Micro- and Nanoplastics and the Oral Cavity: Implications for Oral and Systemic Health, Dental Practice, and the Environment—A Narrative Review

Background: Micro- and nanoplastics (MNPs) have emerged as increasing environmental and public health concerns. Dentistry contributes to this exposure through polymer-based materials and personal oral care products. This review summarizes the current evidence on the sources, release mechanisms, physicochemical properties, and toxicological and biological effects of MNPs derived from dental sources and oral care products, as well as the synergistic effects of MNP oral exposure with environmental exposure. Methods: An electronic search was performed across the PubMed/MEDLINE, Scopus, and Web of Science databases to identify studies investigating the source, release mechanisms, physico/chemical properties, and toxicological/biological impact of MNPs related to dental materials, oral care products, and the synergic effects of MNPs oral and environmental exposure. Results: MNPs are released in the dental setting from resin-based composites, clear aligners, and prosthetic and impression materials through degradation, wear, and handling processes. Home-use products like toothpastes, toothbrushes, floss, and mouthwashes contribute to chronic oral exposure. Evidence from in vitro, in vivo, and human biomonitoring studies supports the biological activity and systemic distribution of MNPs. Despite this, clinical awareness remains limited, and regulatory oversight insufficient. Conclusions: Dentistry is both a source and vector of MNP exposure. Encouraging the use of safer, MNP-free materials, and raising awareness among dental professionals, may support more responsible and health-conscious practices. Further research and alignment with global policy strategies could help guide future innovation and risk mitigation in the dental field.