Association between trabecular microarchitecture and impaction pattern in unilateral maxillary canines: CBCT-based fractal analysis

Alveolar bone characteristics have been suggested as potential contributors to maxillary canine impaction; however, the relationship between trabecular bone microarchitecture and impaction pattern remains unclear. This study aimed to compare alveolar trabecular microarchitecture between impacted and non-impacted sides in unilateral maxillary canine impaction using cone-beam computed tomography (CBCT)-based fractal dimension (FD) analysis and to evaluate its association with impaction pattern. This retrospective observational study included 90 individuals: 45 patients with unilateral impacted maxillary canines and 45 controls. The impaction group was subdivided into palatal ( n = 31) and buccal ( n = 14) impactions. FD analysis was performed on standardized regions of interest using the box-counting method. A linear mixed-effects model was used to assess the effects of group, side, and their interaction. A significant main effect of group was observed ( p < 0.001), whereas no significant effect of side or group × side interaction was detected ( p > 0.05). The palatal impaction group demonstrated significantly higher FD values compared with both the buccal impaction and control groups ( p < 0.01), while no significant difference was found between the control and buccal impaction groups. These findings indicate that trabecular bone microarchitecture varies according to impaction pattern. The absence of a side effect suggests that palatal impaction is associated with broader maxillary structural characteristics rather than localized adaptations. CBCT-based fractal analysis provides a non-invasive, reproducible approach for assessing trabecular complexity, offering potential insights for individualized orthodontic risk assessment.