What is bruxism and how does it impact sleep?

Bruxism is the act of clenching or grinding your teeth, either out of habit or unconsciously. Though some people grind their teeth unwittingly during the day, most tooth grinders engage in what's called nocturnal bruxism — nighttime tooth grinding or clenching that occurs during sleep. Doctors and dentists sometimes refer to these people as "bruxers."

If you are a nocturnal or sleep bruxer, your upper and lower teeth come clench together forcefully during the night — with a pressure of up to 700 pounds per square inch. (Normal daytime pressure, if you were to clench your teeth right now while reading this article, would be 200 pounds per square inch.) 

There are two forms of night bruxism: clenching and grinding.

Both forms of bruxism can lead to side effects like headaches and dental damage.

All bruxism is classified as a parafunctional behavior, meaning it's a movement of the body that serves no purpose. Nocturnal bruxism is considered a movement disorder, and it's quite often associated with other sleep disorders like obstructive apnea and restless leg syndrome.

However, if you grind your teeth at least 2 to 4 times per hour, your bruxism may be diagnosed as a sleep disorder in and of itself. (A sleep study would be required to verify this.)


Why do people grind or clench their teeth?

The simple answer is, we aren't sure. Nocturnal tooth-grinding is an unconscious activity and it serves no practical biological function. Most people who grind their teeth or clench their jaws in their sleep aren't aware they're doing it. 

Previously, experts speculated that tooth grinding might have been caused by infections or mechanical issues in the mouth, such as blockages or poorly-fitting dental prostheses. However, this is no longer thought to be the case.

More recently, research points to origins in the central nervous system. We still don't know the precise mechanism that triggers bruxism, but researchers have theorized that for some people, it may be an inherited genetic condition. For others, stress may play a role. Studies have shown that people (children included) who grind their teeth are also more sensitive to stress and hostility and more likely to have depression. 

Bruxism is extremely common, affecting nearly one in eight people, mostly children and adolescents. Adults who experience bruxism are likely to have first experienced it as a child, and they may find that the condition ebbs and flows as they go through life. During some more stressful periods of their lives, for example, they may be more likely to brux.

Bruxism: symptoms & side effects

Bruxism isn't always easy to detect immediately. In many cases, people with bed partners are more likely to become aware they have the disorder; the sound of teeth rubbing against each other in the night wakes up their partners.

If you share your bed with someone, ask him or her if they can hear your teeth gnashing when you sleep. Many bed partners complain that the sound of grinding (or even squeaking!) teeth can wake them up or keep them from falling asleep.


However, there are some more subtle symptoms that can indicate you're a bruxer. These can include:


Tooth grinding, TMJD, and apnea: how they affect your sleep

For many people, these three conditions overlap.

Together or individually, bruxism, TMJD, and obstructive sleep apnea can wreck your sleep by causing nighttime awakenings due to cessation of breathing (classic obstructive apnea events) or night headaches that mimic migraines. 

How a sleep apnea mouthpiece can help


The most common treatment for sleep bruxism is to wear an acrylic mouth guard custom-fitted to your teeth. This mouth piece won't stop the actual grinding and clenching (and, therefore, won't stop headaches), but it does provide a protective barrier to prevent you from wearing away at your enamel or chipping your teeth. Generic mouth guards can be purchased in drugstores or you can visit your dentist to have a custom set made.

However, if you have been diagnosed with obstructive sleep apnea in addition to bruxism, a special sleep apnea mouth piece can be a good option for preventing some of the damage from grinding. These mouth guards — sometimes called mandibular advancement splints, or MAS — shift the position of your lower jaw to prevent airway obstructions and snoring. 

Because they cover the upper and lower teeth and prevent direct contact, they may offer a similar level of protection from tooth grinding that you'd get from an acrylic mouth guard. But as an added bonus, they may also help to prevent the airway obstructions that could be waking you up multiple times per hour.

What to do if you think you're a grinder

If you have some of the bruxism or TMJD symptoms listed above but you're sleeping fine and feel rested, you may only need a trip to the dentist to get fitted for a mouth guard. 

However, if you have the symptoms of bruxism combined with classic apnea side effects like daytime sleepiness, sore throat, brain fog, and concentration problems, you may want to visit a sleep specialist about doing a sleep study. 


National Institute of Dental and Craniofacial Research

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