Pre-treatment radiographic features predict root resorption of treated impacted maxillary central incisors

Objectives- To determine independent predictors of root resorption for surgical-orthodontic treatment of impacted maxillary central incisors. Setting and Sample Population- The Department of Dentistry at Show Chwan Hospital, Changhua, Taiwan. Eighty patients with unilateral osseous-impacted maxillary central incisors receiving a surgical-orthodontic treatment. Material and Methods- This is a retrospective observational study. Root resorption and its predictors were abstracted from patients' charts, pre-treatment cephalometric radiographs, and post-treatment periapical radiographs. Predictors included demographics, treatment duration, crown angle, crown height, crown depth, and root dilacerations. Results- The patients' mean age was 9.2±2.3years (6.4-20.6years), and 60% were females. Impacted maxillary central incisors had greater root resorption than naturally erupted contralateral incisors (Δ=-2.8mm, p<0.001). Independent predictors of root resorption for impacted maxillary central incisors were shown by linear regression analysis to be crown height (β=-0.2, p<0.01), crown depth (β=-0.3, p=0.001), treatment duration (β=0.2, p<0.01), and root dilacerations (β=3.1, p=0.001). Conclusions- Impacted maxillary central incisors had greater root resorption during surgical-orthodontic treatment than their naturally erupted contralateral incisors. Predictors of a greater root resorption were highly and deeply impacted incisors, longer treatment, and root dilacerations. These predictors may help to inform patient and family counseling before treatment.