Bruxism is when a person grinds their teeth while not chewing. The teeth grind or rub together as the jaw moves forcefully either from side to side or back and forth. Often, the person is not aware that they are doing it.
Teeth clenching is when a person holds their teeth together and clenches the muscles, but without moving the teeth back and forth.
People can grind or clench their teeth during the day and the night, but sleep-related bruxism poses a bigger challenge because it is harder to control.
Bruxism is one of the most common sleep disorders. It is an unconscious neuromuscular activity.
Myofascial muscle pain, temporomandibular joint dysfunction, and headaches may occur. Severe cases can lead to arthritis of the temporomandibular joints.
Bruxism involves the grinding or clenching of teeth.
Grinding can wear down the teeth, which can become short, blunt, or fractured. Clenching puts pressure on the muscles, tissues, and other structures around the jaw.
It can lead to:
jaw pain and stiffness
sensitive, loose or broken teeth
clicking or popping of jaw joints
a dull headache
Earache can occur, partly because the structures of the temporomandibular joint are close to the ear canal. There may also be referral pain, in which a person feels pain in a different location to its source.
Other key symptoms include anxiety, depression, eating disorders, and insomnia. If the noise bothers a sleeping partner, relationship problems may develop.
Excessive bruxism can damage the occlusal surfaces of the teeth, particularly the molars. It may contribute to temporomandibular joint (TMJ) syndrome.
Some people clench or grind their teeth without having symptoms.
The cause of bruxism remains unclear, but several factors may be involved.
In children, grinding usually happens after the first teeth appear, and again when the permanent teeth emerge. It usually stops once the adult teeth fully erupt.
Clenching and grinding often happen at times of stress, for example at times of anger, anxiety, or concentration. Research has found that brain activity and heart rate may rise before an episode of bruxism, suggesting that the central nervous system (CNS) plays a role.
Bruxism may be related to an abnormal bite, which means the teeth do not meet properly when the jaw closes. If the top and bottom teeth do not come together properly, this is called an occlusal discrepancy. However, the American Academy of Oral Medicine notes that scientific research has not proven this.
In some people, the facial muscles spasm during sleep.
Having teeth that are missing or crooked can prompt the teeth to grind, and irritation may be a factor.
Bruxism can be a side effect of certain medications, including some antidepressants and antipsychotics, and amphetamines.
Neurological conditions such as Huntington’s disease or Parkinson’s disease can also cause it.
Other factors that may be related include fatigue, alcohol consumption, smoking, sleep apnea, and snoring.
Figures cited by the National Sleep Foundation suggest that 8 percent of adults and between 14 and 20 percent of children under 11 years grind their teeth at night.
In another study, 38 percent of parents reported that their children under the age of 17 grind their teeth.
Bruxism is most common in childhood. The lowest rates are in people aged over 65 years.
In small children, bruxism may be a response to teething pain, or when they feel stressed, say, over a test or an argument. Children with hyperactivity disorder may have bruxism.