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.
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
- sore gums
- 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.
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.
Stress can be a major cause of bruxism.
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.
Diagnosis and treatment
A doctor or dentist will ask about the patient's history and carry out an examination. Signs they will look for include:
- jaw discomfort on waking
- tooth wear
- enlarged jaw muscles
Tooth wear can also result from over-vigorous brushing, abrasives in toothpaste, acidic soft drinks, and hard foods, but a trained professional can tell the difference between the characteristic wear patterns of each cause.
The most reliable way to diagnose bruxism is through electromyographic (EMG) measurements. These pick up electrical signals from the chewing the masseter and temporalis muscles, the muscles used for chewing.
In the case of a child, a dentist may ask if they are worried about anything, or if they are angry, and how they feel at bedtime, to uncover any causes of stress.
Treatment will depend on the cause of the bruxism. There is no cure for bruxism, but options are available to relieve symptoms, and an underlying cause can be dealt with.
Daytime clenching or grinding may improve with increased awareness, physical therapy, or exercises, but nocturnal bruxism needs other strategies, as it is outside the individual's control.
If the underlying problem is stress or sleep apnea, treating these conditions may help. After treatment, the situation can be reassessed.
In 2002, researchers found that treating sleep apnea reduced symptoms of bruxism.
Getting enough sleep at night or exercising regularly may help.
A mouth guard can be worn at night to protect the teeth, and short-term use of a muscle relaxant is a possible option.
The American Academy of Oral Medicine recommend a hard plastic mouth guard that covers all the teeth in either the upper or the lower arch.
Generic sports mouth guards are not advised, as they can come out of place, can be very bulky and cause more discomfort than they solve.
Over time, a mouth guard can wear down and lose its effectiveness. If the person stops using the mouth guard pain and symptoms may return, so it may not be a permanent solution.
Splints are another option. Some splints fit over the top teeth, some on the bottom. Depending on the design, a splint may keep the jaw in a more relaxed position or provide a barrier so that the splints, rather than the teeth, are damaged. Splints can be adjusted or replaced.
14-20% of children grind their teeth at night.
When bruxism is caused by a misaligned jaw or by crooked and uneven teeth, a dentist or orthodontist may offer to realign the jaw or fitting a person for braces to treat the condition. However, the AAOM do not advise this, as misalignment has not been proven as a cause.
Avoiding foods and drinks that contain high concentrations of caffeine or alcohol may be beneficial, as these can increase grinding. Chewing gum may encourage bruxism, as it can embed clenching and grinding into the muscle memory.
Another tip is to relaxing the jaw muscles with a warm washcloth or a heating pad at least once a day, to ease their tension.
Tips for preventing bruxism
Stress and anxiety management may help reduce or prevent bruxism in people who are susceptible to it.
The National Sleep Foundation encourages good sleep hygiene, including a cool, dark, quiet room to sleep in, with no televisions, computers or other work-related items.
They suggest relaxing in the hours before bedtime and maintaining a "soothing bedtime routine." For children, this may include a warm bath, reading a book, or listening to music.
Other tips include sleeping on the side or stomach and getting plenty of exercise.
A pediatrician may help if a child has bruxism.