Clinical Evaluation of Customized Attachment Composites in Clear Aligner Therapy

The study is a prospective, observational, split-mouth clinical investigation conducted at the University of Health Sciences, Gülhane Faculty of Dentistry, Department of Orthodontics. It aims to compare the surface wear resistance and clinical performance of attachments fabricated with different composite resins used in clear aligner therapy. Four composite materials will be evaluated: GC G-ænial A'Chord (control), Spectra ST HV, Spectra ST LV, and GC Aligner Connect. Each patient will receive four different materials applied to separate quadrants following a randomized split-mouth allocation. The study planning and randomization were performed by a single researcher to ensure methodological consistency. All attachments will be fabricated using standardized digital templates based on the virtual treatment plan. The bonding procedure will be carried out by one investigator using Transbond XT adhesive and 37% phosphoric acid etching for 15 seconds. Intraoral scanning will be performed at baseline, 1 week, 1 month, 3 months, and 6 months. The scanned data will be analyzed using Zeiss Inspect software to quantify volumetric and surface wear. All 3D alignments and superimpositions will be performed by a blinded evaluator to ensure objectivity. Lost or fractured attachments will be recorded and replaced but excluded from quantitative wear analysis. All participants will be followed for six months. Statistical analysis will include repeated-measures ANOVA and post-hoc testing with a significance level of p \< 0.05. Reliability will be evaluated using the intraclass correlation coefficient (ICC). This study has been approved by the Gülhane Scientific Research Ethics Committee of the University of Health Sciences (Approval No: 2024/015, August 19, 2025). The findings are expected to enhance understanding of how different composite materials influence attachment wear and longevity in clear aligner therapy, thereby improving the accuracy and clinical predictability of treatment outcomes.