Bruxism is the involuntary clenching, grinding, or bracing of the teeth and jaw, classified as sleep bruxism when it occurs nocturnally or awake bruxism when present during waking hours. Affecting an estimated 8–31% of the general population, it is recognized as a significant parafunctional behavior capable of causing lasting structural damage to the dentition and surrounding oral tissues.
Common Causes and Risk Factors
Bruxism is multifactorial in origin, with contributing factors spanning psychological, physiological, and lifestyle domains:
- Psychological stress, anxiety, or chronic emotional tension
- Sleep disorders, particularly obstructive sleep apnea
- Certain medications, including selective serotonin reuptake inhibitors (SSRIs)
- Stimulant use — caffeine, alcohol, or tobacco
- Genetic predisposition and central nervous system dysregulation
Clinical Significance
The occlusal forces generated during bruxism can far exceed those of normal mastication, sometimes reaching several hundred pounds per square inch. This sustained overloading progressively wears through enamel — the hardest substance in the human body — exposing the softer dentin beneath and increasing thermal sensitivity. The periodontal ligament and alveolar bone also absorb abnormal parafunctional loads, which over time may contribute to tooth mobility and accelerated bone loss. Clinicians typically observe one or more of the following:
- Flattened, chipped, or fractured occlusal surfaces
- Dentinal hypersensitivity, especially to temperature changes
- Jaw muscle soreness or fatigue, most pronounced upon waking
- Temporomandibular joint (TMJ) pain, clicking, or restricted opening
- Recurring headaches originating at the temples
Diagnosis and Management
Diagnosis is primarily clinical, based on characteristic wear facets, patient-reported symptoms, and muscle palpation findings. Polysomnography may confirm sleep bruxism in complex or ambiguous cases. Management is individualized and commonly includes occlusal splints (nightguards) to redistribute bite forces and protect tooth structure, behavioral interventions such as cognitive behavioral therapy or biofeedback, and treatment of contributing conditions like sleep apnea. Where an occlusal discrepancy is identified as a factor, selective occlusal equilibration may be considered.
Because enamel does not regenerate, damage from bruxism is permanent — early identification and consistent use of protective appliances are the most effective strategies for preserving tooth structure and avoiding the need for extensive restorative intervention.