Bruxism and voluntary maximal bite force in young dentate adults

Bruxism may increase the activity and volume of the masticatory muscles, yet its resulting effect on bite force is controversial. This study evaluated the relationship between voluntary maximal bite force (MBF) and presence of bruxism in 80 dentate young adults (40 men, 40 women, 20 to 38 years old), controlling for sex, body mass index (BMI), and presence of orofacial muscular pain during the MBF measurement.

MBF was measured with a compressive load transducer at the first molar region. Information about the presence of bruxism was collected by means of self-report of centric or eccentric bruxism during the day or night and/or presence of tooth wear. Data on MBF were analyzed by analysis of covariance, with bruxism and sex as fixed factors, and BMI and orofacial muscular pain as covariates (.05 level of significance).

The mean +/- standard deviation values of MBF were 859 +/- 304 N for nonbruxers (n = 49) and 806 +/- 282 N for bruxers (n = 31), with no significant difference between groups (P = .842). BMI was not a significant covariate for MBF (P = .237), and neither was the presence of orofacial muscular pain (P = .560). Sex was statistically significant for MBF (P < .001), and men (1,009 +/- 290 N) had higher MBF than women (668 +/- 179), but there was no interaction between sex and bruxism in relation to the MBF (P = .861).

These results suggest that bruxers and nonbruxers did not have different voluntary MBF in this sample of young dentate adults.