Buccal ectopia of maxillary canines with no crowding

Introduction: Buccally displaced canines (BDC) are usually found in crowded dentitions. Nevertheless, a small but significant number of patients with BDC have no crowding. In this study, we compared BDC dentitions with no crowding (BDC-nc), BDC dentitions with crowding (BDC-c), and uncrowded dentitions with normally erupted canines (C). Methods: The mesiodistal (MD) widths of maxillary permanent teeth, the prevalence of maxillary lateral incisor anomalies, and the dental age were compared in BDC-nc (n = 30; 17 male, 13 female), BDC-c (n = 41; 21 male, 20 female), and C dentitions (n = 40; 20 male, 20 female). Results: No differences in the MD dimensions of the teeth in the BDC-nc and C subjects were found; teeth in the BDC-c group were slightly larger. Only the lateral incisor was consistently smaller in the BDC-nc group. The prevalence of lateral incisor anomalies was markedly increased in the BDC-nc (28.3%) compared with the BDC-c (7.6%) and the C (8.6%) groups. No discrepancies were found in dental age. Conclusions: These findings suggest that, in addition to a genetically based etiology, buccal displacement in BDC-nc subjects might also be the result of lack of guidance from an adjacent anomalous lateral incisor. (Am J Orthod Dentofacial Orthop 2009;136:218-23)