Classification of maxillary tooth transpositions.

Tooth transposition is a severe disturbance of tooth order and eruptive position, involving certain teeth, that may occur at any of several specific sites in the mouth. Published cases of transposition involving maxillary teeth were gathered from worldwide sources to study, identify, and classify these occurrences of orthodontic interest. With a sample of 201 cases and on the basis of anatomic factors, five types of maxillary tooth transpositions were discerned: canine--first premolar (Mx.C.P1), 143 cases; canine--lateral incisor (Mx.C.I2), 40 cases; canine to first molar site (Mx.C to M1), 8 cases; lateral incisor--central incisor (Mx.I2.I1), 6 cases; and canine to central incisor site (Mx.C to I1), 4 cases. As a benefit from this large-scaled study of an uncommon anomaly, new analyses are presented on cause and treatment aspects for each of these five classes of maxillary tooth transpositions.