Bruxism (Teeth Grinding): Causes

Pathogenesis (development of disease)

The causes of primary bruxism are not yet known. One possible explanation is a disturbed temporomandibular joint function: due to a faulty or non-existent bite of the upper and lower jaws together, the two rows of teeth rub against each other, which consequently increases the muscle tone (muscle tension) and leads to a misuse or overuse of the masticatory muscles. However, bruxism can also be an acquired habit.

Secondary bruxism occurs as a result of various diseases or other factors (see below).

Waking bruxism (WB) seems to be more likely due to emotional causes and sleep bruxism (SB) due to central nervous disorders.

Etiology (causes)

Biographical causes

  • Genetic burden – a specific genetic defect causes a higher risk for bruxism
    • The following genetic conditions are associated with bruxism:
      • Angelman syndrome – rare genetic alteration on chromosome 15 associated with mental and motor developmental delays as well as cognitive disability, hyperactivity, and severely reduced development of phonology
      • Prader-Willi syndrome (PWS; synonyms: Prader-Labhard-Willi-Fanconi syndrome, Urban syndrome and Urban-Rogers-Meyer syndrome) – genetic disease with autosomal dominant inheritance, which occurs in approximately 1: 10,000 to 1: 20,000 births; characteristic are, among other things, a pronounced overweight with a lack of a sense of satiety, short stature and intelligence reduction.
      • Rett syndrome – genetic disease with X-linked dominant inheritance, thus only in girls occurring profound developmental disorder due to an early childhood encephalopathy (collective term for pathological changes in the brain).

Behavioral causes

  • Consumption of stimulants
    • Alcohol (female: > 20 g/day; male: > 30 g/day) – high alcohol consumption is associated with a 1.9-fold risk of bruxism
    • Caffeine consumption (> 8 cups per day) – 1.4-fold risk of bruxism.
    • Tobacco (smoking) – studies show a dose-dependent relationship between smoking and bruxism; smokers have a 1.6- to 2.85-fold risk of bruxism
    • Passive smoking – children of smoking parents have an increased risk of bruxism.
  • Drug use
    • Amphetamines
    • Ectasy (synonym: Molly; MDMA: 3,4-methylenedioxy-N-methylamphetamine).
    • Cocaine
  • Psycho-social situation
    • Anxiety disorder
    • Stress
      • Children: from divorced parents, working mothers; lights and noises in the bedroom; frequent quarreling in the family.
    • Shift work

Causes due to illness

  • Insomnia (sleep disorders)
  • Coma
  • Pyrosis (heartburn)
  • Reflux (reflux of acid gastric juice and other gastric contents into the esophagus (esophagus)) – if reflux is present, the prevalence for sleep bruxism (SB) is 74%.
  • Rhonchopathy (snoring).
  • Traumatic brain injury (TBI)
  • Sleep apnea (cessation of breathing during sleep) – risk of 3.96

Medication

  • Antidepressants
  • Anticonvulsants
  • Antipsychotics
  • Antihistamines
  • Dopaminergic drugs
  • Cardio-active drugs
  • Narcotics

Further

  • Altered bite position due to faulty tooth contacts – even a deviation of 0.01 mm is perceived by TMJ; therefore, it is important that crowns, bridges, etc. are perfectly adjusted