One or more of the following:
Abnormal tooth wear
Grinding sounds
Discomfort of the jaw musclesWith the following criteria supporting the diagnosis:

C. polysomnography shows both:
Activity of jaw muscles during sleep
No associated epileptic activity
D. No other medical or mental disorders (e.g., sleep-related epilepsy, which may cause abnormal movement during sleep). E. The presence of other sleep disorders (e.g., obstructive sleep apnea syndrome). Definition examples
Bruxism is derived from the Greek word βρύκειν (brykein) "to bite, or to gnash, grind the teeth". People with bruxism are called bruxists or bruxers and the verb itself is "to brux". There is no widely accepted definition of bruxism. Examples of definitions include:

"Bruxism is a repetitive jaw-muscle activity characterized by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Bruxism has two distinct circadian manifestations: it can occur during sleep (indicated as sleep bruxism) or during wakefulness (indicated as awake bruxism). "All forms of bruxism entail forceful contact between the biting surfaces of the upper and lower teeth. In grinding and tapping this contact involves movement of the mandible and unpleasant sounds which can often awaken sleeping partners and even people asleep in adjacent rooms. Clenching (or clamping), on the other hand, involves inaudible, sustained, forceful tooth contact unaccompanied by mandibular movements. "A movement disorder of the masticatory system characterized by teeth-grinding and clenching during sleep as well as wakefulness." "Non-functional contact of the mandibular and maxillary teeth resulting in clenching or tooth grinding due to repetitive, unconscious contraction of the masseter and temporalis muscles."
Necrotizing bronchiolitis is an acute inflammatory lesion of the lower airway, a potential complication of mechanical ventilation. == References ==