Orthodontic Root Resorption in the Long-Term Perspective

The long-term consequences of orthodontic root resorption on the stability of tooth position and tooth mobility was analyzed in a retrospective study. From a group of 178 patients who finished orthodontic treatment at least 9 years before, 2 groups of 32 patients were selected. One group developed severe root resorptions in the upper incisor area during treatment, one group only minimal resorptions. Treatment records before treatment (T1), after treatment (T2) and at least 9 years later (T3) were available. The root status of the upper incisors was analysed with the resorption index according to Malmgren. Stability of tooth position was measured on plaster casts with Little's irregularity index. Periotest measurements were made in 15 patients of each group at T3 to determine tooth mobility. The results showed that root resorptions do not continue after cessation of active treatment. Stability of tooth position was comparable in both groups. Tooth mobility was largely within normal limits in both groups. In cases with extreme resorptions a slight increase in mobility could be detected. The decrease of root length due to orthodontic root resorption did not have a negative bearing on the stability of the dentition.