From the football field to the hockey rink, concussions are a major concern for athletes. To find out if mouth guards could help athletes avoid concussions, a team of researchers examined two different types of mouth guards.

What the researchers wanted to know: What kind of mouth guard is better for preventing concussions—a custom-made mouth guard or a non-custom-made mouth guard?

What they did: Researchers contacted the head trainer of every NCAA Division I-A football team before the start of the 2001 college football season. Of the 114 teams, 94 trainers agreed to participate. Each week, each trainer opened a study website and entered the number of games and practices the team had that week, how many athletes were at each, how many were wearing a mouth guard, and about how many of those were custom mouth guards. Then for each concussion that week, the trainer answered more detailed questions about the concussion and what type of mouth guard the player was wearing, if any. Custom mouth guards are made by a dentist to match a mold of the player's teeth; the most common kind of mouth guard is a non-custom-made "boil-and-bite" mouth guard. A boil-and-bite mouth guard is fitted by softening it in hot water, then biting on it as the plastic cools so it adapts to the teeth.

What they found: In nearly 800 games and about 4,500 practices, there were 369 concussions, but only six of those concussions were caused by a blow to the jaw—the only kind of injury that a mouth guard might help prevent. The researchers looked at all 369 concussions and found no statistical difference between athletes wearing custom mouth guards and non-custom mouth guards for the number of concussions or the severity of concussions.

What this study means to you: Custom-made mouth guards are much more expensive than the boil-and-bite variety.

Caveats: The players were all wearing helmets, so these data may not apply to contact sports done without helmets—or to sports where you get whacked on the jaw a lot.

Find out more: The 2003–04 NCAA Sports Medicine Handbook includes a section on mouth guards.

Read the article: Wisniewski, J.F. et al. "Incidence of Cerebral Concussions Associated With Type of Mouthguard Used in College Football." Dental Traumatology. June 2004, Vol. 20, p. 143.