus to be swallowed and transferred to the oral pharynges.18 Some findings19 evidenced that edentulous subjects without dentures present difficulties concerning the oral phase of swallowing, since the contact between tongue and palate is reduced during the food bolus transport, making it more delayed in the hypopharynx,20 leading to the risk of dysphagia.19,2 0 These episodes may elevate the chance for the life-threatening aspiration pneumonia.21
It is believed that maximum tongue pressure (MTP) can be a predictive measureme nt of oral function deterioration, whereas the tongue performs controlled movements on palate in coordination with the mandibular jaw.22 Seeing that, in a scenario of an impaired functio na l capacity of the tongue, the need for oral function examinations is increased, once dysphagia episodes might occur, especially in aged elderly.23 In CD wearers, chewing motion is facilita ted and food bolus can be proper swallowed,19,20 however, there is no evidence on the influence of tongue pressure on the masticatory function of elderly who avoid the use of lower CD.
25
Therefore, the aim of this study was to assess how the absence of lower CD significa nt ly impact on masticatory function and investigate whether the oral rehabilitation with new upper and lower CD interferes on MP, OSA, MTP and the possible consequences to the muscle thickness of edentulous elderly. Finally, we evaluated a possible correlation between MTP and OSA before and after the rehabilitation with CD.
Materials and Methods
This prospective clinical paired study was approved by the Ethics Committee from Piracicaba Dental School, University of Campinas (registration number: 56839216.9/2016). It was also registered in the database Brazilian Registry of Clinical Trials – ReBEC (code RBR-37gdst). Study participation was completely voluntary, and participants signed an infor med consent form prior to enrolling in this research.
Edentulous elderly without race or ethnics restriction from the community of Piracicaba city or those who seek for oral rehabilitation by CD at the dental clinic of the Piracicaba Dental School were included in this study. They were selected according to the following inclus io n criteria: (1) aged between 60 to 85-year-old, (2) completely edentulous for at least 6 months but not using the lower denture for at least 3 months, (3) alveolar ridges classified as type III and IV, according to Cawood and Howell (1988),24 and finally (4) salivary flow equal or higher than 0.6 ml/minute. Elderly with physical disabilities, parafunctional habits, signals, and symptoms of temporomandibular disorders were excluded. Elderly people with mental impairments were also excluded based on cognitive evaluations performed by the Brazilia n version of Mini-Mental State Examination (MMSE).25 The sample size was established on basis of a previous study14 considering the masseter muscle size in maximum voluntary contraction. The calculus indicated that 11 volunteers would be sufficient to detect differences of 0.14mm
26
on masseter muscle contraction, with a test power of 80% and an error of 5%. To compensate for possible losses, 15 elderly people were selected (Figure 1).
The stimulated salivary flow rate was estimated using a 0.02 mm thick piece of Parafilm (Parafilm M, Bemis Company, Inc., Pennsylvania, USA). The volunteer was instructed to chew with their upper CD in place one piece of Parafilm for 5 minutes, expectorating the produced saliva at 30-seconds interval into a pre-weighed container. Salivary flow rate (ml/min) was calculated by subtracting the initial weight from the final weight of the container.26
All elderly subjects were submitted to clinical examination and a medical report was filled. Sociodemographic status and information on oral mucosa and the main reason to refuse using the lower CD were also collected.
Once selected, participants had their MP, MT, OSA and MTP assessed (baseline) with their old upper CD in the mouth. After, new upper and lower CD were manufactured follow ing the conventional technique27 and adjusted to a bilaterally balanced occlusal scheme. Once
installed, subjects received verbal and written instructions on how to use and clean their new CD. They were also instructed to return to the clinic to adjust occlusal contacts and possible interferences of the new prosthesis to the alveolar ridge and oral mucosa. After no complaints on their new dentures, variables were reassessed following 1, 3 and 6 months after prosthesis use.
Masticatory performance
Portions of seventeen cubic samples (weighed approximately 3.7g) of an artificial test food (Optocal) were fabricated as previously described.28 Elderly were asked to chew one portion of Optocal for 40 masticatory cycles, mentally counted by the calibrated examiner.5 The comminuted particles were spilled up in a recipient and were let dry in for 7 days. They were fractioned in a system of 10 sieves, with aperture openings ranging from 0.5 to 5.6 mm.5 The
27
MP was calculated by means of Rosin-Rammler equation (non-linear regression analysis): Qw-
(X) = 1 - (2-X / X50) b), where Qw- represents the percentage by weight of the particles with a
diameter smaller than X (measure of sieve opening); X50 is the median particle size and corresponds to the opening of a theoretical sieve by which 50% by weight of the total chewed material would pass; and b represents the amplitude of the particle size distribution. The higher the X50, the worse is the masticatory performance.5,29
Masseter thickness
MT was evaluated using an ultrasound equipment (Just Vision Toshiba ™, Otawara, Japan, 56-mm / 8-MHz, with linear transducer), directly on device's screen with an accuracy of 0.1 mm. The evaluations were performed in a darkened room, with the subject seated in an upright position, with the Frankfort horizontal plane parallel to the ground,30,31 keeping the head comfortably relaxed and supported by the chair. The assessments were performed by a single examiner, who was previously calibrated by measuring the masseter thickness of 5 edentulous elderly individuals, within two weeks interval (K = .967). Firstly, the masseter muscle was detected by palpation aimed to place the transducer perpendicular to the direction of the muscle fibers, which is approximately 2 cm above the mandible branch.32 After, an inert hermetic gel was applied on transducer tip to avoid tissue compression.14,31,33 Then, a small pressure was applied to the cheek and the contrast between muscle and subcutaneous tissue could be noticed by requiring the elderly to tighten and relax the muscle alternately.31 Masseter muscle thickness was measured bilaterally, twice, during relaxation and maximal voluntary contraction with teeth at the maximum intercuspal position.31 Masseter thickness (mm) was expressed as the mean thickness values obtained from left and right sides, for relaxation and maximum voluntar y contraction.
28
Oral Sensory ability
Oral stereognosis test was used to measure the OSA, according to Hirano et al. (2004) protocol.33 Six geometric shapes (square, rectangle, triangle, semicircle, circle, and ellipse) measuring 8 x 8 x 2 mm were made with a raw carrot. For scoring purposes, the objects were grouped into three pairs, with respect to shape similarity: (a) square and rectangle; (b) triangle and semicircle; (c) circle and ellipse. The OSA test was performed by a single operator, and the elderly were comfortably seated in a dental chair and asked to remain with eyes closed. Each geometric piece shape was randomly placed on the mid-dorsal surface of the tongue.34 They were then allowed to freely move the piece inside the mouth aiming to recognize its shape, without time limit. Once identified, a table containing illustrations of all geometric shapes was displayed in front of the elderly, who were instructed to point the shape of the tested piece. The operator collected the answers and the time needed for identification of each piece shape. The three-point scale was used for punctuation, classifying the answers as correct (2 points); partially correct (1 point), whose forms were within the same group; and incorrect (0 points).16,35–37 Therefore, patients scored between 0 and 12 points. Higher scores represent better OSA.
Maximum tongue pressure
MTP was evaluated by power transducers composed of Standard FRS ™ 400 sensors (Interlink Electronics Sensor Technologies, Schenzen, China), with dimensions 5 mm x 38 mm x 0.3 mm. Three sensors were covered with a plastic to protect from saliva and temporaril y fixed in the upper CD base using adhesive tape (Durex Packaging Tape, 3M, São Paulo, Brazil). One sensor was fixed in the anterior region corresponding to the midline of central incisor teeth, and the other two sensors were located in the posterior region corresponding to the left and right
29
first molars.38 The upper CD containing the three sensors was positioned inside the mouth of the elderly and adjusted to show no interferences during maximum intercuspal position.38
Elderly subjects were asked to close their mouth and press the tongue against the upper CD palate as hard as they could for 14 seconds, to allow the software to record the pressure. During baseline evaluation, subjects were not using lower CD, thus they were instructed to keep the mandible in a rest position, and then forced the upper CD with maximum tongue pressure . A rest of 5 minutes was allowed and the procedure was repeated. Signals from each sensor were amplified and recorded with QuantumX MX840B amplifier (HBM, Darmstadt, Germany) and Catman Easy Software (HBM, Darmstadt, Germany).38 MTP was calculated based on the highest sum of the three measurements and expressed in N/m2.
Statistical analysis
Data homogeneity was confirmed by Shapiro-Wilk normality test. ANOVA for repeated measures was applied and Tukey posthoc test was used to identify differences between the periods of evaluation (baseline, 1, 3 and 6 months). Pearson’s correlation coefficient was used to calculate the degree of interconnection of MTP and OSA values. All analysis were performed with a significance level of 5% using SAS software version 9.3 (SAS Institute, Inc., Cary, North Carolina).
Results
During the development of this study, two elderly subjects (one man and one woman) were lost just after the insertion of the new upper and lower CD, because they changed their address to another city. Thus, only their baseline data were included for statistical purposes. Thus, the final study cohort after new prosthesis insertion consisted of 13 edentulous elders (Fig 1).
30
The socio-demographic data, time of edentulism, time and reasons for not using the lower CD and salivary flow rate of the study population are presented in Table 1. Among all elderly, women counted as the majority in the sample. Besides, most of the subjects (73.33%) had not completed the middle school, characterizing a sample with low educational level. The time of edentulism varied from 6 months to 47 years, while the time without using the lower CD ranged from 5 months to 40 years. In addition, salivary flow rate was 0.94 ± 0.59 ml/min, which is considered to be within the normal range.39
The X50 values decreased (P = 0.028) just after 1 month of new upper and lower CD use (Fig 2). Once MP is inversely proportional to X50 values, it has raised up after 1 month and remained steady after 3 (P = 0.01) and 6 months (P < 0.0001) of new dentures use. (P < 0.05) The MT during rest and maximum voluntary contraction is presented in Table 2. Since no differences in MT (P > 0.05) were found between right and left sides, data were presented according to its relaxation and contraction positions. During relaxation, MT increased (P = 0.0002) after 3 months of new dentures use, increasing approximately 9.81%. More quickly, MT during maximum voluntary contraction increased (P = 0.024) just after 1 month of new dentures use, and continued to increase with time, until 6 months (P < 0.0001).
There were no differences (P > 0.05) in the oral stereognosis scores before and after any periods of new dentures use (baseline = 8.23 ± 2.31; 1 month = 8.62 ±2.75; 3 months = 6.91 ± 3.27; and 6 months = 6.85 ± 3.00). Time of responses were also similar before and after CD use (baseline = 25.37 ± 9.42; 1 month = 16.63 ± 10.09; 3 months = 16.57 ± 9.45; and 6 months = 17.09 ± 11.32).
Figure 3 shows a remarkable decreasing of MTP values (P = 0.0001) just after 1 month of new prosthesis use. It can also be noted that MTP was not recovered even after 6 months of using the upper and lower CD (P = 0.0032). The Pearson's coefficient of MTP and OSA was obtained (r =0.08; P = 0.57) and no significant correlations were found.
31
Discussion
Prosthetic treatment involving upper and lower CD is one of the most common procedures in the daily routine.2 However, several edentulous people do not use their lower CD and evidences are needed to know the influence of this condition on the masticatory system. The present study evaluated MP, MT, OSA and MTP after upper and lower CD insertion, in elderly people who did not use their lower prosthesis.
The most common reason for our study population refuse using the lower CD was its inadequate retention, followed by financial reasons, fracture, and loss of the denture itself. In spite of the reason for not using the lower CD is not our dependent variable, it meets with Berg et al. (1993)8 who reported determinants of subjects’ acceptance of CD, including not only those related to mechanical properties of dentures but also to the oral conditions and individ ua l attitudes towards the oral rehabilitation.8 The decision for using the lower denture may be attributed to the psychological factors involved in the way subjects face the edentulism as a handicap and how satisfying they feel during denture construction.3,40 The success of an oral rehabilitation with CD also depends on personal reasons and good interpersonal approaches between patient and dentist.40
As expected MP was improved within 1 month of both, upper and lower CD use. Obviously, the presence of artificial teeth in both arches recovered the occlusal support and it implied on a raised MP, as the surface area for food interposition was established.4,40 Our findings corroborate with a previous study9 which verified that the higher the number of tooth occlusal units, including premolars and molars, the better the masticatory function of edentulous subjects wearing CD.9 Likewise, even in partially edentulous subjects, after prosthetic rehabilitation, it has been reported an increased masticatory performance, as the maintena nce of occlusion was obtained.32
32
Regarding the recovery of occlusal support, provided by new CD, masticatory muscles changes are expected, especially for masseter muscles thickness.12,14,15 In this sense, our elders needed 3 months of upper and lower CD use to increase their MT, measured in the relaxed state. This is consistent with data related by Bhoyar et al. (2012)14 that observed an improvement of masseter thickness in relaxed states within 3 months after prosthetic rehabilitation. On the other hand, MT during maximum voluntary contraction recovered even faster in our study patients, with improvements after only 1 month of new prosthesis use in both dental arches. It is important to point that our data showed a remarkable increase in MT thickness during voluntar y contraction (11.41 ± 1.92) when compared to baseline assessments. Similar values (11.98 ± 1.84) were found by a cross-sectional study of Muller et al.,42 during contracted states of masseter muscles for edentulous patients wearing CD on both arches. In addition, the last authors42 found that the increased MT in CD wearers was not different when compared to those using implant-supported dental prosthesis, suggesting that CD is enough to warrant muscle thickness recovering. Therefore, from our prospective clinical trial it can be advocated that the use of conventional CD, specially the lower one, was responsible for the gain on masseter thickness after the period of 6 months. These results can be explained by the reestablishment of occlusal vertical dimension, which promotes masseter muscle fibers stretch and, consequently, stimulation of protein synthesis, new sarcomeres development and muscle size enlargement.14 Concerning that the insertion of lower dentures might have affected the tongue movements and its position,41 it is reasonable to suppose that OSA scores could be influe nced by both CD use. However, our OSA scores were not different before and after new upper and lower CD insertion, and it contrasts with some authors,16,36 who found increased OSA values after CD insertion. These contradictio ns may be due to methodological differences since the last authors16,36 have used thicker and larger test pieces,16 shape forms made of acrylic resin,3 6 or assessed edentulous non-experienced denture wearers.16 On the other hand, similar to our
33
study, Garret et al. (1994)35 verified no differences between OSA values of edentulous patients with or without their CD in the mouth. Given that the mechanism of identification of shape pieces involves the physiological sensory-motor receptors, mainly present on tongue dorsal surface,18 the replacement of new upper CD seems not impact the OSA test. In this sense, previous researchers have also shown that denture palate coverage does not affect the identification of the forms.34,43 Accordingly, it is supposed that the use of lower CD would not impact on OSA values, as the lateral region of the tongue is the greatest part in contact with these prostheses.
MTP was drastically reduced within 1 month of using the new upper and lower CD, which was not recovered even after 6 months of prosthesis use. Despite the importance of this topic, there is a lack of well-designed studies concerning MTP in CD wearers. A previous report44 verified similar values of MTP in elderly people, however, no mention was made if their elders were completely edentulous, dentures wearers or even dentate, making it diffic ult to compare data. Furthermore, during mastication, the tongue may compensate the missing teeth41, occupying the correspondent area of the alveolar ridge, where it is possible to act in an exacerbated function on placement of food against the occlusal surface of the upper CD artificial teeth. Thus, it can be hypothesized that the decreased MTP is probably due to the new position the tongue assumes in the oral cavity after the insertion of the lower CD. Additiona l ly, it was expected the reduced MTP could have some influence on OSA data. However, there is no correlation between MTP and OSA, contributing to explain our findings.
It is important to mention that, as the main purpose of the present study was to identify the impact of the lower CD use, a paired design was chosen, in which participants were prospectively evaluated. Nevertheless, several studies4,9,32,36 are available in the literat ure showing the improvement of masticatory function after the CD replacement, even with impla nt support. On the other hand, studies with a long-term assessment are necessary to identify if
34
OSA and MTP would be changed with time. It must also be emphasized that our sample presented great variability in the time of edentulism, as well as in the time without using the lower CD. Thus, further studies are also necessary to verify the impact of the period of edentulism on masticatory function. In addition, a control group may be incorporated to predic t quantitative differences on masticatory muscles and chewing function of edentulous elderly, allowing comparisons between upper and lower CD wearers and those who avoid using the lower CD.
The clinician should be aware that using lower CD is crucial, not only for masticat io n improvement but also for muscle maintenance. Thus, elderly patients must be informed about the importance of wearing both CD and encouraged to use them, even facing difficult ies concerning the lower prosthesis adaptation.
Conclusion
The absence of lower CD use significantly impacts on the masticatory function of edentulous elderly. The X50 values decreased over time, which explained the increased MP, and MT improved with the use of new upper and lower CD, showing a recovery of masseter muscles thickness. Also, MTP values dropped after insertion of the new dentures. OSA was not affected before or after the use of both CD, and no correlations were found between MTP and OSA.
Acknowledgements
This research was supported by São Paulo Research Foundation (FAPESP, grant number 2015/21704-1) Brazil.
References
35
mandible: a Delphi method survey of academic prosthodontists in the United States. J Am Dent Assoc. 2012;143(8):881-889.
2. White GS. Treatment of the edentulous patient. Oral Maxillofac Surg Clin North Am. 2015;27(2):265-272.
3. Carlsson GE, Omar R. The future of complete dentures in oral rehabilitation. A critical review. J Oral Rehabil. 2010;37(2):143-156.
4. Fontijn-Tekamp FA, Slagter AP, van Der Bilt A, et al. Biting and chewing in overdentures, full dentures, and natural dentitions. J Dent Res. 2000;79(7):1519-1524.
5. Slagter AP, Bosman F, van der Bilt A. Comminution of two artificial test foods by dentate and edentulous subjects. J Oral Rehabil. 1993;20(2):159-176.
6. Nakata M. Masticatory function and its effects on general health. Int Dent J. 1998; Dec;48(6):540-8. Review: Erratum in: Int Dent J 1999 Feb (1):preceding 3.
7. N’Gom PI, Woda A. Influence of impaired mastication on nutrition. J Prosthet Dent. 2002;87(6):667-673.
8. Berg E. Acceptance of full dentures. Int Dent J. 1993;43(3 Suppl 1):299-306.
9. Yamashita S, Sakai S, Hatch JP, Rugh JD. Relationship between oral function and occlusal support in denture wearers. J Oral Rehabil. 2000;27(10):881-886.
10. van Kampen FMC, van der Bilt A, Cune MS, Bosman F. The Influence of various attachment types in mandibular implant-retained overdentures on maximum bite force and EMG. J Dent Res. 2002;81(3):170-173.
11. Farias-Neto A, Martins APVB, Rizzatti-Barbosa CM. The effect of loss of occlusal support on mandibular morphology in growing rats. Angle Orthod. 2012;82(2):242-246.
36
12. Tetsuka M, Saga T, Nakamura M, Tabira Y, Kusukawa J, Yamaki K-I. Relations hip between masseter muscle form and occlusal supports of remaining teeth. Kurume Med J. 2012;59(1-2):5-15.
13. Kiliaridis S, Engström C, Chavez LME. Influence of masticatory muscle function on craniofacial growth in hypocalcemic rats. Eur J Oral Sci. 1992;100(6):330-336.
14. Bhoyar PS, Godbole SR, Thombare RU, Pakhan AJ. Effect of complete edentulism on masseter muscle thickness and changes after complete denture rehabilitation: an ultrasonographic study. J Investig Clin Dent. 2012;3(1):45-50.
15. Schimmel M, Loup A, Duvernay E, Gaydarov N, Muller F. The effect of mandibular denture abstention on masseter muscle thickness in a 97-year-old patient: a case report. Int J Prosthodont. 2010;23(5):418-420.
16. Müller F, Link I, Fuhr K, Utz KH. Studies on adaptation to complete dentures. Part II: Oral stereognosis and tactile sensibility. J Oral Rehabil. 1995;22(10):759-767.
17. Meenakshi S, Gujjari AK, Thippeswamy HN, Raghunath N. Evaluation of oral stereognostic ability after rehabilitating patients with complete dentures: in vivo study. J Indian Prosthodont Soc. 2014;14(4):363-368.
18. Steele CM, Hill L, Stokely S, Peladeau-Pigeon M. Age and strength influences on lingua l tactile acuity. J Texture Stud. 2014;45(4):317-323.
19. Kondoh J, Ono T, Tamine K, et al. Effect of complete denture wearing on tongue motor biomechanics during swallowing in edentulous older adults. Geriatr Gerontol Int. 2015;15(5):565-571.
20. Yamamoto H, Furuya J, Tamada Y, Kondo H. Impacts of wearing complete dentures on bolus transport during feeding in elderly edentulous. J Oral Rehabil.
2013;40(12):923-37
931.
21. Langmore SE, Terpenning MS, Schork A, et al. Predictors of aspiration pneumonia: how important is dysphagia? Dysphagia 1998;13:69-81.
22. Hori K, Ono T, Nokubi T. Coordination of tongue pressure and jaw movement in mastication. J Dent Res. 2006;85(2):187-191.
23. Tsuga K, Yoshikawa M, Oue H, et al. Maximal voluntary tongue pressure is decreased in Japanese frail elderly persons. Gerodontology. 2012;29(2):1078-1085.
24. Cawood JI, Howell RA. A classification of the edentulous jaws. Int J Oral Maxillo fac Surg. 1988;17(4):232-236.
25. Folstein MF, Folstein SE, McHugh PR. “Mini-mental state”. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12(3):189-198.
26. van der Bilt A, Engelen L, Pereira LJ, Glas HW, Abbink JH. Oral physiology and mastication. Physiol Behav. 2006;89(1):22-27.
27. Zarb GA, Hobkirk J, Eckert S JR. Prosthodontic treatment for edentulous patients. St Louis: Mosby; 2013. 464 p.
28. Pocztaruk RDL, Frasca LCDF, Rivaldo EG, Fernandes EDL, Gavião MBD. Protocol for production of a chewable material for masticatory function tests (Optocal - Brazilia n version). Braz Oral Res. 2008;22(4):305-310.
29. Fontijn-Tekamp FA, Slagter AP, van der Bilt A, van’t Hof MA, Kalk W, Jansen JA. Swallowing thresholds of mandibular implant-retained overdentures with variable portion sizes. Clin Oral Implants Res. 2004;15(3):375-380.
38
30. Emshoff R, Emshoff I, Rudisch A, Bertram S. Reliability and temporal variation of masseter muscle thickness measurements utilizing ultrasonography. J Oral Rehabil. 2003;30(12):1168-1172.
31. Serra MD, Duarte Gavião MB, dos Santos Uchôa MN. The use of ultrasound in the investigation of the muscles of mastication. Ultrasound Med Biol. 2008;34(12):1875-1884.
32. Goncalves TMSV, Campos CH, Goncalves GM, de Moraes M, Rodrigues Garcia RCM. Mastication improvement after partial implant-supported prosthesis use. J Dent Res. 2013;92(12 Suppl):189S-194S.
33. Hirano K, Hirano S, Hayakawa I. The role of oral sensorimotor function in masticatory ability. J Oral Rehabil. 2004;31(3):199-205.
34. Mantecchini G, Bassi F, Pera P, Preti G. Oral stereognosis in edentulous subjects rehabilitated with complete removable dentures. J Oral Rehabil. 1998;25(3):185-189.
35. Garrett NR, Kapur KK, Jochen DG. Oral stereognostic ability and masticatory performance in denture wearers. Int J Prosthodont. 1994;7(6):567-573.
36. Ikebe K, Amemiya M, Morii K, Matsuda K, Furuya-Yoshinaka M, Nokubi T. Comparison of oral stereognosis in relation to age and the use of complete dentures. J Oral Rehabil. 2007;34(5):345-350.
37. Ladha KG, Verma M. The effect of oral submucous fibrosis on oral stereognostic abilit y. A preliminary study. J Prosthodont. 2011;20(6):428-431.
38. Meirelles L, Cunha Matheus Rodrigues Garcia R. Influence of bruxism and splint therapy on tongue pressure against teeth. Cranio. 2016;34(2):100-4.
39
clinical study to compare between resting and stimulated whole salivary flow rate and pH before and after complete denture placement in different age groups. J Indian Prosthodont Soc. 2015;15(4):356.
40. Fueki K, Igarashi Y, Maeda Y, et al. Factors related to prosthetic restoration in patients with shortened dental arches: a multicentre study. J Oral Rehabil. 2011;38(7):525-532.
41. Kikutani T, Tamura F, Nishiwaki K, et al. Oral motor functio n and masticatory performance in the community-dwelling elderly. Odontology. 2009;97(1):38-42.
42. Müller F, Hernandez M, Grütter L, Aracil-Kessler L, Weingart D, Schimmel M. Masseter muscle thickness, chewing efficiency and bite force in edentulous patients with fixed and removable implant-supported prostheses: a cross-sectional multicenter study. Clin Oral Implants Res. 2012 Feb;23(2):144-50.
43. Dalaya MV. A study of oral stereognostic proficiency in dentulous and edentulous persons. J Clin Diagnostic Res. 2014;8(5):6-11.
44. Furlan RMMM, Valenti AF, Perilo TV de C, et al. Quantitative evaluation of tongue protrusion force. Int J Orofacial Myology. 2010;36(1980):33-43.
40
