Effect of side switch frequency on masticatory performance and rhythm in adults with natural dentition: A randomized crossover trial

Abstract

Background: The relationships between the frequency of masticatory side switches (MSS) and other aspects of masticatory function are not clear. Objectives: In this study, we determined the effect of MSS frequency on masticatory performance and rhythm in dentate adults and explored the between-subject relationships among side switch frequency, masticatory rhythm and laterality. Methods: In this crossover study, subjects performed six masticatory patterns of five trials each, chewing bagged silicone for 20 cycles. The six patterns were freestyle, unilateral right, unilateral left, and switching sides one, three and five times. Masticatory performance and rhythm were determined for each style by median particle size (MPS) and chewing cycle duration, respectively. In the freestyle mastication pattern, masticatory laterality was assessed by the unilateral chewing index, and the frequency of MSS was assessed by the MSS Index. Data were analysed using Friedman's test and repeated measures analysis of variance. Results: We included 29 participants (15 women; median age, 23 years). No significant between-subjects differences in the MPS were detected obtained by switching one, three or five times per trial. Chewing cycle duration increased with the MSS number per trial. During freestyle mastication, the MSS Index was inversely correlated with the unilateral chewing index (Rho -0.569; 95% CI -0.25 to -0.78; p = .001; Spearman test), but not with the MPS or chewing cycle duration. Conclusion: Differences in MSS frequency do not affect masticatory performance, but they do alter the masticatory rhythm. Individuals with a higher MSS frequency also have a more symmetrical chewing pattern.