Dental splints, also known as occlusal splints or night guards, are appliances made to protect the teeth and supporting structures from damage during grinding or clenching.
Clenching or grinding of teeth, termed bruxism, can occur when patients are awake or asleep. It has been reported that 20% of adults engage in bruxism when awake while for 8% of adults it occurs when they are asleep. Sometimes, it is incorrectly thought that the arrangement of teeth in the mouth or occlusion is responsible for the bruxism. However, stress is the primary cause of bruxism both when awake and asleep and sleep bruxism is understood to be a sleep-related disorder. In sleep bruxism, the brain causes activation and contraction of the jaw opening and jaw closing muscles and this generally occurs just before the onset of rapid eye movement sleep.

Chronic clenching and grinding may eventually lead to temporomandibular disorders (TMDs). Temporomandibular disorders are a group of conditions that involve the muscles controlling the lower jaw, the jaw joint (temporomandibular joint) and supporting structures. Chronic bruxism can cause overuse of the muscles controlling the lower jaw leading to pain from those muscles. The load on the joint itself can also cause changes to occur inside the joint leading to pain and limited mouth opening.

Your dentist may recommend a night guard if you have wear facets on your teeth that indicate you may be clenching or grinding your teeth at night or if you are suffering from temporomandibular disorders. Since they prevent the upper and lower teeth from coming into contact while you sleep, they are extremely effective at protecting the teeth from further damage caused by bruxism. Occlusal splints are one of the treatment modalities your dentist might suggest if it is determined that you are suffering from a temporomandibular disorder.Other treatments include changing to a soft diet, reducing stress, improving sleep, avoiding extreme jaw movements such as yawning, applying warm packs to the joint and in some cases, prescription of anti-inflammatory or muscle relaxant medications.

A ‘stabilisation’ type of occlusal splint is recommended, which can be either soft or hard or both (bilaminar). These distribute the forces generated by bruxism equally between the upper and lower teeth, reduce muscle strain and joint overloading. However, these do not cure bruxism itself and patients may continue to clench and grind their teeth at night. Behavioural management has been found to be effective for patients suffering from TMDs. This involves making the patient aware of times during the day they may be unconsciously clenching or grinding such as in front of the computer or studying or when faced with stress at work along with reducing stress.