Dental anomalies as a microsystem of palatal canine displacement: S. Leifertand and I. E. Jonas Journal of Orofacial Orthopedics 2003;64:108-20

Abstract

The ectopic eruption of the permanent maxillary canines is a problem encountered relatively frequently in clinical orthodontics. The aims of the study were to investigate whether there was an increased incidence of certain anomalies in conjunction with palatal canine displacement and to identify risk factors that would enable the clinician to make an early diagnosis and thus treat the eruption disturbance at an early age. The study was conducted on a group of 235 patients (130 females, 105 males) each with at least 1 palatally displaced canine, selected from the complete records of 8556 treated clinic patients. This group was compared with a control sample of similar size (121 females, 114 males). The anomalies sought on radiographs and models included the following: impaction and congenital absence of further teeth; hypoplastic, peg-shaped, rotated, and congenitally missing maxillary lateral incisors; supernumerary teeth; Angle classification; and cover bite (deep overbite with or due to retroclination of maxillary incisors). The data were compared with those of a control sample having normal physiologic maxillary canine eruption. The results of the study showed the prevalence of palatal canine displacement to be 2.75% in the 235 patients comprising the palatally displaced canine group, exhibiting a total of 281 palatally displaced canines. The risk of palatal canine displacement was shown to be significantly higher in patients with hypoplasia, peg-shaped or congenital aplasia of the maxillary lateral incisors, other impacted or congenitally missing teeth, and cover bite. Intergroup differences in terms of sex, rotation of maxillary lateral incisors, and Angle classification were not statistically significant. A significantly higher risk of palatal canine displacement was associated with an adjacent hypoplasia or peg-shaped lateral incisor and with aplasia of the contralateral maxillary incisor. The clinical significance of the study is that the occurrence of palatally displaced canines is often linked with the aforementioned dental anomalies. Thus, in patients having any of the stated microsystems, a close follow-up of the maxillary permanent canine eruption during the late exfoliation period is strongly recommended.