Aoife Stack reviews the evidence to explore the connection between bruxism and airway instability from a dental perspective.
According to Lobbezoo and colleagues (2013a), bruxism is a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible.
Bruxism has two distinct circadian manifestations. It can occur during sleep (indicated as sleep bruxism) or during wakefulness (indicated as awake bruxism).
It has long been considered a parafunctional habit associated with stress or occlusal imbalances. However, emerging evidence increasingly implicates sleep-disordered breathing (SDB) and airway obstruction as major contributors – particularly in cases of sleep bruxism (Kostrzewa-Janicka et al, 2015).
This connection has profound implications for how we diagnose, treat and refer patients – not only in adults but also notably in paediatric populations, where early intervention can significantly alter craniofacial growth and long-term health outcomes.
Bruxism is broadly classified into two types:
- Awake bruxism – often linked to stress, anxiety or concentration habits
- Sleep bruxism – occurs during sleep and is considered a sleep-related movement disorder, often associated with micro-arousals and changes in autonomic nervous system activity.
While the aetiology of sleep bruxism is multifactorial, airway instability during sleep is now considered a key contributing factor, particularly in patients exhibiting signs of respiratory effort-related arousals (RERAs) or obstructive sleep apnoea (OSA).
These key clinical signs, particularly when combined with reports of snoring, daytime fatigue, headaches, ADHD-like behaviour, or clenching upon waking, should prompt further investigation into airway health:
- Tooth wear – flat occlusal surfaces, chipping, or enamel cracks
- Masseter hypertrophy
- Scalloped tongue or tongue indentations
- Cheek ridging
- Tori or exostoses – often linked to chronic oral parafunction
- TMJ symptoms or muscle tenderness
- High Mallampati scores
- Narrow arches.
The bruxism-airway link: what the evidence shows
1. Micro-arousals and protective mechanisms
Several polysomnographic studies have demonstrated that sleep bruxism episodes are often preceded by brief arousals related to increased respiratory effort (Lavigne et al, 2007). This includes RERAs – subtle, non-apnoeic breathing disturbances that cause arousals without full airway collapse.
In this scenario, bruxism may serve as a protective reflex to reopen the airway by activating upper airway dilator muscles and repositioning the mandible forward, thereby improving airflow (Kato et al, 2003).
2. RERAs: the missing link in ‘normal’ sleep studies
Many patients with classic OSA symptoms (eg, snoring, fatigue, behavioural issues) have normal apnoea-hypopnoea index (AHI) scores.
In these cases, RERAs may be present and significant. This is sometimes referred to as upper airway resistance syndrome (UARS) – a condition where bruxism may be one of the only physiological signs of disturbed sleep (Guilleminault et al, 2001).
Unfortunately, RERAs are frequently missed without full polysomnographic analysis that includes oesophageal pressure monitoring or other airflow resistance assessments. Working with a skilled sleep medicine team will help the dentist to diagnose this condition.
Bruxism in children
Paediatric bruxism is common and often dismissed as a phase, but research increasingly ties it to nasal obstruction, enlarged tonsils/adenoids and mouth breathing. These are all classic signs of airway dysfunction.
Key studies have shown:
- Children with mouth breathing and tonsillar hypertrophy have a significantly higher prevalence of sleep bruxism (Serra-Negra et al, 2012)
- Snoring and sleep-disordered breathing are strong predictors of night-time grinding in children (Lobbezoo et al, 2013b)
- Bruxism in children may precede or coexist with behavioural issues, poor sleep quality and neurocognitive delays, likely due to fragmented sleep from undiagnosed RERAs or UARS. Sleep-disordered breathing was associated with 40% and 60% more behavioural difficulties at four and seven years, respectively (Bonuck et al, 2012). This supports a shift in thinking: bruxism in children is not benign, and should prompt airway screening.
The dentist’s role in airway screening
Dentists are uniquely positioned to identify the interplay between bruxism and airway instability. Incorporating airway-focused assessments into routine dental visits – especially in paediatric and orthodontic evaluations – is becoming standard practice in progressive practices. In 2017, American clinical guidelines introduced this as a directive.
The following tools can help flag patients who may require referral for ENT evaluation, sleep study or myofunctional therapy:
- The Fairest 6 screening tool for paediatrics (Zaghi et al, 2020)
- The STOP-bang questionnaire for adults
- Observation of tongue posture, lip seal, tonsil size and breathing pattern.
Treatment implications
Historically, bruxism treatment focused on nightguards to protect the dentition. While these remain valuable, especially in managing symptoms and protecting teeth, they do not address underlying causes such as airway instability.
A more comprehensive approach may include:
- Airway management: referral for ENT, CPAP therapy (in diagnosed OSA), mandibular advancement devices or surgery for anatomical obstructions
- Myofunctional therapy: exercises to improve tongue posture and nasal breathing
- Orthodontics: especially in children – palatal expansion can significantly improve nasal airflow and reduce SDB symptoms
- Behavioural therapy or stress management in awake bruxism cases.
It is critical to match treatment to aetiology, not just symptoms.
Rethinking bruxism as an airway symptom
Bruxism, particularly during sleep, is more than a mechanical habit. In both children and adults, it may represent a neurophysiological response to airway compromise, such as those seen in RERAs and UARS.
Recognising this link changes how we approach diagnosis and treatment – encouraging a collaborative, airway-centred mindset in dentistry.
As the understanding of craniofacial and airway development continues to evolve, the dental profession must embrace its critical role in recognising early warning signs of sleep-disordered breathing.
By doing so, we not only preserve the dentition but contribute to the patient’s broader health and quality of life.
Interested in finding out more about integrative dentistry and holistic care? Dive in to a different way of thinking with our essential guide to holistic dentistry, curated by Dr James Goolnik.
Holistic care
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