Are occlusal contact area asymmetry and masticatory muscle activity asymmetry related in adults with normal dentition?

Objective: To examine whether asymmetry in the area of occlusal contact and near contact (ACNC) and asymmetrical masticatory muscle electromyographic activity are correlated in healthy dentate adults.Methods: Ninety-one healthy subjects with full dentition were included. Seven levels of ACNC were registered, and the asymmetry indexes (AsI) for each level of ACNC (AsI-ACNC) were determined. Surface EMG was used to record bilateral anterior temporalis activity and masseter muscle activity. The AsI for the anterior temporalis, masseter, and the combination of both muscles were calculated.Results: Pearson's correlation analysis revealed all levels of AsI-ACNC were significantly, negatively correlated with the AsI of the anterior temporalis and the combination of both muscles (p < 0.05), but not the AsI of the masseter muscle (p > 0.05).Conclusion: The side with greater ACNC has significantly lower anterior temporalis activity and combined anterior temporalis and masseter muscle activity on the ipsilateral side.

Masticatory performance is influenced by masticatory muscle activity balance and the cumulative occlusal contact area.

OBJECTIVE: To investigate the influence of masticatory muscle activity balance, occlusal contact area balance and the area of occlusal contact on masticatory performance in healthy dentate adults. DESIGN: This cross-sectional study included ninety-three healthy subjects with complete dentition. Surface electromyography (sEMG) was used to record bilateral anterior temporalis activity and masseter muscle activity during maximum voluntary clenching and while chewing a test food. Seven levels of area of occlusal contact and near contact (ACNC) were registered and calculated cumulatively. The percentage overlapping coefficients were calculated for both muscle groups at maximum voluntary clenching and chewing and all levels of ACNC. Masticatory performance was measured by determining the median particle size of frankfurter sausage after 15 chewing cycles. Pearson's correlation and stepwise multiple linear regression analyses were used to assess the correlations between variables and the influence of the variables on masticatory performance, respectively, at the 0.05 level of significance. RESULTS: Muscle balance during clenching and chewing, all near contact levels of cumulative ACNC and ACNC balance correlated negatively with median particle size (P <  0.05). The model based on stepwise multiple linear regression analysis showed muscle balance during clenching and cumulative ACNC at < 250 µm influenced median particle size. CONCLUSION: Masticatory muscle activity balance during maximum voluntary clenching and the cumulative amount of near contact area were associated with masticatory performance, suggesting the amount of occlusal contact area-as well the balance of masticatory muscle activity-play a role in masticatory performance.

Assessment of the relationship between masticatory performance, occlusal contact area, chewing time and cycles, and gastric emptying scintigraphy in dentate subjects.

BACKGROUND: Good mastication is thought to help digestion in the stomach, hence promoting the health of the gastrointestinal system. However, the correlation between masticatory and gastric function has been controversial. This is partly explained by different food types used to assess the performance of the two organs. Recently, frankfurter sausage has been proposed to be suitable for both masticatory performance and gastric emptying tests. OBJECTIVES: To examine the relationship between masticatory performance, occlusal contact area, chewing time and cycles, and gastric emptying scintigraphy parameters in healthy dentate adults. MATERIALS AND METHODS: Forty healthy subjects (15 men: 25 women, age 23.9 ± 3.8 years) underwent masticatory performance tests and gastric emptying scintigraphy using frankfurter sausage as a test food. Masticatory performance was calculated as the median particle size (MPS) of chewed frankfurter sausage cubes after 30 chewing cycles. Gastric emptying scintigraphy was performed using frankfurter sausage mixed with technetium-99 m-labelled microwaved egg meal. Cumulative occlusal areas of contact-near contact (cACNC) were determined by silicone bite registration and image-analysed. Chewing time and cycles before swallowing were also recorded. RESULTS: No significant differences in MPS, cACNC, chewing time and cycles, or gastric emptying parameters were observed between gender. Bivariate correlation showed masticatory performance, occlusal contact area, chewing time and cycles were not correlated with gastric emptying parameters (P > 0.05). CONCLUSION: Using the same test food to assess the masticatory and gastric function in dentate subjects, the present study showed that masticatory performance, occlusal contacts, chewing time and cycles did not affect gastric emptying.