If you’ve ever heard the awful gnashing sound of someone grinding his teeth while he’s sleeping, you can imagine how bad it might be for his teeth. Grinding and clenching (also known as bruxism) while sleeping can lead to a number of painful and costly problems — chipped or cracked teeth, worn enamel, jaw or facial pain and headaches.

Yet as intense as the grinding is, many people have no idea they’re doing it. Others who think they grind their teeth actually don’t. Dentists are also quick to over-diagnose the problem, according to Gary Klasser, DMD, associate professor in the department of comprehensive dentistry and biomaterials at the Louisiana State University School of Dentistry. But some key information from you can help your dentist make the right diagnosis.

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The daily (or not so daily) grind

Here are some signs and symptoms to look for:

Your partner’s word. The most accurate way to know if you’re grinding your teeth at night is to have someone hear you do it. Clenching, on the other hand, doesn’t make noise.

Broken or cracked teeth and/or broken crowns and fillings. If you regularly get tiny teeth cracks and deteriorating fillings, ask your dentist to exam you for other signs of bruxism.

Pain. People with bruxism may have morning headaches or wake in the morning with pain in their jaw or cheek area. Keep in mind that if you do grind your teeth, you may not do it every night. Some people do it once every few nights or just once in a while. Paradoxically, people who constantly grind their teeth tend to experience less pain from the activity. “They’re the Arnold Schwarzeneggers of sleep bruxism. Their body has adapted to it over a period of time,” says Klasser.

Worn teeth. Your dentist can confirm if you’re grinding or clenching by checking your teeth for uneven or excessive wear. But wear and tear on the teeth alone does not necessarily mean you’re a grinder. “One hundred percent of sleep bruxists have tooth wear, but 40 percent of people who have tooth wear are not bruxists,” says Klasser. The cause could be something as simple as brushing too hard, or the wear may be caused by health issues such as acid reflux.

Sleep apnea. This is more of an association than a symptom. People with obstructive sleep apnea tend to have a higher likelihood of having bruxism. Sleep apnea is diagnosed through a sleep study, which is also the gold standard for diagnosing bruxism. But because these are time-consuming and costly, they are generally recommended only for people with serious, persistent sleep problems.

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What to do if you grind or clench

No therapy has proven entirely effective for people with bruxism. But some of these steps may help.

Reduce stress. This classic advice may be helpful for some bruxists, but not others. New research finds that stress is not always involved, says Klasser. Early research mistakenly lumped together daytime and nighttime bruxism, leading to a lot of misinformation, he says: “To make the blanket statement that everyone who has bruxism is incorrect. We now understand they are two different phenomena with probably different causes.” While daytime bruxism often stems from stress, studies show that stress is not always associated with nighttime bruxism.

Cut down on possible triggers such as drinking alcohol, smoking or drinking too much coffee. These may increase the likelihood of teeth grinding.

Wear a bite guard. A bite guard can help protect the tops of your teeth to minimize the damage when you clench. But whether it can reduce clenching is still debatable. Studies show a temporary effect, for two to four weeks. But even this break may help break the cycle of pain.

Splurge on a custom-made bite guard. While boil-and-bite guards are available at the local drugstore, these are one size fits all and not likely to fit your teeth. Also, they’re softer than custom guards and have been associated with more clenching, not less. “Your brain views it like a chew toy, and it may actually increase activity,” says Klasser. Have your dentist make a custom-made hard bite guard. They’re slimmer, sized exactly for your teeth and made of hard plastic. If you have dental insurance, check with the company to see if its cover them.

Try biofeedback or cognitive behavioral therapy. If your bruxism is causing a lot of pain and discomfort and bite guards are ineffective or you can’t afford a custom one, consider biofeedback or cognitive behavioral therapy (CBT), offered by psychotherapists trained in it. Biofeedback has proven effective in some cases. Research has also found that CBT therapy for 12 weeks reduced bruxism in sufferers, but it wasn’t significantly more effective than bite guards.

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Laurie Tarkan is an award-winning health journalist for the New York Times, national consumer magazines and websites.