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The Biosafety or Biocompability of Clear Aligner

Open Science Framework 2025
Wenyu Feng

Summary

This review examined the biosafety of clear aligner orthodontic appliances, finding that prolonged intraoral wear can cause release of chemical leachates (including bisphenol A and residual monomers) and microplastic particulates, with potential biological effects that remain inconsistently characterized in the literature.

Models

Clear aligners are widely used in orthodontics, which mainly relies on thermoplastic trays and resin attachments. Patients with clear aligners are instructed to wear aligners for at least 22 hours per day, so the materials experience prolonged intra-oral exposure. Thermal processing during fabrication and the oral environment may alter polymer properties and lead to the release of chemicals (e.g., bisphenol A, residual monomers, additives) and particulates (e.g., microplastics). These potential biological effects have attracted increasing attention, yet the evidence base is highly heterogeneous in materials, methods, outcomes, study types and reporting. The main aim of this study is to provide an up-to-date overview of the biological side effects of clear aligners.

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