A Comprehensive Review of a Published Clinical Case “Heart Rate Variability Biofeedback in the Management of TMD and Bruxism: Case Report” by Dr. David Cheng – DDS, BA, FAGD, FICOI
Chronic jaw pain and temporomandibular disorders (TMD) and sleep bruxism are very common afflictions affecting millions of individuals across the globe; however, most current treatments for TMD and bruxism continue to be based upon mechanical approaches and methods like occlusal splint and bite guard therapy. Although the mechanical appliances do help protect the teeth during grinding at night; unfortunately, they have been shown by researchers to have no effect on treating the underlying causes of the bruxism and TMJ dysfunction.
The Journal of the California Dental Association has recently published a new case study which presents an innovative approach to the treatment of patients afflicted by TMD, bruxism, and sleep disorder by using two non-invasive, low-cost methods to assist in their recovery: Heart Rate Variability Biofeedback (HRVBF); and Resonance Frequency Breathing (RFB). The HRVBF/RFB method is aimed at restoring autonomic nervous system balance, correcting dysfunctional breathing patterns and reducing stress responses within the body that have been linked to anxiety, bruxism and orofacial pain through scientific studies.
This in-depth article will examine the results from the above referenced journal article and discuss how HRV biofeedback may significantly shape the future of treatment and management of TMJ and bruxism.
What does this Study Show about HRV Biofeedback?
For over 20 years, this man experienced jaw pain, TMJ pain, bruxism, and chronic headaches. He also reported problems sleeping, anxiety and general physical symptoms – all indicators of an imbalance in his autonomic nervous system.
Due to the patient’s aversion to wearing foreign objects in his mouth (a common complaint among individuals who are sensitive to their senses), few treatment options were available to him.
Using a structured protocol for heart rate variability biofeedback (HRVBF), the clinician used:
- Monitoring of heart rate variability
- Capnography (petCO2) monitoring
- Breath awareness and correction
- Resonance frequency breathing (five to six breaths/minute)
- Gradually re-training the patient’s autonomic responses
He showed a dramatic improvement;
- All of his TMJ pain went away
- His sleep returned to normal
- His bruxism symptoms greatly diminished
- He no longer had headaches
- His anxiety level went from moderate to minimal
- His physiological measures of breathing and HRV greatly improved
As the report notes, “the patient expressed gratitude… stating that his mind now felt so clear that he could ‘do the work of three people’.”
Why Traditional Bite Guards Often Fall Short
The study supports an increasing body of evidence demonstrating that occlusal guards are insufficient to address the underlying reasons for bruxism.
As stated by the journal, “bite guards protect the teeth from further wear and tear but they do nothing to alter the origins of bruxism.” Many bruxism patients have both awake bruxism and sleep bruxism and bite guards will not address either. Furthermore, studies demonstrate that for many individuals with sleep apnea, the use of occlusal devices can exacerbate their respiratory issues. The clinical efficacy of occlusal devices has yet to be definitively established in research studies.
Moreover, a landmark review referenced within this case report pointed out that tooth wear is NOT predictive of the intensity of sleep bruxism — meaning that dentists may recommend splints to patients even if the patient’s bruxism has no association with grinding behavior.
Therefore, it is critical that clinicians consider approaches to addressing the autonomic nervous system rather than merely treating the teeth.
How HRV Biofeedback Works in TMD and Bruxism
1. What Is Heart Rate Variability (HRV)?
HRV is the measurement of how much time elapses between each heartbeat. A higher variability indicates a healthy functioning parasympathetic nervous system (rest-and-digest). Low HRV is associated with:
- stress
- pain-related disorders
- anxiety
- irregular breathing patterns
- sympathetic dominance
The journal confirmed that HRV is a “biomarker for reliable physiological stress and autonomic function.”
2. Why Does Breathing Matter?
Initially, the patient’s PetCO₂ levels (18-34 mmHg) were indicative of hypocapnia or chronic low CO₂ — a hallmark of dysfunctional breathing or hyperventilation.
Hypocapnia results in:
- vasoconstriction
- reduced oxygen transport to tissues
- muscle tension
- dizziness
- anxiety
- headache
- disrupted sleep
PetCO₂ levels < 35 mmHg result in “insufficient oxygen off-loading” and resultant symptoms such as dizziness, anxiety and fatigue.
3. How Does Resonance Frequency Breathing (RFB) Work?
The RFB protocol was used to train the patient to breathe at approximately 5.5 breaths per minute which synchronized his:
- heart rhythms
- blood pressure oscillations
- vagal tone
- baroreflex sensitivity
These processes resulted in a very coherent HRV pattern — indicating a high degree of parasympathetic activation.
The case demonstrated:
- Incoherent HRV → prior to treatment
- Coherent, wave-like HRV → post RFB training
Deep Dive: The Patient’s Symptoms and Transformation Before Treatment and After Treatment
Before Treatment
The patient was experiencing numerous chronic complaints, which included:
• TMJ pain
• Masseter muscle discomfort
• 20 years of severe headaches
• Brain fog
• Blurred vision
• Trapezius pain
• Frequent nighttime urination
• Chest pain
• Tingling in extremities
• Anxiety
• Frequent nocturnal awakenings (i.e., four each night)
In addition to these symptoms, the patient was also exhibiting abnormal breathing patterns when assessed, which were characterized by:
• Aborted breaths
• Fast exhalations
• Chest breathing
• Mouth breathing
These abnormal breathing patterns were indicative of an autonomic imbalance, which led to the development of bruxism and the subsequent orofacial tension experienced by the patient.
Eight Biofeedback Sessions Later
There was a significant transformation with regard to the patient’s behavior, and his physical status:
• PetCO2 returned to within the normal range of 35-45 mmHg
• Strong coherence was seen in HRV
• The patient no longer exhibited symptoms of bruxism
• Jaw pain and TMJ-related pain had completely ceased
• Headaches were no longer present
• Sleep has been normalized
• The patient’s anxiety level decreased significantly, from a score of 16 to a score of 5
• HRV patterns indicated that the patient’s nervous system was now activated in a parasympathetic manner
As the report states:
“The patient reported resolution of dental and systemic symptoms… including jaw pain, bruxism, frequent nighttime awakenings, and chronic headaches.”
Science Behind Stress, Breathing, and Bruxism
This case study is supported by an abundance of research conducted across multiple disciplines, and demonstrates how stress can lead to bruxism and how breathing affects the presence of TMD, anxiety, and bruxism. Specifically, the research shows that:
Stress leads to bruxism
Research studies have shown that patients who experience sleep bruxism exhibit moderate positive correlation between the severity of their bruxism and their cortisol levels.
Stress exacerbates TMD
Research studies have demonstrated that there is a strong relationship between TMD pain and both psychological stress and autonomic hyperactivity.
Anxiety contributes to bruxism and OSA
Research studies have shown that individuals who experience sleep-disordered breathing are at a greater risk of developing anxiety and depression.
Autonomic dysfunction is responsible for many of the symptoms described
The sympathetic nervous system suppresses HRV, leading to increased pain, jaw tension and disrupted breathing.
HRV biofeedback is effective in addressing all of the previously listed symptoms
Several meta-analyses have confirmed that HRV biofeedback (HRVBF):
• Reduces anxiety
• Decreases stress
• Improves pain conditions
• Stabilizes autonomic functioning
The journal cited HRVBF as an “Evidence-Supported Intervention” for treating the effects of stress on pain and autonomic symptoms.
What this case indicates for dentists and their patients:
1. Expands the role of dentistry to include more than just mechanical treatment of teeth.
Although dentistry traditionally emphasizes occlusion (the way upper and lower teeth fit together), splints (used to stabilize the upper and/or lower jaw) and structural issues (such as those related to the alignment of the teeth, the structure of the jaw, etc.), this case expands the role of dentistry to include systemic wellness as well, specifically when breathing, sleep, autonomic regulation, and stress physiology intersect with oral health.
2. Supports the application of HRV biofeedback as an adjunctive or alternative treatment.
Biofeedback, particularly Heart Rate Variability Biofeedback (HRVBF) is supported as a safe, effective and low-cost (non-invasive) treatment for patients who are experiencing a range of problems including, but not limited to:
- sensitivity to oral appliances
- comorbid sleep apnea
- awake bruxism
- chronic pain
- symptoms of stress
3. Highlights the importance of evaluating breathing rather than just the teeth.
While some patients with Temporomandibular Disorders (TMD) experience dysfunction with their bite (how the upper and lower teeth fit together), many do not, and even if they do, it’s possible that dysfunctional breathing is also contributing to their symptoms. The reason for this is that dysfunctional breathing can lead to increased stress (sympathetic activation), overload of the accessory neck muscles and increase in the overall level of muscle tension in the face and head, which can result in:
- overuse of the accessory neck muscles
- an increase in jaw tension
- worsening of TMJ disorders
4. Provides objective, quantifiable, physiological changes.
In contrast to the subjective nature of splint therapy (i.e., whether the patient experiences relief from their symptoms), HRV biofeedback allows for measurement of objectively determined physiological changes (e.g., CO2 levels, heart rate variability (coherence), breathing frequency and anxiety scores). These measures support the increasing trend toward providing data-driven healthcare.
How This Relates to the Future of TMJ and Bruxism Treatment
Based upon the findings of this case study, it appears that the future of TMJ and Bruxism treatment will increasingly move away from solely managing symptoms at the surface level and towards treating the underlying causes of symptoms through physiological regulation. This is consistent with the larger trend in dentistry to address more systemic issues that contribute to the development of symptoms such as bruxism (e.g., breathing dysfunctions, autonomic imbalances).
As the report concludes:
“By addressing dysfunctional breathing and autonomic imbalance, these interventions resolved long-standing symptoms… further research is warranted.”
It appears that HRV biofeedback has the potential to become a valuable addition to the toolkit of dentists providing comprehensive care for their patients.
Last thoughts
This study demonstrates how a dental practice using HRV Biofeedback can assist patients suffering from:
- Chronic Temporomandibular Disorder (TMD)
- Sleep Bruxism
- Symptoms caused by stress
- Anxiety
- Dysfunctional Breathing
It was not simply a dental treatment that transformed this individual; it was an overall system of wellness. The structured biofeedback allowed the individual to regain their clarity of thought, restful sleep, ability to eat comfortably, and their ability to function normally each day. He described the changes as life changing.
As there is increasing evidence of the value of HRV Biofeedback, it could potentially become an essential tool in dental practice and functional medicine practice.