Bruxism is a topic covered in the Select 5-Minute Pediatrics Topics.

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  • Bruxism is defined as habitual nonfunctional forceful contact of teeth, which is involuntary. These movements can include excessive grinding, clenching, or rubbing of teeth.
  • Other nonfunctional (or “parafunctional”) oral habits include movements not involved with normal chewing, swallowing, or speaking, such as chewing pencils, nails, cheek, or lip.
  • Sleep bruxism should be distinguished from daytime awake bruxism.
  • Awake bruxism is rare with little or no audible sound during clenching, compared to the loud grinding sound commonly occurring in sleep bruxism.


  • May occur throughout life but frequently tends to peak in early childhood, then decreases with age
  • Infants have been known to grind their teeth during the eruption of primary teeth.
  • May be temporarily or intermittently present, which makes diagnosis difficult
  • Recent systematic review of literature reported no gender differences in prevalence. Previous studies suggested girls may be more affected than boys.
  • Some studies support higher incidence in children with developmental disabilities, Down syndrome, sleep disorders, and autism.
  • No genetic mechanism has been explained. Based on self-reports, 20–50% of children with sleep bruxism have an immediate family member who experienced bruxism as a child.


In children, prevalence in the literature is highly variable with a range of 4–40%. Prevalence decreases with increasing age. Sleep bruxism progressively diminishes around 9–10 years of age.


The exact cause is not known. It is likely to be a multifactorial process including pathophysiologic, psychologic, or morphologic factors.

  • Awake bruxism is more commonly associated with psychosocial factors and psychopathologic symptoms.
  • Dental factors (current evidence suggests that they play a small role, only ∼10% of cases)
    • Occlusal interferences, including malocclusions, in which teeth do not interdigitate smoothly
    • High dental restorations (e.g., fillings or crowns)
    • Intraoral irritation (e.g., sharp tooth cusp)
    • Teething
  • Psychological factors
    • Nervous tension (related to stress, anger, and aggression)
    • Personality disorders
    • Posttraumatic stress disorder
  • Common systemic factors
    • Moving between levels of sleep
    • Sleep-disordered breathing
    • Snoring and sleep apnea
    • Tonsil/adenoid hypertrophy
    • Neurodevelopmental disorders (e.g., cerebral palsy)
    • Brain injury
    • ADHD
  • Other possible factors
    • Asthma
    • Allergies
    • Nasal obstruction
    • Exposure to secondhand smoke
    • Medications (amphetamines, antidepressants—particularly serotonin reuptake inhibitors)

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