Mouthguard

Last updated: May 2, 2026

What is a mouthguard in MMA?

In MMA, a mouthguard refers to a custom-shaped piece of soft thermoplastic, typically EVA (ethylene-vinyl acetate) rubber, that fits over the upper teeth. Its job is to spread the force of an impact across multiple teeth and create a barrier between the upper and lower jaws when a fighter takes a strike or bites down under pressure.

Every reputable MMA organization in the world requires fighters to wear one in competition. The Unified Rules of Mixed Martial Arts list it alongside open-fingered gloves and groin protection as mandatory gear, and an attending physician must inspect and approve the mouthguard before each round can begin.

MMA mouthguards differ from those used in helmeted sports. Football and hockey players have a helmet absorbing some of the impact before it reaches the face. Fighters do not. Their mouthguards tend to be thicker because the protection has to come entirely from the guard itself, with no helmet sharing the load.

How a mouthguard works

The mechanics are straightforward. When a fighter takes a punch to the face, the force travels into the teeth and jaw. Without a mouthguard between them, the upper and lower teeth slam together. That can chip enamel or fracture roots, and harder strikes are capable of knocking a tooth out of its socket entirely. With one in place, the bite force is distributed across the surface area of the device rather than focused on a few teeth.

The same cushioning works against soft tissue inside the mouth. Fighters frequently bite or cut their own lips and tongue on their teeth during impact, and a layer of soft polymer reduces those injuries.

Mouthguards also prop the jaw open slightly, keeping the lower jaw from being driven hard into the upper jaw on an uppercut or upward knee. Researchers studying head trauma have suggested this small gap may reduce some of the force transmitted from the jaw into the base of the skull, though the link to actual concussion prevention is unsettled.

Types of mouthguards used in MMA

Three types of mouthguards are used in MMA: stock, boil-and-bite, and custom. They differ mainly in fit, cost, and how well they protect.

A stock mouthguard comes pre-formed in standard sizes and is ready to wear straight from the package. It is the cheapest option, but the fit is generic. Most fighters move past stock guards quickly because they shift around in the mouth and can interfere with breathing.

A boil-and-bite mouthguard is the most common choice for amateurs and beginners. The wearer drops it into hot water until the thermoplastic softens, then bites down to mold it to the contours of their teeth. According to Damage Control Mouthguards, around 99% of mouthguards sold worldwide are boil-and-bite, and they typically cost between $10 and $40.

A custom mouthguard is made to a fighter’s individual dental impression. The polymer is shaped by a dentist or specialist lab, which produces a closer fit and thinner profile than any boil-and-bite can match. Specialist brands like Damage Control and OPRO supply most professional fighters.

Type	Fit Method	Typical Cost	Fit Quality	Common In MMA
Stock	Pre-formed, no fitting	$5 to $15	Poor	Beginners only
Boil-and-bite	Softened in hot water, bitten to mold	$10 to $40	Good	Amateurs, hobbyists, some pros
Custom	Made from dental impression by lab or dentist	$50 to $400+	Excellent	Most professional fighters

Single vs double mouthguards

Most MMA fighters wear a single mouthguard covering only the upper teeth. A double mouthguard covers both upper and lower teeth, but it makes breathing harder and is mostly used by beginners or in heavy-impact training. Single guards remain the standard at professional level because cardio and oxygen flow matter through five rounds.

Mouthguard rules in MMA

Mouthguards are mandatory in every sanctioned MMA bout. The Unified Rules of MMA, adopted by the Association of Boxing Commissions in 2009 and used by the UFC and most U.S. promotions, require all fighters to wear an approved mouthguard from the start of round one. An attending physician must check it before each round begins, and a round cannot start without it in place.

When a mouthguard falls out mid-fight, the referee waits for an opportune moment to pause the action, retrieves the guard (or has it cleaned), and replaces it before allowing the round to continue. Stopping the fight immediately can put a fighter at a tactical disadvantage during a scramble, so the referee uses judgment about when to step in.

Intentionally spitting out a mouthguard is treated as a foul. The Unified Rules categorize it under timidity, the same category as faking an injury, and a fighter who repeatedly does it can lose a point or face disqualification.

Some MMA organizations also mandate mouthguards in training. The UFC requires its athletes to wear approved mouthguards during all contact sparring at the UFC Performance Institute and any sanctioned camps.

Mouthguards and concussion risk

One of the most common assumptions about mouthguards is that they help prevent concussions. The actual research is mixed.

A 2020 case-control study published in the International Journal of Environmental Research and Public Health found a statistically significant association between mouthguard use and reduced concussion incidence among college athletes. A separate 2007 study using neurocognitive testing on football players, however, found no measurable difference in symptom severity between mouthguard users and non-users after concussion.

Researchers at the University of Colorado Anschutz Medical Campus have noted the theoretical mechanism: a strike from below the chin transmits force through the teeth and into the base of the skull, and a mouthguard may absorb part of that force before it reaches the brain. Whether that absorption is enough to reliably reduce concussion rates is still under study.

What is settled is the dental and orofacial protection. Mouthguards reliably reduce broken teeth and jaw fractures, and they protect the lips and tongue from cuts during impact. The concussion question is still being investigated, including through NFL-funded research using sensor-equipped mouthguards to measure head impact in real time.

Frequently Asked Questions

Are mouthguards mandatory in MMA?

Yes. The Unified Rules of MMA require every fighter to wear an approved mouthguard from the start of round one until the fight ends. A round cannot begin without one in place.

How long does an MMA mouthguard last?

It depends on use and type. A boil-and-bite guard worn for daily training typically lasts a few months before deformation makes it less effective. Custom guards last longer, often a year or more, because of higher-quality materials and a more secure fit. Cracks, tears, or loose fit are signs to replace it.

What is the difference between a mouthguard and a mouthpiece?

In MMA, the two terms are used interchangeably. Both refer to the same piece of equipment. “Gum shield” is a third name, more common in British MMA and boxing.

Can a mouthguard prevent broken teeth in MMA?

It significantly reduces the risk but does not eliminate it. A well-fitted custom mouthguard absorbs and spreads impact across the upper teeth, but a clean strike with full force can still cause damage, especially given the 4-ounce gloves used in MMA.

Why do most MMA fighters wear only an upper mouthguard?

A single upper-arch guard allows for better breathing and clearer communication with corners. Cardio is the limiting factor in long fights, and a double mouthguard restricts oxygen flow more than most professional fighters are willing to accept.

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Sources

1. UFC. “Unified Rules of Mixed Martial Arts.” ufc.com. Accessed May 2026.
2. Association of Boxing Commissions. “Unified Rules of Mixed Martial Arts (2019 Edition).” abcboxing.com. Accessed May 2026.
3. Damage Control Mouthguards. “MMA and Mouthguards: Basics and Common Rules.” dcmouthguards.com, June 2023. Accessed May 2026.
4. ONE Championship. “How To Pick The Best Mouthguard For Martial Arts.” onefc.com. Accessed May 2026.
5. University of Colorado Anschutz News. “Mouthguards Protect Your Mouth and Potentially Your Brain from Sports-Related Injuries.” news.cuanschutz.edu, April 2024. Accessed May 2026.
6. Brain Research Bulletin / PMC. “A brief descriptive outline of the rules of mixed martial arts and concussion in mixed martial arts.” pmc.ncbi.nlm.nih.gov, 2022. Accessed May 2026.
7. Maeda Y, Kumamoto D, et al. “Association between Sports-Related Concussion and Mouthguard Use among College Sports Players.” International Journal of Environmental Research and Public Health, 2020. Accessed May 2026.
8. Mihalik J, McCaffrey M, et al. “Effectiveness of Mouthguards in Reducing Neurocognitive Deficits Following Sports-Related Cerebral Concussion.” Dental Traumatology, 2007. Accessed May 2026.

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