Materials for Clear Aligners—A Comprehensive Exploration of Characteristics and Innovations: A Scoping Review

Introduction: Transparent orthodontic aligners have revolutionized dentistry and orthodontics since the 1990s, offering advantages over traditional fixed appliances in terms of hygiene, comfort, and aesthetics. With the increasing demand for invisible orthodontic treatments, clear aligners have gained popularity, prompting research into materials to enhance their efficacy and performance. Materials and Methods: A scoping review was conducted using electronic databases (Pubmed, Medline, Cochrane Library, Embase, and Scopus) to identify studies on clear aligner materials published in the last decade. Selection criteria focused on studies specific to dental materials, excluding those unrelated to materials or clear aligners. Results: The review included 11 relevant studies evaluating 17 different clear aligner materials. Materials such as polyvinyl chloride derivatives, thermoplastic polyurethanes (TPU), and polyethylene terephthalate glycol (PETG) were commonly used. The studies assessed mechanical, physical, chemical, and optical properties, as well as thermoforming effects, stress decay, and surface characteristics. Discussion and Conclusions: Various materials exhibited distinct properties, with PETG materials offering transparency and flexibility, while TPU-based materials like Smart Track providing durability and elasticity. Thermoforming affected mechanical properties, with both PETG and TPU materials showing decreased efficacy post-thermoforming. Polymer blending improved mechanical properties, but variations existed among different brands and materials. Clear aligner materials exhibit diverse characteristics, influencing their suitability for orthodontic use. PETG-based materials offer transparency and flexibility, while TPU-based materials provide durability and elasticity. However, both materials undergo mechanical changes post-thermoforming, emphasizing the need for further research to optimize material performance for clinical use.