Have you ever woken up with a sore jaw or a headache? It could be due to a condition known as Sleep Bruxism, a phenomenon where individuals grind or clench their teeth during sleep. This intriguing sleep-related movement disorder is a primary cause of many individuals moderate to severe wear resulting in flat teeth and future complications in maintaining excellent dental health. New meta analysis research published in the Journal of the American Dental Association April 2024 Issue by Davis C. Thomas, et al. explores the history of research on sleep bruxism based on the review of 4,612 articles spanning a 70 year period!
Sleep bruxism has been a topic of discussion and research for decades. Initially, it was thought to be caused mainly by factors like the way your teeth come together. However, recent research, including the comprehensive review by Davis C. Thomas and his team, sheds light on the significant shift in our understanding. The consensus now points towards central factors, such as the autonomic nervous system and genetics, playing a more pivotal role in the onset of bruxism than previously believed. Here are some highlights of the findings:
1. Oral Factors: Occlusion and Orofacial Anatomy
- Early Theories: Initially, occlusal factors were considered crucial in the etiology of sleep bruxism. Early treatments focused on occlusal adjustments to manage bruxism.
- Current Understanding: Recent studies refute the direct influence of occlusal factors on bruxism, showing no significant difference in bruxism activity between patients with and without occlusal interferences.
- Likelihood of Relationship: Low, based on robust evidence shifting the focus from peripheral to central factors.
2. Psychological Factors: Stress and Anxiety
- Supported by Early Literature: Stress was seen as a significant trigger, with heightened jaw-muscle activity during stressful periods.
- Diverging Findings: While self-reported studies support the stress-bruxism link, EMG-based studies offer conflicting results, suggesting that the relationship may not be direct or may involve multiple contributory factors.
- Likelihood of Relationship: Moderate to high in self-reported and clinically diagnosed bruxism, but inconsistent in EMG-based studies.
3. Exogenous Factors: Medication and Substance Use
- Substances: Includes medication (especially SSRIs), illicit drugs, caffeine, alcohol, and tobacco. Some associations have been observed, but the evidence quality is variable.
- Likelihood of Relationship: Moderate, with the understanding that more high-quality evidence is needed to establish clear cause-and-effect relationships.
4. Genetic Factors
- Familial Predisposition: Some studies report a genetic predisposition to bruxism, with certain gene variants linked to a higher risk.
- Likelihood of Relationship: Moderate, recognizing the potential role of genetic polymorphisms rather than a single gene.
5. Comorbidities
- Systemic Conditions: Associations with conditions like hypertension, metabolic disturbances, and obstructive sleep apnea have been reported.
- Localized Conditions: Links to gastroesophageal reflux disease and temporomandibular disorders, among others.
- Likelihood of Relationship: Moderate to high, especially for conditions that can affect the autonomic nervous system or cause arousal from sleep.
6. Neurochemicals and Neurotransmitters
- Involvement in Pathogenesis: Dopamine, serotonin, norepinephrine, and other neurotransmitters have been implicated in the pathogenesis of bruxism.
- Likelihood of Relationship: Moderate, with evidence supporting their role in motor neuron activity control and sleep-wake regulation.
7. Airway Patency
- Association with Sleep Bruxism: Studies suggest that sleep bruxism may be associated with maintaining airway patency, particularly in patients with conditions like obstructive sleep apnea (OSA).
- Protective Role Hypothesis: The hypothesis suggests that bruxism movements may serve a protective role by aiding in the restoration and maintenance of upper airway patency during sleep, potentially preventing obstructive respiratory events.
- Efficacy of Mandibular Advancement Devices: Supporting the airway patency hypothesis, mandibular advancement devices that increase the cross-sectional diameter at the oropharynx have been found to reduce the frequency of sleep bruxism episodes, further hinting at the interplay between bruxism and airway patency.
- Likelihood of Relationship: Moderate, with an understanding that the literature indicates a potential association, but more direct evidence and studies are needed to fully establish the protective role of sleep bruxism in airway patency and its implications for treatment, particularly in the context of OSA.
The prevalence of bruxism is reported to be 5% through 40% in children and 10% through 30% in adults. There is a higher prevalence of [sleep bruxism] SB in younger people and drops after the age of 50 years. In the pediatric population, SB is more prevalent in girls.
Thomas, Davis C., et al. “Sleep bruxism: The past, the present, and the future—evolution of a concept.” The Journal of the American Dental Association (2024).
We may identify you as a possibly Bruxism patient based on the following:
Soft Tissue Considerations:
- Hypertrophy of the masseter and temporalis muscles
- Trauma to the soft tissue of the mouth
- Blockage of the parotid gland.
- Notable prominence of the linea alba buccal white line on the inside of your cheek, which might indicate static bruxism.
Hard Tissue Damage Indicators:
- Wear and tear on the enamel and dentin.
- Failure of dental implants.
- Cracks and fractures in teeth.
- Damage to dental restorations.
- Tooth loss and exposure of the dental pulp.
- Appearance of vertical lines on the enamel, indicating stress on teeth.
Presence of Tori:
- Tori are extra bumps inside your mouth most commonly found below your tongue on the inside wall of your lower teeth (mandibular tori).
- Other places can be on the outside of your upper teeth (buccal exostosis) or in the middle on the roof of your mouth (palatal tori).
- There’s a stronger connection observed with mandibular tori compared to others. This has been long suspected, but current research does not definitively link tori formation with bruxism due to a lack of comprehensive evidence.
Key Takeaways for Everyone
For those experiencing symptoms of sleep bruxism, such as morning jaw soreness or headaches, it’s essential to consult with us where we can offer guidance based on the latest research. For many, a sleep appliance like a night guard or sometimes even a snore guard can provide the relief needed to protect your teeth when your autonomic nervous system is in control.