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.
Metyrapone, sold under the brand name Metopirone, is a medication which is used in the diagnosis of adrenal insufficiency and occasionally in the treatment of Cushings syndrome (hypercortisolism). Medical uses
Metyrapone can be used in the diagnosis of adrenal insufficiency. Metyrapone 30 mg/kg, maximum dose 3,000 mg, is administered at midnight usually with a snack. The plasma cortisol and 11-deoxycortisol are measured the next morning between 8:00 and 9:00 am. A plasma cortisol less than 220 nmol/L indicates adequate inhibition of 11β-hydroxylase. In patients with intact Hypothalamo-pituitary-adrenal axis, CRH and ACTH levels rise as a response to the falling cortisol levels. This results in an increase of the steroid precursors in the pathway. Therefore, if 11-deoxycortisol levels do not rise and remain less than 7 µg/dL (202 nmol/L) and adrenocorticotropic hormone (ACTH) rises, then it is highly suggestive of adrenal insufficiency. If neither 11-deoxycortisol nor ACTH rise, it is highly suggestive of an impaired hypothalamic–pituitary–adrenal axis at either the pituitary or hypothalamus. The metyrapone test may aid in verifying the cause of Cushings syndrome. Most patients with pituitary dysfunction and/or pituitary microadenoma will increase ACTH secretion in response to metyrapone, while most ectopic ACTH-producing tumors will not. Pituitary macroadenomas do not always respond to metyrapone. Metyrapone is used for the medical control of hypercortisolism in Cushings syndrome (ACTH dependent or independent). The aim for medical treatment is to achieve pre-operative control of hypercortisolism, or for control of residual disease persisting post-operatively (TSS, adrenalectomy).