Exploring botulinum toxin's impact on masseter hypertrophy: a randomized, triple-blinded clinical trial.

The present study aimed to assess the effectiveness and functional adverse effects of a single and multiple injections of botulinum toxin A (BoNT-A) for masseter hypertrophy (MH). Twenty-six women complaining about lower third facial enlargement due to MH, received 75 U of BoNT-A (abobotulinum toxin) in each masseter muscles. After 3 months, patients were randomly assigned to receive a second treatment session of Saline Solution: (G1; n = 11) or BoNT-A: (G2; n = 12). Muscle thickness (ultrasound), electrical activity (electromyography; EMG), masticatory performance, and subjective perception of MH were evaluated. Follow-up was performed at 1, 3 and 6 months. Muscle thickness, EMG activity, and masticatory performance were analyzed using ANOVA two-way and Sidak test as post-hoc. Masticatory performance was analyzed by the Friedman's test and Mann-Whitney test. Regarding inter-groups comparisons, there was a significant decrease in the left masseter muscle thickness in the G2 group at the 6 month follow-up (p < 0.02). For EMG, significant differences were evident at the 6 month assessment, with higher masseter activity for G1 (p < 0.05). For masticatory performance, no significant differences were observed throughout the study (p > 0.05) and a higher improvement in subjective perception of MH was observed in the 1 month follow-up for G2 (p < 0.05). In conclusion, BoNT-A is effective for MH, however multiple injections cause functional adverse effects in masseter muscle.

Influence of the radius of Monson's sphere and excursive occlusal contacts on masticatory function of dentate subjects.

OBJECTIVE: To determine the influence of the radius of Monson's sphere, the number of posterior laterotrusive, mediotrusive, and protrusive contacts, and the chewing rate on food comminution. DESIGN: Sixty healthy dentate subjects, aged 21.22 ± 2.30 years, were selected. The three-dimensional coordinates of the cusp tips of the lower canine, premolar, and molar teeth were identified from the subjects' digital models. Monson's sphere was designed using the simplex method for function minimisation by adjusting the coordinates on its surface. The contacts were verified using 12 µm metal strips in jaw excursions at 0.5, 1.0, 2.0, and 3.0 mm. The masticatory performance and efficiency, swallowing threshold, and chewing rate were assessed through particle size fractionation. Data were analysed with multiple linear regression (α = 0.05). RESULTS: The sphere's radius, laterotrusive and protrusive contacts at 0.5 mm, and chewing rate were found to be negative predictor variables for masticatory performance until 20 chewing cycles (R2 = 0.429). For 40 cycles, the radius and total contacts (0.5 mm) were also explanatory factors (R2 = 0.223). Only the radius (R2 = 0.176) and the chewing rate (R2 = 0.082) were found to be significant for 60 cycles and swallowing threshold, respectively. Masticatory efficiency was influenced by masticatory performance until 40 and 60 cycles, as well as the radius and total contacts at 2.0 and 3.0 mm (R2 = 0.958). CONCLUSION: A larger radius of Monson's sphere and a greater number of posterior excursive contacts were found to be related to better masticatory function.

Effect of artificial eccentric occlusal interferences on masticatory performance: A randomised double-blind clinical trial.

BACKGROUND: Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known. OBJECTIVE: To determine the immediate effect of eccentric occlusal interferences on masticatory performance. METHODS: This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi-adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1-week washout period was applied between tests. RESULTS: Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p < .05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p < .05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p < .05). The chewing rate did not differ among conditions (p = .1944). CONCLUSION: Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles. CLINICAL TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (RBR-8g5zfg8).

Rendimiento y fuerza masticatoria máxima funcional en pacientes con prótesis parcial removible dentomucosoportadas y dentoimplantosoportadas

Introducción: Debido al desdentamiento, el rendimiento y la fuerza masticatoria disminuyen, lo que implica una desorganización y descompensación del sistema estomatognático con fuerzas provocadas por la masticación, que se distribuyen en el hueso a través de dientes y mucosas y provocan la reabsorción ósea en zonas edéntulas. Objetivo: Comparar el rendimiento masticatorio y la fuerza masticatoria máxima funcional en pacientes desdentados parciales portadores de prótesis parcial removible dentomucosoportadas, antes y después de la instalación quirúrgica de implantes oseointegrados como pilares protésicos auxiliares. Métodos: Se seleccionaron 10 pacientes rehabilitados mediante prótesis parcial removibles. Se les realizaron el test biomecánico de medición de fuerza masticatoria y test de Manly para la evaluación del rendimiento masticatorio antes de la instalación del implante y a los tres y seis meses poscirugía. Resultados: Se obtuvo un valor promedio de rendimiento masticatorio de 24,2 ( 9,73 % antes de la cirugía de implantes, de 44,1 ( 13,28 % a los tres meses y de 45,6 ( 14,33 % a los seis meses posterior a esta (p = 0,001). Antes de la cirugía implantaria se obtuvo como promedio una fuerza masticatoria de 10,6 ( 4,34 kg, de 12,5 ( 4,28 kg a los tres meses y de 15,1 ( 5,12 kg a los seis meses posterior a esta (p = 0,008). Conclusiones: La utilización de implantes oseointegrados como pilares auxiliares en prótesis removibles dentomucosoportadas se asocian a un mayor rendimiento masticatorio y a un aumento de la fuerza masticatoria máxima funcional, asociado al alivio de la carga directa sobre los rebordes maxilares edéntulos.

Introduction: Due to edentulousness, masticatory performance and masticatory force decrease, which implies a disorganization and decompensation of the stomatognathic system with forces provoked by mastication, which are distributed in the bone through teeth and mucous membranes and cause bone resorption in edentulous areas. Objective: To compare masticatory performance and maximum functional masticatory force in partially edentulous patients with dentomucosally supported removable partial dentures before and after surgical installation of osseointegrated implants as auxiliary prosthetic abutments. Methods: Ten patients rehabilitated with removable partial dentures were selected. The biomechanical test of masticatory force measurement and the Manly test were performed to evaluate masticatory performance before implant installation and at three- and six-months post-surgery. Results: An average masticatory performance value of 24.2 ( 9.73 % was obtained before implant surgery, 44.1 ( 13.28 % at three months and 45.6 ( 14.33 % at six months after implant surgery (p = 0.001). Before implant surgery, an average masticatory force of 10.6 ( 4.34 kg, 12.5  4.28 kg at three months and 15.1 ( 5.12 kg at six months after implant surgery was obtained (p = 0.008). Conclusions: The use of osseointegrated implants as auxiliary abutments in dentomucosally supported removable prostheses are associated with increased masticatory performance and increased maximum functional masticatory force, associated with relief of direct load on edentulous maxillary ridges.

Cambios en parámetros masticatorios con prótesis parcial removible para dientes posteriores perdidos / Changes in masticatory parameters with removable partial dentures for missing posterior teeth

Introducción: el reemplazo de dientes perdidos aspira a mejorar la función masticatoria. Aunque hay diferentes opciones para ello, la conveniencia de la prótesis parcial removible (PPR) es su bajo costo. Objetivo: comparar el desempeño masticatorio (DM) después de 20 ciclos masticatorios y al umbral de la deglución (UD) en adultos de 50 a 70 años con dientes posteriores perdidos (DPP), con/sin PPR; y los ciclos hasta la deglución. Material y métodos: estudio transversal en 35 adultos con dientes anteriores y PPR bien ajustadas y utilizadas para comer. El lado de prueba fue el lado con más DPP. El DM se evaluó después de 20 ciclos y al UD utilizando un alimento prueba artificial (Optosil Comfort®) con/sin la PPR en orden aleatorizado. Las partículas se tamizaron para determinar el tamaño medio de partícula (TMP) como medida del DM. Los ciclos se contaron visualmente. Estadística descriptiva y comparaciones con SPSS-v23. Resultados: hubo diferencias significativas (p ≤ 0.05) al masticar con/sin PPR. El TMP fue más pequeño (mejor DM) con la PPR después de 20 ciclos y al UD (3.9 vs 4.4 mm y 3.2 vs 4.2 mm). Los ciclos para llegar al UD disminuyeron con la PPR (40 vs 47). Conclusión: a pesar de una mejora limitada de la función masticatoria, las PPR ayudan a preparar los alimentos en partículas más pequeñas antes de deglutirlas. La mejoría en DM con PPR es de 24% al UD, realizando menos ciclos antes de deglutir sus alimentos (AU)

Introduction: replacement of missing teeth should improve masticatory function. Although there are different options removable partial dentures (RPD) are used due to their lower cost. Objective: to compare masticatory performance (MP) after 20 chewing-cycles and swallowing-threshold (ST) in 50-70 year-old adults with missing posterior teeth (MPT) with and without their cast-metal RPD; chewing cycles until swallowing were also compared. Material and methods: 35 adults participated in this cross-sectional study. Subjects with anterior teeth and welladjusted RPDs, used for eating were included. The side with more MPT was selected as the test side. MP was evaluated after 20 cycles and ST using an artificial test-food (Optosil Comfort®) with/without the RPD (subject-own-control) (randomized order). Chewed particles were sieved to determine medium-particle-size (MPS) as a measure of MP. Chewing cycles were visually counted. Descriptive statistics and comparisons were run with SPSS v23. Results: there were significant differences (p ≤ 0.05) for all parameters when chewing with/without the RPD. MPS was smaller (better MP) with the RPD (3.9 vs 4.4 mm and 3.2 vs 4.2 mm) after 20 cycles and ST respectively. Cycles required to reach ST were less when chewing with the denture (40 vs 47). Conclusion: despite a limited improvement of masticatory function RPDs help patients prepare their food into smaller particles before swallowing. Improvement in MP with RPDs for patients with MPT is 24% at ST and they perform fewer chewing cycles before swallowing food (AU)

Prosthetic aftercare, mastication, and quality of life in mandibular overdenture wearers with narrow implants: A 3-year cohort study.

OBJECTIVES: This cohort study investigated clinical, functional, and quality of life outcomes, along with prosthetic maintenance events in mandibular overdenture (MO) wearers for 3 years. METHODS: Thirty MO wearers with narrow diameter implants (NDIs) and locking taper stud abutments (Facility-Equator system) were annually monitored by registering the visible plaque index (VPI), peri­implant inflammation (PI), calculus presence (CP), probing depth (PD), bleeding on probing (BOP), secondary implant stability (ISQ), marginal bone loss (MBL), masticatory performance and dental impact in daily life (DIDL) questionnaire domains. Multilevel mixed-effects linear regression was performed to analyse changes over time. Chi-square tests were performed to analyse the relationship between the appearance of prosthetic complications and maintenance occurrences. The survival rate of patients with NDIs was calculated using the Kaplan-Meier test. RESULTS: Twenty-six individuals attended all follow-ups, the survival rate of 83.3% in the first year was maintained, and no one implant was lost over the 3-year period. There were significant differences for PD between 1 and 3 years (p ≤ 0.01) and between 2 and 3 years for PI (p ≤ 0.01), GI (p ≤ 0.01), ISQ (p = 0.02), and MBL (p ≤ 0.01). All masticatory performance outcomes showed significant differences (p ≤.01). Prosthetic maintenance events decreased significantly over time. Appearance, general performance, and eating and chewing domains presented high effect sizes. CONCLUSION: Continued changes were observed in the clinical parameters of MO users over the 3-year period. In addition, most functional parameters, except for particle homogenization, improved significantly over time. The positive impact on quality of life is likely related to the significant reduction in prosthetic maintenance events. CLINICAL SIGNIFICANCE: Periodic returns to assess peri­implant tissues and MO maintenance should be performed to ensure the success of rehabilitation to assure improvements in masticatory function and oral health-related quality of life.

Manual para evaluar la deglución y el rendimiento masticatorio en las clínicas de odontología / Manual to evaluate swallowing and chewing performance in dental clinics

Objetivo: desarrollar y aplicar un manual para evaluar los procesos de deglución y rendimiento masticatorio, dirigido a estudiantes y profesionales de odontología. Método: se realizó un estudio con enfoque cuali-cuantitativo, a partir de dos técnicas de recolección de información: documental para reunir información de los procedimientos y observacional para la aplicación del manual. Los métodos seleccionados fueron el rendimiento masticatorio (Albert T) y de deglución (Técnica Payne); el diseño se esbozó según la metodología para mejorar la calidad de los procesos y una guía técnica de elaboración de manuales de procedimientos en salud. Así, el manual cuenta con introducción, antecedentes históricos, alcance y objetivo, flujograma, descripción de procedimientos de evaluación de la deglución, del rendimiento masticatorio y bibliografía. Este fue aplicado en 27 pacientes de la clínica de ortodoncia, a quienes se les diagnosticó deglución atípica, y se midió el rendimiento masticatorio para conocer la mediana de tamaño de partícula (MTP) de cada individuo. Resultados: el manual se realizó basándose en dos procedimientos, uno con el diagnóstico de deglución y otro con rendimiento masticatorio. Este último fue aplicado por dos estudiantes investigadores a una muestra de 27 pacientes, cuyo resultado fue una mediana de tamaño total de partícula de MTP = 5.35 mm2. Hubo una diferencia estadísticamente significativa entre sexos (MTP en hombres: 6,0 mm2 y mujeres 5.1 mm2) siendo las mujeres quienes presentaron mejor desempeño masticatorio. Conclusión: al aplicar el manual, los estudiantes evaluaron el rendimiento masticatorio y la deglución, con lo cual lograron resultados medibles, aplicables y reproducibles.

Objective: To apply a manual to evaluate swallowing and chewing performance aimed at dental students and professionals. Method: A study was carried out with a qualitative-quantitative approach developing two information gathering techniques: documentary to gather information on procedures and observational in the application of the manual. The methods of chewing performance (Albert T) and swallowing (Payne Technique) were selected; the design was outlined according to the methodology to improve the quality of the processes and a technical guide for the elaboration of manuals of health procedures; in the development phase, the thematic units were created and the manual was prepared with: cover, back cover, authors, introduction, historical background, scope and objective, flow chart, description of swallowing evaluation procedures, chewing performance and bibliography; this was applied to 27 patients from the orthodontic clinic, who were diagnosed with atypical swallowing, and the masticatory performance was measured to determine the median particle size (MTP) of each individual evaluated. Results: The manual was made based on two procedures, one with swallowing diagnosis and the other with masticatory performance, which was applied by two student researchers to a sample of 27 patients, yielding a median total particle size of MTP = 5.35 mm2. There was a statistically significant difference between the sexes (MTP in men: 6.0 mm2 and women 5.1 mm2), with women presenting the best masticatory performance Conclusion: when applying the manual, the students evaluated the chewing performance and swallowing, achieving measurable, applicable and reproducible.

Evaluation of bite force and masticatory performance: complete denture vs mandibular overdenture users

Abstract: This cross-sectional observational study with 24 patients evaluated differences in bite force (BF) and masticatory performance (MP) between conventional complete denture (CCD) and implant mandibular overdenture (IMO) users and the correlation between these variables. The BF test was performed bilaterally with an occlusal force device. During the MP test, patients were asked to chew Optocal particles for 40 cycles. The Shapiro Wilk test was employed to verify the normality of the data, the student t test to identify differences between groups, and Pearson's correlation to investigate interrelationships between variables. A multiple linear regression was subsequently performed via the stepwise method. P values ≤0.05 were considered statistically significant. Unlike IMO users, CCD users presented a significant difference (25.6%) in BF between the dominant and non-dominant chewing side (p=0.04). IMO users presented significantly higher BF (p=0.01) without presenting a dominant side (p=0.38), and also performed significantly better for the following MP parameters: MPX50 values decreased by 27.25% in IMO users (p=0.01), MPB decreased by 48.38% (p=0.01), and ME 5.6 decreased by 53.25% (p=0.02), while ME2.8 increased by 151.57% (p=0.01). The BF and MPX50 in the IMO wearers group were negatively correlated (-0.57; p=0.05); this correlation coefficient was the only parameter included in the multivariate regression model. IMO users have higher BF and better masticatory performance than CCD users, especially in terms of chewed particles size reduction. MP is correlated with a higher BF in IMO users through better particle trituration.

Resumo Este estudo observacional transversal com 24 participantes teve como objetivo avaliar as diferenças na força de mordida (FM) e na PM (performance mastigatória) entre usuários de prótese total convencional (PTC) e de overdenture mandibular (OM) e a correlação entre essas variáveis. O teste de FM foi realizado bilateralmente com um dispositivo de força oclusal. Durante o teste de PM, os pacientes foram solicitados a mastigar uma porção padronizada de Optocal por 40 ciclos mastigatórios. O teste de Shapiro Wilk foi empregado para verificar a normalidade dos dados, o teste T de Student para identificar diferenças entre os grupos e os coeficientes de correlação de Pearson para investigar inter-relações entre variáveis. Uma regressão linear múltipla foi realizada pelo método stepwise. Valores de p≤0,05 foram considerados estatisticamente significantes. Diferentemente dos usuários de OM, os usuários de PTC apresentaram uma diferença significativa (34%) na FM entre o lado dominante e o não dominante (p=0,04). Os usuários de OM apresentaram FM significativamente maior (p=0,01) sem apresentar um lado dominante (p=0,38) e obtiveram PM significativamente melhor nos seguintes parâmetros: os valores de PMX50 diminuíram 27,25% (p=0,01), PMB diminuiu em 48,38% (p=0,01), e EM 5.6 diminuiu 53,25% (p=0,02), enquanto EM2.8 aumentou 151,57% (p=0,01). A FM e PMX50 no grupo de usuários da IMO foram negativamente correlacionados (-0,57;p=0,05); esse coeficiente de correlação foi o único parâmetro incluído no modelo de regressão multivariada. Os usuários da OM possuem maior FM e melhor performance mastigatória do que os usuários de PTC, observados principalmente na redução do tamanho das partículas mastigadas. A PM está correlacionada com um maior FM nos usuários da OM através de uma melhor trituração de partículas.

Nutritional status and masticatory function of the indigenous compared with non-indigenous people of Nayarit, Mexico.

OBJECTIVE: The objective of this study was to compare the nutritional statuses and masticatory function of the non-indigenous and indigenous adult people of the state of Nayarit, Mexico. DESIGN: Forty-two indigenous (Cora or Huichol ethnic group) and 100 non-indigenous people, all adults with natural dentition, participated in this cross-sectional study. They performed a free-style masticatory test consisting five trials of chewing silicon pieces for 20 cycles. Masticatory performance was determined by sieving the silicon particles, masticatory laterality was determined by calculating the asymmetry index, and the cycle duration was also recorded. Weight and body fat mass were measured using a portable digital weighing machine and height and body circumferences were recorded to calculate the body mass index (BMI), body fat percentage, and the waist-hip ratio. Each aspect of masticatory function and each nutritional variable were compared using T-test, analysis of variance, and Kruskal-Wallis or Mann-Whitney tests, as appropriate. RESULTS: Body fat percentage, BMI, and waist-hip ratio were higher (P < 0.0005) in the indigenous group compared to the non-indigenous. The indigenous group had a significantly shorter stature than the non-indigenous group. Cora group had a higher BMI and higher percentage of body fat than the Huichol group (P < 0.05). No significant differences were detected between the groups for any aspect of masticatory function. CONCLUSIONS: Indigenous people from the Nayarit, especially the Cora ethnic group, are more obese, have more total body fat, and more abdominal fat than non-indigenous people. Indigenous people show similar masticatory function.

Individual factors associated with masticatory performance of complete denture wearers: A cross-sectional study.

AIM: The aim of this study was to assess whether differences in inter-individual clinical and prosthodontic variables affect masticatory performance (MP) of edentulous subjects who received new complete dentures. MATERIALS AND METHODS: There were 204 edentulous participants who received new maxillary and mandibular complete dentures between October 2014 and March 2018 at a university clinic. MP was measured by a mixing ability test with a two-coloured chewing gum for 20 and 50 chewing cycles. The outcome variable was the degree of colour mixing of the chewed gum, expressed by the variation of hue (VOH) and measured by electronic colourimetric analysis. Explanatory variables included gender and age, quality of the dentures, classification of edentulous ridges and prognostic features, time since the insertion of the new dentures and patient-reported outcomes related to complete denture treatment. Bivariate correlation tests, multiple linear regression and a linear mixed model were used for data analysis. RESULTS: Mean VOH values were 0.57 (±0.13) and 0.43 (±0.16) for 20 and 50 chewing cycles, respectively. Mixing ability was higher in females than in males for 20 (P = 0.036) and 50 (P = 0.006) chewing cycles. No effects on the patient-reported outcome measures were observed. The time since denture delivery, gender, age and Prosthodontic Diagnostic Index (PDI) score were independently associated with masticatory performance at 20 and/or 50 chewing cycles. Overall masticatory performance tested by the linear mixed-effect model confirmed that VOH value was negatively influenced by male gender, older age and shorter time since denture delivery. CONCLUSION: Masticatory performance seems to be improved with the continuous use of newly inserted dentures and negatively influenced by advanced age.

The Influence of Age, Gender, Mandibular Bone Height, Previous Experience with Prostheses, and Fabrication Methods on Masticatory Performance of Complete Denture Wearers.

PURPOSE: To evaluate the influence of age, gender, mandibular bone height, previous experience with prostheses, and methods for denture fabrication on masticatory performance of complete denture (CD) wearers. MATERIALS AND METHODS: For this study, 29 individuals treated with CDs fabricated by simplified or conventional methods had their masticatory performance assessed 4 weeks after the prostheses' adjustment and control, using the sieve method and almonds as a natural food test. Experimental variables related to age, gender, and previous use of complete dentures were collected from dental records. Panoramic digital radiographs were used to determine mandibular bone height according to the criteria described by the American College of Prosthodontists. Data on masticatory performance were assessed using t-test for independent samples to make comparison between simplified and conventional methods, and a multiple linear regression analysis was performed to evaluate the influence of age, gender, previous experience with CDs, and mandibular bone height on masticatory performance using SPSS software with a significance level of 5%. RESULTS: There was no significant influence regarding the method for CD fabrication (p = 0.92), age (p = 0.36), mandibular bone height (p = 0.37), and previous experience with prostheses (p = 0.15) on masticatory performance of CD wearers. Female patients presented lower masticatory performance than male (p = 0.04) patients did. CONCLUSIONS: Considering the limitations of this study, it was concluded that gender might be considered a risk factor for masticatory performance of CD wearers. Female patients demonstrated reduced masticatory performance in comparison to male patients.

Influence of lower complete denture use on masseter muscles and masticatory function: A longitudinal study.

BACKGROUND: Edentulism can reduce mastication, leading to changes in food pattern, with possible consequences to masticatory muscle thickness. OBJECTIVES: This study verified masticatory function and oral perception in subjects who did not use lower CDs, and whether the insertion of new upper and lower CDs would improve such variables. METHODS: Fifteen edentulous elderly who wore only the upper CD were selected and received new upper and lower CD. Volunteers were evaluated at baseline and after 1, 3 and 6 months of new prosthesis use. Masticatory performance (MP) was assessed by the sieving method (X50 values). Masseter thickness (MT) was evaluated by ultrasonography. Oral sensorial ability (OSA) was assessed by oral stereognosis test and maximum tongue pressure (MTP) was verified by pressure sensors. Data were submitted to repeated measures ANOVA and Tukey-Kramer posthoc tests (α = 0.05). Correlation between OSA and MTP was verified by Person's correlation. RESULTS: X50 and MTP decreased (P < 0.05) after 1 month and remained stable (P > 0.05) for next assessments. After 3 months, MT in rest position was increased (P < 0.05), while during maximum voluntary contraction 1 month was enough to increase MT (P < 0.05). There were no differences for OSA (P > 0.05) and no correlation between OSA and MTP. CONCLUSION: Masticatory performance and masseter thickness of elderly who did not use the lower dentures were improved after 2 months using new upper and lower CDs. However, new CDs in both dental arch decreased MTP. Brazilian Registry of Clinical Trials (ReBEC #RBR-37gdst).

Masticatory performance parameters for young adults with "normal" occlusion.

Objective To develop reference data for young men/women on the variability of parameters used for the evaluation of masticatory function with an artificial test food. Methods Subjects included were 200 18-25-year olds with complete dentition and "normal" occlusion. An artificial test food was chewed in two tests (20 cycles and swallowing threshold), during which sequences/cycles were counted and timed. Medium-particle-size (MPS) and broadness of particle distribution were calculated evaluating the chewed material. Reference data was based on order statistics. Sex-specific 95% reference limits with 90% confidence intervals were calculated with RefVal-v2.1-software. Coefficients of variation were also obtained. Results Tables with reference data for young men/women chewing an artificial test food were constructed with the data collected displaying ample variability: MPS after 20 cycles anywhere between 0.7-3.5 mm or 14-84 cycles to deem the test food ready to be swallowed (C.V. 43% males/34% females). Conclusion There is much variability in masticatory parameters for young adults with good oral health.

Bilateral balanced occlusion compared to other occlusal schemes in complete dentures: A systematic review.

No consensus has been reached regarding the best occlusal scheme for making complete dentures. Thus, the purpose of this systematic review was to compare bilateral balanced occlusion (BBO) with other occlusal schemes (canine guidance, lingualised occlusion and zero degree) in complete dentures. The schemes were compared in terms of quality of life/satisfaction and masticatory performance. Two independent reviewers performed a comprehensive search of studies published in or before October 2017 using the PubMed/MEDLINE, Scopus and Cochrane Library databases. The search was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The focused question was: "In conventional complete denture, is BBO better than lingualised occlusion, canine guidance and zero degree in terms of quality of life, patient satisfaction and masticatory performance/muscle activity?" Seventeen studies were selected for analysis. In total, there were 492 patients with a mean age of 64.78 years and a mean follow-up duration of 2.96 months (range: 1-6 months). All studies compared BBO with the other occlusal schemes. Eleven studies evaluated the influence of the occlusal scheme designs on quality of life and satisfaction, and 8 studies evaluated masticatory performance and muscle activity between BBO and the other occlusion schemes. The present systematic review indicated that BBO does not confer better quality of life/satisfaction or masticatory performance and muscle activity. Thus, lingualised occlusion can be considered a predictable occlusal scheme for complete dentures in terms of quality of life/satisfaction and masticatory performance, while canine guidance can be used to reduce muscular activity.

Reliability of a two-colour chewing gum test to assess masticatory performance in complete denture wearers.

The aim of this study was to test the reliability of a method to measure the masticatory performance of complete denture wearers employing a colour-mixing ability test and assessment by visual and electronic colourimetric analysis. A sample of 75 subjects was selected from patients who received new conventional complete dentures. Masticatory tests were performed using a two-colour chewing gum that was masticated for 5, 10, 20, 30 and 50 chewing cycles, performed in a random order. The mixing level of the two colours of the chewed gum was assessed visually by two independent raters based on a 5-point ordinal scale. The specimens were flattened into a 1-mm-width wafer, scanned and saved as a two-sided digital image. Each pair of images was submitted to an electronic colourimetric analysis to assess the level of colour mixture, measured by the circular variance of hue (VOH). Overall inter- and intra-rater agreements in visual analysis were 64% and 68%, respectively (almost 99% of scores ranged within ±1 point), whilst overall weighted kappa was >0.80. A proportional increase in the level of mixture occurred with increased number of chewing cycles (P < .001). Similarly, VOH and the visual analysis were highly correlated (r = -.89; P < .001). Bland-Altman plots revealed excellent agreement and extremely low systematic error between duplicated VOH measures. It was concluded that the two-colour chewing gum test is a reliable method to assess the masticatory performance in complete denture wearers using both visual and electronic colourimetric analyses.

Influence of removable prostheses on mastication in elderly subjects with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a prevalent disease in the elderly population, and it may affect the temporomandibular joint (TMJ) and the stomatognathic system. This study evaluated masticatory function in elderly patients with RA before and after oral rehabilitation with removable prostheses. Forty-five elders with partial or total edentulism who were using unsatisfactory removable prostheses were selected and assigned to 3 groups: RA with TMJ involvement, RA without TMJ involvement and healthy controls. Masticatory function was assessed in terms of masticatory performance (MP) and maximum bite force (MBF). The former was determined by the sieving method, and the latter was measured by pressure sensors placed in the bilateral molar regions. The variables were first evaluated in elderly subjects wearing unsatisfactory prostheses and re-assessed after participants had received new removable prostheses. Comparisons between groups and among time points were performed with analysis of variance for repeated measures and the Tukey-Kramer test (P < .05). Comparison among groups showed decreased MP in elders with RA before new prosthesis insertion (P < .05). Irrespective of TMJ involvement, MP improved after treatment in subjects with RA. Rheumatoid arthritis groups also showed decreased MBF (P < .05), which improved after new prosthesis insertion. Rheumatoid arthritis might impair masticatory function, and well-fitted removable prosthesis insertion might be very beneficial in elders with RA.

Is the main goal of mastication achieved after orthodontic treatment? A prospective longitudinal study

ABSTRACT Objective: To investigate the masticatory and swallowing performances in patients with malocclusions before and after orthodontic treatment, comparing them to an age- and gender-matched control group with normal occlusion. Methods: Twenty-three patients with malocclusions requiring orthodontic treatment were included in this prospective study. One month after appliance removal, seventeen patients completed a follow-up examination and the data were compared with those of a control group with thirty subjects with normal occlusion. Masticatory performance was determined by the median particle size for the Optocal Plus® test food after 15 chewing strokes, and three variables related to swallowing were assessed: a) time and b) number of strokes needed to prepare the test-food for swallowing, and c) median particle size of the crushed particles at the moment of swallowing. Results: At the baseline examination, the malocclusion group had a significantly lower masticatory performance and did not reach the particle size reduction at the moment of swallowing, when compared with the control group. After treatment, the masticatory performance significantly improved in the malocclusion group and the particle size reduction at swallowing reached the same level as in the control group. Conclusions: The present results showed that the correction of malocclusions with fixed appliances can objectively provide positive effects in both mastication and deglutition processes, reinforcing that besides aesthetic reasons, there are also functional indications for orthodontic treatment.

RESUMO Objetivo: investigar as performances mastigatória e de deglutição em pacientes com má oclusão, antes e após o tratamento ortodôntico, comparando-os com um grupo controle com oclusão normal, equiparado por idade e sexo. Métodos: vinte e três pacientes com má oclusão requerendo tratamento ortodôntico foram incluídos neste estudo prospectivo. Um mês após a remoção dos aparelhos, dezessete pacientes completaram os exames de acompanhamento, e seus dados foram comparados com aqueles de um grupo controle com trinta indivíduos com oclusão normal. A performance mastigatória foi determinada pelo tamanho mediano das partículas do alimento teste Optocal Plus® após 15 ciclos mastigatórios, e três variáveis relacionadas à deglutição foram avaliadas: a) tempo e b) número de ciclos necessários para preparar o alimento teste para deglutição, e c) tamanho mediano das partículas trituradas no momento da deglutição. Resultados: no exame inicial, o grupo com má oclusão apresentou uma menor performance mastigatória e não atingiu a redução do tamanho das partículas no momento da deglutição, quando comparado com o grupo controle. Após o tratamento, a performance mastigatória aumentou significativamente no grupo com má oclusão, e a redução do tamanho das partículas no momento da deglutição atingiu o mesmo nível do grupo controle. Conclusões: os resultados demonstraram que a correção das más oclusões com aparelhos fixos pode, objetivamente, proporcionar efeitos positivos nos processos de mastigação e deglutição, reforçando que, além de razões estéticas, existem também indicações funcionais para o tratamento ortodôntico.

Lack of relationship between masticatory performance and nutritional status in adults with natural dentition.

OBJECTIVE: This study assessed the relation among several aspects of the masticatory function and the nutritional status in adults with natural dentition. DESIGN: One hundred adults with natural dentition participated in this cross-sectional study. They performed one free-style masticatory test consisting of five trials of 20 silicon-chewing cycles. The preferred chewing side was determined by calculating the asymmetry index. Masticatory performance was determined by sieving the silicon particles, and the cycle duration was also recorded. Weight, body water percentage, body fat mass, muscle mass and osseous mass were measured using a portable digital weighing machine. Body mass index (BMI), waist-hip ratio, skinfold thickness and the upper-arm composition were determined. The relation between masticatory function and a nutritional variable were tested using Pearson or Spearman rank correlation coefficients or using analysis of variance or the Kruskal-Wallis H-test and the Mann-Whitney U test, as appropriate. RESULTS: Whereas body fat percentages for women were significantly higher than for men, the body mass index was higher in men than in women. Participants who were underweight chewed more asymmetrically and more slowly than normal weight or obese participants. A negative correlation was observed between body fat percentage and masticatory laterality. No relation between masticatory performance and any nutritional status indicator was detected. CONCLUSION: Being underweight and having a low body fat percentage seem to be related to a masticatory lateral asymmetry and to a large cycle duration in young adults with natural dentition. Masticatory performance does not seem to be related to nutritional status.

Reproducibility, Reliability, and Validity of Fuchsin-Based Beads for the Evaluation of Masticatory Performance.

PURPOSE: Rehabilitation of masticatory function is inherent to prosthodontics; however, despite the various techniques for evaluating oral comminution, the methodological suitability of these has not been completely studied. The aim of this study was to determine the reproducibility, reliability, and validity of a test food based on fuchsin beads for masticatory function assessment. MATERIALS AND METHODS: Masticatory performance was evaluated in 20 dentate subjects (mean age, 23.3 years) using two kinds of test foods and methods: fuchsin beads and ultraviolet-visible spectrophotometry, and silicone cubes and multiple sieving as gold standard. Three examiners conducted five masticatory performance trials with each test food. Reproducibility of the results from both test foods was separately assessed using the intraclass correlation coefficient (ICC). Reliability and validity of fuchsin bead data were measured by comparing the average mean of absolute differences and the measurement means, respectively, regarding silicone cube data using the paired Student's t-test (α = 0.05). RESULTS: Intraexaminer and interexaminer ICC for the fuchsin bead values were 0.65 and 0.76 (p < 0.001), respectively; those for the silicone cubes values were 0.93 and 0.91 (p < 0.001), respectively. Reliability revealed intraexaminer (p < 0.001) and interexaminer (p < 0.05) differences between the average means of absolute differences of each test foods. Validity also showed differences between the measurement means of each test food (p < 0.001). CONCLUSIONS: Intra- and interexaminer reproducibility of the test food based on fuchsin beads for evaluation of masticatory performance were good and excellent, respectively; however, the reliability and validity were low, because fuchsin beads do not measure the grinding capacity of masticatory function as silicone cubes do; instead, this test food describes the crushing potential of teeth. Thus, the two kinds of test foods evaluate different properties of masticatory capacity, confirming fushsin beads as a useful tool for this purpose.

Rendimiento masticatorio y nivel de satisfacción de pacientes tratados con prótesis totales en la Universidad Mayor / Masticatory performance and satisfaction level in patients treated with complete dentures

Se realizó un estudio para medir y comparar el rendimiento masticatorio empleando el Test de Manly en 2 grupos de 18 individuos cada uno. El primer grupo estaba conformado por pacientes desdentados totales tratados en la Universidad Mayor en el año 2012 con prótesis totales removibles, y el segundo grupo, por pacientes con dentadura natural completa. Además, al grupo de pacientes rehabilitados con prótesis totales se le aplicó la encuesta GOHAI para conocer el nivel de satisfacción con el uso de sus prótesis. Los resultados muestran que el rendimiento masticatorio es muy superior en los individuos dentados naturales con respecto a los portadores de prótesis totales, y esta diferencia es estadísticamente significativa. Los pacientes portadores de prótesis totales señalan un bajo nivel de satisfacción con el uso de sus dentaduras completas, en especial durante la función masticatoria.

This study was conducted in order to measure and compare the masticatory performance using the Manly Test in 2 groups of 18 people. The first group was formed by edentulous patients treated in the Universidad Mayor of Santiago, Chile, in 2012 with removable dentures, and the second group consisted of patients with complete natural dentition. In addition, the GOHAI questionnaire was also applied to determinate the level of satisfaction of the group of patients rehabilitated with complete dentures. The results showed that masticatory performance is much higher in individuals with complete natural dentition than in patients rehabilitated with complete dentures, with the difference being statistically significant. Patients with dentures indicated a low level of satisfaction with the use of their complete dentures, especially during masticatory function.