Ultrasonographic evaluation of the association between gonial appositional bone changes and masseter muscle thickness and elasticity in bruxism

Increased muscle activity in bruxism has been reported to be associated with appositional bone changes in the gonial region, referred to as bone peaks (BPs). The aim of this study was to evaluate the relationship between the presence of BPs and masseter muscle thickness and strain ratio. Individuals with bruxism were included in this study. The presence of BPs in the right and left gonial regions was assessed on panoramic radiographs. In all participants, masseter muscle thickness and strain ratio were measured at rest and during contraction using ultrasonography and strain elastography, respectively. Factors associated with BP presence were evaluated using generalized estimating equation (GEE) logistic regression. The mean age of the 117 included individuals was 24.64 ± 6.95 years. BPs were detected bilaterally in 41.9% of cases, only on the right side in 9.4%, and only on the left side in 6.8%. A statistically significant association was found between BP presence on the right and left sides( p < 0.001). Age (OR = 1.14, 95% CI: 1.04–1.25; p = 0.008), male gender (OR = 4.05, 95% CI: 1.57–10.44; p = 0.004), and greater masseter muscle thickness during contraction (OR = 1.31, 95% CI: 1.04–1.65; p = 0.021) were significantly associated with BP presence. Within the limitations of this study, BP formation showed a predominantly bilateral pattern, and BP presence was associated with age, male gender, and greater masseter muscle thickness during contraction among individuals with bruxism.