Orthodontic Materials and 3D Printing: A Systematic Scoping Review

Abstract: This systematic scoping review evaluates the current evidence regarding conventional acrylic- and thermoplastic-based materials, directly printed resins, and emerging materials used in orthodontic appliance fabrication. Particular emphasis was placed on material properties, biocompatibility, manufacturing considerations, aging behavior, clinical applications, and the integration of three-dimensional (3D) printing technologies into contemporary orthodontic workflows. Abstract: A comprehensive literature search was conducted in PubMed, Scopus, Web of Science, and Google Scholar from database inception through May 2026. Experimental studies, review articles, case reports, and relevant technical documents addressing orthodontic appliance fabrication, material performance, biocompatibility, or digital manufacturing technologies were considered for inclusion. Following screening and eligibility assessment, 45 studies were included in the qualitative synthesis. Abstract: The available evidence indicates that 3D printing technologies enable high levels of customization, digital workflow integration, and improved dimensional accuracy. However, material performance varied considerably among printable resins and conventional materials. Thermoplastic materials frequently demonstrated superior stiffness, transparency, color stability, and surface characteristics, whereas directly printed materials offered advantages in manufacturing flexibility and appliance customization. Current evidence generally supports the biocompatibility of contemporary printable resins, although residual monomer release, postprocessing protocols, and polymerization efficiency remain important considerations. Aging studies demonstrated material-dependent changes in mechanical behavior and optical properties, but long-term clinical evidence remains limited. Abstract: Digital manufacturing technologies are becoming increasingly integrated into orthodontic practice and have expanded applications in aligners, retainers, and customized orthodontic appliances. However, the evidence base remains dominated by laboratory investigations, with comparatively limited long-term clinical data. Further standardized experimental studies and prospective clinical investigations are needed to evaluate durability, biocompatibility, clinical effectiveness, and the potential role of emerging materials in orthodontic appliance manufacturing.