Bruxism – How Is It Related To TMJ?

Many people grind their teeth at night, a condition known as bruxism, doing considerable damage to their teeth and annoying their bed partners. For a long time, it has been blamed on stress, even in children. We now know that there is a relationship between bruxism and TMJ disorders as well as sleep-disordered breathing, even in its severe form, obstructive sleep apnea.


The dental and medical community alike have blamed stress for the gnawing and gnashing of teeth at night. Our fast-paced society does indeed pose a considerable level of physical and emotional stress and we do know that bruxism increases with additional stressors. From some of the research done on children, we know there is a link between bruxism and the body’s survival mechanism to keep the airway open. If a child is grinding his or her teeth at night, the first causative factor to look for is an obstructed airway. Enlarged tonsils and adenoids are a common cause for airway obstruction in children and even contribute to obstructive sleep apnea. Bruxism triggers a muscle in the back of the throat to spasm and keep the airway open. It is hard to blame teeth-grinding on stress in a young child. Most children do not have the level of emotional stress that adults do. Adults with compromised airways also brux to keep the airway open. This is particularly apparent in people suffering from sleep-disordered breathing, the most severe cases being obstructive sleep apnea. In adults the cause is usually not enlarged tonsils and adults, but a collapsible windpipe that contributes to the sleep apnea.

When the jaw is in the wrong position, the body attempts to correct it by bruxism. The muscles of the jaw and face spasm and attempt to move the jaw to a more comfortable position. As these muscles spasm, the teeth slide back and forth in response to that muscle activity . This can occur particularly in a person whose facial and jaw muscles are shortened-a muscle cramp in the jaw. The teeth grind to relieve the spasms much like stretching the relieves a cramp in the calf muscles.


– Severely worn teeth

– Receded gums in the absence of gum disease

– Higher incidence of root canals, major dental work on back teeth

– Sore jaw muscles in the morning

– Headaches

– A face that looks shortened between the nose and chin


After even a short period of grinding, the lower jaw can recede backward causing a jaw joint disorder or TMJ disorder. The lower jaw fits in to a socket of the upper jaw and is protected by a cartilage disc. If the lower jaw is allowed to retrude to the back of the socket, a couple of things can occur:

– Compression of the nerves and blood vessels in the back of the jaw joint, which can cause headaches, face, jaw and neck pain

– Displacement of the cartilage disc, indicating a dislocation of the joint and resulting in clicking, popping or grating noises upon opening and closing of the jaw

– Further compromise of the airway, making obstructive sleep apnea even more possible


As in all medical treatment, therapy should be directed towards eliminating the cause of bruxism. If the airway is collapsing, treatment should directed towards opening the airway with the use of oral appliances or dental devices in mild-moderate cases and CPAP therapy in severe cases. If the jaw is in an improper position, treatment should be aimed at repositioning the jaw with specialized oral appliances for day and/or night wear. Proper care must be taken to find the correct therapeutic position of the jaw that creates a healthy jaw joint and opens the airway. Since bruxism is both a cause and effect of a TMJ disorder, proper diagnosis with extensive and thorough testing and records is imperative.