Are Clear Aligners an Unrecognized Source of Microplastic Exposure?

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Are Clear Aligners an Unrecognized Source of Microplastic Exposure?

What orthodontists are starting to ask

Clear aligners have become one of the most successful innovations in modern orthodontics. Patients appreciate the aesthetics and convenience, clinicians value the flexibility, and many practices now run almost entirely on plastic-based appliances. As aligner use becomes routine, however, a new question is quietly entering conversations among orthodontists and patients alike. What happens to these plastics after living in the mouth for 22 hours a day?

Clear aligners are manufactured from medical-grade thermoplastic polymers designed to be durable, biocompatible, and safe for prolonged intraoral use. In real life, these materials are exposed to continuous chewing forces, saliva enzymes, fluctuating pH, repeated temperature changes from food and beverages, and a wide range of cleaning agents. Laboratory studies suggest that under these combined mechanical and chemical stresses, aligner materials can undergo surface changes and measurable wear.1,2

Several in vitro investigations have demonstrated that clear aligners may release microscopic plastic particles during simulated oral use. One widely discussed study found that aligners exposed to artificial saliva and mechanical friction showed detectable microplastic particle release, with particle size and quantity varying by material and manufacturer.1 Additional research evaluating aligner aging has reported surface roughening, micro-cracks, and morphological changes that may contribute to gradual material degradation over time.2

The biological significance of these findings remains unclear. Systematic reviews evaluating the biocompatibility of clear aligners and other orthodontic thermoplastics generally conclude that most materials demonstrate low to moderate cytotoxicity in laboratory conditions, with no clear evidence of clinical harm in patients.3 Studies examining chemical leaching, including concerns about bisphenol A, show mixed results. Some detect trace release under specific conditions, while others find none, highlighting the variability in materials and testing protocols.4

Importantly, there is currently no definitive clinical evidence linking aligner-related microplastic exposure to adverse health outcomes. Professional organizations and public health experts note that while microplastics are an emerging area of concern in medicine, dentistry lacks long-term human data demonstrating harm from orthodontic appliances.5 This places orthodontists in familiar territory. We are asked to reassure patients using evidence-based dentistry while acknowledging that science does not yet answer every question.

Patients, however, are asking better and more informed questions than ever before. Many are increasingly health-conscious and environmentally aware. They want to know whether wearing plastic appliances for months or years differs meaningfully from exposure associated with retainers, composite restorations, or everyday environmental sources. These conversations are rarely confrontational. They are usually thoughtful, and they deserve thoughtful responses.

Those speaking in general emphasize that patient communication is key. Explaining the difference between laboratory findings and proven clinical risk helps maintain perspective. Emphasizing that all dental materials involve tradeoffs also helps frame the discussion. Fixed appliances introduce metals, resins, and ceramics. Aligners introduce polymers. None are entirely inert, and all have long histories of safe clinical use.

From a practical standpoint, many orthodontists are making small adjustments that support both patient confidence and material longevity. These include recommending gentle cleaning methods rather than abrasive or highly chemical solutions, inspecting aligners regularly for cracks or excessive wear, and avoiding marketing language that suggests materials are indestructible or biologically invisible. A little humor can help as well. More than one clinician has joked that if aligners were truly dangerous, orthodontists would have noticed long ago.

Behind these chairside conversations, broader professional questions remain unresolved. Should aligner material degradation and microplastic release be studied more aggressively under real-world conditions? Do orthodontists have an ethical obligation to disclose uncertainty even when no harm has been demonstrated? Should long or complex cases prompt more discussion of fixed appliances as an alternative rather than defaulting to aligners? And are manufacturers sufficiently transparent about material composition, wear behavior, and particle release?

For now, most orthodontists are navigating this issue the same way they approach many evolving topics. They stay informed, avoid alarmism, listen carefully to patient concerns, and keep perspective. Clear aligners remain a safe and effective tool, but popularity alone should never exempt any material from scrutiny. Thoughtful questioning is not a threat to orthodontics. It is a sign of a healthy and self-reflective specialty.

How are you currently addressing patient questions about aligner materials and microplastics, and has it changed how you present treatment options or alternatives? 
What’s your take?

Share your thoughts in the comments below.

Hot Topic articles draw inspiration from active online discussions among orthodontists. Written by the editorial team with the assistance of AI, each piece is thoughtfully developed and refined under full editorial oversight.

References

1. Quinzi V, Orilisi G, Vitiello F, Notarstefano V, Marzo G, Orsini G. A spectroscopic study on orthodontic aligners: First evidence of secondary microplastic detachment after seven days of artificial saliva exposure. Science of the Total Environment. 2023.
2. Stefano AA, Horodynski M, Galluccio G. Can clear aligners release microplastics that impact the patient’s overall health? A systematic review. Materials. 2025.
3. Kolenc L, Oblak J, Ovsenik M, Oblak C, Ovsenik R. Biocompatibility and safety of orthodontic clear aligners and thermoplastic retainers: A systematic in vitro review (2015–2025). Applied Sciences. 2025.
4. Peter E, George SA. Bisphenol-A release from thermoplastic clear aligner materials: A systematic review. Journal of Orthodontics. September 2023.
5. Schlanger Z. Modern dentistry is a microplastic minefield. The Atlantic. Aug. 25, 2025.

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