Does your jaw feel stiff or do you have difficulty opening your mouth wide?
Are your teeth sensitive to cold drinks? Do your jaw muscles feel tired in the morning? You may be grinding your teeth at night (a medical condition called bruxism) or you may be clenching your teeth, which can be just as harmful. People with nighttime grinding habits may wear away their tooth enamel “ten times faster” than those without “abusive chewing habits ” Eventually, your teeth may be worn down and destroyed.
In addition to relieving head, neck, jaw joint and shoulder pains, treating bruxism and clenching is cost-effective compared to ignoring the condition and exposing teeth to continued grinding. Without treatment, crowns (caps), bridges, implants, and dentures are often needed to repair or replace worn and damaged teeth. Ask your dentist if a nightguard can help to provide temporary relief from grinding, bruxing or clenching.

Why You Grind Your Teeth at Night
During the night, the brain cycles through lighter and deeper stages of sleep.
As the brain approaches deep sleep, all the muscles in the body have to fully let go and relax. This easily causes trouble for the airway — the jaw is heavy and easily blocks the airway and the tongue, when fully relaxed, expands to almost twice its size to block the airway as well.
Researchers studied brain scans of people with a partial blockage in their airways while they slept and what they noticed is that it was grinding (also called bruxism) that reopened the airway and got the study participants breathing again.
As soon as they were given something to keep their airway open all night long — like a CPAP machine or a dental appliance that held the jaw in place so the tongue and jaw don’t block the airway — their grinding stopped and so did the “apneic” events or the loss of breathing during sleep.

The Real Consequences of Grinding
If grinding is what saves us, then what’s wrong with it?
While grinding is effective at saving us at night, there are consequences to having interrupted sleep every night.

You’re not sleeping well if you grind your teeth. Even with slight sleep apnea, you’re waking up in a damaged state. Tensing up the muscles to grind bounces the body out of deep sleep, and all the health benefits of sleep you read about come from a deep sleep. This is where human growth hormone (HGH) is released, reversing the aging process, tightening skin, improving memory, burning fat, and building muscle, and potentially warding off diseases like Alzheimer’s. Untreated sleep apnea can have serious and life-shortening consequences like high blood pressure, heart disease, stroke, automobile accidents, diabetes, depression, anxiety, and weight gain. Don’t fall into the eight-hour trap — just because you’re unconscious for eight hours, doesn’t mean it’s quality sleep.

Damages our teeth and jaw joints. Years of grinding and clenching can damage your teeth, cause tooth decay and tooth sensitivity, and lead to permanent jaw pain and damage to the jaw point
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A mouth guard makes things worse. A mouthguard is put in place to protect the teeth from grinding, but since it can reposition the jaw, it can actually make the obstruction of the airway worse.