Clinical Evaluation of Customized Attachment Composites in Clear Aligner Therapy

Three-Dimensional Evaluation of Wear and Clinical Survival of Attachments Reproduced With Customized Composites for Clear Aligner Therapy: A Prospective Observational Clinical Study

This prospective observational clinical study aims to evaluate the three-dimensional surface wear and clinical survival of orthodontic attachments fabricated with customized composite materials used in clear aligner therapy. Attachments play a critical role in the biomechanical efficiency of aligner treatment by facilitating planned tooth movements. However, the mechanical and surface properties of the composites used for attachment fabrication may affect their wear behavior and long-term stability.

In this study, four different composite materials will be tested using a split-mouth design in patients treated with clear aligners. Each quadrant will receive a different composite, including both customized and universal types. All attachments will be fabricated using standardized digital templates and bonded under identical clinical conditions. Surface wear will be evaluated using three-dimensional optical scanning and metrology software at baseline, 1 week, 1 month, 3 months, and 6 months. Lost attachments will be replaced and recorded but excluded from wear analysis.

The results of this study are expected to provide valuable insights into the optimal material selection for clear aligner attachments, improving treatment accuracy and clinical durability.

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.

Inclusion Criteria:

• Fully erupted permanent dentition.
• No existing prosthetic restorations.
• Mild-to-moderate dental crowding or spacing (2-6 mm).
• Patients who are scheduled to undergo clear aligner therapy at the Department of Orthodontics, Gülhane Faculty of Dentistry, between 01.08.2025 and 01.08.2026.
• Patients who agree to participate and provide informed consent.

Exclusion Criteria:

• History of previous fixed orthodontic treatment.
• Patients with poor predicted compliance or low cooperation.
• Presence of severe or generalized periodontal disease.
• High caries incidence or untreated caries.
• Poor oral hygiene
• Habitual consumption of hard foods.
• Bruxism
• Congenitally missing permanent teeth.
• Dental developmental anomalies.
• Teeth with existing composite resin restorations or ceramic crowns on buccal surfaces (which may interfere with attachment bonding or wear analysis)