Dental Science



Bruxism is a repetitive jaw-muscle activity characterized by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible

  • It is an oral parafunctional activity (unrelated to normal function such as eating or talking)
View from above of an anterior (front) tooth showing severe tooth wear which has exposed the dentin layer (normally covered by enamel). The pulp chamber is visible through the overlying dentin. Tertiary dentin will have been laid down by the pulp in response to the loss of tooth substance. Multiple fracture lines are also visible. | CC BY-SA 3.0,


  • Nocturnal bruxism
  • Awake bruxism


  • Psychosocial factors
  • Genetic factors
  • Medications
  • Occlusal factors

Clinical features

  • Hypersensitive teeth
  • Aching jaw muscles
  • Headaches
  • Tooth wear
  • Damage to dental restorations (e.g. crowns and fillings) to teeth


Diagnostic criteria

ICSD-R diagnostic criteria (for sleep bruxism)

  • Minimal criteria (include both):
    • Symptom of tooth-grinding or tooth-clenching during sleep, and
    • One or more of the following:
      • Abnormal tooth wear
      • Grinding sounds
      • Discomfort of the jaw muscles
  • Supporting criteria:
    • Polysomnography shows both:
      • Activity of jaw muscles during sleep
      • No associated epileptic activity
    • No other medical or mental disorders (e.g., sleep-related epilepsy, which may cause abnormal movement during sleep).
    • The presence of other sleep disorders (e.g., obstructive sleep apnea syndrome)


Occlusal splint for upper jaw | Metalhead64 – Public Domain,



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