Effects of refinement procedures on enamel surface integrity in clear aligner therapy: a 3D micro-CT study

Objectives: To evaluate topographic changes on the enamel surface after different debonding methods of clear aligner attachments using three-dimensional (3D) micro-computed tomography (Micro-CT). Materials and Methods: Vertical rectangular attachments were attached to 20 premolars and divided into two subgroups (N = 10) using different debonding methods. Micro-CT scans were performed showing the enamel surfaces of each group before bonding (T0), after the first debonding procedure (T1), and after the second debonding with polishing (T2). In Group 1, excess attachment composite was removed with a 12-blade carbide bur, followed by a 24-blade carbide bur, and then the tooth surface was polished with a Renew stone. In Group 2, the attachment composite was removed with a Komet-H23VIP bur and polished with a compatible polishing kit. Morphological changes in the enamel surface were compared within groups using repeated-measures analysis of variance and between groups using independent samples t-tests. Values of P < .05 were considered statistically significant. Results: Significant decreases in enamel demineralization volume (P < .001), area (Group 1: P < .001; Group 2: P = .020), and mineral density (P < .001) were observed in both groups. Intragroup comparison revealed no significant difference in demineralization volume or area changes, but enamel mineral density was better preserved in Group 2 (T1-T2, P = .006; T0-T2, P = .008). Conclusions: The cumulative effect of repeated attachment debonding is significant, with tissue loss becoming more pronounced after the second application. The need for refinement should be carefully evaluated.