Evaluation of trabecular architecture and bone density in periradicular bone of dilacerated mandibular third molars: a cone beam computed tomography study

This study aimed to evaluate and compare the periradicular trabecular bone density (BD) and microarchitecture of dilacerated and non-dilacerated mandibular third molars using gray values (GVs) and fractal dimension (FD) derived from cone-beam computed tomography (CBCT) images. This retrospective cross-sectional study included CBCT scans of 54 patients with dilacerated mandibular third molars and 60 controls without dilaceration. Root dilaceration was defined as deviation > 20° from the long axis. The dilaceration group was further divided into subgroups based on severity (angle of dilaceration > 60° vs. ≤60°). Standardized regions of interest were selected adjacent to the curvature of the roots, excluding cortical bones. GVs were automatically measured by Romexis 6.2.1 (R®software, Planmeca, Helsinki, Finland), and FD was calculated via ImageJ using the box-counting method. Appropriate statistical analyses were performed, with significance set at p < 0.05. No significant differences were found between dilacerated and non-dilacerated groups in GV (437.12 ± 184.83 vs. 439.25 ± 148.90, p = 0.645) or FD (1.07 ± 0.15 vs. 1.04 ± 0.17, p = 0.204). However, when dilacerated teeth were stratified by severity, roots with > 60° curvature exhibited significantly higher FD values than those ≤ 60° (p = 0.040), whereas GV values did not differ between curvature groups (p > 0.05). Spearman’s correlation revealed no significant association between dilaceration angle and GV or FD (p > 0.05). Within the limitations of this study, fractal analysis was used as a quantitative method to assess periradicular trabecular bone changes adjacent to dilacerated root apices. Although overall GV- and FD-based metrics did not differ between dilacerated and non-dilacerated teeth, the higher FD observed in severely dilacerated roots (> 60°) suggests increased trabecular complexity in the apical region, reflecting a potential biological bone response associated with pronounced root curvature.