DESCRIPTION

• Bruxism is defined as habitual nonfunctional forceful contact of teeth, which is involuntary. These movements can include excessive grinding, clenching, or rubbing of teeth.
• Sleep bruxism should be distinguished from daytime awake bruxism.
  • Sleep bruxism has been classified as a sleep-related movement disorder which is likely centrally mediated and related to activation of the autonomic nervous system and microarousals from sleep.
  • Awake bruxism occurs less commonly than sleep bruxism and can be a habit or related to underlying medical disorders such as Rett syndrome.

EPIDEMIOLOGY

• Age/onset
  • In children, prevalence in the literature is highly variable with a range of 4–40%.
  • May occur throughout life but frequently tends to peak in early childhood and then decreases with age
  • Sleep bruxism usually diminishes around 9 to 10 years of age.
  • Infants may grind their teeth during the eruption of primary teeth.
  • May be temporarily or intermittently present, which can make diagnosis difficult
• No gender differences in prevalence
• Some studies support higher incidence in children with developmental disabilities, Down syndrome, sleep disorders, and autism.

ETIOLOGY

The exact cause is not known. It is likely to be a multifactorial process including oral motor activities, regulation of sleep–wake cycle, autonomic, catecholaminergic, hereditary, and psychosocial influences.

RISK FACTORS

• Environmental factors during sleep time such as noise or light may contribute.
• 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)
  • Posttraumatic stress disorder
• Exposure to secondhand smoke
• Medications (amphetamines, barbiturates, antidepressants—particularly serotonin reuptake inhibitors, serotonin-noradrenaline reuptake inhibitors, and noradrenaline-dopamine reuptake inhibitors)

COMMONLY ASSOCIATED CONDITIONS

• Temporomandibular joint (TMJ) disorders
• Gastroesophageal reflux disease
• Sleep-disordered breathing
• Snoring and obstructive sleep apnea
• Tonsil/adenoid hypertrophy
• Mouth breathing
• Neurodevelopmental disorders (e.g., cerebral palsy)
• Brain injury
• Attention-deficit/hyperactivity disorder (ADHD)