Evaluation of wear amounts of different composite resin attachments used in clear aligner treatment over a 6-month period: a retrospective study

Objectives: To compare surface wear among three different attachment composite resins over a 6-month follow-up period. Materials and Methods: Intraoral scanning was performed on 28 participants immediately after initial bonding of attachments (T0), and at 1 (T1), 3 (T2), and 6 months (T3) after starting aligner treatment. In Group 1 (N = 154 attachments), Tokuyama Estelite Universal Flow; in Group 2 (N = 166 attachments), Filtek Z350 XT Universal Restorative; and in Group 3 (N = 161 attachments), G-ænial Universal Injectable resins were used for bonding the attachments. The surface wear depth on attachments was measured using superimposed digitized models. Kruskal-Wallis and Friedman tests were used with a significance set at 5%. Results: As treatment progressed, surface wear increased significantly in all groups (P < .001). The wear amount for Group 3 was significantly greater than that for Groups 1 and 2 at the 3-month period (P < .001). Regarding T0-T3 surface wear, Group 2 (0.03 mm) and Group 3 (0.0609 mm) exhibited significantly greater wear than Group 1 (0.0243 mm; P = .024 and P < .001). Surface wear was also significantly greater in Group 3 than in Group 2 (P < .001). No significant difference was observed in T3-T0 wear values between conventional and optimized attachments within each group. Conclusions: The wear of orthodontic attachments was greatly influenced by the type of composite resin. During the third and sixth months of the clinical period, G-ænial Universal Injectable resin demonstrated significantly greater surface wear than other resins. After 6 months, Tokuyama Estelite Universal Flow displayed the least surface wear.