A incapacidade de produzir repetidamente no tempo um determinado nível de força ou potência muscular designa-se por fadiga neuromuscular. A etiologia da fadiga muscular tem atraído o interesse de pesquisadores há mais de um século. Contudo, os seus agentes e locais definitivos permanecem ainda por serem identificados. Este trabalho teve por objetivo avaliar a fadiga neuromuscular por meio da análise de frequência do sinal eletromiográfico dos músculos masseter e temporal anterior de ambos os lados em 3 grupos distintos: sujeitos saudáveis assintomáticos para disfunção temporomandibular (DTM), pacientes acometidos por DTM tratados com placa oclusal resiliente e pacientes acometidos por DTM tratados com placa oclusal rígida. Para isso, participaram da pesquisa 100 sujeitos assintomáticos para DTM e 30 pacientes com DTM subdivididos em 2 grupos: tratados com placa rígida tipo FARC; e tratados com placa resiliente. Todos realizaram exame eletromiográfico antes e após o tratamento com placa oclusal. Os resultados demonstraram que houve diferenças estatisticamente significantes na comparação da taxa de fadiga avaliada antes e após o tratamento com placa oclusal, tanto para o grupo Placa FARC como para o grupo Placa Soft. Houve diminuição da taxa de fadiga após o tratamento com placa para os músculos masseter esquerdo e temporal anterior direito para o grupo Placa Soft; e diminuição da taxa de fadiga após o tratamento para o músculo temporal anterior esquerdo para o grupo Placa FARC. Pode-se concluir que o tratamento com ambos tipos de placa oclusal foi eficiente na redução da taxa de fadiga neuromuscular em pacientes acometidos por DTM. / The repeated failure to produce in time a certain level of strength or muscle power is called neuromuscular fatigue. The etiology of muscle fatigue has attracted the interest of researchers for over a century. However, their agents and local definitive remain yet to be identified. This work aimed to evaluate neuromuscular fatigue by frequency analysis of the electromyographic signal of the masseter and anterior temporal muscles of both sides in three different groups: healthy subjects asymptomatic for temporomandibular disorders (TMD), patients suffering from TMD treated with resilient occlusal splint and patients suffering from TMD treated with rigid occlusal splint. For this, 100 subjects asymptomatic for TMD participated in the survey and 30 patients with TMD subdivided into 2 groups: treated with rigid splint type FARC, and treated with resilient splint. All electromyographic examinations performed before and after treatment with occlusal splint. The results showed that statistically significant differences when comparing the rate of fatigue assessed before and after treatment with occlusal appliance, for both groups. There was a decrease in the rate of fatigue after treatment with occlusal splint to the left masseter and right anterior temporal in the group Soft Splint; and decrease in the rate of fatigue after treatment for left anterior temporal muscle to the group FARC Splint. It can be concluded that treatment with both types of occlusal splint was effective in reducing the rate of neuromuscular fatigue in patients affected by TMD.

Objectives: Previous studies in the Oral Neurophysiology Laboratories in Dundee have defined the electromyographic properties of the inhibitory jaw reflex that can be evoked in human subjects by electrical stimulation of the lip. This reflex, in contrast with the more widely studied biphasic inhibitory reflexes evoked by stimulation of intra-oral nerves, consists of just a single phase of inhibition and usually requires the application of stimuli which excite nociceptive nerves. The aims of the present studies were to define the mechanical manifestations of this reflex in the form of changes in biting forces, and to investigate whether the mechanical manifestation of the inhibitory jaw reflex evoked by stimulation of the human upper lip, can be modulated by experimentally-controlled conditions that mimic symptoms of a myogenous temporomandibular disorder. Methods: Three series of experiments were performed on 49 volunteer subjects in total. The experiments involved recording bite forces between the anterior teeth and electromyograms (EMGs) from the masseter muscles. Transcutaneous electrical stimuli were applied to the hairy skin of upper lip while the subjects maintained a biting force of around 50N with the aid of visual feedback. In the first series of experiments, a range of electrical stimuli below and above the nociceptive threshold was delivered. In the second set of experiments, double stimuli with a range of different inter-stimulus intervals were applied. Finally in a third series of experiments, electrical stimulation was repeated before, immediately after, and 5 and 10 minutes following a 3-minute accelerated chewing task. This task consisted of chewing 1.5g of a tough chewing gum at 1.5 times the subject’s natural chewing rate and in 18 cases, muscle fatigue and/or pain were reported by the subjects. Results: Following stimulation at intensities that were described as sharp or painful, all the subjects showed both a suppression of the masseter EMG and a reduction of biting force. When analysing the maximum responses in each subject, the mean reduction in the EMG inhibition was to 15.78 ± 14.4% and 10.39 ± 7.92% of the baseline (for the ipsi- and contra-lateral EMGs respectively), whereas the biting force was reduced only to 83.98 ± 11.04% of baseline (+ S.D.). The latencies of onset of these responses were: 38.17 ± 3.58ms, 38.97 ± 4.49ms and 51.83 ± 6.23ms respectively. The response observed in the force record was weaker than in that observed in either EMG (Paired t tests, P < 0.005 in both cases). When applying double stimuli, it was found that the prolongation of the EMG inhibitory jaw reflex (to 144.70 ± 46.93% of the control level) evoked by double stimulation of the upper lip (with a 10 ms inter-stimulus interval) resulted in a greater increase in the depth of the accompanied relaxation (to 223.63 ± 70.88% of that seen in the control responses) compared to a relatively smaller increase in the duration of the relaxation (to 128.32 ± 27.23% of that seen in the control responses). Following the accelerated chewing task, 17 out of 22 subjects reported pain and/or fatigue in one or both of the masseter muscles. The integral for the bite force relaxation significantly decreased in size immediately following the conditioning procedure (to 76.04 ± 35.63% of the control level, P = 0.014; single sample t-test with Bonferroni correction, test value 100). Conclusion: The inhibitory jaw reflex evoked by stimulation of the human lip can be demonstrated mechanically as well as electromyographically although the mechanical version of the response appears less marked. In addition to that, the onset of reflex relaxation in bite force lags several milliseconds behind the corresponding reductions in electromyographic activity. The depth of force relaxation can be increased by increasing the duration of EMG recorded inhibitory reflex. Finally, the results from a chewing task suggest that induced acute pain and/or fatigue cause clear changes in the mechanical manifestation of this inhibitory jaw reflex.

INTRODUÇÃO: Indivíduos com deformidade dentofacial apresentam alterações faciais verticais e/ou ântero-posteriores, com conseqüente presença de oclusão instável e pobre intercuspidação dentária, que podem causar comprometimentos nas funções do Sistema Miofuncional Orofacial sendo verificadas geralmente adaptações funcionais para cada tipo de deformidade. O objetivo desta tese foi realizar um ensaio clínico randomizado cuja variável de relevância foi a resposta funcional da mastigação após intervenção fonoaudiológica experimental em pacientes submetidos à cirurgia ortognática. MÉTODOS: Todos os pacientes submetidos à cirurgia ortognática, num período de 12 meses, que concordaram em participar do estudo. Os pacientes foram randomicamente distribuídos em dois grupos: grupo experimental (EG=6) e grupo de instrução (IG=5). O grupo controle foi constituído por indivíduos com oclusão dentária normal (CG=6). Os pacientes do EG foram submetidos a um protocolo de tratamento fonoaudiológico estruturado em seis sessões com enfoque técnico na função da mastigação. Os pacientes do IG foram submetidos a duas sessões supervisionadas de instruções direcionadas aos cuidados com a mastigação (tratamento padrão). As variáveis adotadas para a comparação dos grupos foram obtidas por meio de avaliação clínica e de avaliação eletromiográfica de superfície (EMGs), sendo elas: mobilidade orofacial, desempenho durante as funções de deglutição/mastigação, movimentos mandibulares e atividade elétrica dos músculos mastigatórios. Esses parâmetros foram avaliados pré e pós-cirúrgico longo prazo (12 meses). Os indivíduos do CG foram testados em dois momentos distintos com um intervalo de 12 meses entre os mesmos. RESULTADOS: após um ano da realização da cirurgia ortognática o EG apresentou melhora significativa na mobilidade orofacial (p = 0,001); no desempenho durante as funções de deglutição/mastigação (p = 0,001); na lateralização da mandíbula (p = 0,001) e na protrusão da mandíbula (p = 0,011). Os dois grupos de pacientes (EG e IG) não apresentaram diferenças significativas para os resultados da EMGs atividade elétrica dos músculos mastigatórios - nos diferentes momentos. O CG não apresentou variações significativas de desempenho para qualquer das variáveis investigadas na comparação entre os diferentes momentos. CONCLUSÃO: os resultados sugerem que o tratamento fonoaudiológico experimental demonstrou resultado positivo. Não foram identificados efeitos adversos. Houve aderência ao tratamento. O tamanho da amostra, embora relevante para a área, exige cuidado quanto ao poder de generalização dos resultados / INTRODUCTION: Individuals with dentofacial abnormalities present facial alteration - in the vertical and/or anterior posterior plane -, with consequent unstable occlusion and poor dental intercuspation. These alterations can cause impairments in the functions of the orofacial myofunctional system, and functional adaptations are usually observed for each type of deformity. The aim of this thesis was to conduct a randomized clinical trial that the relevance variable was the functional response of the mastication after the rehabilitative experimental program in patients submitted to orthognathic surgery. METHODS: All patients underwent to the orthognathic surgery, in a period of 12 months, which agreed to participate of this study. Patients were randomized assigned into two groups: experimental group (EG = 6) and group instruction (GI = 5). A control group consisted of individuals with normal dental occlusion (CG = 6). The EG patients underwent a structured treatment protocol, in six sessions, with technical focus was on the function of mastication. Patients in the IG were submitted to two supervised sessions for instruction related to the look out of mastication (standard treatment). The variables adopted for the comparison groups were obtained by clinical evaluation and by assessment of surface electromyography (sEMG) that was: orofacial mobility, masticatory/deglutition clinical performance, jaw movements and muscle activation (electrical activity) of the masticatory muscles. These parameters were evaluated pre-and postoperative long-term (12 months). The subjects in the CG were also tested in two distinct moments, with a one year interval. RESULTS: One year after orthognathic surgery, EG showed a significant improvement in orofacial mobility (p=0.001), masticatory/deglutition clinical performance (p=0.001), jaw lateralization (p=0.001) and jaw protrusion (p=0.011). Both groups of patients presented no significant differences for the sEMG results. The CG presented no significant variations in performance for any of the investigated variables when comparing the different time points. CONCLUSION: The results suggest that the rehabilitative experimental program demonstrated a positive result. No adverse effects were identified. There was adherence to the treatment. The sample size, although relevant to the area, requires careful about the power of generalization of the results.

Introdução: A Síndrome de Sjögren (SS) é uma doença crônica, sistêmica, autoimune que afeta diversas glândulas, principalmente lacrimais e salivares, causando sensação de olhos e boca secos. Objetivo: Investigar as características miofuncionais orofaciais e a presença de sinais e sintomas de Desordem Temporomandibular (DTM) em portadores de Síndrome de Sjögren, comparativamente a um grupo controle. Metodologia: Estudo transversal, prospectivo descritivo e comparativo. Participaram 19 mulheres (média de idade: 33,2±8,7 anos), seis portadoras da forma primária da SS e treze portadoras da forma secundária da SS.Vinte mulheres saudáveis, pareadas por idade (média de idade 31,9±9,3 anos) compuseram o grupo controle (grupo C). As avaliações e os exames realizados foram: Protocolo de Avaliação Miofuncional Orofacial com Escores (AMIOFE), medida dos limites de movimentos mandibulares, pressão de língua e de lábios (Iowa Oral PerformanceInstrument- IOPI), palpação dos músculos e das articulações temporomandibulares (ATMs), Instrumento de Autoavaliação da Alimentação (EAT-10), questionário para investigação dos sinais e sintomas de desordem temporomandibular (ProDTMmulti), escala de dificuldade para mastigar, escala de funcionalidade mandibular (JFLS) e eletromiografia de superfície (EMG) dos músculos da mastigação e deglutição. Os dados categóricos ou com distribuição não normal foram analisados pelo teste estatístico não paramétrico de Mann-Whitney e aqueles com distribuição normal pela Análise de Variância (ANOVA), seguida do pós-teste. O nível de significância adotado foi P< 0,05. Resultados: O grupo SS apresentou diferenças estatisticamente significantes na comparação com o grupo C, com piores condições na avaliação miofuncional orofacial, quanto ao aspecto/postura das estruturas orais, a mobilidade de lábios, língua, bochechas e mandíbula, assim como nas funções de mastigação, deglutição e respiração. Foram também estatisticamente menores a abertura bucal, a distância interincisal horizontal, a pressão da língua na protrusão e elevação (valor da média e máximo), bem como no valor da deglutição. Os portadores de SS mostraram, por meio de escores,maior dificuldade para mastigar e risco de disfagia (EAT-10). Também foram maiores no grupo SS, comparado ao controle, os escores de dor à palpação, a severidade dos sinais e sintomas de DTM (ProDTMmulti) e a limitação funcional da mandíbula (JFLS). A atividade dos músculos mastigatórios nas provas de máxima contração voluntária (MCV) foi menor no grupo SS com um maior impacto por ciclo na mastigação unilateral esquerda. As mudanças temporais na deglutição, com duração aumentada para a consistência líquida e reduzida na deglutição de sólido também foram significantes no grupo SS, comparado ao grupo C. Conclusão: os resultados mostraram que os portadores de Síndrome de Sjögren apresentam prejuízos acentuados na musculatura e funções orofaciais e sinais e sintomas de DTM moderados, uma percepção de grande limitação funcional. Portanto, as consequências da SS não se resumem às queixas subjetivas, mas sim envolvem comprometimentos reais do sistema e funções estomatognáticas. / Introduction: Sjögren\'s syndrome (SS) is a chronic, systemic, autoimmune disease that affects several glands, mainly lacrimal and salivary, causing dry eyes and mouth. Objective: To investigate myofunctional orofacial characteristics and the presence of signs and symptoms of Temporomandibular Disorderers (TMD) in Sjögren\'s Syndrome patients compared to a control group. Methodology: Prospective descriptive and comparative cross-sectional study. Participants were 19 women (mean age: 33,2±8,7), with primary (n = 6) or secondary (n = 13) Sjögren Syndrome (SS group) and 20 healthy women, matched by age (mean age: 31,9 ±9,3-C group). The evaluations and examinations were performed with the Protocol of Orofacial Myofunctional Evaluation with Scores (OMES), measurement of limits of mandibular movements, tongue and lip pressure measure with Iowa Oral Performance Instrument (IOPI), Eating Assessment Tool (EAT-10), Temporomandibular Muscles and Temporomandibular Joint (TMJ) palpation, questionnaire for investigation of signs and symptoms of temporomandibular disorder (ProDTMmulti), difficulty of Chewing Scale, Jaw Functional Limitation Scale (JFLS), and Surface Electromyography (sEMG) of chewing and swallowing muscles. The categorical or non-normal distribution data were analyzed by nonparametric Mann-Whitney statistical test and data with normal distribution analyzed by Variance Analysis (ANOVA), followed by post-test. The level of significance was P<0.05. Results: The SS group presented statistically significant differences in comparison with group C, with worse conditions in the orofacial myofunctional evaluation, regarding the appearance / posture of oral structures, mobility of lips, tongue, cheeks and mandible, as well as in the functions of chewing, swallowing and breathing. The oral opening, horizontal interincisal distance, tongue pressure on protrusion and elevation (mean and maximum value), as well as the value of swallowing were also statistically lower. SS patients showed by scores greater difficulty in chewing and risk of dysphagia (EAT-10). There were also higher in the SS group, compared to control, pain scores at palpation, the severity of TMD signs and symptoms (ProDTMmulti) and functional limitation of the mandible (JFLS). The activity of the masticatory muscles in the tests of maximum voluntary contraction (MCV) was also lower in the SS group with a greater impact per cycle during the masticatory EMG. The temporal changes in swallowing, with increased duration for the liquid consistency and reduced for solid swallowing were also significant in the SS group, compared to the control. Conclusion: the results showed that patients with Sjögren\'s Syndrome present marked impairments in musculature and orofacial functions and moderate TMD signs and symptoms, a perception of great functional limitation. Therefore, the consequences of SS are not limited to subjective complaints, but rather involve real system compromises and stomatognatic functions.

The jaw adductor muscles in strepsirrhines were dissected and their fiber architecture was quantified. Bite force and leverage were estimated using values for physiological cross-sectional area (PCSA) of the jaw adductors and lateral photographs of skulls. Jaw adductor mass, PCSA, fiber length, and bite force scale isometrically to body size. An experiment carried out at the Duke Lemur Center demonstrated that ingested food size also scales isometrically to body size. Folivorous strepsirrhines are characterized by short jaw adductor fibers, uniformly small ingested food size, large masseter and medial pterygoid muscles (in PCSA and mass), and large estimated bite force for their jaw length. Large-bodied folivores have especially large jaw adductors. Small-bodied folivores have especially short jaws, but do not have especially large jaw adductors. Folivores probably can generate large bite forces; they possess short jaws (short bite load arms) and/or large jaw adductor cross-sectional areas. Frugivorous strepsirrhines are characterized by long jaws, large (but variable) ingested food size, large temporalis muscles, and small estimated bite force for their jaw length. Frugivores have long jaw adductor fibers that likely maintain tension during the ingestion of large objects (e.g., fruits). The temporalis is large in frugivores, not because it has superior leverage during incision, but because its fibers likely do not stretch as much at wide gapes as those of the other adductors. Correlations between osteological landmarks and jaw adductor dimensions in strepsirrhines were used to infer jaw adductor dimensions in <em>Adapis parisiensis</em> and <em>Leptadapis magnus</em> (Adapinae) from the Eocene of Europe. Inferred PCSA and lateral photographs were used to estimate bite force and leverage in these adapines. An analysis of shearing quotients was also performed. Inferred jaw adductor mass, PCSA, bite force, and shearing quotients are great in adapines relative to extant strepsirrhines. All anatomical signals suggest a diet rich in tough leaves and other structural plant parts, perhaps with some small fruits. <em>Adapis</em> was likely more folivorous than <em>Leptadapis</em>. / Dissertation

Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 3 uppsatser.

Chimpanzees spend ~40% of their day chewing fruits, seeds, and tough leaves and pith, while in contrast modern humans spend significantly less time eating (5%), and the foods that they consume are extremely soft and processed. How have these differences, especially the advent and increasing use of foods processing techniques, influenced masticatory effort and ultimately the morphology of the jaws and teeth? This dissertation addresses this question by measuring the effects that early hominin food processing methods (slicing, pounding, and roasting) have on food material properties, masticatory performance and functional integration of the teeth and jaws. Using standard testing techniques, the material properties of plant tubers and meat were quantified. Processing had contrasting effects on the properties of these foods, and were correlated with masticatory performance changes measured in human experiments. Mechanical processing techniques decreased tuber toughness, leading to lower chew force (CF). Roasting further decreased tuber toughness and other material properties, which led to lower comminution efficiency (CE) and CF. In direct contrast to tubers, mechanical processing techniques did not alter meat toughness, yet did increase CF and CE. Roasting the meat also increased CF and CE, likely because of higher toughness and stiffness, coupled with less elastic energy loss. The generation of lower masticatory forces resulting from processing have undoubtedly affected cranio-dental morphology. In particular, it is hypothesized that forces functionally integrate the masticatory system, and reduced forces, especially in modern human populations, lead to malocclusions (dis-integration). An animal experiment was performed to test this hypothesis, and the results indicate that masticatory effort (eating hard or soft foods) coordinates jaw and dental growth. Further testing the hypothesis, the effects of morphology on masticatory function were studied by coupling subject masticatory performance with occlusal scores. Multiple regressions of occlusion and tooth size explained a high proportion of masticatory performance variance (significantly more than tooth size alone), suggesting that occlusal integration does indeed affect masticatory function. Taken together, the results of this dissertation document the significant reductions in hominin masticatory forces and changes in cranio-dental growth and integration that may have resulted from the use of food processing techniques. / Human Evolutionary Biology

This thesis investigates how individuals perceive and describe the texture of solid foods. To date, minimal research has been done to investigate individual texture perception and the influence of oral physiological parameters. The current study is a three phase project. First, using Temporal Dominance of Sensation (TDS), the dynamic process of panellists’ texture perception was investigated. The results showed two very distinct groups of panellists who differed based on their texture perception response. The second phase attempted to understand these groups by testing oral physiological parameters surrounding the individuals and their bolus. Few significant results were found between the two groups indicating. The final phase of this project supported the hypothesis that vocabulary use was not a factor in the division of the two groups. To conclude, saliva, both in regard to the amount and composition, seems to have a large influence on how individuals perceive the texture of solid food. / New Zealand Ministry of Business, Innovation and Employment (MBIE) under contract C02X0807 (Food Structure Platform).

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Submitted by Vivian Barnabé Policastro null (vivianbpolicastro@foar.unesp.br) on 2016-05-12T16:12:26Z No. of bitstreams: 1 Dissertação final - Vivian B. Policastro.pdf: 1510147 bytes, checksum: 9f419c0a576b25cc5a8d89d0bb0d04a1 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-16T13:03:00Z (GMT) No. of bitstreams: 1 policastro_vb_me_arafo.pdf: 1510147 bytes, checksum: 9f419c0a576b25cc5a8d89d0bb0d04a1 (MD5) / Made available in DSpace on 2016-05-16T13:03:00Z (GMT). No. of bitstreams: 1 policastro_vb_me_arafo.pdf: 1510147 bytes, checksum: 9f419c0a576b25cc5a8d89d0bb0d04a1 (MD5) Previous issue date: 2016-04-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Overdentures retidas por um implante têm sido apresentadas como uma opção de tratamento para pacientes que apresentam problemas relacionados à retenção e estabilidade de suas próteses totais inferiores, podendo representar uma alternativa à reabilitação com overdentures retidas por dois implantes. O objetivo deste estudo foi avaliar a movimentação da prótese total superior em usuários de overdentures mandibulares retidas por um ou dois implantes durante a mastigação de dois alimentos teste. Vinte e um pacientes usuários de próteses totais bimaxilares novas foram divididos em dois grupos e posteriormente submetidos à instalação de um (G1; n=11) ou dois (G2; n=10) implantes na região anterior da mandíbula. Após 4 meses foram instalados pilares o’rings sobre os implantes e realizou-se a captura das cápsulas e anéis de retenção por meio de alívio e reembasamento das próteses totais inferiores. Um cinesiógráfo foi utilizado para registrar a movimentação da prótese total superior, nos seguintes períodos: antes da cirurgia (baseline), 3, 6 e 12 meses após a ativação dos implantes, durante a mastigação voluntária de dois tipos de alimentos teste, pão e poliéter. O teste de ANOVA de três fatores de medições repetidas mistas seguido pelo teste de Bonferroni foram utilizados na análise dos dados (α=0,05). Para o eixo vertical, houve uma menor intrusão da prótese total superior quando os pacientes apresentavam prótese total convencional inferior (µ=0,60±0,28 mm), em comparação aos períodos 3 meses (µ=0,79±0,40 mm), 6 meses (µ=0,89±0,63 mm) e 12 meses (µ=0,93±0,71 mm) após ativação dos implantes. Ainda, pacientes reabilitados com overdentures retidas por 1 implante obtiveram uma maior intrusão da prótese total convencional superior (µ=0,95±0,55 mm) em comparação com aqueles reabilitados com overdentures mandibulares com 2 implantes (µ=0,65±0,46 mm). Observou-se que houve um deslocamento da prótese total superior em direção inferior apenas quando os pacientes utilizavam PT convencional mandibular (µ=0,23±0,23 mm), sendo que essa deslocamento foi significante apenas em comparação ao período de 12 meses após a ativação dos implantes (µ=0,14±0,25 mm). Para o eixo anteroposterior, observou-se que houve em pacientes reabilitados com 1 implante um maior deslocamento da prótese total superior em direção para anterior no período de 12 meses (µ=0,97±0,77 mm), em comparação ao baseline (µ=0,44±0,33 mm), 3 meses (µ=0,43±0,42 mm) e 6 meses (µ=0,49±0,67 mm). Ainda, no período 12 meses, foi observado que o deslocamento da PT para anterior foi maior nos pacientes reabilitados com 1 implante (µ=0,97±0,77 mm) em comparação aos pacientes reabilitados com 2 implantes (µ=0,26±0,63 mm). Conclui-se que: (1) reabilitação com overdentures mandibulares retidas por um ou dois implantes promove uma maior intrusão da prótese total superior; (2) após substituição de próteses mandibulares convencionais por overdentures, não se observou um deslocamento em direção inferior da prótese total superior; (3) overdentures mandibulares retidas por um implante promoveram uma maior intrusão vertical e movimentação para anterior da prótese total superior; (4) o tipo de alimento não influenciou na movimentação da prótese total superior. / Overdentures retained by one implant have been presented as a treatment option for patients with problems related to retention and stability of their mandibular complete dentures, which may represent an alternative to rehabilitation with overdentures retained by two implants. The objective of this study was to evaluate the movement of the conventional maxillary complete denture among users of overdentures retained by one or two implants during chewing of two food test. Twenty-one patients received new maxillary and mandibular dentures and were divided into two groups and subsequently receive one (G1; n = 11) or two (G2; n = 10) implants in the mandibular arch. After four months, the ball attachments were inserted to the implants and a processed denture reline was made to incorporate the implant retention using retentive elements. A kinesiograph was used to record the maxillary complete denture movement in the following periods: before surgery (baseline), 3, 6 and 12 months after implants retention, during voluntary chewing two types of test foods: bread and polysulphide blocks. Data were analyzed using three-way ANOVA followed by Bonferroni test (α=.05). For the vertical axis, a lower vertical intrusion of the maxillary denture was observed when patients had convencional mandibular complete denture (µ=0,60±0,28 mm), in comparison with 3 months (µ=0,79±0,40 mm), 6 months (µ=0,89±0,63 mm) and 12 months (µ=0,93±0,71 mm) after implants retention. In addition, patients that received overdentures retained by one implant had a higher intrusion of the maxillary denture (µ=0,95±0,55 mm) in comparison with those patients that received overdentures mandibular retained by two implants (µ=0,65±0,46 mm). It was observed that there was a displacement of the maxillary complete denture against the support area only with the patients that used conventional mandibular denture (µ=-0,23±0,23 mm) and this displacement was significant only in comparison with the period of 12 months after implants retention (μ = 0.14 ± 0.25 mm). For the anteroposterior axis, it was observed that there was a higher maxillary denture anterior movement at 12 months (µ=0,97±0,77 mm), in comparison with baseline (µ=0,44±0,33 mm), 3 months (µ=0,43±0,42 mm) and 6 months (µ=0,49±0,67 mm) for patients rehabilitated with one implant. Also, at 12 months, it was observed a higher maxillary denture anterior movement in patients with 1 implant (μ = 0.97 ± 0.77 mm) compared to patients that received two implants (μ = 0.26 ± 0.63 mm). It is concluded that: (1) Overdentures retained by one or two implants produced higher vertical intrusion of the maxillary denture; (2) after replacement of conventional mandibular dentures for overdentures, it was not observed a dislocation of the maxillary denture against the support area; (3) mandibular overdentures retained by one implant promoted higher vertical intrusion and anterior movement of the maxillary complete dentures; (4) the type of test food had no influence on the maxillary complete denture movement.