Prevalence and severity of apical root resorption and alveolar bone loss in orthodontically treated adults.

This study assessed the frequency of root resorption and alveolar bone loss in 88 adults who had undergone orthodontic treatment. Pretreatment and posttreatment periapical radiographs were used to determine the amount of external apical root resorption and alveolar bone loss of the maxillary and mandibular incisors. Alveolar bone loss in the posterior quadrants was determined from bite-wing radiographs. The number of incisors showing root resorption, including blunting, increased from 15% before treatment to 73% after treatment. The number of incisors having moderate to severe apical root resorption was 2% before treatment and 24.5% after treatment. The number of anterior sites in which loss of alveolar bone height exceeded 2 mm from the cementoenamel junction to the alveolar crest increased from 19% before treatment to 37% after treatment; the number of posterior sites was 7% before treatment and 14% after treatment. Bone LOSS > or = 1.5 mm from the pretreatment to posttreatment stages occurred in 11% of the incisors and 3% of the posterior sites. A marked increase in the prevalence of root resorption and alveolar bone loss occurred over the course of treatment. The prevalence of iatrogenic effects for adults may be higher for incisors than in previously reported adolescent studies. A small subgroup with multiple sites of either root resorption or bone loss account for a disproportionate number of iatrogenic sequelae. However, in general, the iatrogenic experience did not preclude the orthodontic treatment of adults.