September 20, 2011 — Teenagers think they cannot be hurt, so surveys finding that most young athletes will not wear mouth guards come as no surprise.
But what if a mouthful of plastic could make them jump higher or run faster?
"I couldn't make enough mouth guards," Academy for Sports Dentistry President Paul Nativi, DDS, told Medscape Medical News.
That is the promise held out by some mouth guard manufacturers, and a new study published in the September issue of the Journal of the American Dental Association suggests there may be more than wishful thinking to the claim.
Researchers at the Citadel University in Charleston, South Carolina, compared a group of athletes wearing mouth guards with a group wearing no mouth guards and breathing through their mouths, and with a group wearing no mouth guards but breathing through their noses.
They found that the athletes using the mouth guards breathed in more oxygen and breathed out more carbon dioxide than the athletes in the other groups.
"I was surprised," Dena Garner, PhD, an associate professor of exercise and sports science, told Medscape Medical News. "I was skeptical that we would see any effect at all."
What Can a Mouth Guard Do?
It is not the first time someone has tried to show that a mouth guard can do more than protect teeth — and Dr. Nativi is not convinced by any of the evidence — but he does not reject the possibility either.
So why should wearing a bit of plastic over the teeth help someone run faster or farther?
Exercise physiologists and mouth guard makers have come up with several theories.
Dr. Garner thinks the Bite Tech brand mouth guards create an opening between the maxillary and mandibular teeth and cause the athletes' tongues to move forward, contracting the genioglossus muscle and relaxing the pharyngeal airway. She also points to previous research suggesting that biting on something hard can reduce levels of the stress hormone cortisol, and perhaps epinephrine. Together these effects could improve athletes' ability to exercise without fatigue.
Shawn M. Arent, PhD, an exercise scientist at Rutgers University in New Brunswick, New Jersey, offers an alternate theory for a brand of mouth guards he tested: Pure Power Mouthguards.
These mouth guards were custom designed to put each athlete's teeth in ideal occlusion. The effect, he said, is similar to wearing orthotics, and getting the user's jaws aligned could improve the alignment of the rest of the body.
In a study published in the August 2010 issue of Comparative Exercise Physiology, Dr. Arent and colleagues compared athletes wearing mouth guards made in a typical customization procedure with those wearing mouth guards in a special procedure for Pure Power. In the Pure Power procedure, dentists used a low-voltage pulse to relax their patients' jaws before making impressions.
In Arent's study, the athletes wearing the Pure Power guards were able to jump slightly farther, bench press a bit faster, and score somewhat higher on Wingate anaerobic test.
What to Use
Dr. Nativi does not find the studies showing better performance convincing. First, he pointed out, they are small: Dr. Garner's study had only 13 participants, and Dr. Arent's had only 22. The findings were statistically significant (P < .05) for the improved performance in Dr. Arent's trial and the improved biomarkers in Dr. Garner's trial, but Dr. Nativi says much larger trials are needed.
Second, Dr. Garner and colleagues received honoraria from Bite Tech. Although Pure Power, which has since gone out of business, did not pay Dr. Arent and colleagues, it did pay their expenses.
"I want to see independent research," said Dr. Nativi, so he has not used either brand in his practice. And he does make a lot of mouth guards: He is the team dentist for both St. Louis University in Missouri, and Southern Illinois University at Edwardsville.
Similarly, Dr. Nativi said, the research showing that mouth guards can protect against concussions is very mixed.
However, he firmly believes — along with the American Dental Association — that mouth guards are valuable in protecting against injuries to the mouth.
So what kind of mouth guard should a dentist make? The American Dental Association and Dr. Nativi believe that custom-made mouth guards are better than either the preformed stock guards or the boil-and-bite variety. That is because they fit better, athletes are more likely to use them, and they stay better in the athlete's mouth.
The mouth guards should be laminated for extra strength, Dr. Nativi said. He designs them at different thicknesses for different sports; the more likely the impact, the thicker he makes them.
He does not recommend using vacuum-form machines, which are sold to keep in the dentist's office. Instead, he prefers the heat-pressure machines used in most laboratories because the guards adapt better to the model using this method, he said.
Finally, he warns dentists that mouth guards are not likely to become a great source of income. "I think it's a good practice builder," he said. He advises young dentists to get involved in their local high school sports teams.
"It gets your name out there," he said. "It shows you're concerned."
Dr. Nativi has disclosed no relevant financial relationships. Dr. Garner received honoraria from Bite Tech. Dr. Arent's research was supported by Pure Power Mouthguards.
J Am Dental Assoc. 2011;142:1041-1047. Abstract
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Cite this: Could Mouth Guards Boost Sports Performance? - Medscape - Sep 20, 2011.