A mouthguard is a resilient, flexible appliance worn over the teeth, typically the upper arch, to provide protection during physical activities or sleep. This device functions as a physical barrier against impact, reducing potential trauma to the oral structures. Its primary purpose is to safeguard the teeth from fracture, displacement, or loss caused by a direct blow to the face. The guard’s construction allows it to absorb and manage the energy of an external force, preventing serious dental injury.
The Physical Mechanism of Force Dispersion
A mouthguard protects the teeth by employing three primary biomechanical actions: cushioning, force redistribution, and separation. The guard’s material, often a thermoplastic like ethylene-vinyl acetate (EVA), acts as a shock absorber, compressing upon impact to effectively absorb kinetic energy from a blow to the mouth or jaw. This absorption reduces the peak force that would otherwise be transmitted directly to the teeth and the underlying bone structure.
The material then disperses the remaining force over the entire surface of the dental arch, rather than concentrating it on a few points of impact. This redistribution spreads the mechanical stress across all teeth and the alveolar ridge. This minimizes the pressure on any single tooth, preventing localized damage such as chips or fractures.
The appliance also functions as a physical buffer, creating separation between the upper and lower teeth. This protective layer prevents direct, violent tooth-on-tooth contact, which is a major cause of chipping and severe wear. By stabilizing the teeth, the mouthguard mitigates the risk of trauma caused by the jaws snapping shut rapidly. The guard’s thickness, typically at least four millimeters, is directly related to its capacity for shock absorption.
Understanding the Different Levels of Fit
The effectiveness of a mouthguard is linked to how accurately it fits the wearer’s dental anatomy, categorized into three main types. Stock mouthguards are pre-formed and ready to wear, providing the lowest level of retention and protection because they cannot be customized. They are often bulky and can interfere with breathing and speaking, offering a less secure interface for force absorption.
Boil-and-bite mouthguards are an intermediate option, made from a thermoplastic material softened in hot water and molded by the wearer. While they offer better adaptation than stock guards, the resulting fit is often compromised, leading to reduced stability and less efficient force dispersion. The material may also thin out unevenly during molding, decreasing its protective capacity.
Custom-fitted mouthguards, fabricated by a dental professional from an impression of the patient’s teeth, provide the highest degree of protection and comfort. This tailored fit ensures excellent retention and a uniform thickness across the entire appliance, maximizing the surface area for shock absorption. A secure, custom fit allows the guard to work most efficiently, resulting in superior injury prevention.
Guarding Against Soft Tissue and Jaw Injuries
Beyond protecting the teeth, a mouthguard safeguards the soft tissues of the mouth. The appliance creates a protective barrier that prevents the lips, cheeks, and tongue from being lacerated or bruised when driven against the sharp edges of the teeth or orthodontic brackets during an impact. This cushioning effect minimizes the likelihood of painful cuts and bruises.
The mouthguard also contributes to the stability and cushioning of the temporomandibular joint (TMJ), which connects the lower jaw to the skull. By providing a resilient space between the upper and lower arches, the guard helps absorb upward force that might otherwise compress or damage the joint during a blow to the chin. This mechanism helps protect the lower jawbone, or mandible, from potential fracture or displacement.
While mouthguards prevent dental and soft tissue trauma, evidence regarding their ability to prevent concussions is inconclusive. Although they stabilize the jaw and cushion a blow, the benefit of reducing brain injury remains a subject of ongoing research. Therefore, the primary focus of mouthguard use remains centered on preventing injuries to the teeth and surrounding oral structures.