Impacted canines and premolars root dilaceration. Is there a relationship? A cross-sectional study

Background: Dental arch anomalies can result from disrupted tooth development processes. While maxillary canine impaction is a common clinical challenge with multiple known causes, the relationship between premolar root abnormalities and canine impaction remains understudied. This study investigates the association between maxillary canine impaction and premolar root dilaceration. Methods: Analysis was performed on 5,181 cone-beam computed tomography (CBCT) scans to identify cases of maxillary impacted canines (IC) and premolar root dilaceration (PRD). Multiplanar reconstructions and three-dimensional imaging were used to characterize the location and features of both conditions. Statistical associations were assessed using Fisher’s exact test, and odds ratios were calculated with 95% confidence intervals through bivariate logistic regression. Results: The overall incidence was 2.35% for impacted canines, while premolar root dilaceration occurred in 2.18% of first premolars and 1.21% of second premolars. Of 151 CBCT scans (2.92%) showing either condition, 96 scans (63.6%) revealed impacted canines, totalling 122 impactions. Notably, 86 scans (57%) showed PRD and impacted canines. Statistical analysis revealed a significant association between impacted canines and PRD in first and second premolars. Conclusion: The findings suggest that premolar root dilaceration is an important indicator for maxillary canine impaction, potentially playing a significant role in its aetiology.