Night guards are a safe, effective way to protect your teeth from grinding and clenching — but not all night guards are created equal. From BPA and BPS to phthalates, MMA, and other additives, the materials in your mouth guard matter for your long-term health.
This guide, medically reviewed by Dr. Lara Coseo (DDS, FAGD), breaks down everything you need to know about the safety of night guard materials, how to spot hidden risks, and why Sentinel Mouthguards are designed to be the safest option available.
What Makes a Night Guard “Safe”?
When we talk about a safe night guard, we’re really talking about whether the materials are biocompatible. In dentistry, biocompatible means the material can stay in your mouth for hours every night without causing irritation, leaching harmful chemicals, or triggering allergic reactions.
Dental-grade materials are held to a higher standard than ordinary plastics. They are tested for long-term contact with the sensitive tissues in your mouth and must be free from toxins that could impact your overall health.
A safe night guard should be:
- ✅ BPA & BPS-free (beyond just “BPA-free” claims)
- ✅ Latex-free (no risk for common latex allergies)
- ✅ Phthalate-free (no hormone-disrupting plasticizers)
- ✅ MMA-free (no methyl methacrylate, which can trigger irritation)
- ✅ Silicone-free (avoiding potential respiratory and skin irritants)
- ✅ Medical-grade (materials designed and tested for dental use)
BPA & BPS in Night Guards
One of the biggest concerns people have about plastics is BPA (bisphenol-A). BPA is a chemical often used to harden plastics, and it’s been studied for decades because of its impact on the human body. Research has linked BPA exposure to:
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⚠️ Hormonal disruption (mimics estrogen in the body)
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⚠️ Cardiovascular issues
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⚠️ Increased risk of breast, brain, and prostate cancer
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⚠️ Fertility and reproductive concerns
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⚠️ Early puberty and developmental problems in children
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⚠️ Diabetes and obesity-related risks
Because of these risks, BPA has been banned in certain products like baby bottles in the U.S., Canada, and the European Union. The American Dental Association (ADA) notes that most modern dental materials are manufactured without BPA, but the concern remains valid for patients who want absolute assurance of safety.
What about BPS?
Here’s the catch: many manufacturers proudly claim “BPA-free”, but replace it with a chemical called BPS (bisphenol-S). Unfortunately, research shows BPS may carry many of the same endocrine-disrupting risks as BPA. The Sleep Foundation warns that consumers should look beyond just “BPA-free” claims and verify that dental products are truly safe across the board.
📦 Sentinel Mouthguards are both BPA- and BPS-free.
We don’t stop at the bare minimum. Every guard is made from verified, U.S.-sourced dental materials that are free from BPA, BPS, and other harmful additives—so you can wear your guard with confidence.
Shop Our BPA & BPS-Free Guards →
Phthalates, MMA, and Other Additives
Not all plastics are created equal. Some night guards on the market are made with chemical additives that make the material easier to process or more flexible, but these additives can raise health concerns.
Phthalates
Phthalates (commonly called plasticizers) are chemicals added to certain plastics to make them softer and more flexible. While widely used in consumer products, research has linked high levels of phthalate exposure to:
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⚠️ Hormonal disruption
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⚠️ Reproductive and developmental issues
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⚠️ Potential impacts on fertility
The Centers for Disease Control and Prevention (CDC) notes that phthalates are found in many everyday items, but consumers should minimize unnecessary exposure where possible — especially in products worn inside the mouth for hours at a time.
MMA (Methyl Methacrylate)
MMA is another additive sometimes used in dental acrylics. In some individuals, MMA can trigger oral irritation, sensitivity, or allergic reactions. Common symptoms include redness, burning sensations, or swelling in the mouth.
Why This Matters for Your Mouth Guard
Your night guard is in close, prolonged contact with delicate oral tissues every night. Choosing one that is free from unnecessary additives reduces your risk of irritation and avoids exposure to chemicals that may disrupt your health.
📦 All Sentinel Mouthguards are completely free from phthalates, MMA, PVC, latex, and silicone.
We use only U.S.-sourced, dental-grade materials so you can protect your teeth without worrying about hidden additives.
Do Boil-and-Bite Guards Leach Microplastics?
See our in-depth guide on microplastics in night guards.
EVA vs Acrylic vs 3D Printing Resins
Not all night guards are made from the same materials—and the type of material matters when it comes to both safety and performance.
EVA (Ethylene Vinyl Acetate)
EVA is a flexible, medical-grade plastic commonly used in soft night guards. It’s considered one of the safest options because it’s BPA- and BPS-free, latex-free, and phthalate-free. EVA is also biocompatible, meaning it can be worn safely in the mouth for long periods of time without irritation. Its flexibility makes it comfortable and ideal for people with mild to moderate grinding or clenching.
Acrylic
Acrylic materials are much harder and more rigid. They’ve been used for decades in dentistry, particularly for retainers and hard night guards. While durable, some acrylic-based guards may include plasticizers or additives such as phthalates or MMA (methyl methacrylate). Certain competitors openly list these ingredients in their material disclosures, and in rare cases, they can trigger irritation or sensitivities. If you’re considering an acrylic guard, it’s important to ask about the material composition.
Copolyester: A Safer Alternative to Acrylic
Traditional hard night guards are often made with acrylic, a durable material but one that may include additives like methyl methacrylate (MMA) or phthalates. These additives can sometimes cause irritation, allergic reactions, or simply raise concerns for health-conscious patients.
At Sentinel, we use copolyester for our hard guards instead of acrylic. Copolyester is a medical-grade thermoplastic that provides the same strength and durability as acrylic, but without the need for harmful plasticizers or MMA.
Benefits of Copolyester vs. Acrylic
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🛡 Safe & Biocompatible – Free from BPA, BPS, phthalates, MMA, PVC, latex, and silicone.
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💪 Durable Protection – Withstands heavy clenching and grinding without cracking.
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😌 Gentle on Oral Tissues – Less risk of irritation or allergic response compared to acrylic.
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✅ Trusted in Dentistry & Medicine – Commonly used in FDA-compliant medical and dental devices.
📦 All Sentinel Hard Guards are made with copolyester — never acrylic — giving you maximum protection without compromising your safety.
3D Printing Resins
3D printing has become a new frontier in dental appliances. Not all resins are created equal—some can contain unreacted monomers or additives that aren’t safe for long-term intraoral use. That’s why the source of the resin matters. At Sentinel, we’ve partnered with Keystone Industries, an industry leader in biocompatible dental resins. Their materials are rigorously tested, FDA-registered, and proven safe for night guard use.
While 3D printing is in our future, we’re not quite there yet—today, all Sentinel guards are still hand-crafted using safe, medical-grade thermoforming materials (EVA and copolyester). When we do transition to 3D printing, we will exclusively use Keystone’s rigorously tested, FDA-registered dental resins to ensure the same level of safety and quality.
Allergies & Sensitivities
Although dental night guards are generally considered safe, a small number of people may experience sensitivities or allergic reactions to certain materials. These reactions are uncommon, but it’s important to understand the signs and take precautions.
Possible Triggers
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Acrylics – Some hard acrylic guards may include additives (such as methyl methacrylate) that can cause irritation in sensitive individuals.
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EVA (Ethylene Vinyl Acetate) – EVA is widely recognized as safe, but in rare cases, it can cause mild irritation.
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Metal Components – Night guards with clasps or wires (more common in retainers than guards) can trigger reactions in people with nickel or metal sensitivities.
Symptoms to Watch For
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Redness or inflammation in the gums or cheeks
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Oral discomfort or burning sensations
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Small rashes or itching inside the mouth or around the lips
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Swelling in areas where the guard makes contact
How to Prevent Reactions
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Inform your provider: Always share any known allergies or material sensitivities with your dentist or manufacturer before getting a guard.
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Choose safe materials: Select night guards that are clearly labeled BPA- and BPS-free, latex-free, phthalate-free, and MMA-free.
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Monitor closely: If you notice unusual symptoms after wearing your guard, discontinue use and consult a dental professional immediately.
✅ All Sentinel Mouthguards are made from hypoallergenic, medical-grade materials that are free from common irritants—giving you peace of mind if you have known sensitivities.
FAQs About Night Guard Safety
Are night guards safe to wear every night?
Yes. Custom night guards made from medical-grade, biocompatible materials are safe to wear nightly. They’re specifically designed for long-term intraoral use and can help protect teeth from grinding and clenching damage.
Do boil-and-bite guards leach microplastics?
Boil-and-bite guards are often made from lower-quality plastics and can break down more quickly under heat and pressure. Studies suggest this can release microplastics or unreacted monomers into the mouth. Custom-made guards from dental-grade materials are safer and more durable.
Are Sentinel Mouthguards BPA-free?
Yes. All Sentinel Mouthguards are completely BPA- and BPS-free, as well as free from latex, PVC, MMA, phthalates, and silicone.
Which material is best for sensitive mouths?
For those with allergies or sensitivities, EVA (ethylene vinyl acetate) is often the best choice. It’s flexible, comfortable, and free from common irritants like latex, phthalates, and MMA.
What’s safer: soft, hard, or dual-laminate guards?
All three are safe if made from verified dental-grade materials. The difference lies in comfort and durability:
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Soft guards = gentle and flexible, good for light grinding or sensitive mouths
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Hard guards = strongest protection, best for heavy grinding
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Dual-laminate = combines a soft inside for comfort with a hard outside for durability
📦 Every Sentinel guard is handcrafted in the U.S. from verified safe materials—so no matter which style you choose, you can wear it with confidence.