The Science of Impact Protection

How Does a Mouthguard Actually Work?

When a fast-moving object — a hockey puck, an opponent's elbow, or a fall to the ground — strikes the face, the forces involved are immense. A mouthguard's job is to intercept those forces before they reach your teeth and jaw.

But how, exactly, does a thin piece of material accomplish this?

The answer lies in two primary mechanisms: force distribution and energy absorption.

Mechanism 1: Force Distribution

The first line of defense is spreading the impact over a larger area. Instead of concentrating force on a single tooth, a properly fitted mouthguard distributes traumatic forces across broader tooth surface areas.

Research shows that a custom guard absorbs and dissipates approximately 40–60% of impact force that would otherwise concentrate directly on teeth and supporting structures.

Think of it like this: stepping on a nail with bare skin is devastating. Stepping on the same nail with a thick shoe spreads the force across your entire foot. Same principle.

Custom-fabricated mouthguards reduce the incidence of orofacial injury by 82% to 93% compared to wearing no mouthguard at all.

Mechanism 2: Energy Absorption

The second mechanism is more sophisticated. When a mouthguard is struck, the material vibrates and converts the kinetic energy of the impact into heat and sound energy. This is the same principle that makes car crumple zones and bicycle helmets work.

The soft layers of the mouthguard absorb impact energy through compression, effectively extending the time of impact. This time extension is critical — a longer impact time means lower peak force, which means less damage.

Athletes wearing mouthguards experience significantly lower impact forces and damage to the teeth compared to those without protection.

The Material Science Behind It

Most modern mouthguards are made from ethylene vinyl acetate (EVA) — a material that excels at shock absorption.

EVA is viscoelastic, meaning it combines the properties of a viscous liquid and an elastic solid. This allows it to:

Deform under impact (absorbing energy)
Return to its original shape
Provide consistent protection across multiple impacts

EVA is a proven material for mouthguards — its hardness, thickness, and composition directly influence shock absorption effectiveness and impact energy reduction. The Journal of Sports Engineering and Technology confirms that the mechanical properties of EVA mouthguards provide effective protection against dental trauma.

The Impact of Thickness and Design

Thicker mouthguards are associated with increased absorption of energy from an impact. Typical custom designs incorporate:

3–4 millimeters of thickness over the dental arch for maximum shock absorption
2–3 millimeters over palatal surfaces for comfort and retention

Research shows that bi-layer and tri-layer guards offer superior protection compared to monolayer guards by combining the requirements of cushioning and support. A harder frontal region can distribute load and absorb impact energy through bending, while a softer layer enlarges the time of impact and absorbs energy through compression.

The Protection Gap: Stock vs. Custom

The difference in protection between mouthguard types comes down to this science.

Mouthguard Type	How It Works	Injury Risk Reduction
Stock	One-size-fits-all; poor fit = poor force distribution	15–25%
Boil-and-Bite	Thermoplastic molded by athlete; fit deteriorates with wear	40–55%
Custom-Fabricated	Precise adaptation to individual tooth anatomy; optimal material thickness	85–95%

Custom-fabricated guards provide optimal protection through:

Precise adaptation to individual tooth anatomy
Optimal material thickness for shock absorption
Retention characteristics that minimize displacement

The SORT evidence rating confirms that custom-made mouthguards provide superior protection and comfort compared to over-the-counter options. Custom-made mouthguards are identified as the most effective measure for preventing dental injuries.

The Concussion Connection

Emerging research suggests mouthguards may play a role in concussion prevention. By absorbing forces that would otherwise transmit to the skull and brain, mouthguards can help protect against concussive impacts.

A systematic review in the Journal of Sports Dentistry found evidence that mouthguards can help reduce the forces transmitted to the head. While more research is needed, the potential is significant.

Why Custom Fit Matters for Impact Protection

The science is clear: a mouthguard works by distributing force across a broader area and absorbing impact energy through material compression and deformation. The better the fit, the better the protection.

Custom-fabricated guards — with their precise fit and optimal material thickness — offer the most effective protection available. When you wear a properly fitted mouthguard, you're not just protecting your teeth — you're protecting your entire head and neck.

The Bottom Line

Mechanism	What It Does	Effectiveness
Force Distribution	Spreads impact across broader area	40–60% force absorption
Energy Absorption	Converts kinetic energy to heat/sound	Up to 95% injury reduction
Material Science	EVA viscoelastic properties	Maximum shock absorption
Custom Fit	Precise adaptation to anatomy	85–95% risk reduction

When you wear a custom-fitted mouthguard, you're not just protecting your teeth — you're protecting your head, your neck, and your future in the game. The science is clear: protection works. And it works best when it's made to fit you.