Assessment of impacted canine patterns and correlations with craniofacial discrepancy

The objective of this study was to determine the prevalence, spatial patterns, and craniofacial skeletal associations of impacted maxillary canines using panoramic and cephalometric analyses in a large patient cohort.

This retrospective cross-sectional study evaluated 9593 panoramic radiographs of individuals aged ≥ 14 years. Cephalometric analysis was achieved on subjects aged ≥ 18 years with skeletal maturity (Cervical Vertebral Maturation Index stage ≥ 6), comparing 94 cases with maxillary impacted canines (MIC) to 100 age- and sex-matched controls. Positional measurements (sector, depth, and angulation) were compared with skeletal patterns using independent t-tests, analysis of variance, and chi-square tests (α = 0.05).

Analysis revealed a maxillary canine impaction prevalence of 2.02%, with a significant female predilection (54.1%) and a maxilla-to-mandible ratio of 4:1. The predominant spatial pattern was mesioangular inclination (67%) in Sector 0 (35.2%) at coronal depth (54.1%). Compared to controls, MIC cases exhibited significant maxillary skeletal deficiency (e.g., anterior nasal spine - posterior nasal spine [ANS-PNS]: 50.1 ± 5.1 mm vs. 53.1 ± 3.7 mm; p < 0.001) and vertical hyperdivergence (Sella-Nasion to Gonion-Gnathion angle [SN-GoGn]: 32.8° ± 6.2 vs. 29.8° ± 6.4; p = 0.001). Upper incisor inclination showed no intergroup difference.

Maxillary canine impaction is strongly associated with maxillary skeletal deficiencies and vertical growth discrepancies. The common finding of mesioangular impactions in Sector 0 at coronal depth indicates a high risk for adjacent root resorption. We recommend incorporating cephalometric screening (focusing on ANS-PNS < 50 mm and SN-GoGn > 32°) into early adolescent assessments to identify at-risk patients and guide timely interceptive strategies such as maxillary expansion.