MICRO- AND NANO-PLASTICS: HEALTH, DENTAL PRACTICE, AND ENVIRONMENT

Micro- and nanoplastics (MNPs) are emerging contaminants with proven biological activity and systemic distribution. Generated throughout the plastic life cycle, they pose health risks to exposed populations and ecosystems. Dentistry contributes to MNP exposure via polymer-based materials and microplastic-containing oral care products. Degradation of resins, impression materials, clear aligners, and polishing agents releases MNPs directly into the oral cavity, where they may cross mucosal barriers, accumulate in tissues, and trigger oxidative stress, inflammation, immune dysregulation, and dysbiosis.1–4 Human biomonitoring studies have detected MNPs in blood, placenta, lungs, and stool, challenging prior assumptions of their inertness.5 Once internalized, MNPs may act as vectors for environmental toxicants and contribute to chronic disease, including carcinogenesis.6–7 The oral route is especially concerning, yet underinvestigated. Patients and clinicians face chronic, low-dose exposure, while awareness and regulation remain limited.8 This narrative review explores MNP sources, exposure routes, and health implications in dentistry, emphasizing the need for preventive strategies. These include eliminating intentionally added microplastics, reformulating dental materials, and improving labeling. Integrating environmental safety into dental practice is essential to reduce MNP exposure and protect oral and systemic health. References 1. Wang, Z et al. We Need a Global Science-Policy Body on Chemicals and Waste. Science (1979) 2021, 371, 774–776, doi:10.1126/science.abe9090.2. Protyusha, G.B et al. Microplastics in Oral Healthcare Products (OHPs) and Their Environmental Health Risks and Mitigation Measures. Environmental Pollution 2024, 343, 123118, doi:10.1016/j.envpol.2023.123118.3. Zha, H. et al. Alterations of Gut and Oral Microbiota in the Individuals Consuming Take-Away Food in Disposable Plastic Containers. J Hazard Mater 2023, 441, 129903, doi:10.1016/j.jhazmat.2022.129903.4. Winiarska, E. et al. The Potential Impact of Nano- and Microplastics on Human Health: Understanding Human Health Risks. Environ Res 2024, 251, 118535, doi:10.1016/j.envres.2024.118535.5. Tanna, D. et al. World Acad Sci J 2025, 7, 35, doi:10.3892/wasj.2025.3236. De Stefano, A.A et al. Can Clear Aligners Release Microplastics That Impact the Patient’s Overall Health? A Systematic Review. Materials 2025, 18, 2564, doi:10.3390/ma18112564.7. Martina, S. et al. In Vitro Cytotoxicity of Different Thermoplastic Materials for Clear Aligners. Angle Orthod 2019, 89, 942–945, doi:10.2319/091718-674.1.8. Premaraj, T. et al. Oral Epithelial Cell Reaction after Exposure to Invisalign Plastic Material. American Journal of Orthodontics and Dentofacial Orthopedics 2014, 145, 64–71, doi:10.1016/j.ajodo.2013.09.011.