Sports mouthguards: the stock type protects less than patients believe

Dental trauma in sport chiefly affects the upper incisors, and the mouthguard is the only device shown to prevent it.

The three available categories perform very differently, and patients tend to regard them as equivalent because they apparently serve the same function.

The stock guard is bought in sizes and does not adapt. To stay in place it requires the athlete to clench, which interferes with breathing and with speech.

The practical consequence is that it is removed during activity, and a mouthguard in a pocket protects nothing. It is the category's principal defect.

The boil-and-bite softens in hot water and adapts on biting. It is an acceptable compromise, but the thickness thins precisely where the athlete bites hardest, on the occlusal surfaces.

Adaptation also worsens with use and must be repeated periodically, something almost nobody does.

The custom guard is built on an impression, with thickness controlled area by area. It is the only one that maintains thickness where needed without compromising it where it interferes.

The thickness over the buccal surface of the upper incisors is the measure that counts, because that is where impact arrives. Figures cited in the literature run to several millimetres, far more than a boil-and-bite retains after adaptation.

On the occlusal surfaces enough thickness is needed to absorb, but not so much as to alter mandibular position uncomfortably, and that balance is what distinguishes a device worn from one abandoned.

Posterior extension reaches the first permanent molar: stopping short leaves uncovered the teeth onto which part of the impact is discharged.

In the orthodontic patient the custom guard is particularly indicated, because it also protects the mucosa from the appliance and must be remade as treatment progresses.

In mixed dentition it must be revised as the permanent teeth erupt. A guard built on an arch that has changed no longer fits, and reverts to being an object one takes out.

In summary: the stock guard is removed during activity and protects nothing, the boil-and-bite thins where it matters, the custom type maintains controlled thickness area by area, and in the growing patient it must be remade as eruption proceeds.