Researchers looked at players who sustained a concussion during play, and those who sustained an injury but did not have a concussion. They also looked at two types of mouthguards, those that were a dental custom fit, and those that were off-the-shelf.

Both protected against concussion, reporting a 64-per-cent reduction in the odds of concussion when mouthguards were worn. However, this protection was statistically significant for off-the-shelf mouthguards and not the custom dental. Hagel noted it could be related to a smaller sample size once considering mouthguard type and that more work is needed in this area.

Mouthguards may protect against concussion because they reduce the forces transmitted to the brain, but further research is necessary to understand the protective mechanism.