Classification of maxillary canine transpositions in Japanese children: A report of 10 cases

The aim of the present study was to examine the prevalence rate and treatment outcome of maxillary canine transposition in Japanese children according to the conventional standard and our new additional consideration of the classification. From 140 cases with ectopic canines diagnosed in the Pediatric Dental Clinic of Niigata University Medical and Dental Hospital, we selected 10 transposition cases as the present subjects. Out of 10 cases, 4 were males and 6 females. Six were classified into type A: the mesio-distal positional interchange of the canine and the first premolar, 2 cases into type B: the mesio-distal transposition of the canine and the lateral incisor, and the other 2 cases into type C: the present new classification that showed the vertical transposition of the canine and the first premolar within the developmental bone. The prevalence rate of types A and B resembled the previous papers regarding the ratio of sex and bilateral occurrence. Although 3 cases in type A, one case in type B and one case in type C could finally be aligned in the normal tooth order, every one of the types A and B cases were aligned in the reverse order. For every one case in types A and C, the transposed canines were extracted. It is recommended that pediatric dentists take an orthopantomogram during early mixed dentition as a routine practice in order to detect anomalies of tooth eruption, such as tooth transposition, as early as possible.