Teeth are made for collisions. They mash hamburgers and break hard candy into tiny pieces. But when they grind together, they can wear down and lead to other health problems.
Tooth grinding is a condition that affects many people, but exactly how many is not clear.
The prevalence is difficult to know, because tooth grinding is poorly defined, according to Leonard Lausten, associate professor at the University of Missouri-Kansas City School of Dentistry. Because of the lack of definition, a significant portion of the statistics on the subject may be in error, he said.
While the problem is still being explored, experts have some ideas about why some people grind their teeth as well as the consequences and treatments.
Sleep problems and tooth grinding have been suspected companions, and one may lead to the other.
Disturbances in normal sleep can serve as triggers for grinding behavior, said Alan Glaros, a psychologist who researched nocturnal alarms, one possible treatment for tooth grinding. While there is compelling evidence that grinding is a sleep-related disorder, there is no research to support the theory that better sleep leads to less grinding, Glaros said.
Traditionally, dentists assumed that the teeth not fitting together properly caused grinding, but evidence to support this stance also is lacking, Glaros said.
Stress is also thought to contribute to grinding, but that relationship might not be justified.
“It’s hard to say that there’s a clear-cut relationship between the two events,” Glaros said.
Despite the debate over the causes, the consequences of grinding are apparent.
Ramsey Shouman, a general dentist in Columbia, said grinding can lead to jaw, muscle and tooth pain, headaches or wear on the teeth not normal for the grinder’s age. Grinders who have pain in their jaws or teeth often engage in habits such as gum-chewing or nail-biting, Shouman said. These habits can make the problem worse.
And once grinding does its damage, the results are irreversible.
“Tooth grinding can be very damaging to the teeth,” Glaros said.
Most cases, which are mild, result in wear on the teeth; severe cases can destroy the chewing surfaces of the teeth and also shorten them in length, he said.
Grinding can also expose dentin — the material that makes up the interior structure of the tooth — which is susceptible to decay, Glaros said. Loss of enamel, or the exterior of the tooth, from grinding can also lead to sensitivity to hot and cold substances and unattractive teeth, he said.
“Once tooth structure is worn away, it’s gone for good. A dentist can try to restore teeth to their original shape and function, but his or her work will never be as good as the original tooth,” he said.
Hard acrylic mouth guards made by dentists are a well-known treatment, though they can come with uncertainty. Cheap sports mouth guards seem like a good alternative, but they have their weaknesses, too.
Acrylic guards are less bulky than the store-bought guards, can be adjusted by a dentist and ultimately fit better, Shouman said. Consequently, people are more likely to wear them.
Lausten said the acrylic guards are traditionally effective at reducing pain, although they may not stop the grinding behavior. There are a lot of questions about why they work, he said.
One reason the guards may work is the psychological cuing they develop.
“When I feel my teeth touching this piece of plastic, I’m not supposed to grind my teeth,” Lausten said to provide an example.
The other may be the muscle relaxation that the guard promotes, he said.
For Glaros, durability is what sets the acrylic guards apart from store-bought guards. The $5 mouth guards may serve the protective purpose, he said, but they also deteriorate quickly as a result of the grinding, which means frequent replacement. Plus, people who clench their teeth at night may chew on the cheap guards, and the chewing can lead to pain in the joints and muscles of the jaw, Glaros said.
Still, what makes for effective treatment can be difficult to pinpoint.
“There are a lot of questions about what works and what doesn’t,” Lausten said.
Finally, the cost of the guards can be considerable. Even if a patient wants to get the guard, he or she may not be able to afford it.
At Shouman’s office, three different kinds of guards are available: two that cost $150 to $200, and one that runs from $400 to $500. Insurance coverage for the devices is unpredictable.
“You just never know whether insurance will cover it,” Shouman said.
Delta Dental of Missouri has more than 2,700 Missouri dentists in its network, according to the group’s Web site.
Pam Martin, chief operating officer for the company, said that some of Delta’s plans cover mouth guards, but the coverage is given only when the group specifically requests it.
Most Delta members’ dental visits are for cavities, gum disease or simply a checkup, she said.
With a potentially high price tag, unpredictable insurance coverage and uncertain results, the acrylic mouth guards seem as if they can be a bigger headache than the ones associated with grinding. But they may be the best option to treat a condition that is still being researched.