Sleep Disorder - Bruxism

Bruxism is the grinding of the teeth, typically accompanied by the clenching of the jaw. It is an oral Para functional activity that occurs in most humans. Bruxism is caused by the activation of reflex chewing activity; it is not a learned habit. Chewing is a complex neuromuscular activity that is controlled by reflex nerve pathways, with higher control by the brain. During sleep, the reflex part is active while the higher control is inactive, resulting in bruxism. In most people, bruxism is mild enough not to be a health problem; however, some people suffer from significant bruxism that can become symptomatic.

The aetiology of bruxism is unknown, but may include asymmetrical occlusion, anxiety, digestive problems, a disturbed sleep pattern, or hypersensitivity of the dopamine receptors in the brain. Bruxism can cause indentations in the teeth, wear of the biting surface, abfractions and cracks in the teeth. This type of damage is categorised as symptomatic of an occlusal disease.

Bruxism often occurs during sleep and can even occur during short naps. In a typical case, the canines and incisors are moved against each other laterally, i.e. with a side-to-side action by the lateral pterygoid muscles that lie above and to the sides behind the mouth. This lateral movement abrades tooth enamel, removing the sharp biting surfaces and flattening the edges of the teeth. People with bruxism sometimes also grind the molars together, which can be loud enough to wake a sleeping partner. Some will

clench without significant side-to-side jaw movement. Bruxism is one of the most common sleep disorders: 30 to 40 million Americans grind their teeth on a nightly basis. Given enough time, dental damage will usually occur. Bruxism is the leading cause of occlusal disease and a significant cause of tooth loss.

Over time, bruxing shortens and blunts the teeth being ground, and may lead to myofacial muscle pain and headaches. In severe, chronic cases, it can lead to arthritis of the temporomandibular joints (the joints of the jaw). Most people are not aware of their bruxism and only 5 to 10 percent go on to develop symptoms such as jaw pain and headache. Teeth hollowed by previous decay (caries) may collapse as the pressure exerted by bruxism on the teeth is extraordinarily high.

A recently introduced device called the BiteStrip enables at-home overnight testing for sleep bruxism and might help diagnose bruxism before damage appears on the teeth. The device is a miniature electromyograph machine that senses jaw muscle activity while the patient sleeps. A dentist can establish the frequency of bruxing, which helps in choosing a treatment plan. Anyone having major occlusal rehabilitation should be aware that bruxism can and does ruin dental work.

The effects of the condition may be quite advanced before sufferers are aware they brux. Abraded teeth are usually brought to the patient's attention during a routine dental examination. If enough enamel is abraded, the softer dentine will be exposed and abrasion will accelerate. This opens the possibility of dental decay and tooth fracture--and in some people, gum recession. Early intervention by a dentist is advisable.Bruxism is not the only cause of tooth wear. Overly vigorous brushing, abrasives in toothpaste, acidic soft drinks and abrasive foods can also be contributing factors; each has characteristic wear patterns that a trained professional can identify.