Mouth Guards and Why We Use Them in MMA
There is no doubt that MMA is one of the most vulnerable sports on the planet. You’re expected to defend yourself from a pursuing attacker with your bare hands and no protection. Well, almost no protection. There is the ever lauded mouth guard that is mandatory in MMA. In theory, some studies have attempted to prove its effectiveness for dental injuries, spinal injuries, facial injuries and concussions. A wide array of protection for such a small piece of equipment, but what is it really and why do we use it?
Most MMA fighters use a custom-fit maxillary mouth guard, fitted by a dentist. You may see some amateurs or early pros using the boil and bite version most of us used in high school sports, but in this article we will be looking at the best fit for MMA, the custom mouth guard. The reason being that a Custom-fit mouth guard provides a higher degree of protection against over-the-counter brands. This was shown in a study comparing the two types of mouth guards, “According to the study, 8.3 percent of athletes in the OTC mouth guard group suffered MTBI/concussion injuries. For those with custom-made mouth guards, however, the rate was only 3.6 percent.” They went on to provide further context as to why, “Mouth guard thickness also has been shown to be a factor that contributes to the level of protection. The average thickness of the custom-made mouth guards in this study was 3.50 millimeters, while the average thickness of the OTC mouth guards was only 1.65 millimeters.” The argument simply is that a larger mouth guard is better at stabilizing your jaw and absorbing shock. This suggests a benefit against concussions, which we will touch on later in this article.
Of course, facial injuries are common in MMA but, as sense would dictate, mouth guards do in fact reduce these injuries. A randomized control trial was conducted in 2005 of high school Australian rules football, a sport which also only uses a mouth guard. It showed a drastic reduction in Heterotopic Ossification injuries, stating: “The H/O injury rate was 2.7 injuries per 1000 hours of participation (95% CI 1.6 to 4.5). The most common H/O injury was a facial laceration (38% of all H/O injuries) and these were 1.4 times more common in control players than MG players. Concussions (19% of all H/O injuries) were distributed roughly equally across study arms. The only player from the MG arm to receive a dental injury was not wearing their mouth guard at the time of injury.”
One study in 2007 found that, “meta-analyses indicated that the risk of an orofacial sports injury was 1.6-1.9 times higher when a mouth guard was not worn.'“ the author later went on to say “However, the evidence that mouth guards protect against concussions was inconsistent and no conclusion regarding the effectiveness of mouth guards in preventing concussion can be drawn at present.”
The study from 2007 found that mouth guards have no beneficial effect against concussions. This is further supported by a 2001 study in the British Journal of Medicine, which looked at precisely this issue. The Meta-analysis found that most studies supporting evidence for protection against concussions and spinal injuries were anecdotal at best, “The ability of mouth guards to protect against head and spinal injuries in sport falls into the realm of “neuromythology” rather than hard science. Reading the original studies cited as evidence for this effect reveals anecdotal claims that can best be described as bizarre rather than reflecting established medical principles. It is unlikely that a mouth guard would offer effective protection against brain or spinal cord injury, and the limited published data are not compelling in this regard nor does it accord with the known pathophysiology of such injuries.” At this stage, mouth guards provide no added protection to TBI injuries or spinal injuries and whats even worse is they may impact performance. Now we have contradictions between studies within these studiess, all carrying varrying results for concussions.
Fortunately this was cleared up by a 2018 study in military medicine by Oxford that touched on the varying results of concussions and mouth guards, “traditional mouth guards are only fitted to the top teeth and have a smooth opposing bite surface for the bottom teeth. The opposing smooth side creates greater jaw misalignment and instability and further allows the mandible (lower jaw) to slam into the skull during contact. A historical mouth guard study proposed that mouth guards dissipated forces on the jaw and reduced the risk of concussions; however, the study was based solely on an experiment done on a fixed skull with a linear acceleration force. The reality of contact sports, although, is that the head and jaw are in constant motion and the forces and acceleration are multidirectional. Barbic and Wisniewski reported no statistical difference in the effects on concussions with athletes wearing either dentist-fitted or self-fitted mouth guards, whereas Winters & DeMont showed a significant difference in the concussion rates between custom-made and over-the-counter mouth guards with high school football athletes.” There is a high degree of probility that poorly fitted mouth guards are increasing risk of concussions and TBI as they offset the jaw, which is why custom fit guards should be the only ones used in MMA.
While custom fit mouth guards obviously offer some protection, this needs to be weighted against its potential downfalls and one study had explored just this area. A 1991 study from the British Journal of Sports Medicine explored the possible challenges of breathing with a mouth guard, measuring the forced expiatory air volume(FEV1), peak expiatory flow rates(PEF1) and Oxygen consumption(VO1) in three mouthguard types, one maxillary mouth guard and two types of bi-maxillary mouth guards. What they found with the FEV1 and PEF is not shocking, the authors research says, “In each case, the wearing of a mouth guard significantly (P less than 0.05) reduced FEV1 and PEF in comparison with no mouth guard. FEV1 was reduced 8% with mouth guard 1, and 12% and 14% with mouth guards 2 and 3 respectively. PEF was reduced by 7, 15 and 15.8% with mouth guards 1, 2 and 3 respectively.’" This indicates that breathing with a mouth guard impacts flow and ultimately consumption, this could be extremely problomatic for an already fatigued fighter that is attempting to increase their oxygen consumption, commonly reffered to as “catching their breath”.
Astonishingly tough, the VO1 was effected by something peculiar, “The wearing of the different mouthguards did not significantly change VO2 while exercising at the lower work level whereas VO2 was significantly ( P < 0.05) reduced at the heavier workload. This surprising reduction in VO2 during heavy exercise may be due to a 'pursed-lip' type of breathing which has been shown to decrease CO2 tension, increase oxygenation and exercise tolerance. It can be concluded that although mouthguards may be perceptably uncomfortable and restrict forced expiratory air flow, they appear to be beneficial in prolonging exercise by improving ventilation and economy.”
This seems to suggest that the forced breathing improves ventilation and movement of air which is a surprising upside, the forced nasal breathing seems to generate good circulation. This comes with a polar opposite, should a fatigued fighter begin to breath through their mouth, they may only be making their situation exponentially worse. Mouth breathing is restricted due to the mouth guard, which causes one to breath less effectively, resulting in lower oxygen consumption for muscles, further fatiguing a fighter. Training with a mouth guard may prevent this minor downside and getting your cardiovascular system prepared for such a circumstance, it could be similar to training at alititude.
In conclusion, a mouth guard provides an overall upside as it reduces facial injuries and may even come with a positive element for breathing, but a clear downside for someone who is already fatigued and attempting to increase oxygen consumption. The minor downside clearly doesn’t match the potential upside as not only will it keep fights from being medically stopped but, with training, may increase endurance and make the fights longer. The negative takeaway is the limited to no evidence available for TBI and Spinal cord injuries meaning the fighters are still taking a major risk without any real protection. All in all MMA has become a modern day gladiator event that has ironically utilized safety to protect their combatants, and all it took was removing anything sharp and adding a tiny piece of rubber.
