Biocompatibility of Orthodontic Materials. A Comprehensive Review

Biocompatibility is a fundamental requirement for orthodontic materials because these materials remain in prolonged contact with oral tissues and biological fluids. Inadequate biocompatibility may result in local or systemic adverse effects, compromising patient safety and treatment outcomes. To review the principles of biocompatibility and summarize the biological properties, potential adverse effects, and safety considerations associated with commonly used orthodontic and dental materials. A narrative review of the literature was conducted to evaluate the biocompatibility of various dental and orthodontic materials, including dental alloys, resin-based materials, polymethyl methacrylate (PMMA) resins, ceramics, impression materials, glass ionomer cements, clear aligners, rubber chemicals, oral hygiene products, and bisphenol A (BPA)-containing materials. Relevant concepts such as toxicity, immunotoxicity, allergic reactions, and methods for biocompatibility assessment based on international standards were also reviewed. The biocompatibility of dental materials is influenced by factors such as material composition, corrosion, ion release, residual monomers, and individual patient susceptibility. Although most contemporary orthodontic materials demonstrate acceptable biocompatibility and clinical safety, adverse effects including cytotoxicity, allergic reactions, local tissue irritation, and inflammatory responses may occur in susceptible individuals. Advances in material science, including bioactive materials, digital technologies, and 3D printing, have significantly improved the safety and performance of orthodontic appliances. Nevertheless, concerns related to BPA release, latex hypersensitivity, and the environmental impact of aligners warrant continued investigation. Modern orthodontic materials are generally biocompatible when properly selected and used according to recommended protocols. Careful material selection, adherence to regulatory guidelines, and ongoing research into advanced biomaterials are essential to ensure safe, effective, and patient centered orthodontic treatment.