Combined radiographic evaluation of mandibular asymmetry across skeletal malocclusion patterns: prevalence and associations with menton deviation and condylar-ramal indices

Mandibular asymmetry is common in orthodontic patients, but its distribution across skeletal malocclusion patterns and its relationships with menton deviation and condylar-ramal indices remain unclear. This study aimed to compare mandibular asymmetry among skeletal Class I, Class II, and Class III groups and to evaluate associated factors. This retrospective study included 192 adults equally distributed among skeletal Class I, Class II, and Class III groups. Mandibular asymmetry was assessed using posteroanterior, panoramic, and lateral cephalometric radiographs. Menton deviation (MD) ≥ 2 mm was considered clinically significant, and condylar-ramal asymmetry was evaluated using two symmetry indices (SI1 and SI2). Group comparisons used chi-square and one-way ANOVA tests. Pearson correlations were adjusted using the Benjamini–Hochberg false discovery rate procedure. Multivariable binary logistic regression models evaluated associations with MD, SI1, and SI2 asymmetry after adjustment for sex, age, skeletal class, and vertical skeletal pattern. Skeletal class × vertical skeletal pattern interactions were also tested. Crude MD prevalence did not differ significantly among skeletal groups ( p = 0.126), whereas SI1 asymmetry was more frequent in Class II than Class I subjects (68.8% vs. 46.9%; p = 0.042). SI2 asymmetry did not differ significantly among groups ( p = 0.137). After multivariable adjustment, Class II malocclusion was associated with lower odds of MD (adjusted OR = 0.394, 95% CI: 0.179–0.867; p = 0.021) and SI1 asymmetry (adjusted OR = 0.440, 95% CI: 0.208–0.931; p = 0.032) compared with Class I. Male sex was also associated with lower odds of MD asymmetry (adjusted OR = 0.509, 95% CI: 0.262–0.990; p = 0.046). No significant predictors were identified for SI2 asymmetry. No interaction effect was significant, and no correlation remained significant after multiple-testing correction. Differences in mandibular asymmetry observed across skeletal classes were attenuated after adjustment for demographic and vertical skeletal factors. Vertical skeletal pattern did not significantly modify these associations, and no radiographic correlations remained statistically significant after correction for multiple testing. These findings support a multifactorial interpretation of mandibular asymmetry.