Is Exercise Bad for Your Teeth?

By GRETCHEN REYNOLDS SEPTEMBER 24, 2014 12:01 AM

Vigorous exercise is good for almost all of the body — except perhaps the teeth, according to a surprising new study of athletes. The study, published in The Scandinavian Journal of Medicine & Science in Sports, found that heavy training may contribute to dental problems in unexpected ways.

There have been hints in the past that athletes could have a heightened risk for cavities and other oral issues. In a studypublished last year in The British Journal of Sports Medicine, dentists who examined 278 athletes at the 2012 Summer Olympics in London reported that a majority displayed “poor oral health,” including high levels of tooth decay, often in conjunction with gum disease and erosion of the tooth enamel. The athletes came from the United States and Europe as well as less-developed parts of the world, and most had access to good-quality dentistry, although many had not visited a dentist in the last year.

The study didn’t examine why the athletes were at such high risk of dental problems, although many of us might assume that sugary sports drinks and bars would be a primary cause. Other studies, however, have found little if any link between consuming sports drinks and developing cavities.

So to better understand what is going on inside the mouths of athletes, researchers with the dental school at University Hospital Heidelberg in Germany and other institutions recruited 35 competitive triathletes and 35 age- and gender-matched healthy adults who were not athletes.

All of the volunteers visited the hospital’s dental lab for a full oral examination, including collection of their saliva after they had been sitting quietly. They also completed questionnaires about their diets, including consumption of sports drinks and other beverages, their normal oral hygiene routines, and their exercise habits, if any.

Fifteen of the athletes also completed an increasingly strenuous run of about 35 minutes on an outdoor track, during which their saliva was collected several times.

Then the researchers compared the groups’ teeth and spit, which turned out to be different in telling ways.

Compared with the control group, the athletes showed significantly greater erosion of their tooth enamel. They also tended to have more cavities, with the risk increasing as an athlete’s training time grew. Over all, the more hours that an athlete spent working out, the more likely he or she was to have cavities.

The researchers found no correlation, however, between consuming sports drinks or any other elements of the athletes’ diets and their oral health.

They also found no differences in the amount or chemical make-up of their volunteers’ saliva after the athletes and the non-athletes had been at rest.

But that situation changed when the athletes worked out. During their experimental runs, the amount of saliva that they produced progressively lessened, meaning that their mouths became drier, regardless of whether they consumed water or other beverages during the workout. The saliva’s chemical composition also shifted, growing more alkaline as the workout continued. Excess alkalinity in saliva is thought to contribute to the development of tartar plaques on teeth and other problems.

The extent of the changes in the athletes’ saliva during a workout were something of a surprise, said Dr. Cornelia Frese, a senior dentist at University Hospital Heidelberg, who led the study.

“We had thought sports drinks and nutrition might have the most detrimental influence on dental decay,” she said, “but we saw no direct link” between them. Instead, it was the changes in saliva during exercise that differentiated the athletes’ mouths from those of the control group. Since saliva “has a very protective function” for teeth, Dr. Frese said, having less of it or a chemically different version during exercise could be problematic.

But, she cautions, this study was small, short-term and in many ways unrepresentative of the oral risks most of us would likely face from exercise. “The athletes participating in our study had a mean weekly training time of nine hours,” she said. They were, in technical parlance, hard-core.

“All we can say” based on the data from this group, she said, “is that prolonged endurance training might be a risk factor for oral health.” Whether less frequent or intense exercise would likewise affect oral health is uncertain but unlikely, Dr. Frese said.

Still there are a few precautions that anyone who exercises and has concerns about their oral health might want to take, she said. Drinking water during workouts could be a start, although the connection between hydration and oral health is not scientifically established, Dr. Frese said. More generally, brush and floss, as you know you should. And if you’re a serious endurance athlete, consider visiting a dentist with a specialty in sports dentistry, she said. The goal is to ensure that your teeth remain in as good shape as the rest of you.

Nocturnal Teeth Grinding May Suggest a Sleep Disorder

Posted: 10/24/2013 8:21 am

By Gerard Meskill, M.D.

The occurrence of gnashing or grinding of teeth is not new. The Bible makes reference to this phenomenon both in the Old Testament, "His anger has torn me and hunted me down; he has gnashed at me with his teeth," (Job 16:9) and in the New Testament, "But the children of the kingdom shall be cast out into outer darkness: there shall be weeping and gnashing of teeth" (Matthew 8:12). While this problem is many centuries old, it is only recently that we have come to understand why this may occur, particularly at night while we are asleep.

Teeth clenching or grinding -- a behavior known as bruxism -- is a common problem that can lead to broken teeth, enamel damage, headaches, and temporomandibular joint (TMJ) disorders. The term "bruxism" comes from the Greek word "brychein," which means "to grind or gnash the opposing rows of upper and lower teeth." The American Academy of Orofacial Pain defines bruxism as "diurnal or nocturnal parafunctional activity which includes clenching, gnashing, gritting and grinding of teeth." Data on the prevalence of bruxism varies based upon research criteria, working definition, population samples, and clinical criteria. Indeed, almost everyone clenches or grinds their teeth at some point. However, this becomes pathologic (and thus clinically significant) when it leads to tooth damage or other symptoms, as described above. In 2004, Basić and Mehulić estimated that at least 10 percent of the adult population engages in clinically significant nocturnal bruxism.

For many years (centuries even), physicians and dentists alike have been perplexed as to the cause of this nocturnal behavior. However, we now understand that a significant cause of nocturnal bruxism is airway instability during sleep, such as what occurs in Upper Airway Resistance Syndrome (UARS) and Obstructive Sleep Apnea (OSA). Intuitively, this makes sense. As we fall asleep, muscle tone regulation changes, leading to relaxation of our muscles. The upper airway largely is comprised of muscles and soft tissue. As we fall asleep, the tongue becomes less tense, regressing toward the back of the airway. The mandible, which is held in place by facial muscles, also has a tendency to retrude as those muscles relax. Since the base of the tongue is anchored to the mandible, this leads to further regression of the tongue toward the back of the throat. In individuals with narrower craniofacial anatomy, this can lead to significant upper airway resistance or obstruction during sleep. One possible defense against this process is to clench the teeth, holding the mandible in place to combat this retrusion and keep the airway more patent.

In recent years, clinical research has shown that treatment of the obstructive respirations during sleep leads to improvement or resolution of nocturnal bruxism in many cases. Oksenberg and Arons demonstrated that treatment of OSA with positive airway pressure (e.g., CPAP) led in many cases to resolution of nocturnal bruxism previously observed in affected individuals.

This result was reproduced by Simmons and Prehn, who also demonstrated the same trend in patients with UARS. To distinguish this more subtle form of obstructive respirations during sleep, they used esophageal manometry to measure intra-thoracic pressure during sleep. As the upper airway becomes narrower, the body compensates by expanding the chest to create a more negative intra-thoracic pressure, thus increasing the driving force of air into the lungs. Unlike more severe OSA, in cases of UARS the increased effort to breathe may cause brief disruptions in the normal sleep pattern before the airway collapses, and therefore the measurement of intra-thoracic pressure serves to identify periods of time in which increased breathing effort is causing disruptions of normal sleep. Simmons and Prehn showed that patients with UARS who were treated with CPAP also had significant improvement in nocturnal bruxism, with more than half of the treated patients having complete resolution and most of the rest having at least partial resolution.

So if you grind or clench your teeth at night, wake up with temporal headaches or TMJ pain, or you have been told you're wearing down your teeth, you should consider seeing a sleep specialist, because you may have restricted airflow during sleep that could be causing cardiovascular problems as well. This issue may be as old as the Bible, but finally treatment is now available.