Does Your Jaw Click? TMJ Disorders

One of the more common findings upon clinical exam, or even while taking a client's history, is TMJ. They often don't report it when I ask about prior diagnosis because this is their normal, every day issue, and they feel there is little to nothing to do about it. Accept and move on.

Every now and then, I'll have a chiropractic client find relief, yet not often. Other times my client may have seen a craniosacral therapist or a dentist who has provided them a mouth guard, but again, not any real relief that is long lasting. Because this seems to be on every exam this week, I thought I would offer some of my thoughts. However, first, let me discuss #TMJ for those who are yet unfamiliar.

Common temporomandibular disorders (TMJ) symptoms include pain in the area of the jaw joint or limited jaw movement, especially with clicking and locking. There may also be pain in the ear or masticatory muscle particularly while chewing. There are some conditions which mimic TMJ symptoms though, but more often the occasional click or pop happens and like a sprained ankle, this self-resolves without treatment. For others this severely affects their lives and is chronic.

The jaw is one of the more complex joints and the least understood in medical literature. It is critical for talking, eating, breathing, smiling, and even kissing. Some people have rather severe pain, while others have no pain but do have limitations in their jaw movement.

Like many aspects of healthcare, we are learning that TMJ is not just about the jaw. The underlying cause may be neurological, immunological, digestive, related to the respiratory system or endocrine system, or musculoskeletal. Either way, it does seem to be related to chronic systemic inflammation and possible autoimmunity.

Other health concerns that seem to be common when TMJ is present are back, neck and joint pain. Chronic #headaches, chronic fatigue syndrome, Ehlers-Danlos Syndrome, endometriosis, #fibromyalgia, interstitial cystitis, irritable bowel syndrome, heart disease, juvenile idiopathic arthritis and Rheumatoid arthritis in other joints, Sjogren's syndrome, sleep disorders, #tinnitus, vertigo, and vulvodynia are also common to both TMJ and functional medicine practices. Interestingly, all of these health conditions are much more common to women particularly when childbearing, and vary throughout their menstrual cycle which suggests association with #estrogen.

Research Available is Inadequate

TMJ is not just an isolated dental condition that only impacts your jaw and teeth, although there is evidence of chronic inflammation. It isn't even an issue that can or should only be treated by #dentists. The reality is that there is very little really well done research studies on TMJ and the condition itself is just not really well understood. Providers as well, don't have good education or training on the topic. The treatments often offered clients today are not proven to be safe or effective. We're largely guessing to be quite frank.

The National Academy of Medicine undertook its first study of temporomandibular disorders in 2019 which resulted in a landmark report, published in March of 2020. It examined the entire continuum of TMJ disorders with regards to research, education and training, diagnosis and assessment, clinical management and treatment, comorbidities, treatment efficacy, models of care, insurance practices, clinical translation and other issues. Some of the major findings include the profound neglect of healthcare towards this issue, but also that a systems approach is vital for full recovery.

Grinding of Teeth: Bruxism

This is often diagnosed by the dentist and more often a splint or removable appliance similar to a mouthguard is provided to the client. This is thought to ease pain in the mouth, face, and jaw. Sometimes these are provided as well to minimize headaches, clicking jaws, or to reduce wear on the teeth. A large review of the evidence has demonstrated that there is no evidence these splits reduce pain when compared to not wearing a splint or when compared with minimal treatment, such as jaw exercise, advice, or education. These may not be worth the money. (However, there is some evidence that the NTI-tss splint is beneficial).

Nearly 20 percent of adults suffer from repetitive clenching or grinding of the teeth though so this is no small issue. Interestingly, definitive studies have shown us that TMJ is not about teeth grinding as many are led to believe. Many people grind their teeth at night, but that activity cannot account for your pain. If anything, people who suffer from the most severe TMJ pain are actually the least likely to grind their teeth at night (Raphael, Sirois, Janal, Wiegren, Dubrovsky, Nemelivsky, Klausner, Krieger, & Lavigne, 2012).

Bruxism can cause enlargement of the jaw muscle, tooth wear and cracks, even fractures of the tooth, as well as pain in the teeth and surrounding musculature. Interestingly some medications can cause bruxism, such as commonly used #antidepressants, specifically SSRIs and antipsychotics. More commonly this is reported with fluoxetine, venlafaxine and sertraline. This tends to occur about three or four weeks into treatment, but can happen as soon as a few doses. It does seem to be dose-dependent as well, and usually takes about three to four weeks to resolve following discontinuation of the medication. Antipsychotics in particular are associated with bruxism because they inhibit dopamine receptors.

Teeth grinding isn't the only effect of these medications though. Some individuals suffer from tardive dyskinesia which presents as lip-smacking, grimacing, rapid eye blinking and dyskinetic tongue movements such as protruding the tongue and tongue rolling. It amazes me how infrequently this is brought up in consults with clients, as if they simply accept these behaviors or believe this is just who they are, and clinicians don't ask if clients don't share concern. I suppose it is assumed both are aware so no need to mention it. However, maybe a bit too curious for comfort, it seems every time I ask for more clarity on these observations myself, clients often share relief, thanking me for even asking and nearly begging me for some sort of understanding and remedy. Many times though, this is the result of long term treatment with #antipsychotic medications.

Not just depressed clients take these medications though as the clinical indication for many antidepressants and antipsychotics now includes anxiety, mania, behavioral disturbances of dementia and autism. It is my thought that we will see more and more of these behaviors into the future as more medications are prescribed, and in a wider patient age range. Either way, this issue is one often overlooked.

In my own practice, asking about teeth grinding is a normal part of my history because when clients have gut issues, they often have teeth grinding or at least they report that their "dentist told me I did" and I've started to find this associated with #parasite activity. Anecdotal for sure, but intriguing nonetheless. When parasites are most active, in the dark and during the full moon, this grinding seems to be most intense, so for now, this finding causes me to dig deeper into investigating gut health and detoxification pathways. A higher body burden of toxins will welcome parasites as they attempt to reduce our overall burden in a symbiotic relationship, yet where toxins are abundant that symbiotic relationship can go awry.

Dental Visits

It is not uncommon for patients to experience pain in their TMJ following routine dental visits. Treatments such as removing dental caries, crown procedures, root canal therapy, tooth extractions, and other orthodontic procedures sometimes require the individual's mouth to be open for extended periods of time, which can result in inflammation and pain in the TMJ and associated muscles which can result in inflammation and last for days. This may feel dull or even sharp, but it usually subsides. For some though it is prolonged and quite severe.

Personally, I've had a lot of dental work - hindsight is 20/20, right? A root canal was poorly done which resulted infection and lasted seemingly forever, which made treatments far more challenging. I was left in those mouth widening apparatuses for sometimes hours. After one of those events many years ago now, if I open my jaw too widely, while I don't feel a click or pop and have never experienced this with chewing, my jaw will lock up in a cramp. It's quite painful.

There are a number of journal articles now which relate TMJ to having the mouth extended open wide for longer periods of time, primarily while at the dentist's office, as this leads to activation and prolonged sensitization of the #trigeminal system. This has also been known to happen with those who are intubated for surgery or for life-support.

Tight Frenulum

Structurally though, I have had several clients share a history of TMJ and on further evaluation there was evidence of a tight #frenulum or tongue tie. While this isn't even the slightest bit enjoyable in a newborn or wee little one, in an adult, I can better numb them and then suture the mucosa so healing is much less uncomfortable, but the impact is immediate. In fact, if I am being honest, one of the first frenectomies I performed in an adult, I had asked permission to record to share for learning purposes, but when I did the release her shoulders dropped so dramatically and the relief came over her face so profoundly, that I slipped an almost-curse word and made the video a bit too candid to share more widely. Trust me though, this is one procedure I've never had anything other than great reviews and now evaluate the frenulum when clients complain of headaches, #migraines, or jaw and neck pain.

Estrogen & Temporomandibular Joint Pain

One notable feature of TMJ pain is its increased prevalence among women. Why? No one is quite sure, as we aren't even confident why TMJ occurs, but the leading theories relate to a range of genetic, psychological, and biological factors. Estrogen is one of those key biological factors and its role is thought to be in how it impacts the trigeminal pain control system.

TMJ occurs most frequently during the reproductive years and decreases after #menopause and because postmenopausal women given #estrogen have a great incidence of TMJ than those without replacement therapy. Moreover, the menstrual cycle seems to worsen pain from TMJ. Its severity in many women has its peak during the phase of rapid estrogen fluctuations, and women utilizing hormonal contraceptives have a higher risk of TMJ. Polymorphisms of the gene for the estrogen receptor are associated with a greater susceptibility toward developing TMJ.

The ESR1 gene is responsible for encoding the estrogen receptor alpha, which regulates numerous physiological activities such as cell growth, reproduction, differentiation, and development. This also acts as a regulator of cartilage tissue and in mandibular condylar fibrocartilage.

Cytokines, Chemokines, Autoantibodies & Nonspecific Inflammatory Markers

The autoimmune and inflammatory association does seem significant within the literature. One study found the level of IL-8 and IgG were significantly higher in high pain groups who suffered with TMJ and IL-2, IL-8, IL-13, IFN-y, RANTES, PGE2, and thrombopoietin levels showed a significant effect on indices reflecting jaw function, generalized pain intensity, and health related quality of life.

These results imply that longer pain duration and higher pain intensity is associated with higher levels of systemic inflammation suggesting the possible role of immunologic disturbance as an underlying factor of chronic TMJ pain and warranting further investigation for its consideration in diagnosis and treatment.

Genetic Vulnerability

Unlike monogenic diseases, as in the case of family hemiplegic migraine in which there is only a gene responsible for disease, TMJ is a complex disorder whose inheritance cannot be explained by the simple genetic segregation of a single gene and therefore it is not trivial to identify the associated genetic cause. Rather, there is more a network of genes (112 known associations known to date) that interplay with each other, plus environmental effects, which ultimately result in the phenotype of the disease.

Estrogen epigenetics (ESR1 gene) were touched on just a bit above, and here is where we have the most robust findings, but the polymorphism catechol-O-methyltrasferase (COMT) needs attention as all studies have concluded there is significant impact on the occurrence of the disease. This gene encodes an enzyme present in the metabolic degradation of numerous neurotransmitters, such as dopamine, norepinephrine, or epinephrine; hence, why COMT is also associated with anxiety. COMT is a primarily studied gene alongside the literature, considered as a potential genetic determinant in chronic pain syndromes. Distinct polymorphisms determine COMT activity, but the most investigated one is definitely the rs4680.

MTHFR gene encodes an enzyme crucial for homocysteine metabolism, necessary in the processing of vitamin B1, B6, B12, and folate. Some studies have found that vitamin supplementation (folate, vitamin B6 and B12), decreasing homocysteine concentrations, improves migraine frequencies and many other concerns. Nutritional deficiencies of these vitamins can induce myofascial dysfunction and pain, and these efficiencies are relatively common in cases of TMJ mechanical stress. Although, for lack of solid evidence, there doesn't seem to be a lot of impact of the methylenetetrahydrofolate reductase (MTHFR gene) regulation on TMJ.

The FTO gene has been reported as an obesity-associated gene and is also considered a risk gene for osteoarthritis (OA). Studies are starting to see association between the occurrence of TMJ and the CC allele of rs8044769 in the FTO gene.

There is also some evidence to suggest involvement of the GA genotype of the -308G/A tumor necrosis factor alpha (TNF-a) and the AA genotype of the -1082A/G IL-10 polymorphisms in the pathogenesis of chronic temporomandibular disorder pain. The majority of TMJ patients show elevated TNF-a levels and a possible explanation for this could be the presence of the -308/A polymorphism.

Tumor necrosis factor alpha is an important proinflammatory cytokine that contributes considerably to inflammation and immune response. Only a few studies have evaluated the presence of interleukins and genetic #polymorphisms in TMD patients, but they have provided important results regarding the role of tumor necrosis factor. This has pointed to the possibility of the inclusion of this immune-inflammatory marker of immunity in the evaluation of TMD, as well as in the development of a more selective treatment based on monoclonal antibodies.

As of today, this hasn't really offered a great solution for therapy, but has identified innovative approaches that may be considered in future research, even potentially new medication development that are not exclusively pain relievers. Genetic polymorphisms can provide relevant information about an individual’s health status, the risk of development of TMD or its severity, and specific treatment options. We do know that TNF-a inhibitors reduce the risk of joint damage, improve physical function, and consequently, the quality of life of patients with rheumatoid arthritis, an autoimmune disease that causes chronic pain and joint pain, including TMJ. For now, the TNF-a levels and analyzing for these polymorphisms can be utilized as an inflammatory marker so more targeted treatment protocols could be implemented.

Psychological Factors & Chronic Pain

We know well that there are associations between TMJ pain and several psychological issues such as anxiety, depression, and somatisation and even social concerns, such as quality of life. This isn't really an ancillary finding, as these issues have great impact on one's vulnerability in transitioning from acute to chronic TMJ pain as well as treatment outcomes.

When clients have lower mood or a high tendency to worry, they have a higher predisposition to developing chronic pain, or even a tendency to be hypervigilant, brace their facial muscles and joints, or when really exaggerated, this can be part of a learned coping mechanism or a learned behavior for playing the sick role.

Pain of the orofacial region is debilitation and can arise from various structures innervated by the cranial nerves in particular the trigeminal nerve. Majority of the orofacial structures transmit impulses through trigeminal pathways to the brain where pain is perceived as a subjective sensation by the dynamic interaction of cognitive, affective, and sensory elements. In clinical settings, pain conditions are characterized as either acute or chronic, and chronic is typically defined as persistent pain beyond when normal healing typically occurs or sometimes for practicability, a duration exceeding 3 months.

Acute pain is an adaptive, self-limited involving activation of nociceptors and chemical mediators with clearly defined causes. It may be very intense, often accompanied by anxiety and restlessness but the cause-and-effect relationship is usually apparent and treatment measures are usually effective. Chronic pain is persistent and resistant to treatment measures because of neuroplastic changes in the structures of central and peripheral nervous system. Interestingly, chronic TMJ is often associated with comobidities such as headaches, fibromyalgia, neck and back pain, depression, and pain catastrophe and other visceral comorbid conditions such as irritable bowel syndrome and pelvic pain.

What's a TMJ Suffer to Do?

My advice is to find a practitioner who is aware of the complexity of this complaint. A thorough evaluation is necessary for proper diagnosis, but then a genuine curiosity for the underlying cause is vital. Currently, there are very few dental experts who are trained to precisely diagnose and treat this complex disorder, although most will tell you this is simple (as will chiropractors) which should be a red flag for not having a full understanding of this disorder.

Treatment is often very broad and general, often including medications such as NSAIDs and muscle relaxants, although sometimes antidepressants. Physiotherapy, splints, biofeedback, and cognitive behavioral therapy may also be helpful too particularly when the underlying issue is stress and anxiety, but not all of these have support in the literature and many are bandaids. Laser therapy, dry needling, intramuscular injection of local anesthesia or even #botulinum toxin-A are other approaches. Hypnosis and relaxation therapy, oxidative ozone therapy, manual therapy or no treatment at all are also options.

From a public health perspective, TMJ really does need to be a research priority. Understanding the epigenetics of each individual can help guide therapy. If you're interested in digging in further to your own TMJ, connect with me.

References

Alvarado, C., Arminjon, A., Damieux-Verdeaux, C., Lhotte, C., Condemine, C., Cousin, A-S., Sigaux, N., Bouletreau, P., & Mateo, S. (2022). Impaired tongue motor control after temporomandibular disorder: a proof-of-concept case-control study of tongue print. Clin Exp Dent Res, 8(2), 529-536.

Campello, C. P., de Lima, E. L. S., Fernandes, R. S. M., Porto, M. & Muniz, M. T. C. (2022). TNF-a levels and presence of SNP-308G/A of TNF-a gene in temporomandibular disorder patients. Dental Press J Orthod, 27(1), e2220159.

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