What is TMD, TMJ, how common is it and why is it associated with headache and migraine:
Dr. Paul Mathew is a headache specialist and fellow of the American Headache Society. He’s also an Assistant Professor of Neurology at Harvard Medical School, where he serves as the Director and Founder of the Advanced Neurology Clerkship.
- 1 Transcript
- 2 How Many People Clench Excessively?
- 3 Symptoms Of Clenching & Grinding (Bruxism)
- 4 What’s The Difference Between Grinding, TMJ And TMD?
- 5 How many people have TMD?
- 6 What causes clenching or grinding?
- 7 How To Treat Clenching And Grinding?
- 8 Conclusion
Click here to view video transcript
Dr. Mathew: First, we have to start with the terminology. TMJ, 100% of people have TMJ because TMJ stands for temporomandibular joint, and all of us have a jaw joint. The term that they probably mean is TMD, Temporomandibular Disorder. Probably one of the more prevalent studies conducted in the UK showed that 26% of people complain of some form of oral facial pain. Six percent of people actually complain of temporomandibular disorders. It is quite prevalent. It is more common in women, 1.7 times more common in women than men. It tends to affect people in the 18-45 range, so it’s a really large age range of people that are affected by this disorder.
Many people have stiffness, tightness in this area, even a little bit of pain and don’t even know why they have that problem. The reason is many of them will clench or grind in their sleep. The temporomandibular joint is a very complex joint; there’re many muscles that actually work in order for you to open and close your jaw, and people take it for granted, because of its complexity. It allows you to phonate and make different sounds, to chew, to do all these different things. In the joint, are multiple tendons, so tendons are things that connect the muscle to bone and ligaments are things that connect bone to bone. There’s a lot of tendons, cartilage and things that are in the joint, that kind of work in orchestra to do those functions of the jaw.
TMD tends to occur more often in people with migraine, tension-type headache, as well as chronic daily headache, which is why it’s really important for headache specialists to be aware of TMD and how common it is.
Carl Cincinnato: Why is there an association with headache and migraine?
Dr. Mathew: My belief, and the belief of many headache experts, is that any type of stress, whether it’s emotional or physical, can actually contribute as a trigger to developing migraine or other headache disorders. If you’re constantly clenching and have this tightness, no muscle acts by itself in a silo. When you have dysfunction of one muscle group, some of the adjacent muscle groups will also kind of take on some of that tension and stress and will also malfunction, causing pain and tightness and things like that. Interestingly enough, the temporalis muscle, which is this muscle up here [pointing to temple], it’s kind of broken down functionally into two segments. There’s the anterior temporalis, which tends to help close the jaw, but also brings it forward, and then there’s the middle and the posterior, which actually does the final elements of closing and brings the jaw back a little bit.
People that work at a desk are constantly in this kind of a position, and in that kind of situation [crouching over a computer screen with poor posture], the TMD would more likely affect the anterior section. People that grind and clench in their sleep, gravity is affecting it, and they’re more likely to have problems in the middle and the posterior section.
People who grind their teeth are three times more likely to experience headache according to the Bruxism Association in the UK. Most of the population will grind their teeth some point in their lifetime.
Clenching and grinding occur naturally when eating but some people may also clench or grind involuntarily and excessively throughout the day or night.
Teeth are not designed to be in constant contact. They can briefly touch when you swallow or chew but if they are in contact too often it can wear down tooth enamel. Enamel is the outer part of the tooth which protects the inner structure. The risk of tooth decay increases without the protection of the enamel.
How Many People Clench Excessively?
During the day, 20% of the general population report awareness of clenching their teeth. The same study also found that this was more common in females. [iii]
Teeth clenching occurs when the bottom and top teeth clamp together. Grinding occurs when the teeth move horizontally or back-and forth whilst the teeth are clenched. Bruxism is the medical name given to either clenching or grinding during the day or night.
Bruxism tends to decrease with age. Prevalence peaks in childhood and reaches it’s lowest rates in those over 65 years old.
Symptoms Of Clenching & Grinding (Bruxism)
Signs you may have bruxism include:
It’s easy to understand how the jaw might lead to headache and migraine when you to see how far reaching the jaw muscles stretch.
- Headaches, earaches, migraine, sinus pain: Headache around the temples or even an earache can be a sign of excessive clenching or grinding especially in the morning. In those susceptible, migraine can result from a recent bruxism episode.
- Tender jaw or facial muscles or joints: Soreness, tenderness and fatigue can be caused in the muscles and joints around the jaw and face.
- Stiff neck: Muscles around the jaw from clenching and grinding affect muscles in the surrounding areas including the neck. A stiff neck may not be an obvious sign of clenching or grinding but it is one to look out for, especially if other symptoms are present.
The muscles in the jaw affect many other MUSCLEs around the head and neck.
Dental wear: Chipped, cracked, sensitive and even lose teeth are not uncommon from the wear and tear that excessive clenching and grinding can cause. Extreme pressure can be exerted whilst clenching and grinding teeth, particularly at night when you are not consciously able to control the force of clenching or grinding. Teeth can also be worn down and shortened if left untreated.
Enlarged jaw muscles: The act of clenching and grinding can be so strenuous over time that the patient may notice enlarged or overdeveloped jaw muscles.
Reduced oral function: In severe cases bruxism can compromise basic oral functions such as chewing, speaking and swallowing. [iv]
Your partner tells you: Most people aren’t aware that they themselves are clenching or grinding – it’s often your bed partner who hears you grinding at night or the dentist who can see the visible signs of excessive clenching or grinding.
Bruxism is typically diagnosed by a dentist after a clinical evaluation. Other physicians who might diagnose bruxism are a maxillofacial surgeon or sleep specialist. An overnight sleep study may also be warranted if there is the suspicion that a sleep disorder is involved.
What’s The Difference Between Grinding, TMJ And TMD?
TMJ refers to the temporomandibular joint which connects the jaw to the skull. TMD is a disorder of the temporomandibular joint which can lead to pain and discomfort. TMD is simply an abbreviation for the temporomandibular joint dysfunction (TMD). TMD may be treated with surgery.
The Temporomandibular Joint (TMJ)
TMD will often share the same symptoms as bruxism, however, a clicking sound when the jaw opens or closes is often characteristic of TMJ.
Teeth grinding doesn’t typically affect the temporomandibular joint. In severe and long term cases clenching or grinding may lead to TMD as the joint is worn down.[v]
How many people have TMD?
TMD is quite common but in the vast majority of cases symptoms and clinical issues are mild. Only 4-7% of the population will have any symptoms of sufficient severity to warrant medical advice. [xix]
What causes clenching or grinding?
During the day, bruxism is typically seen as a jaw clenching habit in response to stress and anxiety. [vi]
At night whilst sleeping there could be many different or multiple causes:
- Intense concentration: The American Academy of Oral Medicine suggests that concentration itself is sufficient to trigger bruxism.
- Stress, Anger or Anxiety: Emotional stress is believed to be a common trigger for grinding or clenching teeth. This may lead to bruxism during the day and/or at night.
- Allergies or blocked nose: Not being able to breathe through your nose due to allergies or being in a stuffy or dry room may contribute to more mouth breathing, which triggers the autonomic nervous system when sleeping. When this is switched on muscle activity is out of your control and bruxism may be more likely to occur.
- Smoking: Bruxism is twice as common in smokers than non-smokers. [v]
- Excessive Alcohol or Caffeine: These can reduce the quality of your sleep, overstimulate and cause or exacerbate bruxism.
- Illness: Physical stress or illness, poor nutrition may also be a contributing cause.
- Dehydration: Insufficient fluids throughout the day may worsen bruxism.
- Sleep Disorders: Sleep bruxism is considered a type of sleep disorder. It can also be caused by other sleep disorders such as sleep apnea and snoring. When the body approaches deep sleep, muscles are required to fully relax. This can cause problems in some cases for the airways. The tongue when fully relaxed expands significantly. Another potential airway impediment is the relaxed jaw.
- According to Dr Mark Burhenne, researchers discovered those with a partial blockage in their airways would grind or clench to re-open the airway in their sleep. Once the patients were able to keep their airways open all night the grinding stopped.[xx]
- Airway obstruction could be a root cause of sleep bruxism. A sleep study might be warranted for some patients. If you have sleep apnea, a night guard could be making both the sleep apnea and bruxism worse.
- Teeth misalignment: a poor bite or malocclusion has historically been thought to play a role in bruxism but a number of studies have failed to demonstrate the link. That said, poorly designed filings that sit too high may also cause grinding.
- Genetic factors: If family members clench or grind then you are more prone to develop the habit as well. [vii]
- Having a long neck: This increases the chances of sleep apnea which also corresponds with a greater likelihood of bruxism.
- Medications: Bruxism can be a side effect of some medications. The most common types of medications listing bruxism as a potential side effect are the second generation antidepressants (including SSRIs and SNRIs) and antipsychotics. [viii]
- It’s a symptom of another condition: in some instances bruxism has been associated with other neurological disorders. Drug resistant Temporal Lobe Epilepsy, Dystonia, Alzheimers, Stroke, Tramautic Brain Injury and Huntington’s disease have associations with bruxism. [viii]
How To Treat Clenching And Grinding?
Studies have acknowledged that treating daytime bruxism is challenging due to increased levels of anxiety and somatic symptoms reported in these patients. [viii]
Somatic symptoms refer to psychological distress of some kind expressing itself as physical symptoms in the body. Despite the absence of a physical cause, somatic symptoms such as pain, nausea, and clenching are real, not imagined.
Most people will experience somatic symptoms at some point. For example, a nervous public speaker may feel nauseous and even vomit from the fear of speaking in front of a large audience.
Few high quality studies have been conducted to evaluate treatments directed at clenching or grinding during the day.
Without evidence-based treatments for daytime bruxism only general suggestions can be made cautiously, which are listed below. There have been several randomized control trials evaluating the treatment of sleep bruxism. Evidence supporting the treatment is mentioned where available:
1) Good sleep hygiene: treating clenching and grinding at night often begins with practicing good sleep hygiene. (6) This includes restricting caffeine, smoking and drinking alcohol at night. Limiting physical and mental activity before going to bed and ensuring optimal sleeping conditions in the bedroom can also assist. The bedroom should be dark and quiet. A TV in the bedroom is not helpful for sleep quality.
- One randomized controlled trial evaluated the effect of 4 weeks of sleep hygiene with relaxation techniques for sleep bruxism but failed to find significant changes. [ix] Despite this result, practicing good sleep hygiene is a good idea. Alcohol, tobacco and coffee consumption before bed are known risk factors for sleep clenching or grinding. [x] Sensitivity to stress is also commonly reported in patients. [xi]
2) Mouth guard: Also known as a night guard or occlusal splint, these devices are considered to be the first line of defence for preventing further tooth wear and grinding noises at night.
- A mouth card is one of the best treatments available to help relieve the strain from strenuous jaw clenching and grinding. It helps prevent sore jaw muscles and joints.
- It does not have any lasting effects on reducing the frequency of clenching throughout the night, only the severity. [viii]
- In rare cases, occlusal splints may interfere with breathing airways during sleep in those with obstructive sleep apnea (OSA). If you have OSA, then special care is required when the splint is devised. [xii] Those with OSA may benefit from a mandibular advancement device which can help with both OSA and bruxism.
3) Mandibular advancement devices: These devices are typically used for the management of sleep apnea and snoring. Like the night guard these devices are inserted into the mouth at night to wear whilst sleeping. The mandibular advancement device brings forward (or advances) the lower jaw (mandible) by around 8 to 10mm. This helps keep the airways open.
- The Bruxism Association of the UK indicates that these devices have often shown more positive results for bruxism but with the cost of some discomfort whilst wearing the device.
4) Stress management: Two commonly suggested techniques for stress management are Cognitive Behavioral Therapy (CBT) and Biofeedback. Whilst these have been reported as helpful for stress management, initial studies of CBT and Biofeedback for bruxism did not correlate with any improvements on their own. Practitioners suggest the use of stress management alongside other strategies to reduce the frequency and severity of bruxism.
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5) Regular Exercise: Exercise has been proven to help better manage stress. It releases endorphins, it can relieve minor aches and pains, and it provides a sense of well being. This may assist those with bruxism.
6) Behavior Therapy: Bruxism, particularly daytime bruxism is a habit that we can slip into subconsciously over time. By the time we become aware of it, we may have already become deeply rooted in our behavior. Behavioral modification and habit reversal may offer helpful techniques to break the stubborn habit. In more difficult cases psychological counseling may be required.
7) Botox: Recent studies have reviewed Botox as a treatment option for bruxism. Results indicated that the force and strength of the activity were reduced significantly but no change in frequency was found. [xiii] In addition, it is expected that as the effect wears off from Botox around the 12-week point the force of the clenching and grinding return.
8) Electrical stimulation: Like Botox, Contingent Electrical Stimulation has been trialed with bruxism. Results from two experimental studies found a reduction in the frequency of bruxism during sleep but with no change in pain or muscle tension. This suggests that whilst the frequency is reduced the severity and force of clenching and grinding is not. Another study confirmed this result as well as finding that the benefits were realized only whilst the device was being used. Results did not continue after the device was stopped. [xi]
9) Hypnosis: This is one alternative approach which has been suggested by some dental organizations although it lacks clinical evidence.
10) Physical therapy: may be used to relieve some of the tension and stiffness caused by excessive use of the jaw muscles.
11) Meditation: This and other relaxation techniques can produce a greater sense of self-esteem; help manage anxiety, stress, and control over one’s body. There is no strong evidence in the literature regarding its efficacy. Its use may be more beneficial to those with stress or anxiety-related causes.
12) Muscle relaxants: These may be suggested by the physician to use modestly for a short period. Caution should be exercised so as not to develop any dependencies or damage internal organs from excessive use.
13) Medications: The drugs investigated for sleep bruxism were found in small and often experimental studies with short treatment periods. Caution should be exercised when interpreting these results. Due to a lack of quality of evidence, none of the below are recommended as standard treatments.
- Despite its seemingly positive initial findings, Levodopa is not considered a treatment. There is not enough reliable evidence, and an unknown clinical relevance and lack of further research supporting its use. [xiv]
- Clonidine was found to have significant side effects which included morning hypotension, REM sleep suppression and dry mouth. [xv] An independent Cochrane review of Clonidine found no significant reductions in frequency of bruxism when compared to placebo. [xvi]
- The study on Clonazepam was a small (n=10) single blind non randomized trial. Therefore the results cannot be drawn as conclusive. High quality, double blind, randomized control trials are required with larger sample sizes and longer durations are needed. [xvii]
14) Magnesium: A deficiency in magnesium can result in anxiety, irritability, insomnia, restlessness, and hyperactivity. A regular dose of a high quality chelated form magnesium may assist these symptoms and potentially reduce clenching or grinding activity.
15) Vitamin C: Stress management is a key component for many with bruxism. Vitamin C may complement stress management efforts by supporting our adrenal glands which affect stress responses. Vitamin C is also essential to make dopamine which is used to regulate mood and help prevent illness. Illness is another potential trigger of bruxism so this may have some synergy in prevention.
16) B-Complex vitamins: Deficiency in B-vitamins can lead to psychological stress, depression, and anxiety. The efficacy of a B-complex has been demonstrated in overall health and wellness. Beginning the day in a balanced state of mind sets you up for success.
17) Valerian root: This has been used for centuries as a natural sedative. It has anti-anxiety properties and has been shown to improve quality of sleep without side effects. [xviii] Since bruxism is considered a sleep-related movement disorder, Valerian root may be beneficial.
There is weak evidence from studies supporting the above medications and vitamins. They may be helpful but randomized clinical trials are required to establish their true efficacy in treating bruxism. Without these studies only tentative suggestions can be made based on hypothesis.
This article was written because clenching has become one of the most significant contributors to my own migraine condition. I’ve had countless headaches and several migraine attacks from clenching during the day and probably more that I’m not aware of from the night before.
I’m disappointed to say that there is no single successful treatment that addresses the root cause of clenching or grinding. Therefore the first clinical focus of bruxism is often to prevent further dental wear, grinding noise and relieve any muscular and joint discomforts or dysfunction.
One of the best ways to do this and protect your teeth is with a custom made night guard (occlusal splint) of some kind. This also helps relieve the extreme pressure on your teeth as well as the fatigue and soreness in your muscles and joints. I have found it very helpful.
With the urgent symptoms covered, you can then begin working on the root cause.
The best treatment strategy will be those which best address your potential causes.
Could it be due to a sleep disorder, stress, anxiety or lifestyle factors or all of the above? I’m still working it out personally. Are you aware of clenching or grinding? I’d love to hear from you in the comments.
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