As research continues, mouthguards evolve with science watching from the sidelines
by Cathleen Terhune Alty, RDH, BA
Since their invention, mouthguards have been both a bane and blessing to athletes around the world. It is estimated by the ADA that an athlete is 60 times more likely to suffer harm to the teeth when not wearing a mouthguard. The U.S. Centers for Disease Control and Prevention (CDC) research says that "approximately one-third of all dental injuries and approximately 19% of head and face injuries are sports-related." The National Youth Sports Safety Foundation (NYSSF) estimates for every tooth avulsed and not handled properly, spending to replace function can cost $15,000 to $25,000 over a lifetime.
It isn't a question of whether mouthguards protect, but to what degree they protect. Mouthguards can help protect teeth and soft mouth tissues from impact by absorbing or deflecting the force of the blow to the teeth. Their low cost, availability, and ease of use (particularly the boil-and-bite type) have ensured that they are within the reach of every child, teen, and adult athlete. However, due to bulk, discomfort, and other issues, athletes' compliance is low even with mandated usage. In addition, the scientific evidence proving the best material and best design for maximum safety continues to challenge researchers.
In search of the perfect mouthguard
In search of the perfect mouthguard, what design considerations would be ideal? Obviously a comfortable custom fit, with minimal bulk and low interference with talking and breathing, are important. Also important is how well it stays in the mouth and keeps its shape, in addition to how easy it is to clean. One should also require that it be made of biocompatible materials (no odor, taste, or toxicity) and have a replacement indicator. Engineers would address the importance of tensile strength, resistance to tearing, stiffness, shock absorption, low water absorption, and bacteriostatic composition. It would need to fit a wide variety of mouth shapes, including those with braces, and yet still be protective on impact.
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Other articles by Cathy Alty
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The nature of the collision the athlete might experience – who or what they might impact – is also a design consideration. The soft tissues such as cheeks, lips, and gingiva need to be protected not only from the teeth but also from objects such as hockey sticks. With side impacts, the TMJ and jaw need protection. Protection from impact to the under-chin area or a face plant on a hard surface would be important. It becomes easy to see that a mouthguard cannot always be counted on to provide total mouth protection from the many unique injury hazards of sports.
The role of mouthguards in preventing concussions
One controversial topic is whether mouthguards can protect an athlete from concussions. There is a lack of scientific evidence on mouthguard performance in preventing concussions and other head and/or spinal cord injuries.
Dr. Paul McCrory, neurologist and sports physician at the University of Melbourne, wrote in the British Journal of Sports Medicine in 2001, "The ability of mouthguards to protect against head and spinal injuries in sport falls into the realm of ‘neuromythology' rather than hard science. … It is unlikely that a mouthguard 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."
Gathering data on the impacts athletes experience may help to discover ways to protect from injuries. The Impact Intelligence Mouthguard by i1 Biometrics allows real-time monitoring of athletes as they play. By wearing a special mouthguard made of polyolefin elastomers (POEs) called Vistamaxx embedded with electronics, an athlete can wirelessly transmit impact data to a computer on the sidelines.
"In essence, the i1 Biometrics mouthguard can tell how hard a hit has impacted an athlete's brain, and from that information a real-time injury assessment can be made on the sideline," according to i1Biotmetrics.com. "The front portion of the mouthguard, which protrudes between the lips, houses both an accelerometer and a gyroscope, which measure head movement in all directions. The key to the technology is the gyroscope, which records how much a player's head twists on any given hit. The degree of that twisting can affect different parts of the brain depending on the force of the hit. The system is not intended for use as a diagnostic tool, particularly since individual instances of concussion occur under a wide range of external input conditions. No clear threshold for concussion has been established to date for any of the measured impact parameters."
i1 Biometrics is hoping that the data they collect can help scientists more fully understand this part of concussion science. This database to measure the various impacts an athlete experiences may usher in changes in safety equipment as well as provide a tool to help give medical staff more information about the health status of a particular athlete.
i1 Biometrics plans to track the football teams at Purdue University and the University of South Carolina for the 2013 season. By 2014, they hope to make the product commercially available to high schools and colleges.
The role of mouthguards in athletic performance
There is also anecdotal evidence that mouthguards may improve athletic performance. Several companies are working on mouthguards to increase the strength, stamina, speed, and balance of athletes, mainly by repositioning the mandible. For example, exercise physiologists are testing a "neuromuscular mouthguard" that pulls the mandible forward to open the airway for increased endurance and power. Some of the initial research claims these mouthguards help with upper body load power exercises in men and women and lower body power exercises in men.
Mouthguards have also found uses in medical procedures that have crossed over into sports. Dr. Jan Akervall is an otolaryngologist (ENT) in Michigan who specializes in head and neck cancer. Because of the number of endoscopic procedures performed, he and his surgical team battled dental injuries. "The endoscope is a metal tube with some bends in it and we were finding it difficult to insert and remove it without occasionally damaging a patient's teeth," he said. Dr. Akervall began experimenting with different materials to protect the patient.
From his own research, Akervall discovered that instead of a thick, soft material, a thin, hard polymer worked the best. It was easily moldable in the ER and would stay on the patient's teeth. "We have done over 1,000 procedures since using the material and have had no dental injuries," he reports.
When his daughter began playing field hockey, he soon discovered that the same material made an excellent mouthguard for use in sports. "The forces are spread over the surface of the material," said Dr. Akervall. "We see the kids on the field chewing on their mouthguards, biting through them. You cannot chew through this noncompressible material. It is eight times tougher than a double thickness of a regular mouthguard. You can drink with it in your mouth. You can talk with it in your mouth. It's so comfortable we've had athletes report they forgot it is even in their mouth." Soon the doctor was making mouthguards for the team and decided he needed to introduce this new polymer into the sports market.
Akervall and his wife, Sassa, started Akervall Technologies in Ann Arbor, Michigan, and began marketing the SISU Mouthguard. "We released our first product in 2009. By 2011, it really took off and sales went up 400%. We anticipate a 30% to 50% increase per year in sales," says Dr. Akervall. "Today we have seven people on payroll and a few hourly workers as well."
The SISU mouthguard is unique in several ways. It is a rigid, hard, thin plastic wafer that is covered with small holes. It is available in a 1.6 mm and a 2.4 mm thickness depending on the anticipated heaviness of the impact (elbow compared to hockey stick). The SISU mouthguard has undergone various tests at the University of Michigan engineering laboratories.
Dr. Akervall says they were approached by the Department of Defense to see if they could develop a mouthguard that would decrease concussions in military personnel. "We have researched it carefully," he said. "However, it became clear that there was no evidence that a mouthguard could protect against concussion injuries. It's the head movement, not the jaw movement, that leads to a concussion."
The use of nanotechnology is leading the development of a new material at the lab of Akervall Technologies. "This new material changes properties under different circumstances. The nanoparticles in the polymer respond to different levels of impact. It's softer with low impact and hardens under a different impact," he said.
SISU mouthguards are sold online at their website, at sports events, and trade shows in addition to being represented in around 300 independent sporting goods stores in the U.S. and Canada. They also have distributors in the U.S., Canada, Australia, New Zealand, and Europe. (www.sisuguard.com) RDH
CATHLEEN TERHUNE ALTY, RDH, is a frequent contributor who is based in King George, Va.
Delano Romero is a mixed martial arts fighter in Albuquerque who fractured some teeth while sparring in Brazilian jiu-jitsu.
"My sparring partner's head collided with my chin. Then my bottom teeth collided with my upper teeth, causing the fracture," said Romero. His wife, who is a dentist, was surprised he was not wearing a mouthguard at the time. "When my wife fixed my teeth she asked me why I was not wearing my mouthguard. I told her it was more of a distraction than anything else; it was big and bulky, it would shift in my mouth, it would obstruct my breathing, and sometimes it would cause me to gag." His wife recommended a custom mouthguard, took impressions, and sent them out to a local lab to have one fabricated. "When I received it, I loved it! It resolved all the issues I had before with my boil-and-bite mouthguards. Since it literally snapped onto my teeth, I could breathe with it, I could talk with it, and I could drink water with it. I would put it in during practice and just forget about it. It was no longer a distraction. I had become a big advocate of custom mouthguards because of the big difference it made on my training."
Word spread among the students at his gym and he began making custom mouthguards after learning how from his wife and her dental assistants. Romero wanted to improve his mouthguard fabrication technique and began reading and attending CE courses to learn more. He soon discovered the experts didn't know which material offered the best shock absorption, how thick the material should be, or how to customize the fabrication process for different sports. In 2011, Romero applied for technical assistance from the New Mexico Small Business Assistance Program (NMSBA), a public-private partnership among Sandia National Laboratories, Los Alamos National Laboratory, and the state of New Mexico to connect small business owners with scientists and engineers. Romero was partnered up with a Sandia organic chemist, James McElhanon, who helped him discover which material was best for shock absorption and effective mouthguard thickness.
"The program offered $10,000 to $20,000 in research (manpower and use of their machinery) to small businesses in New Mexico that [had] technical questions [but not the] technical means, know-how, or resources to answer," said Romero. "I applied for the program, and our business was fortunate enough to qualify. The two questions I wanted answered were: ‘What is the optimal thickness for protection for a combat sports mouthguard?' and ‘What is the best shock absorption material available in the market?'" Romero submitted three materials for testing: a hard plastic polytetrafluoroethylene (PTFE), polyethyl vinyl acetate (EVA), and PolyShok (EVA with a polyurethane additive). McElhanon tested and analyzed the materials and helped Romero identify the best one for a mouthguard and figured out its ideal thickness.
"The PolyShok is what was proven to be the most shock absorbent," said Romero. "As a result of the tests, this is what we make all our custom mouthguards with, and the boil-and-bite mouthguards we now sell are made out of the same material. Now that I have been in the business for a while and have other material available, I wish I could have had the others tested just to have a wider spectrum, and so other companies could know where their material stands on that spectrum. I am confident, however, that PolyShok would have still been the number one shock-absorbing material.
"As a result of working with NMSBA, Damage Control Mouthguards now makes custom-fit mouthguards that are lightweight, strong, shock absorbent, and even customizable with color and design," said Romero. "We have high hopes in making both our custom mouthguards and boil-and-bite mouthguards more available to the masses through retail outlets across America. We have recently started selling over-the-counter boil-and-bite mouthguards. They are the best fitting, most comfortable, and most shock-absorbent mouthguards on the market. We put popular MMA designs on the boil-and-bite mouthguards, making our mouthguards distinct from others in the market. Our boil-and-bite mouthguards are also made out of the same material our studies showed to be the most shock absorbent. Also, we are aggressively letting other dentists know about us, in hopes of operating as their go-to lab for custom-fit and boil-and-bite mouthguards. We offer a multitude of colors and custom designs for teams, and if a patient wanted their own personal custom design, we can do that too." (www.DCMouthguards.com)
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