Relationship between habitual chewing side and masticatory performance: a pilot study

There have been few studies on the effect of Angle's classification of first molars on the difference in masticatory performance between the habitual chewing side (HCS) and the non-habitual chewing side (NHCS) in young people with healthy dentition. Thus, this study aimed to investigate the masticatory performance of the HCS and NHCS in individuals under 20 years of age with complete permanent dentition, divided into Class I and non-Class I first molar relationship groups (Class I group and non-Class I group). The participants were first- and second-year female dental hygiene students at the Nippon Dental University College in Niigata in 2024. Twenty-eight participants were classified into two groups based on the Angle's classification: Class I and non-Class I first molar relationships. HCS was determined using the cotton roll test, and masticatory performance was evaluated using glucose-containing gummy jelly. Participants were asked to chew a gummy jelly for 20 s on the HCS, and the amount of glucose extracted was measured as an indicator of masticatory performance. The same measurement was then performed on the NHCS. In the Class I group, the median (interquartile range, IQR) of the HCS was 202.00 (186.00-231.00) mg/dL and of the NHCS was 191.00 (120.50-238.50) mg/dL. In the non-Class I group, the HCS was 188.00 (140.00-225.00) mg/dL and the NHCS was 167.00 (156.00-235.00) mg/dL, respectively. A significant difference between the HCS and NHCS existed in the Class I group (p = 0.041), whereas not in the non-Class I group (p = 0.423). The null hypothesis of the study-that there is no difference in masticatory performance between HCS and NHCS, regardless of Angle's classification of the first molar relationship-was rejected.