Are dental anomalies risk factors for apical root resorption in orthodontic patients?

Regression analyses suggest a weak prediction power of identified risk fact ors for apical root resorption in orthodontic patients, indicating the pres ence of etiologic or causative factors that have not yet been disclosed. To investigate the possible significance of dental anomalies as risk factors, pretreatment and posttreatment periapical radiographs of 84 patients with presence of at least one dental anomaly and of 84 patients without such ano malies were compared. The patients in the two groups were matched according to age, gender, Angle Class, extraction therapy, overbite, and treatment t ime. Apical root resorption was calculated by subtracting posttreatment too th length measurements from the corresponding pretreatment measurements. Tw o sample t tests revealed no differences in mean root resorption between th e patients in the two groups (P = .88). Stepwise regression analyses did no t identify any of the individual anomalies as risk factors. In addition, pa tients with more than one anomaly did not appear to be at increased risk.