A retrospective study on 69 cases of maxillary tooth transposition.

The published literature on tooth transposition includes only a few studies that have involved more than 50 subjects. The aim of the present study was to investigate the prevalence of true maxillary tooth transposition and possible associated dental anomalies in a larger sample of children. The dental records and radiographs of children who had been diagnosed as having true maxillary tooth transposition at a School Dental Clinic in Hong Kong were studied retrospectively. Data were analyzed for sex and side distribution, as well as for associated dental anomalies. Trends of differences were analyzed statistically using the Fisher exact or chi-squared test. A total of 69 cases of true maxillary tooth transposition were identified and studied; its prevalence in Hong Kong Chinese children was 0.81%. More females than males were affected, and the difference between the sexes was statistically significant (P < 0.05). The prevalence of congenitally missing teeth, microdontia of the maxillary lateral incisors or dental impaction was higher in patients with maxillary tooth transposition than in the general population (P < 0.05, P < 0.0005, and P < 0.0001, respectively). The fact that patients with maxillary tooth transposition were more likely to have congenital absence or microdontia of the maxillary lateral incisors lent further support to the contention that a developmental field defect plays a role in the pathogenesis of maxillary tooth transposition.