Dental morphologic characteristics of normal versus delayed developing dentitions with palatally displaced canines.

An earlier study reported on the delayed dental age in about 50% of patients with palatally displaced canines (PDC), suggesting the possible existence of 2 different PDC phenotypes. The present study aimed to determine whether the PDC subgroup with late dental age displays different dental features from the PDC subgroup with normal dental age, supporting the above assumption. The 3 dental parameters examined were mesiodistal and buccolingual tooth sizes, the presence of anomalous maxillary lateral incisors, and other congenitally missing teeth. Fifty-eight subjects with PDC, 37 girls and 21 boys, were divided according to dental age and compared with age- and sex-matched controls. The results revealed marked sexual dimorphism. Delayed dental development was twice as prevalent among the PDC males. The existence of 2 distinct PDC subgroups was supported for males only. One subgroup was characterized by delayed dental development, smaller-than-average teeth, and a marked increase in the prevalence of anomalous lateral incisors. The second subgroup more closely resembled the controls, presenting a timely developed dentition, a moderate and nonsignificant increase of anomalous lateral incisors, and a reduction in the dimensions of only the central incisors and the first molars. In females, although the prevalence of anomalous lateral incisors was slightly increased in the late dental age subgroup, tooth sizes were remarkably similar, negating the existence of 2 distinct subpopulations. Studying the overall PDC group as a single entity produced confusing results because important differences were obscured when the 2 sexes and the 2 dental age subgroups (in males) were combined.