Causes of Bruxism
Bruxism is primarily driven by central nervous system factors including psychological stress, anxiety, and emotional distress, rather than peripheral dental or occlusal factors, with genetic predisposition and sleep disorders also playing significant roles. 1, 2
Primary Psychological and Psychiatric Causes
Stress and anxiety are the dominant triggers, activating neural circuits in the hippocampus and subcortical structures that increase masticatory muscle tension 1
Emotional excitation including rage, fear, annoyance, and embarrassment directly trigger or worsen bruxism episodes, particularly in contexts involving anxiety 1
Depression is present in approximately 18% of bruxism patients, representing a significant comorbid condition that requires assessment 1
Patterns of rumination, worry, or obsessive thinking contribute to jaw clenching behaviors, especially during waking hours 1
Chronological relationship between stressful life events and bruxism onset should be assessed, as worsening at night or during rest suggests psychological components 1
Central Nervous System Regulation
Bruxism is centrally regulated by the CNS rather than peripherally influenced by dental factors, representing a fundamental shift in understanding etiology 2, 3
Changes in CNS function contribute to the development and maintenance of bruxism activity 2
The condition is regulated by pathophysiological and psychosocial factors, not morphological or occlusal factors as previously believed 3
Genetic and Constitutional Factors
Genetic predisposition plays a role in susceptibility to developing bruxism 2, 4
Genetic disposition combined with stress and anxiety syndromes appears to be the dominant combination leading to increased muscle tension 4
Sleep-Related Factors
Sleep disorders and sleep-related breathing disorders including apnea and hypopnea syndrome are linked to bruxism occurrence 5
Sleep positioning has been associated with bruxism episodes 6
Sleep bruxism occurs in approximately 13% of adults, representing a distinct circadian manifestation from awake bruxism 3
Secondary Contributing Factors
Oral parafunctions and oromandibular parafunctional activities may precipitate bruxism occurrence but are not primary causes 2, 5
Temporomandibular disorders often coexist with bruxism but the relationship is bidirectional rather than purely causal 5
Malocclusion and occlusal disorders have historically been cited but current evidence suggests these are not primary etiological factors 6, 3
Medications and behavior disorders can be associated with bruxism development 5
Allergies have been associated with bruxism in some studies, though the mechanism remains unclear 6
Age-Specific Considerations
In children, bruxism occurs in approximately 15% of cases and is often self-limiting, requiring primarily observation 6, 5
In adults, bruxism may occur in as many as 96% to some degree, though clinically significant bruxism is less common 6
Critical Clinical Caveat
The etiology is multifactorial, meaning multiple contributing factors typically coexist in individual patients rather than a single cause 5, 3
A biopsychosocial approach is essential because patients often have comorbid chronic pain conditions including headaches, temporomandibular disorders, and fibromyalgia 1