Wear resistance of orthodontic attachments: a comparative analysis of different composite resins in clear aligner therapy

OBJECTIVE: Clear aligner attachments play a crucial role in facilitating tooth movement in clear aligner treatments. This in-vitro study evaluates the wear of attachments made from 4 different composite resins during orthodontic therapy. MATERIALS AND METHODS: The study included 32 extracted human premolar and molar teeth, divided into four groups based on the composite resin used: Flow Tain, Transbond XT, G-aenial Universal Flo, and Filtek Z350 XT. Horizontal rectangular attachments were bonded to the teeth, which underwent thermal cycling and tooth brushing to mimic clinical conditions. Micro-CT analysis measured volumetric and linear changes in attachment wear. Statistical analyses were conducted using the Wilcoxon Signed-Rank Test and Kruskal-Wallis test, followed by pairwise comparisons with the Mann-Whitney U Test. RESULTS: All composite resins exhibited a significant decrease in attachment volume after aging. The greatest volume reduction was observed in the Transbond XT group, while the least reduction occurred in the G-aenial Universal Flo group. Significant differences were found in the occlusal and gingival thirds of the attachments, with Flow Tain showing the highest wear in all regions. CONCLUSION: The study shows that the wear of orthodontic attachments is greatly influenced by the type of composite resin used. The results indicate that G-aenial Universal Flo composite resin may offer superior wear resistance, preserving attachment integrity more efficiently throughout orthodontic treatment than the other 3 composite resins. CLINICAL RELEVANCE: The findings can assist clinicians in choosing composite materials that improve treatment effectiveness by preserving attachment integrity over time.