Eruption disturbances of mandibular permanent canines in Japanese children

Objectives. The purpose of this study was to clarify the cause and prognosis of eruption disturbance of mandibular permanent canines. Sample and Methods. Fifteen Japanese children who visited Niigata University Dental Hospital between 1979 and 1997 with unerupted and/or impacted mandibular permanent canines were examined. Results. All cases showed unilateral disturbances. The eruption disturbance of 6 mandibular canines was associated with a calcified obstacle such as an odontoma (5 cases) or a supernumerary tooth (1 case). After removal of the obstacle, 5 canines were aligned within the dentition. Out of 10 cases, where the permanent canine germ showed malpositioning or aberrant eruption path, 5 primary predecessors had undergone endodontic treatment. In these 10 cases, 6 canines erupted after treatment, two were extracted and the remaining two were left in their impacted position. Conclusions. The present results suggest that it is relatively easy for the position of unerupted mandibular canines associated with calcified obstacles to be improved by removal of the obstacle, but that it is more difficult for teeth showing anomaly in the position of the canine germ to be aligned within the dentition.