###### Abstract  
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 polyurethane (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: Thermforming affected mechanical properties, with both PETG and TPU materials showing decreased efficacy post-thermodforming. 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-thermodforming, emphasizing the need for further research to optimize material performance for clinical use. orthodontics appliance; clear aligners; thermoplastic polymers; simulated oral environment; mechanical properties; physical properties; chemical properties +
Footnote †: journal: Medical Imaging and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine and Biomedicine andomic  
Furthermore, the growing desire for \"invisible\" alternative treatments has contributed to the spread of mass-used clear aligners, a set of dental positioners based on precise impressions or digital scans of the patient's teeth. The main advantages are the transparent appearance of the devices and the possibility of extracting them when eating while maintaining oral hygiene, together with greater comfort and ease of use. Treatment with clear aligners has a shorter duration and requires less chair time than traditional fixed appliances [5,6].