TEETH GRINDING (BRUXISM)
Severely worn teeth
in a 55 year old
WHAT IS BRUXISM?
Bruxism is an excessive clenching or grinding of the teeth that is not a part of normal chewing movements. It can lead to excessive wear on the teeth and may cause permanent damage to the teeth and the jaw joints. Excessive clenching and grinding are not normal, healthy actions of the jaws. In some adults and children, clenching and grinding may occur during the day or at night. They typically have no conscious control over this excessive clenching and grinding, particularly when it occurs during sleep.
The Function of the Jaws
Three muscle groups are associated with bruxism, as shown in the figure. The temporalis and masseter muscles bring the jaws together. The lateral pterygoid muscles move the jaw from side to side. The strength of jaw clenching determines the force of tooth grinding. Grinding does not occur if the person clenches, or if the mouth is open. Slight relaxation of the clenched jaw allows grinding movements across the teeth as the jaw is moved slightly forward and slightly to the side.
The Causes of Bruxism
The causes of bruxism are still being studied. A combination of physical and psychological factors are believed to contribute to bruxism:
- physical stress such as illness, nutritional deficiencies or dehydration, particularly in children
- psychological stress, anxiety and tension in adults and children
- studies have shown that night bruxism is a sleep disorder
- other abnormal anatomy of the teeth or jaws (including 'high spots' on fillings) that can cause an improper occlusion (also called 'bite') and lead to bruxism behaviour.
Signs and Symptoms of Bruxism
The signs and symptoms of bruxism vary according to the nature, frequency, duration and strength of excessive clenching and grinding. Signs and symptoms include:
- pain in the teeth and sensitivity to heat and cold
- chronic muscular facial pain with tension headaches, caused by intense muscle contraction
- the noise, noticed by partners, friends or relatives, that occurs as the teeth are ground together
- an abnormal alignment of the teeth, caused by uneven tooth wear
- flattened and worn tooth surfaces, which may reveal the underlying yellow or orange dentine layer
- microfractures of the tooth enamel
- broken or chipped teeth
- loose teeth with possible damage to the tooth sockets
- stiffness and pain in the jaw joint (temporomandibular joint or 'TMJ') that cause restricted opening and difficult chewing; sometimes the jaw joint may suffer damage that is slow to heal (refer to the ADA patient education pamphlet Common Disorders of the Jaw Joint, available from your dentist)
- earache or pain in the jaw joint.
The variation in signs and symptoms reflects the strength of clenching and grinding involved in bruxism. People who clench their teeth tightly may experience tension-related headaches but may have little or no damage to the teeth or jaw joint. Tight clenching alone puts minimal pressure on the jaw joint. Those who experience severe grinding may have damaged teeth and jaw joint problems. People with mild tooth grinding may have worn teeth surfaces but no jaw joint pain or teeth sensitivity. These individuals may not even realise that they have bruxism.
Before Treatment
Your dentist needs to know your medical history to plan the best treatment. Fully disclose any health problems you may have had. Tell the dentist if you have had:
- an allergy or bad reaction to antibiotics, anaesthetics, or other medicines
- previous treatment related to bruxism or jaw surgery
- psychological distress or psychiatric illness.
Give the dentist a list of ALL medicines you are taking or have recently taken. Include medicines prescribed by your family doctor and those bought 'over the counter' without prescription.
Treatment of Bruxism
Treatment aims to:
- find and remove the causes of bruxism
- change the behaviour that causes bruxism
- repair the damage that bruxism often causes.
Finding and Removing the Causes of Bruxism
Your dentist will look for local problems likely to lead to abnormal contact among upper and lower teeth. Your bite may need to be improved. If pain is a symptom, your dentist will look for related causes, such as an ear infection or a temporomandibular disorder. Your dentist may prescribe:
- painkillers for muscular facial pain, headaches and jaw joint pain
- muscle relaxant medication to help relax the jaw muscles.
If your dentist suspects that you have general
health problems, he or she may recommend an examination by a medical practitioner. Your dentist
may recommend counselling, stress management or relaxation methods for stress-related causes
of bruxism.
Occlusal splint
Changing Bruxism Behaviour
Therapy aims to achieve changes in behaviour
by teaching the patient how to rest
the mouth.
- An occlusal splint (also called a night guard) is an option for someone with mild to severe grinding behaviour. Worn at night, the splint is made from moulded plastic that fits over the upper or lower teeth. It prevents further wear of the tooth surfaces.
- Biofeedback is a treatment option for people who primarily clench their teeth
during the day. Biofeedback techniques use electronic monitors to measure tension in the jaw
muscles. People use the monitors to learn how to relax their muscles and reduce tension.
Newer biofeedback techniques are under development to treat
night-time clenching. - Patients with severe tooth grinding problems often use a combination of splint and biofeedback techniques.
- Some patients may require muscle relaxant tablets at night.
Repairing Damage to Teeth
Treatment may be necessary to repair damaged teeth. Dental fillings, crowns or inlays can replace damaged tooth surfaces. Root canal treatment may be required where tooth fractures extend into the pulp. In extreme cases, extraction of badly damaged teeth may be the only option. Partial dentures, dental bridges or implants can replace missing teeth. Orthodontic treatment can realign misplaced and crooked teeth.
