UCSF

Objective: This study investigated maxillary skeletal structures and dentition shape and size in subjects with palatally impacted maxillary canines using geometric morphometric analysis. Methods: In this cross sectional study, cone-beam computed tomography images for 40 subjects (22 females, 18 males, mean age 16 years) with palatally impacted canines and 40 subjects (22 females, 18 males, mean age 17 years) with nondisplaced canines were included from a single radiology center. On cone-beam computed tomography images the nasal cavity, palate, sinus, alveolar crest, maxillary lateral walls, and dentition were landmarked by three examiners. Landmarked CBCT images were evaluated for shape using geometric morphometric analysis by performing procrustes superimpositions and principle component analysis. Shape differences were further investigated by using logistic regression and linear regression analyses. Results: Principle component analysis revealed subjects with palatally impacted maxillary canines had a nasal cavity that was more constricted, the palate was more deeply vaulted and constricted, the sinus extended less vertically, canines were wider both mesial-distally and buccal-palatally in relation to length, and the lateral incisors were more narrow both mesial-distally and buccal-palatally in relation to length. Logistic regression depicted five variables that were associated with palatally impacted maxillary canines: Maxillary basal width at the first molar area, palatal depth, canine centroid size, lateral incisor centroid size, and central incisor centroid size (p<.05). Conclusions: In palatally displaced maxillary canines, both the canine and lateral incisor size was diminished while the central incisor size was comparatively increased. The nasal cavity was constricted, the palate perimeter was constricted, the palate was more deeply vaulted, the sinus extended less vertically, and the basal maxillary width was constricted at the first molar area.