Relationship between chewing side preference and handedness and lateral asymmetry of peripheral factors

Abstract

Objective: To determine whether chewing side preference is related to handedness and lateral asymmetry of occlusal characteristics, muscular force and temporomandibular disorders (TMD) in a dentate population. Design: One hundred and seventeen dentate adults participated in this cross-sectional study. Static and dynamic occlusal characteristics were determined at the maximal intercuspal position and at the lateral excursions by scanning interocclusal records and analysing them using image software. Unilateral maximum bite force and finger-thumb grip force were measured by means of a gnathodynamometer. TMD were assessed according to the Research Diagnostic Criteria for TMD. Chewing side preference and masticatory laterality were determined by observing the jaw's movement while each subject chewed silicone. Asymmetry or side difference of the variables was calculated. Correlation between side difference variables and masticatory laterality was studied using Spearman correlation coefficient. Results: Fifty-nine subjects chewed on the right, 15 on the left and 43 chewed on both sides. There was no relationship between preferred chewing side and handedness, lateral asymmetry of TMD or side difference in finger-thumb grip force. Significant and positive correlations were observed between masticatory laterality and side differences in bite force and side differences in occlusal contact area at intercuspal position (P<0.01). Conclusions: Chewing side preference in a dentate population is related to lateral asymmetry of bite force and asymmetry of occlusal contact area at the intercuspal position but not to handedness.