In this example, when the jaws are brought together, the lower back teeth contact the prominent upper wisdom tooth before the other teeth, and the lower jaw has to move forward to allow the rest of the teeth to meet. The difference between a premature contact and a deflective interference is that the latter implies a dynamic abnormality in the bite. Possible associations
Several associations between bruxism and other conditions, usually neurological or psychiatric disorders, have rarely been reported, with varying degrees of evidence (often in the form of case reports). Examples include:

Diagnosis
Early diagnosis of bruxism is advantageous, but difficult. Early diagnosis can prevent damage that may be incurred and the detrimental effect on quality of life. A diagnosis of bruxism is usually made clinically, and is mainly based on the persons history (e.g. reports of grinding noises) and the presence of typical signs and symptoms, including tooth mobility, tooth wear, masseteric hypertrophy, indentations on the tongue, hypersensitive teeth (which may be misdiagnosed as reversible pulpitis), pain in the muscles of mastication, and clicking or locking of the temporomandibular joints. Questionnaires can be used to screen for bruxism in both the clinical and research settings.For tooth grinders who live in same household with other people, diagnosis of grinding is straightforward: Housemates or family members would advise a bruxer of recurrent grinding. Grinders who live alone can likewise resort to a sound-activated tape recorder.
The efficacy of such devices is debated. Some writers propose that irreversible complications can result from the long-term use of mouthguards and repositioning splints. Random controlled trials with these type devices generally show no benefit over other therapies. Another partial splint is the nociceptive trigeminal inhibition tension suppression system (NTI-TSS) dental guard. This splint snaps onto the front teeth only. It is theorized to prevent tissue damages primarily by reducing the bite force from attempts to close the jaw normally into a forward twisting of the lower front teeth. The intent is for the brain to interpret the nerve sensations as undesirable, automatically and subconsciously reducing clenching force. However, there may be potential for the NTI-TSS device to act as a Dahl appliance, holding the posterior teeth out of occlusion and leading to their over-eruption, deranging the occlusion (i.e. it may cause the teeth to move position). This is far more likely if the appliance is worn for excessive periods of time, which is why NTI type appliances are designed for night time use only, and ongoing follow-ups are recommended.A mandibular advancement device (normally used for treatment of obstructive sleep apnea) may reduce sleep bruxism, although its use may be associated with discomfort. Botulinum toxin
Botulinum neurotoxin (BoNT) is used as a treatment for bruxism.