● Have you ever woken up with an agonizing headache, a tense jaw, and muscle soreness surrounding the mouth area?
● Do you (unconsciously or otherwise) grind, clench, or gnash your teeth while asleep?
● Do you feel like your breathing is somehow obstructed or paused during sleep?
● Has anybody ever told you that you excessively snore or suddenly gasp for air while asleep?
● Do you experience unexplained daytime sleepiness or problems concentrating?
If your answer to any of the above 5 questions is yes and you haven't been able to figure out why – this article is for you! It will clear a lot of your confusion regarding your symptoms and will lead you to a convincing explanation of why such issues often go unresolved. What's more, it will give you information on how such issues can be treated.
You may be suffering from Bruxism and some type of Breathing Disorder (most likely Sleep Apnea)! While Bruxism is characterized by teeth grinding, clenching or biting (typically while asleep), leading to a range of issues like tooth wear, jaw soreness, and headaches, Breathing Disorders primarily relate to the respiratory system where breathing has become heavily restricted (again, during sleep).
Both Bruxism and Breathing Disorders are separate medical conditions, but as medical research continues to unveil complicated relationships between seemingly unrelated symptoms, it turns out that Bruxism and Breathing Disorders may have a strong connection! This is particularly interesting and beneficial for doctors and patients alike, as it increases the possibility of getting to the hidden causes of these issues, thereby increasing the likelihood of treating them successfully. What could be the possible relationship between Bruxism and Breathing Disorders? Let's find out!
1. What Are Breathing Disorders?
While we have already given a bit of an overview of Breathing Disorders in the introduction section, it would be helpful to explore the term in detail before we get to the main topic of our discussion (i.e, the relationship between Bruxism and Breathing Disorders).
Breathing Disorders and Common Variants
In the widest sense, Breathing Disorders refer to a group of conditions that affect a person's ability to breathe properly. Since these disorders are primarily related to the respiratory system, they affect the lungs, airways, and the muscles involved in breathing.
There are many types of Breathing Disorders, but the common ones include:
● Asthma is a chronic condition in which the airways get inflamed and narrowed down, causing difficulty in breathing.
● Chronic Obstructive Pulmonary Disease (COPD) - a progressive lung disease in which the airflow is obstructed, causing difficulty in breathing. Chronic bronchitis and emphysema are its subtypes.
● Sleep Apnea - a disorder in which breathing is repeatedly paused during sleep, causing daytime fatigue and other health issues.
● Bronchitis is a disorder in which the airways (known as bronchial tubes) carrying air to the lungs get inflamed, causing coughing and mucus production. It can be acute or chronic.
● Pneumonia - an infection in which the air sacs in one or both of the lungs are inflamed, causing fever, cough, and difficulty breathing.
● Others include Pulmonary Embolism, Interstitial Lung Disease (ILD), Cystic Fibrosis, and Pulmonary Hypertension.
Causes And Risk Factors For Breathing Disorders
While the specific causes and risk factors vary for each type of breathing Disorder, the most common causes and risk factors include:
● Smoking - especially tobacco smoke
● Environmental Pollutants - including air pollution, chemicals, etc.
● Genetics - some Breathing Disorders are inherited, like Cystic Fibrosis
● Allergies - some people develop Breathing Disorders because they are allergic to certain substances like pollen, mold, etc.
● Obesity - certain Breathing Disorders like Sleep Apnea are related to obesity
● Age - Some breathing Disorders like COPD and ILD are triggered by advancing age
● Other risk factors include Chronic Heart Conditions, Neuromuscular Disorders, and poor lung development.
2. Exploring Sleep Apnea
While we have already brushed on the definition of Sleep Apnea in the previous section, let's explore it a bit more since it's the main focus of our topic (besides Bruxism).
Sleep Apnea And Its Variants
As we've already noted, Sleep Apnea is a Breathing Disorder that's characterized by pauses in breathing during sleep or episodes of shallow breathing. The duration of these episodes may range from a few seconds to minutes, and the frequency may range from once to multiple times during sleep. There are two types of Sleep Apnea:
Obstructive sleep apnea is the type in which the throat muscles get overly relaxed during sleep, closing down the airways.
Central Sleep Apnea - it's the type in which the muscles responsible for breathing during sleep fail to receive the appropriate signals from the brain.
Symptoms Of Sleep Apnea
The most common symptoms of Sleep Apnea include:
● Snoring
● Gasping for air
● Pauses in breathing
● Morning headache
● Feeling sleepy during the day
● Difficulty in concentrating during the day
● Mood changes
● Mouth dryness after waking up
Probable Causes Of Sleep Apnea
The probable causes of Sleep Apnea (both obstructive and central) include:
● Obesity
● Aging
● Narrow airways by birth
● Smoking
● Enlarged tonsils
● Heart disorders
● Stroke
● High altitude
● Opioid use
Up till now, we have discussed all the well-established and documented causes/risk factors for Breathing Disorders (including those of Sleep Apnea).
However, there are certain causes that aren't as well-documented as the others and have managed to remain covert, which we aim to uncover in this article. (Yes, we are talking about Bruxism! We'll get to the relationship between Bruxism and Breathing Disorders in a bit, but let's first explore Bruxism itself!)
3. Exploring Bruxism
You already know what Bruxism is since we've already defined it in the intro, but we need to explore it a bit more so that we can get a clear insight into its relationship with Breathing Disorders (covered in the next section!).
Just to Recap: Bruxism is a condition in which a person unconsciously grinds, clenches, or bites their teeth, typically while sleeping. It can also occur while awake, but most people experience it while they are asleep, which is one of the reasons why it often remains undiagnosed and untreated.
Symptoms Of Bruxism
If Bruxism typically occurs while a person is asleep, then what makes the person aware that he's suffering from Bruxism? Well, Bruxism has a few very apparent symptoms, including:
● Worn tooth enamel - including shortening of teeth and holes in the enamel
● Increased tooth sensitivity - which is a direct consequence of worn tooth enamel
● Raw swollen feeling tongue and inner cheek.
● Jaw soreness/tightness/pain - caused by the continual use of jaw muscles during teeth-grinding
● Headaches - right after waking up
● Ear/facial pain
Probable Causes Of Bruxism
While it's difficult to pinpoint the exact cause of Bruxism in some cases, it's often associated with the following causes:
● Misaligned teeth - either by birth or after experiencing trauma
● Stress - physical as well as psychological stress
● Anxiety - it's one of the most common triggering factors for Bruxism
● Alcohol/caffeine addiction
● Lifestyle and habits
● Sleep disorders – any sleep disorder that leads to poor quality sleep can potentially lead to Bruxism
There’s one probable cause of Bruxism that we have deliberately not included in the list because we will dedicate the entire next section of our article to it. Yes, we are talking about Breathing Disorders! Read through the next section to discover the relationship between Bruxism and Breathing Disorders.
4. The Relationship Between Breathing Disorders And Bruxism
The relationship between Breathing Disorders and Bruxism has been the center of research for many researchers who aimed to pinpoint a direct link between these two conditions. Several studies have been carried out that have successfully uncovered a link between Breathing Disorders (especially Sleep Apnea) and Bruxism, but none of them have been able to claim definitively that one is the cause of the other. Let's discuss some studies connecting Sleep Apnea with Bruxism.
Research Linking Sleep Apnea And Bruxism And The Mechanisms Involved In The Interaction Between Them
Helena Martynowicz and others conducted research titled "The Relationship between Sleep Bruxism and Obstructive Sleep Apnea Based on Polysomnographic Findings," [1] published in 2019. It aimed to find the relationship between Obstructive Sleep Apnea and Sleep Bruxism using polysomnography (a multi-parameter study of sleep). The findings revealed that the relationship between these two conditions depends on the severity of Obstructive Sleep Apnea in the patients. In this study, the patients who were at an increased risk for Obstructive Sleep Apnea were found to have sleep Bruxism.
G J Lavigne et al's 2003 research titled "Neurobiological Mechanisms Involved In Sleep Bruxism" [2] also hinted at the probable relationship between Bruxism and Sleep Apnea. It explored a variety of neurobiological mechanisms underlying Bruxism, one of which was the muscle co-activation mechanism following a Sleep Apnea episode in apneic patients, which was very similar to what happens in Bruxism. They noted the co-activation of jaw opening, jaw closing, and other muscles that are associated with upper airway patency (which happens right after an episode of Sleep Apnea) as a mechanism that links Sleep Apnea with Bruxism.
Takafumi Kato’s 2004 review research article titled “Sleep Bruxism and its relation to Obstructive Sleep Apnea–Hypopnea syndrome” [3] explored the relationship between Bruxism and Sleep Apnea by presenting the physiological and clinical mechanisms relating Sleep Bruxism with Obstructive Sleep Apnea. One mechanism that is reviewed in detail in this study is the transient arousals during sleep in Bruxism patients, which are also observed in Obstructive Sleep Apnea patients (induced by abnormal respiratory events).
Rosana Cid-Verdejo et al performed a study in February 2024 titled “Is there an association between sleep Bruxism and Obstructive Sleep Apnea? A case-control polysomnographic investigation” [4], which explored the relationship between these two conditions using polysomnography type 1. It established a positive relationship between Bruxism and Obstructive Sleep Apnea. The study revealed that patients suffering from mild Obstructive Sleep Apnea had more intense and frequent Bruxism episodes than the ones who had moderate to severe Obstructive Sleep Apnea. The study also took into consideration the theory that Bruxism could be a protective response to upper airway obstruction observed in Sleep Apnea patients.
Ana González et al’s review research article titled “Sleep Apnea–Hypopnea Syndrome and Sleep Bruxism: A Systematic Review" [5] explored the relationship between Bruxism and Sleep Apnea at the pathophysiological level, along with the probable risk factors and signs/symptoms for both the conditions. It reviewed relevant literature from 2013 to 2021, reviewing a total of 9 articles relating to Bruxism and Sleep Apnea. According to this review, Bruxism and Sleep Apnea occur together in 21-41% of cases. It quoted Rhythmic Masticatory Muscle Activity (RMMA) as the most common sign/symptom between these two conditions. The shared risk factors between the two conditions, as explored in this review, included obesity, age, alcohol abuse, and smoking. Interestingly, this article proposes two possible mechanisms underlying the relationship between Bruxism and Sleep Apnea, which are discussed in the next section.
5. How Sleep Apnea And Bruxism Can Be Risk Factors For Each Other
At this point, it's clear that some link between Bruxism and Sleep Apnea exists. But you may be wondering: "Does Bruxism lead to Sleep Apnea, or is Sleep Apnea a contributing factor to Bruxism?" This is a good question! For your ease of understanding, we have extracted and sorted information (from research) on how Sleep Apnea and Bruxism can become possible risk factors for each other.
How Sleep Apnea May Lead To Bruxism
One hypothesis regarding Sleep Apnea being a risk factor for Bruxism is that when an apneic person's airway becomes blocked, the movement of their mouth muscles (Rhythmic Masticatory Muscle Activity or RMMA) helps to reopen the airway. This leads to teeth grinding (Bruxism). In this case, Bruxism actually acts as a protective mechanism against sleep apnea. The grinding of teeth is the body's protective response to shield it from the consequences of sleep apnea. While this hypothesis may not apply to all people with sleep apnea, it's definitely true for those patients who experience grinding teeth following an episode of interrupted breathing.
The second hypothesis also explains the reason for RMMA in apneic patients. According to this hypothesis, in apneic patients, the salivary flow is decreased during sleep, so the brain autonomically brings about RMMA as a means to lubricate the oropharyngeal structures. The lubrication brought about by RMMA helps restore the salivary flow and also increases their swallowing rate.
How Bruxism May Lead To Sleep Apnea
According to some hypotheses (although they are much less common than the one discussed above), Bruxism may lead to Sleep Apnea. These hypotheses talk about signals emerging from the nervous system that stimulate the muscles of the mouth and jaw and also affect the nasal passages and the heart rate. In simple words, electric signals that trigger teeth grinding in Bruxism patients also somehow constrict the airways of the patient, leading to congestion and interrupted breathing. This view is much less common than the one discussed above because only 25% of the patients who suffer from both Bruxism and Sleep Apnea experience teeth-grinding episodes "before" experiencing disturbed breathing associated with Sleep Apnea.
6. Shared Risk Factors And Co-occurrences
We have considered numerous possible links and relationships between Bruxism and Breathing Disorders (specifically Sleep Apnea). We have seen the possible underlying mechanisms relating one condition to the other, and the ways one condition can be a risk factor for the other.
At this point, it's plausible to note that research has only been able to "hypothesize" the relationship between the two conditions and that no "definitive" causal relationship between them has been documented. According to expert researchers, the relationship between Bruxism and Sleep Apnea is not a one-dimensional relationship; it's a multidimensional relationship with a lot of complexities. Both of these conditions may manifest in unpredictable intensities in different patients.
Shared Risk Factors
Sleep Apnea is not just related to a person's respiratory system; it involves the cardiovascular and nervous systems, too, all at the same time. Similarly, there could be many causes for Bruxism, including lifestyle and medical risk factors. Keeping in mind the multifaceted nature of these conditions, it's important to consider the possibility that both Bruxism and Sleep Apnea may be correlated, but they both do seem to arise from another independent cause (or causes) or shared risk factors. Some shared risk factors for these conditions include:
● Genetics
● Abnormalities in neurotransmitter (serotonin and dopamine) pathways
● Obesity
● Aging
● Sleeping positions
● Stress
● Anxiety
● Abnormal anatomy of the airway
● Others
Co-occurrences
Just as it's common for Bruxism and Sleep Apnea to co-occur, it's possible for both of these conditions to co-occur with other conditions, too, besides each other. The most common co-occurring conditions in people having both Bruxism and Sleep Apnea include:
● Anxiety Disorders - Most commonly GAD and panic disorder, which may exacerbate the symptoms of Bruxism and Sleep Apnea.
● Gastroesophageal reflux disease (GERD) - Which often occurs during Sleep Apnea episodes and may also lead to teeth erosion, thereby also contributing to Bruxism.
● Obesity - Being overweight increases the likelihood of airway obstruction during Sleep Apnea episodes, which further increases the chances of teeth clenching.
● Chronic pain condition - Most commonly fibromyalgia, a condition in which widespread pain may cause disturbance in sleep pattern, contributing to Sleep Apnea.
● Heart diseases - Such as coronary artery disease, hypertension, and stroke.
7. Clinical Perspectives And Diagnosis
Bruxism and Sleep Apnea, though they are both commonly occurring conditions, are often difficult to diagnose and treat. Let's have a look at how and why both of these conditions may go undiagnosed (and therefore untreated) in a large number of cases.
Challenges In Diagnosing And Treating Both Conditions
There are a lot of reasons which make Bruxism and Sleep Apnea difficult to diagnose and treat. One of the reasons is the subjective nature of symptoms in each patient and the overlap of symptoms between both conditions. For example, some patients may present with symptoms like headache, fatigue, jaw pain, irritability, etc., all of which are also characteristic symptoms of other diseases. This makes it difficult to pinpoint the exact cause of the symptoms, thereby causing difficulty in diagnosis and treatment. Secondly, the nocturnal nature (i.e., occurring during sleep) of both conditions presents another challenge in its diagnosis and treatment since nobody would be able to identify the symptoms without the presence of a sleeping partner or some type of monitoring source. Thirdly, as we've discussed in the above section, the co-occurrence of these conditions with other medical/psychological conditions further complicates and confounds its diagnosis. Fourthly, a proper diagnosis of these conditions requires the administration of specialized tests (like polysomnography and electromyography), which are not readily accessible to most patients.
Importance Of Interdisciplinary Collaboration
Having seen the complicated nature of Bruxism and Sleep Apnea and the difficulties in their diagnosis and treatment, it's important that doctors take an interdisciplinary approach to tackling them. Interdisciplinary collaboration would allow for a comprehensive assessment of the conditions, thereby encouraging holistic treatment. This will bring about optimized treatment outcomes for the patients and will lead to long-term comfort and quality of life for the patients.
8. Management And Treatment Approaches
There are different lifestyle modifications and behavioral therapies that have resulted in the successful management of Sleep Apnea and Bruxism symptoms. Let's discuss both of them separately.
Lifestyle Modifications And Behavioral Therapies
For Sleep Apnea, they include:
● Weight loss
● Alteration of sleep positions
● Reducing, if not elimination of alcohol or drug use, if any.
● Quitting smoking or drug use, if any.
● Maintaining a healthy sleep schedule
For Bruxism, they include:
● Stress management
● Jaw exercises
● Reducing, if not elimination of triggering substances (especially caffeine and alcohol)
● Wearing customized mouthguards/splints
● Practicing good sleep habits
● Undergoing cognitive behavioral therapy (CBT)
Medical Interventions
Doctors may prescribe different medications for the alleviation of Sleep Apnea and Bruxism symptoms, especially in patients who suffer from uncontrollable pain that may interfere with their daily functioning. For example, many Bruxism patients suffer from agonizing jaw pain and mouth soreness, which makes them unable to carry on with their daily life tasks normally. In such cases, doctors may prescribe painkillers to alleviate the pain. Similarly, the fatigue and daytime irritability brought about by sleep apnea may also need medical intervention for successful management.
Conclusion
Breathing Disorders (particularly Sleep Apnea) and Bruxism may have a direct connection in patients in which both conditions co-occur, if not coexist. Understanding the intricacies of these conditions (such as their symptoms, risk factors, and underlying neurobiological and physiological mechanisms) may help patients gain a deeper insight into the relationship between these conditions. This will ultimately lead to their successful diagnosis and treatment.
References:
Martynowicz H, Gac P, Brzecka A, Poreba R, Wojakowska A, Mazur G, Smardz J, Wieckiewicz M. The Relationship between Sleep Bruxism and Obstructive Sleep Apnea Based on Polysomnographic Findings. J Clin Med. 2019 Oct 11;8(10):1653. doi: 10.3390/jcm8101653. PMID: 31614526; PMCID: PMC6832407.
Lavigne GJ, Kato T, Kolta A, Sessle BJ. Neurobiological mechanisms involved in sleep bruxism. Crit Rev Oral Biol Med. 2003;14(1):30-46. doi: 10.1177/154411130301400104. PMID: 12764018.
KATO, T. (2004), Sleep bruxism and its relation to obstructive sleep apnea–hypopnea syndrome. Sleep and Biological Rhythms, 2: 1-15.
Cid-Verdejo R, Domínguez Gordillo AA, Hallal-Peche F, Ardizone García I, Martínez Orozco FJ. Is there an association between sleep bruxism and obstructive sleep apnea? A case-control polysomnographic investigation. Sleep Med. 2024 Feb;114:1-7. doi: 10.1016/j.sleep.2023.12.006. Epub 2023 Dec 16. PMID: 38141521.
González González A, Montero J, Gómez Polo C. Sleep Apnea-Hypopnea Syndrome and Sleep Bruxism: A Systematic Review. J Clin Med. 2023 Jan 23;12(3):910. doi: 10.3390/jcm12030910. PMID: 36769558; PMCID: PMC9918154.
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