Enamel Integrity and Residual Composite Following Clear Aligner Attachment Removal: A Systematic Review

This systematic review evaluated enamel surface alterations and residual composite following the removal of clear aligner attachments, with particular emphasis on the influence of removal techniques, instrument selection, operator experience, and the use of magnification on enamel preservation and cleaning efficiency.

A comprehensive electronic search was performed in PubMed, Scopus, Embase, Web of Science, and Scielo up to October 2025. In vitro, ex vivo, and clinical studies assessing enamel loss, residual composite, surface roughness, or removal time after clear aligner attachment removal were included. Study selection, data extraction, and methodological assessment followed the PRISMA 2020 guidelines and Cochrane Handbook recommendations. Risk of bias was evaluated using a modified Joanna Briggs Institute checklist for laboratory-based studies. Due to substantial methodological heterogeneity, a narrative synthesis was conducted.

Of 656 identified records, three in vitro/ex vivo studies were assessed for eligibility. Reported enamel loss ranged from approximately 15 µm to more than 50 µm, depending on the removal protocol and visualization conditions. Residual composite covered approximately 20-40% of the treated enamel surface. Multi-step protocols combining tungsten carbide burs with silicone polishers under magnification demonstrated the most favorable balance between composite removal efficiency and enamel preservation. Fiberglass burs were associated with smoother enamel surfaces but increased enamel loss, whereas one-step polishing systems (OneGloss, Enhance, SM104) resulted in reduced surface roughness and shorter procedural time. The use of magnification loupes (≥2.5×) consistently improved removal precision and reduced residual composite. Meta-analysis was not feasible due to heterogeneity in outcome measures and testing methodologies. Overall risk of bias was deemed acceptable.

Based on the limited number of available in vitro/ex vivo studies, removal of clear aligner attachments appears to be associated with measurable enamel loss and residual composite, largely influenced by the instruments and visualization aids used. Sequential carbide-silicone polishing protocols performed under magnification appear promising based on limited in vitro/ex vivo evidence, demonstrating a favorable balance between composite removal and enamel preservation under controlled laboratory conditions. However, given the scarcity of evidence and absence of clinical trials, these findings cannot be directly extrapolated to routine clinical practice. Further well-designed studies are required before definitive clinical recommendations can be established.