Surface wear and adhesive failure of resin attachments used in clear aligner therapy – a prospective study

Introduction & Aim Attachments are used in clear aligner therapy (CAT) to improve efficiency of tooth movement. This study was done to assess the surface wear and adhesive failure of conventional and optimized attachments used in CAT.Materials & Methods This prospective study recruited 13 participants with 211 resin attachments. Seventy-five teeth with conventional attachments (3 mm, 4 mm rectangular, ellipsoid) and 136 teeth with optimized attachments were scanned with iTero scanner. Meshmixer 3.5 was used to superimpose teeth bearing attachments initially (T1) with 3 month follow up scans (T2) based on best-fit registration. Deviation incidences were recorded. Adhesive failure of the attachments was also evaluated among the attachments.Statistical Analysis Shapiro–Wilk normality test, the Intraclass Correlation Coefficient (ICC), and Mann–Whitney test were employed.Conclusion Both attachment types showed no significant difference in wear after 3 months of CAT. A higher frequency of adhesive failure was observed in conventional attachments and in the upper molar region. However, given the observational study design, limited sample size and limitations pertaining to unit-of-analysis, these findings should be considered preliminary. The clinical significance of the observed wear patterns remains uncertain since treatment outcomes were not directly assessed.Results Deviations between samples were computed at 0.1 mm to 0.4 mm levels and revealed that both attachment types experienced similar amounts of wear after 3 months of aligner therapy. A higher frequency of adhesive failure was observed in conventional attachments and in the upper molar region. Surface wear was most frequently observed in upper anterior attachments.