Invisalign aligners are BPA-free. The company’s SmartTrack material, used in all current Invisalign trays, is manufactured without bisphenol-A (BPA). That said, the full picture is slightly more nuanced than a simple yes or no, especially if you’re the type of person who wants to understand exactly what’s going into your mouth for months at a time.
What Invisalign Aligners Are Made Of
SmartTrack is a multilayer polyurethane plastic developed specifically for Invisalign. It replaced the company’s earlier single-layer material in 2013 and is engineered to be more flexible and apply gentler, more consistent force to teeth. Polyurethane-based plastics are widely used in medical devices because they’re durable, biocompatible, and can be molded precisely.
Other clear aligner brands use different base materials. Some are made from a modified form of the same plastic found in water bottles (called PETG), while newer direct-to-consumer brands may use 3D-printed resins. The chemical safety profile varies across these materials, so being BPA-free in one brand doesn’t automatically apply to another.
The BPA Question Is More Complicated Than It Seems
BPA is an industrial chemical used to make certain hard plastics and epoxy resins. It mimics estrogen in the body and has been linked to hormonal disruption, which is why many consumers try to avoid it. Invisalign’s manufacturer does not use BPA as an ingredient in SmartTrack.
However, a systematic review published in the Journal of Functional Biomaterials found that several clear aligner brands can release trace amounts of BPA when sitting in saliva. This can happen because BPA sometimes exists as a byproduct or degradation product in plastics, even when it’s not intentionally added. The key finding: the quantities detected were well below toxic thresholds. For Invisalign specifically, the levels measured in studies have not raised safety concerns among researchers.
This distinction matters. “BPA-free” means the manufacturer doesn’t add BPA to the formula. It does not guarantee that zero BPA molecules will ever be present, because trace contamination can occur during manufacturing or as the plastic breaks down over time in a warm, wet environment like your mouth. The amounts involved are extremely small, comparable to what you’d encounter from everyday food packaging.
FDA Classification and Safety Testing
Invisalign is classified by the FDA as a Class II medical device under the category of orthodontic plastic brackets. That classification requires the manufacturer to demonstrate the product is safe before it can be sold. Align Technology (Invisalign’s parent company) submitted biocompatibility testing following ISO 10993, the international standard for evaluating whether medical devices cause harmful biological reactions.
The FDA’s review concluded that the system “does not pose any significant biological risks and is considered safe for its intended use in humans.” Class II devices go through what’s called a 510(k) clearance process, which is less rigorous than the approval required for implanted devices but still involves documented evidence of safety and effectiveness.
What Actually Leaches From Aligners
Every plastic that sits in your mouth will release some molecules over time. Heat, saliva enzymes, and mechanical stress from chewing all accelerate this process. Research on clear aligners has looked at a range of substances beyond BPA, including other small plastic molecules called monomers.
A 2025 systematic review covering a decade of in vitro studies on clear aligners and thermoplastic retainers found that while various materials do release detectable compounds, the levels consistently fall within accepted safety margins. The practical takeaway: aligners are not chemically inert, but the exposure they create is minimal and well within what regulatory agencies consider safe for prolonged oral use.
You can reduce leaching further by following a few common-sense habits. Don’t drink hot beverages with your aligners in, since heat accelerates chemical release from plastics. Rinse your trays with cool or lukewarm water rather than hot. And swap to your next set of trays on schedule, since older, more worn plastic releases more compounds than fresh trays.
How Invisalign Compares to Other Dental Materials
If BPA exposure is a concern for you, it’s worth knowing that traditional dental materials can also contain BPA-related compounds. Some dental sealants and composite fillings use resins derived from BPA, and studies have detected BPA in saliva shortly after these materials are placed. The exposure is temporary and drops quickly, but it’s generally higher in the short term than what clear aligners produce over weeks of wear.
Metal braces avoid the BPA question entirely since they’re made from stainless steel or titanium, but the adhesive bonding them to your teeth may contain BPA-based resins. No orthodontic option is completely free of synthetic chemical exposure. Invisalign’s BPA-free polyurethane formulation represents one of the lower-exposure choices available in modern orthodontics.