Oral splints, clear aligners, mandibular advancement devices: hidden sources of micro- and nanoplastic exposure?

OBJECTIVES: The present narrative review aims to synthesize the current evidence on the release of micro- and nanoplastic particles from oral splints, clear aligners, and mandibular advancement devices. METHOD AND MATERIALS: A bibliographic search was conducted in PubMed, supplemented by a search in Consensus, an AI-supported academic search engine (based on Semantic Scholar). The reference lists of relevant articles were manually screened. The final literature search update was updated in March 2026. RESULTS: Micro- and nanoplastic particles are ubiquitous in the environment and have also been detected in numerous human tissues. Experimental and epidemiologic studies suggest that particles measuring less than 10 µm in size may accumulate in organs and induce inflammatory, infectious, hormonal, and DNA-damaging effects. In the field of dentistry, multiple sources of micro- and nanoplastic particles have been identified, including oral appliances. The mechanical wear of oral splints, clear aligners, and mandibular advancement devices leads to surface degradation and the release of plastic particles, which may be ingested. However, clinical data concerning the quantity, size distribution, and long-term fate of micro- and nanoplastic particles released from these appliances is scarce. Most of the available evidence is derived from in vitro or simulated oral environment studies. CONCLUSION: Given the widespread use of oral appliances and the subsequent emergence of associated health concerns, there is an imperative for rigorous, human-centered research to elucidate the potential health risks posed by cumulative, low-level exposure to microplastics released from these products.