The displaced maxillary canine--a retrospective study.

OBJECTIVE

The re-alignment of retained maxillary canines was studied in relation to the degree of displacement in panoramic radiographs, mesiodistal root deviations, length of treatment and side-effects. The aim was then to determine whether the decision between surgical removal and orthodontic re-alignment can be made on the basis of panoramic radiographs alone.

MATERIALS AND METHODS

Forty-seven panoramic radiographs with 59 displaced canines were used to determine their distance and inclination to the occlusal plane (similar to the method described by Dausch-Neumann [8]), the position of the crown tip, and the frequency of mesiodistal root deviations. The length of active treatment was recorded and analyzed statistically in relation to the degree of displacement and incidence of root deviation. Finally, pre- and post-therapeutic panoramic radiographs were compared to determine the incidence of root resorptions and marginal bone defects.

RESULTS

The mean values for the angle of inclination and the distance of the maxillary canines from the occlusal plane were 57.4 degrees (+/- 14.3 degrees ) and 10.5 mm (+/- 3.8 mm), respectively. In 21 canines, the crown tips projected most frequently between the central and lateral incisors. Twelve canines presented root deviations. Treatment lasted an average of 1.9 years (+/- 0.7 years). No correlation was found between the treatment time and the canine's distance from the occlusal plane (r = 0.03), its angle of inclination (r = 0.06), position of the crown tip (r = 0.12), or root deviation (r = -0.07). Root resorptions were found in nine canines (15.3%) and marginal bone defects in 24 canines (40.7%).

CONCLUSION

Fifty-nine retained maxillary canines, some showing extreme displacement, were re-aligned in an average of 1.9 years. There was no correlation between the degree of canine displacement in the panoramic radiographs or the incidence of mesiodistal root deviations and active treatment time. For this reason, the indication to remove displaced maxillary canines should not be taken from panoramic radiographs alone.