Maxillary tooth transpositions: Characteristic features and accompanying dental anomalies

Transposition is a dental anomaly manifested by a positional interchange of 2 permanent teeth. The maxillary permanent canine usually transposes with the first premolar and occasionally with the lateral incisor. The records o f 65 orthodontically treated individuals with maxillary tooth transposition s (40 females and 25 males) with an age range of 9 to 25 years (mean age, 1 3.4 years) were studied to determine the distribution of transposition and to evaluate the accompanying dental anomalies. Thirty-six individuals (55%) had a transposition of the maxillary canines and first premolars, 27 (42%) of the canines and lateral incisors, and 2 (3%) of the central and lateral incisors. Females had 60% more transpositions than did males. Substantiall y more transpositions were unilateral (88%), with a moderate left side domi nance (58%). All dental anomalies associated with transposition-including m issing lateral incisors and second premolars, undersized lateral incisors, retained deciduous canines, impaction of permanent canines and central inci sors, and severely rotated adjacent teeth-were observed on the side of the transposition. This dominance of the affected side suggested that unknown l ocal factors may play a major role in these dental anomalies.