Nothing funny about bruxism Talk about pressure... mysterious condition gives researchers something to chew on Nov 24, 2007 04:30 AM PAUL VanDeCARR the New York Times I grind my teeth at night. Have for years. It's my secret shame. But now I have the comfort of knowing that at least 8 to 10 per cent of adults share my malady. It's called sleep bruxism and it refers to the grinding or clenching of teeth. There's a waking version, too – an unconscious clenching of the teeth, most often owing to stress – but the origins are different and the effects are rarely as bad as during sleep, when certain of the body's protective mechanisms are turned off. Left untreated, it can cause damage to the teeth and surrounding tissue, headaches and jaw pain. Bruxism may be at least as old as the Bible, which describes hell as a state where there is "gnashing of teeth." I might fairly be accused of hyperbole if I reversed the equation and declared that bruxism can turn sleep into a kind of hell. But you get the idea. It's a real nuisance. "It's much like having a large football player standing on the tooth," says Dr. Noshir Mehta, chair of general dentistry at Tufts University School of Dental Medicine in Boston and director of its Craniofacial Pain Center. During sleep bruxism, he explains, the upper and lower teeth may come into direct contact as much as 40 minutes per hour and – for example, on the first molar – with a force of about 115 kilograms. Hence the football player. Compare that with normal circumstances, when a person's teeth make contact for about 20 minutes a day while chewing and with – at most – only 18 kilograms of pressure. Even if I wanted a football player in my bed, I certainly wouldn't want him standing on my teeth. I became aware of his presence the way that many bruxers do. My then-boyfriend told me I woke him up with a dreadful crunching noise that came from grinding; my dentist saw the wear patterns on my teeth and confirmed the diagnosis. Sleep bruxism is not a disease, but a sleep disorder, the third most common one behind sleep talking and snoring. It is more prevalent in children, who often outgrow it, and its origins may be different in adults. "The exact causes are unknown," says Dr. Gilles Lavigne. If anyone would know, it's Lavigne, a professor of dentistry and medicine at the University of Montreal and president of the Canadian Sleep Society, who has published extensively on the topic. In the 1960s, he explains, bruxism was thought to be the body's response to "malocclusion," or problems with how the upper and lower teeth fit together, but that theory was discredited for lack of clinical evidence. Stress was later thought to be the cause, but this failed to explain why not everyone with sleep bruxism was stressed and not everyone with stress ground their teeth. More recent research indicates some relationship of sleep bruxism to neurochemicals like dopamine, but there is still disagreement on how significant a role they play. Lavigne's latest studies have identified a pattern of activation in the autonomic nervous system that correlates strongly with sleep bruxism. (He emphasizes that sleep bruxism is not an indicator of neurological disease.) Whatever underlying causes science may show in time, and they may be several, the more immediate contributing factors for sleep bruxism are better understood. The medical literature shows that stress, smoking, alcohol, caffeine and other factors may set off or worsen the condition. So, what's a grinder to do? Right away, my dentist suggested fitting me with a mouth guard, a small plastic device that covers some or all of the teeth to protect them against damage, but does not stop the grinding or clenching itself. Unable to afford the $300 price tag at the time, I got an over-the-counter version at the drugstore for $20. "The over-the-counter guards are usually better than nothing," says Dr. Charles McNeill, director of the Center for Orofacial Pain at the University of California, San Francisco. They protect the teeth, he says, but may also be more likely to induce a chewing response and increase bruxism; they can also cause irreversible damage to the bite, or arrangement of the teeth, and so should be used only temporarily. Guards made by a dentist last longer, fit better and are generally designed to distribute the force of grinding to reduce jaw pain. Feeling frustrated about my persistent bruxism, I tried relaxation techniques like yoga, exercise, biofeedback and hypnotherapy. Much as these may have helped my overall health, they didn't seem to kick the football player out of my bed. So I did what any reasonable person would do: I turned to drugs. The medical literature on bruxism showed that anti-anxiety medications like buspirone and clonazepam had worked on some patients; buspirone only made me jittery, but clonazepam brought my bruxism to, well, a grinding halt. "Clonazepam would be a fantastic treatment, but it's potentially habit-forming; it works too well," says Dr. Michael Gelb, a clinical professor at the New York University College of Dentistry. "The better the pharmacological treatment works, the more fraught it is with difficulty." In two months, I became habituated to the drug and its effect began to diminish. I now use it only occasionally. So much for drugs. Throughout, I paid attention to which factors seemed to worsen my clenching and grinding, like alcohol and poor sleep habits, and have cut back where necessary. I am also trying acupuncture and have noticed some improvement after a few months of weekly sessions. (Acupuncture has not been clinically proved to cure or calm bruxism, but I'm willing to hang my hopes on anecdotal evidence that suggests it helps.) Finally, I came back to where I started: I got a mouth guard that covers all my teeth, this time custom-fitted by my dentist. After all, if you're going to square off against a football player every night, you need padding.

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