Teeth grinding, or bruxism is a medical condition characterised by ‘rhythmic masticatory muscle activity’ at a frequency of once per second without functional use. In other words, it’s chewing without food in your mouth.
The muscles involved in chewing move the jaw on either side like hinges and allow it to slide forward and back at the jaw joint. Some muscles lift the jaw to close the mouth and others allow lateral or side-to-side movements.
Chewing is a complex process involving neuromuscular activity that can be either subconsciously or consciously done. Usually, the jaw is at rest and opposing teeth are not in contact except while chewing, speaking or swallowing.
Effects of teeth grinding
The voluntary muscles are inactive during sleep and the jaw is usually relaxed, but in a person who grinds their teeth, opposing teeth are continuously in contact with each other causing the jaw muscles to tense and creating pain in the face and jaw and, often, headaches.
In addition to this, bruxism further causes attrition or excessive tooth wear leading to the shortening of teeth, exposing dental pulp and abfraction – where notches are formed at the gum line near the neck of the tooth.
Causes of teeth grinding
Stress and anxiety. Involuntary, night-time habitual grinding of teeth can be caused by many factors, including stress, anxiety and depression. It is estimated that almost 70% of bruxism occurs due to stress.
At times of stress, people nervously clench their teeth to relieve tension. Stress for adults can be job related – due perhaps to irregular work shifts, excessive responsibility or high expectations from employers. Stress for children and young people can be due to teething, illness, moving house or going to a new school, examination tension or sibling rivalry.
Daytime bruxism includes jaw clenching as well as teeth grinding, and can occur while concentrating on something or while angry or anxious. Daytime teeth grinding is thought to be semi-voluntary and is often associated with stress caused by family responsibilities or work pressures.
Occlusal factors: Occlusion is defined as unusual contact between upper and lower teeth and refers to how the teeth actually meet. Abnormal alignment of upper and lower teeth can cause discomfort, leading to teeth grinding. For example:
- a missing tooth
- an extra tooth
- erupting wisdom tooth
- improper contact of crown with opposing jaw
These can all contribute to discrepancies in occlusion. Occlusal problems can be treated by replacing a missing tooth with a crown, denture or implant; a decayed tooth can be restored with cements and an impacted or extra tooth can be extracted.
Sleep disorders. Snoring, breathing pauses during sleep and obstructive sleep apnoea – complete or partial obstruction of the upper airway – can cause bruxism.
Research shows that people who experience sleep talking, violent behaviour in their sleep, sleep paralysis (the temporary inability to move or talk while waking), semiconscious hallucinations between sleep and waking or other reasons for disturbed sleep may be prone to bruxism.
Sleep disorders may be treated by consulting a professional counsellor and taking prescribed medicines. Self-directed therapies such as jaw aligning exercises can also help.
Lifestyle. Certain lifestyle choices can also increase the chances of developing bruxism. These include: drinking alcohol excessively, smoking or using recreation drugs such as ecstasy or cocaine, and having more than six cups of tea or coffee per day. Reducing or cutting out these triggers may help to reduce bruxism.
Medication. Bruxism can also occur due to the side-effects of certain medicines such as antidepressants and antipsychotics, including dopamine agonist, dopamine antagonists, and tricyclic antidepressants. Long-term use of some medication can cause bruxism, but reducing the dose can alleviate or completely remove the problem. The medication prescribed for Parkinson’s disease, for example, can cause bruxism as a side-effect.
Diseases. Bruxism can occur in patients with neurogenic abnormalities, for example:
- Autism: A developmental disorder that impairs the ability to interact and communicate.
- Huntington’s Disease: This causes uncontrolled, involuntary movements of fingers, face, feet and trunk. Bruxism associated with Huntington’s Disease may be cured by the use of botulinum toxin (Botox).
- This is a sleep disorder in which an individual finds difficult to fall sleep.
- Reflux of stomach acid into the oesophagus.
Hyperactive Personality. Personality can also contribute to teeth grinding. Bruxism is more common in aggressive, competitive and hyperactive people. Hyperactive people with attention deficit or hyperactivity disorder tend to exhibit a higher level of bruxism. This is due to excess nervous energy that the body combats through teeth grinding.
Whenever you feel pain due to bruxism, it can be cured temporarily by applying ice on a sore jaw and avoiding hard foods and chewing gum.