Do Invisalign, Clear Aligners, and Retainers Release Microplastics? What the Research Says

You may have seen headlines asking whether Invisalign, clear aligners, and retainers release microplastics. Here’s the short answer:

Yes, laboratory studies have found that clear aligners and other dental plastics can release microscopic particles under certain conditions. But no clinical study has shown that wearing Invisalign, clear aligners, or retainers causes health problems in patients.

That distinction is important.

As an orthodontist, I think patients deserve to know both what the science has found and what it has not found. Here’s what we currently know about clear aligners, retainers, and microplastics.

Are Microplastics Harmful to Human Health?

Microplastics are an important and rapidly developing area of medical research.

Researchers have detected micro- and nanoplastics in human tissues, including blood, placenta, and arterial plaque. A 2024 study published in the New England Journal of Medicine found that patients with micro- and nanoplastics detected in carotid artery plaque had a higher rate of cardiovascular events during follow-up.

However, this study showed an association — not proof that microplastics caused those events.

Other research has raised concerns about possible digestive, reproductive, respiratory, and cardiovascular effects.

But most of this research concerns cumulative exposure from many sources — including food, water, air, packaging, textiles, and the environment — over many years.

That is very different from asking whether one particular dental appliance poses a meaningful health risk.

Do Clear Aligners Release Microplastics?

Laboratory research shows that clear aligner materials can release microscopic plastic particles when exposed to artificial saliva, friction, mechanical loading, and simulated wear.

Researchers have found that:

Different aligner materials behave differently.
Mechanical stress and surface wear can contribute to particle release.
The amount and size of particles vary among materials and manufacturers.
More research is needed to determine the significance of these findings during normal clinical use.

Most importantly, these are primarily laboratory and simulated-wear studies.

Finding particles in a laboratory experiment does not establish that those particles cause disease in people wearing aligners.

At this time, there is no clinical evidence showing that microplastics released from clear aligners cause adverse health effects in patients.

Does Invisalign Release Microplastics?

Invisalign has also been studied.

A 2023 laboratory study published in Science of the Total Environment evaluated seven clear aligner systems after seven days of artificial saliva exposure and simulated mechanical friction.

Invisalign had the lowest number of detected microplastic particles among the seven aligner systems tested.

This is reassuring, but it needs to be interpreted appropriately.

It does not mean Invisalign releases no particles, and one laboratory study cannot establish that one aligner system is universally safer than another.

What it does tell us is that not all clear aligner materials behave the same way, and material composition and manufacturing may influence how an appliance responds to wear.

Should I Stop Wearing Invisalign Because of Microplastics?

No. Current evidence does not show that wearing Invisalign or another clear aligner causes health problems from microplastic exposure.

Stopping treatment also has known consequences. Teeth may stop moving as planned, treatment may be prolonged, and teeth can shift without appropriate retention.

If you have concerns about the material in your aligners, discuss them with your orthodontist rather than stopping treatment on your own.

Do Clear Retainers Release Microplastics?

Clear removable retainers, sometimes called Essix retainers, are also made from thermoplastic materials and are subject to wear over time.

Unlike an aligner that is regularly changed during active treatment, a retainer may be worn for much longer.

Over time, a clear retainer can become:

Cloudy or scratched
Rough
Cracked or distorted
Thin or worn
Loose or poorly fitting

There is no universally established replacement interval based specifically on microplastic exposure.

Instead of replacing a retainer according to an arbitrary number of years, I recommend having it evaluated when it becomes visibly worn, damaged, rough, loose, or no longer fits properly.

What About Hawley Retainers?

Traditional Hawley retainers contain an acrylic base, usually made from PMMA, along with a metal wire.

PMMA and other dental polymers are also being studied for particle release and degradation. Laboratory research involving acrylic dental materials has demonstrated particle release under certain conditions.

Again, this has not been shown to cause health problems in patients wearing Hawley retainers.

Switching from one dental polymer to another does not necessarily eliminate the broader question of material wear.

Are Permanent Metal Retainers an Alternative?

A bonded or permanent retainer uses a thin metal wire attached behind the teeth and therefore avoids the large plastic surface of a removable clear retainer.

Bonded retainers can work very well, but they have their own considerations. Plaque and tartar can accumulate around the wire, the bonding material can loosen, and occasionally a damaged wire can allow unwanted tooth movement.

Some stainless-steel orthodontic wires also contain nickel. Patients with a known nickel allergy should tell their orthodontist so appropriate alternatives can be considered.

For many patients, I use a combination of fixed and removable retention depending on their bite, treatment, and risk of relapse.

How Can I Reduce Wear on My Aligners and Retainers?

You don't need to panic or dramatically change your routine. A few sensible habits can help protect your appliance:

Clean gently. Follow your orthodontist's cleaning instructions and avoid abrasive scrubbing.

Avoid very hot water. Heat can distort thermoplastic aligners and retainers.

Don't chew or repeatedly flex your appliance. Unnecessary mechanical stress can damage the material.

Change aligners as prescribed. Follow the wear and change schedule given by your orthodontist.

Have worn retainers evaluated. If a retainer becomes rough, cracked, distorted, loose, or no longer fits correctly, it may be time to replace it.

Keep regular dental and orthodontic visits. Your dentist and orthodontist can evaluate both your oral health and the condition of your appliances.

Frequently Asked Questions

Do Invisalign aligners contain microplastics?

Invisalign aligners are made from polymer material. Laboratory studies show that microscopic particles can be released from clear aligners under certain experimental conditions. This does not mean Invisalign aligners themselves are “made of microplastics,” nor has particle release been shown to cause disease in patients.

Does Invisalign release fewer microplastics than other aligners?

In one laboratory study comparing seven clear aligner systems, Invisalign had the lowest number of detected microplastic particles among the systems tested. More research is needed to understand how different materials behave during real-world use.

Are clear retainers safe?

Current evidence has not demonstrated that wearing a clear orthodontic retainer causes health problems from microplastic exposure. Retainers should be kept clean and evaluated if they become worn, cracked, rough, distorted, or poorly fitting.

How often should I replace my clear retainer?

There is no single scientifically established replacement interval based on microplastics. Replace a retainer when its condition, fit, or function indicates that replacement is appropriate. Your orthodontist can evaluate it during regular visits.

Should I switch from a plastic retainer to a metal retainer?

Not necessarily. Clear, Hawley, and bonded retainers each have advantages and disadvantages. The best retainer depends on your teeth, bite, treatment history, hygiene, and risk of relapse.

Should I stop wearing my aligners or retainer because of microplastics?

No. Current evidence does not show that orthodontic aligners or retainers cause health problems from microplastic exposure. If you have concerns, speak with your orthodontist before changing your treatment or retention routine.

The Bottom Line: Should You Be Worried About Microplastics From Invisalign or Retainers?

Microplastics deserve serious scientific study. Laboratory research shows that clear aligner and retainer materials can release microscopic particles under certain conditions.

But detecting particles is not the same as demonstrating harm.

At this time, there is no clinical evidence showing that wearing Invisalign, clear aligners, or retainers causes disease from microplastic exposure.

My advice to patients is simple: don't panic and don't stop wearing your appliance. Take good care of it, avoid unnecessary wear and heat, replace a retainer when it becomes worn or no longer fits properly, and continue regular dental and orthodontic care.

Science will continue to evolve, and so will our recommendations. As an orthodontist, my job is to follow that evidence carefully and help patients make decisions based on research rather than headlines.

This article is for general educational purposes and is not a substitute for individualized advice from your dentist or orthodontist.

References

Barile C, et al. “Experimental Assessment of Damage and Microplastic Release During Cyclic Loading of Clear Aligners.” PLOS ONE. 2025.

Chartres N, et al. “Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review.” Environmental Science & Technology. 2024.

Chen Y, et al. “Release of Microplastics During Dental Procedures and Denture Wear: Impact on Dental Personnel and Patients.” Journal of Hazardous Materials. 2025.

De Stefano AA, Horodynski M, Galluccio G. “Can Clear Aligners Release Microplastics That Impact the Patient's Overall Health? A Systematic Review.” Materials. 2025.

Jokstad A, Gussgard AM. “Environmental Impacts From Intraoral Polymer Devices: A Systematic Review.” Dental Materials. 2025.

Li Y, et al. “The Oral-Systemic Interface of Micro- and Nanoplastics.” Advances in Colloid and Interface Science. 2026.

Marfella R, et al. “Microplastics and Nanoplastics in Atheromas and Cardiovascular Events.” New England Journal of Medicine. 2024.

Quinzi V, et al. “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.

Sanna F, et al. “Evaluating Chemical and Surface Stability of Thermoformed and 3D-Printed Clear Aligners After Intraoral Exposure.” PLOS ONE. 2025.