Evaluation of Changes in Muscle Thickness, Bite Force and Facial Asymmetry during Early Treatment of Functional Posterior Crossbite

Objective: To determine morphological and functional effects on masticatory system of early treatment of functional posterior crossbite in young children. Study design: 23 children were divided into two groups: deciduous (DecG, n=11) and early mixed dentition (MixG, n=12), which received slow maxillary expansion. Maximal bite force, ultrasonographic masticatory muscle thickness and facial asymmetry were evaluated in three stages: before the start of treatment (s1), after three months of retention (s2), and after three months of observation (s3). The results were analyzed by Mann-Whitney U-test, correlation test, repeated measures ANOVA and backward stepwise multiple regression. Results. Bite force and temporalis thickness increased from s1 to s2 and s3 in both groups (p