Polymer-based dental materials, oral care products and routine clinical procedures may all contribute to the release of microplastics and nanoplastics, but the scale and implications of this exposure remain uncertain. Dental Tribune International spoke to Dr Akash Kumar Giri, a dentist at Lumbini Zonal Hospital in Nepal and a co-author of a recent narrative review on microplastics and nanoplastics in dentistry, about possible sources of exposure, the current evidence and practical steps that dental professionals can take to reduce unnecessary release.
Dr Akash Kumar Giri, co-author of a recent review on microplastics and nanoplastics in dentistry, says that dentistry does not need to abandon polymer-based materials; however, dental professionals should reduce unnecessary release where it is most predictable. (Image: Dr Akash Kumar Giri)
Dr Giri, why did you think dentistry warranted closer attention in research on microplastics and nanoplastics?
This review arose from a personal concern of mine. Microplastics and nanoplastics are being talked about in environmental and systemic health, but are still somehow strangely absent in dentistry. The question I wanted to explore was straightforward: how might patients and dental professionals be exposed to these particles via the mouth, both in the clinic and at home? Our review indicates that the oral cavity remains an under‑explored site where individuals may regularly ingest—and occasionally inhale—particles released from dental materials and oral care products.
The need for research has also become more pressing as several developments have converged. Polymer-based materials are now central to modern dentistry. Recent biomedical studies have detected microplastics in human blood, placenta and brain tissue, bringing the issue into sharper focus. Also, policy attention has shifted from a broad discussion of pollution towards the regulation of specific products.
I was struck by the level of fragmentation of the existing literature. There were studies on toothbrushes, toothpastes, aligners, composites, aerosols, wastewater and biological effects. However, there were few attempts to bring those studies together in a way that answered the practical question dentists face: how much exposure might be occurring through the mouth, the most routine route?
Based on the current evidence, which dental materials or oral care products appear to be the most significant sources of microplastics and nanoplastics?
Instead of a single ranking, the most honest framing would be to separate the chronic everyday exposure and short-term, high-intensity clinical and laboratory exposure. In the case of repeated exposure at home, toothbrushes and toothpastes containing polymers are among the best examples: because they are used daily, they may contribute to routine particle exposure even in people who are not undergoing dental treatment.
One analysis estimated that toothbrush use may release at least 2.33 million particles per person per year and toothpaste use up to 1.18 million particles per person per year. Depending on the formulation, toothpastes may contain polymers such as PE, EVA, PET, PP, PTFE and PMMA. Toothbrush bristles are commonly made from PP, PA, PE or PET. This distinction matters because not all products result in the same level of exposure. However, everyday oral care is the most consistent source of exposure to microplastics and nanoplastics in the general population.
The picture is different in the clinic and laboratory: exposure may be shorter in duration but more concentrated during specific procedures. Finishing and polishing of resin composite, grinding or milling of resin and PMMA prostheses, and trimming and grinding of aligners seem to be the most important sources of exposure. Resin composite polishing can generate a dense, short-duration ultra-fine aerosol in the air close to the clinician’s nose and mouth. Trimming PMMA appliances produces acrylic dust and fine particles. Additionally, aligners may release debris during fabrication and trimming, and they are subjected to prolonged intra-oral mechanical forces and chemical exposure.
Your review mentions possible biological effects such as oxidative stress and inflammation. How strong is the evidence at this stage, and where are the biggest knowledge gaps?
There is sufficient biological evidence for the issue to be taken seriously. At this point, evidence is largely mechanistic. Microplastics and nanoplastics may be internalised by oral cells and may induce oxidative stress, inflammatory signalling and genotoxic effects, suggested by in vitro studies and some in vivo studies. These effects have been linked to cellular signalling systems involved in inflammation and stress responses. Possible effects on the oral microbiome, local tissue irritation and inflammatory dysregulation also remain plausible.
“Microplastics and nanoplastics may be internalised by oral cells and may induce oxidative stress, inflammatory signalling and genotoxic effects.”
However, direct human clinical evidence supporting a link between disease and exposure to microplastics released from dental materials and procedures remains limited. Biologically plausible but as yet unproven clinical outcomes include potential links to periodontal inflammation, oral carcinogenesis and systemic effects. Another concern is that biological effects may not be caused by the particles alone. Leachable chemicals, including residual monomers and plastic additives, may also contribute, making it difficult to distinguish between particle-driven effects and chemical effects.
My moderated response would be that the strongest evidence points to cellular stress, inflammation and biological plausibility, but that evidence of disease causation in humans remains weak. I would not say that routine dental or home exposure has been proved to cause clinical disease. However, release of microplastics and other plastic particles is occurring, the biological mechanisms are sufficiently worrying and a precautionary approach is warranted.
There are major gaps in practical knowledge. Further research should focus on exposure models that reflect realistic clinical and home-use doses, improved detection of submicron and nanoscale particles in saliva and other oral samples, and a clearer distinction between the effects of the particles themselves and those of chemicals leached from the materials. It should also prioritise standardised reporting of particle count, size and mass, as well as long-term studies in exposed populations such as dental practitioners, aligner users and denture wearers. Real-world clinical and laboratory studies are also needed to demonstrate the extent to which high-volume evacuation, wet finishing, filtration and laboratory dust control reduce particle exposure.
What practical steps can dental professionals and laboratories take now to reduce microplastic release without making routine clinical and laboratory work less efficient?
I believe that we do not have to await definitive evidence to mitigate unnecessary exposure. Most of the mitigation measures already fall within good clinical practice and do not undermine the quality of treatment.
Chairside, capture at source should be the priority. When finishing polymer-based materials, high-volume evacuation should always be used and positioned as close to the working area as possible. When feasible, wet finishing with adequate irrigation should be preferred over dry finishing because it generates less airborne dust.
Dust control is particularly important in laboratories and chairside adjustment areas. Trimming, grinding or polishing PMMA appliances, milling CAD/CAM resin blanks, and trimming or finishing aligners and retainers should preferably be carried out under local exhaust ventilation or in an enclosed extraction unit. Airborne spread can also be reduced using wet methods. Fine debris, grinding sludge and particles in traps or filters should be disposed of appropriately rather than being rinsed in sinks. Additionally, suction traps and in-line filters require regular maintenance, since a poorly maintained control system becomes less effective.
For patients, recommendations should be realistic and not alarmist. When performance is similar, replacing worn toothbrushes, using light brushing pressure and choosing microplastic-free toothpaste formulations are reasonable measures.
The aim is not to abandon the use of polymer-based materials in dentistry, because these materials are of clinical significance. Rather, the goal is to reduce unnecessary release where it is most predictable: finishing, grinding, polishing, cleaning, wastewater handling and product selection.
How might emerging regulations such as the EU restriction on intentionally added microplastics under the regulation on the registration, evaluation, authorisation and restriction of chemicals (REACH) affect the dental industry in the coming years?
I believe that the impact will be selective yet significant. The EU REACH restriction primarily applies to synthetic polymer microparticles that are deliberately added to products or mixtures. It is not a general ban on all plastic materials used in dentistry, and particles formed through wear and tear are not the primary target of this restriction.
The greatest impact is likely to be on deliberately added microplastics, particularly microbeads that are used to provide abrasive, polishing or cleaning effects. In dentistry, this is of greatest concern for oral care products and certain professional preparations that may continue to use polymer microparticles. These products are likely to face reformulation pressure first.
“The goal is to reduce unnecessary release where it is most predictable: finishing, grinding, polishing, cleaning, wastewater handling and product selection.”
For dental manufacturers, documentation and classification of products may become more challenging. Companies may need to demonstrate whether a product falls outside the scope of the regulation, is exempt or is affected by it. This can also include requirements for additional information on its use, disposal guidance, reporting and supplier documentation.
I do not expect dentistry to regard this regulation as a new clinical taboo. Rather, it will be more of a push towards product stewardship. There might be more requests for supplier declarations, more polymer-specific technical reports, greater scrutiny of polishing pastes, professional dental products and consumer oral care products, and increased interest in materials that either do not contain intentionally added microparticles or show reduced shedding without compromising clinical performance. In general, regulation can move the field beyond passive awareness towards active accountability while evidence on health outcomes continues to develop.
