Identification of orthodontic patients at risk of severe apical root resorption.

Introduction: Current information suggests that the major variation in orthodontic root resorption can be explained by differences in individual predisposition. Our aim was therefore to test the predictive value of the amount of maxillary incisor resorption about 6 and 12 months after bracket placement for the resorption at appliance removal.

Methods: We measured tooth length of the maxillary incisors on digitally converted periapical radiographs, adjusted for projection errors, made before treatment (T1), about 6 months (T2) and 12 months (T3) after bracket placement, and at the end of active treatment (T4) of 267 prospectively enrolled orthodontic patients, and interpreted reduced tooth length as apical root resorption.