Condylar and ramal vertical asymmetry in unilateral and bilateral posterior crossbite patients and a normal occlusion sample

Introduction: Our objective was to evaluate the condylar, ramal, and condylar-plus-ramal mandibular vertical asymmetry in a group of adolescent subjects with normal occlusion and unilateral and bilateral posterior crossbite malocclusions. Methods: Mandibular asymmetry index measurements (condylar, ramal, and condylar-plus-ramal) were made on the panoramic radiographs of 126 subjects (51 boys, 75 girls). The study groups consisted of 46 unilateral (19 boys, 27 girls; mean age, 13.06 +/- 3.52 years) and 40 bilateral (16 boys, 24 girls; mean age, 12.7 +/- 3.22 years) posterior crossbite patients and a group of 40 subjects (16 boys, 24 girls; mean age, 14.43 +/- 3.05 years) with normal occlusion. One-way analysis of variance (ANOVA) was used to determine possible statistically significant differences between the groups for condylar, ramal, and condylar-plus-ramal asymmetry index measurements at the 95% confidence interval. Results: No group showed statistically significant sex- or side-specific differences for posterior vertical height measurements (P > 0.05). Asymmetry indexes (condylar, ramal, and condylar-plus-ramal) were similar, and no statistically significant differences were found among the unilateral and bilateral posterior crossbite groups and the normal occlusion sample. Conclusions: No statistically significant sex-or side-specific mandibular asymmetry was found among the 3 groups. Condylar asymmetry index values were significantly high compared with the 3% threshold value in each of the 3 groups, but comparisons between groups were not statistically significant. (Am J Orthod Dentofacial Orthop 2009; 136: 37-43)