Morphological Research of Incisor Root Resorption After Camouflaged Orthodontic Treatment of Adult Skeletal Class III Malocclusion

Objective: CBCT and Mimics software were performed to investigate the incisor root resorption after camouflaged orthodontic treatment of adult skeletal class III malocclusion. Methods: Thirty permanent dentition adult patients with skeletal class III malocclusion were included in orthodontic department. CBCT data of each patient at pretreatment and posttreatment were acquired and three-dimensional (3D) digital models were reconstructed. Image registration was performed of each incisor 3D model before and after camouflaged treatment. Observation, classification and statistics of 3D model overlap were performed, as well as the morphological changes of root resorption were described. Results: (1) Either the upper or lower incisors, slope form resorption had the most percentage (49.17%, 46.67%; 51.67%, 49.16%), followed by cone-shaped form resorption, and flat form resorption had the less percentage. In the upper incisors, the root resorption was mainly in the lingual-labial direction (46.67%, 41.67%), while in the lower incisors, it was in the labial-lingual direction. (2) The result of Kappa consistency test is good (K=0.471, 0.441). Conclusions: The root of the upper and lower incisors showed various morphological changes after camouflaged treatment of adult skeletal class III malocclusion. The absorption was mainly manifested as slope form and cone-shaped form, and flat form resorption can be seen. 3D model registration can be used as a reliable auxiliary method for the morphological study of root absorption.