Twelve Current Myths Regarding Temporomandibular Disorders

1. Temporomandibular Disorder (in the singular) represents a “diagnosis,” rather than a category of at least 38-40 distinct diagnoses

While some authors have suggested that Temporomandibular Disorder is a form of illness behavior,^1,2 Temporomandibular Disorders (TMD) are always indicated in the plural because there are at least 38 distinct physical conditions that fall into the category of TMD.³ Thus, while it may be rather easy to decide a patient has TMD, it is another matter entirely to determine accurately which one or more conditions are present. This is complicated by the fact that there is no single corrective treatment available that can be applied successfully to all TMD conditions. (Palliative treatments such as NSAIDS, Opioids, etc. can be applied, but with limited success). Diagnostic tests that include high sensitivities and specificities are required to fully understand a patient’s condition and to select a successful treatment plan.

2. Occlusion is never a factor in any TMD condition

Of all the common treatments for TMD, oral appliances and occlusal adjustments have been the most commonly used treatments providing real successes. However, the success rate has often been tied to the accuracy of the initial diagnosis and the appropriateness of the treatment applied (e.g. When treatments are randomly assigned, results are usually equivocal.)⁴ Occlusal adjustments are only successful long-term when a malocclusion is the primary etiology. Likewise, Oral Appliances are only successful long-term when the maxillo-mandibular relationship is less than ideal. Randomly applying a hard-flat splint, a soft splint or no splint without establishing a specific diagnostic need has been shown to provide an example of equivocal results.⁴ Note: The first recognition of TMD, Costen’s Syndrome, was originally discovered by an ENT physician, Dr. James Costen, in a fully edentulous population, which is the ultimate malocclusion.⁵ More recently, it has been shown that edentulous patients have a greater incidence and intensity of TMD associated signs and symptoms.⁶

3. TMD onset is rarely attributable to a single etiology such as macro-trauma

Traumatic injuries can be the initiating factor in as many as 25 % of patients developing a TMD.⁷ Individuals with a recent whiplash trauma report more jaw pain and disability compared with controls without a history of neck trauma.⁸ It is not unusual that the first incident involving a stomatognathic system dysfunction is a jaw locking event limiting opening.^9,10 Symptoms can evolve gradually due to micro-trauma or suddenly due to macro-trauma for the individual patient, each of whom has a unique condition that may or may not be receptive to any particular treatment. Selecting the most effective treatment depends entirely on an accurate diagnosis.

4. History and clinical assessment are usually sufficient to accurately diagnose all TMD

Numerous publications have called into question the adequacy of using just a history and clinical examination to accurately diagnose many TMD conditions.^11–13 It has been repeatedly shown that clinical examinations do not correlate well with TMJ internal derangements.^14,15 Patient reports are not reliable and clinical evaluations have been shown to be unreliable as well. While the history and clinical examination can identify a TMD patient,¹⁶ they are sorely insufficient to determine with any reasonable certainty which specific disorders are present. While NIDCR spent more than $120,000,000 in taxpayer funded grants to “validate” the RDC/TMD, which is limited to patient history and clinical examination data, the effort failed to do so.^11–13 The replacement DC/TMD fares a little better, but remains unvalidated.^17,18 One study found the Axis I results to be no different between the invalid RDC/TMD and its replacement DC/TMD.¹⁹ Somehow, unexplained, the Axis II scores were lower.

5. Technological devices (EMG, EGN, T-Scan, etc.) cannot contribute to a more accurate TMD diagnoses

A huge body of scientific publications has documented the contributions of the many technological devices and their objective measurements with respect to TMD diagnosis and treatment planning. Just in PubMed there are hundreds of listed studies; 113 referring to “T-Scan AND Occlusion,” 208 referring to “EMG AND TMD,” 223 referring to “MRI AND TMD,” 276 referring to “X-rays AND TMD,” 289 referring to “Joint Vibrations OR Sounds AND TMD,” 395 referring to “Range of Motion AND TMD,” with an overwhelming majority of them demonstrating significant positive applications. The few truly negative articles or “reviews” are based upon biased opinions rather than scientific data. Without the use of technology all diagnostic inputs are subjective opinions from the patient or from the examiner. In contrast, measured data represent facts that are not biased. Of course, individuals can be biased either for or against the use of technology. Those who believe in and promote this myth, who oppose the application of new technologies to the diagnosis of TMD are either ignorant of the technologies, inexperienced in the applications of them or have a personal reason to oppose them. One dichotomy here is that the same authors that claim EMG and Jaw tracking can offer no value for TMD diagnosis, used them to evaluate the masticatory function of their edentulous patients when it serves their purposes.²⁰ This begs the pertinent question: “Is masticatory function less important for TMD patients?”

6. Images (MRI, CBCT) are only required after patients have not responded to some “conservative treatment”

This Myth assumes that conservative treatment should begin with no accurate TMD diagnosis. Then, if the patient doesn’t respond positively to guesswork, imaging should be secured for diagnostic purposes. This is exactly a backwards approach to TMD with a treatment effort being followed by a diagnostic effort. In addition to revealing the current tissue structure, imaging can reveal various disease processes (e.g. cancer, arthritis, etc.). As a general rule in medicine, starting treatment with an accurate diagnosis usually makes failed treatment unnecessary. It is much easier to formulate an effective treatment plan with an accurate diagnosis.

7. TMD treatment should not be focused on any causal factor(s)

Some actually believe that the cause of an individual patient’s TMD can never be determined,²¹ which can partially explain this attitude. However, this opinion, if followed, guarantees that no cure for any TMD patient will ever even be pursued. When treatment is limited to palliative measures, the treatment can be never-ending, which is why palliative treatments are normally associated with terminal illnesses.²² It is true that the diagnostic effort of the clinician may be far easier or non-existent, but a never-ending palliative treatment approach is costly in the long run, both in terms of the drug side-effects and patient suffering.²³ This philosophy of approaching TMD will seldom result in the ideal of a substantially corrective treatment except purely by chance.

8. TMD treatment as symptoms management can be focused on the psychosocial correlates of pain

The painful symptoms of a Somatic Symptom Disorder (SSD) are indistinguishable from those induced by physically painful conditions. Consequently, it is an unavoidable requirement that all physical conditions either be successfully treated or they must be ruled-out from being present before a patient can be accurately tested for an SSD condition. This requirement has been ignored by too many authors within the dental profession.^11–18 Some have even suggested that just counting the number of non-specific pain conditions could predict SSD.²⁴ Although anxiety and depression have been shown endlessly to accompany TMD conditions, any etiologic role for them remains unproven. In contrast, chronic pain is a very strongly acknowledged cause of depression and anxiety. All TMD patients with chronic pain are very likely to be depressed.^25,26 It seems that correcting/improving the physical conditions of TMD patients and relieving their physical pains may be an excellent non-addictive treatment for also relieving depression.²⁶

9. Purely palliative treatments, (commonly referred to as “conservative treatments”), such as physical therapy, oral exercises, massage, relaxation therapy, flat plane oral appliances with no predetermined occlusal design, pain control addictive drugs, NSAIDS and counseling such as cognitive behavioral therapy sessions are usually sufficient for symptoms management.

Palliative treatments maybe appropriate as a temporary emergency action, but they do not correct the underlying condition(s) that have precipitated and may be perpetuating a TMD patient’s symptoms. This means that palliative TMD treatments may continue indefinitely, possibly leading to drug addiction and/or other negative side effects. Purely palliative treatments are most often prescribed by medicine for terminally ill patients as a means of upholding their quality of end of life. Otherwise an effort is made to cure or correct the underlying condition. It is acknowledged through hindsight that some patients eventually adapt successfully to some of their temporomandibular disorders without any treatment. However, there is not one reliably predictive method available to determine in advance which TMD patients or which of their disorders will adapt without treatment. The single exception may be the prediction that adolescents with non-reducing disk displacements are at continuously increasing risk of degenerative joint disease when the TMJ deteriorates further.²⁷ By pursuing an accurate and comprehensive diagnosis the clinician can develop a more definitive and corrective treatment plan that offers longer term successful treatment with minimal side-effects.

10. Irreversible treatments (such as orthodontics, prosthodontics, occlusal adjustments, etc.) should not be used to either prevent or to treat TMD

Most dental procedures are not reversible because they are intended to have long-lasting results. Whether prepping a tooth for a filling, an onlay, a crown or a more complicated restorative procedure, no reversible approach is available. In fact, it seems odd that a dentist would want to reverse treatments. Reversible treatments have only one advantage, the ability to back out of a wrong treatment. It is far better to accurately diagnose the case first and then apply a treatment that does not require reversal. Reversible treatments are promoted by those who approach TMD treatment with “trial and error” or “one size fits all” methods.²⁸ So-called reversible methods are not always completely reversible either, with side effects that alter the status of a patient’s health. There are very few general dentistry procedures that can be completely reversed. Why should TMD treatment be the only dental treatment that requires reversibility? Perhaps that approach would be better characterized as guesswork.

11. The treatment of the chronic pain of TMD requires a multimodal approach with a focus on central sensitization and correcting a maladaptive pain experience

Central sensitization is a theoretical concept over-used to explain any chronic pain that is not understood to be from an overt peripheral cause and to date has limited proof of concept and too few theories describing its mechanisms.²⁹ The evidence for its’ existence can be from the excessive sympathetic tone associated with chronic pain, neurogenic inflammation from neuropeptides, possible nerve compression or regeneration with ectopic discharges.³⁰ It may be a last-grasp diagnosis when other understood potential causes of a pain have been ruled out. A recommendation to apply Cognitive Behavioral Therapy is based upon the assumption of a maladaptive pain experience. However, chronic pain is more commonly associated with chronic physical conditions. With an accurate diagnosis of the chronic physical condition a clinician is more likely to be able to correct it enough to reduce/relieve the chronic pain. While there are many theories attempting to explain central sensitization (e.g., a genetic predisposition, hormonal action, abnormal function of receptor channels of the sensory neurons, dysfunctional neurons regulating peripheral blood flow, suppression of descending pathways that inhibit pain signals, etc.), none of them are fully accepted as the main etiology and as competing theories, none provides a logical pathway towards treatment.³¹ It is also likely that apparent central sensitization is mediated by sensitization of peripheral trigeminovascular neurons that innervate the meninges and followed by the sensitization of the central trigeminovascular neurons, which receive converging sensory input from the meninges.³² Thus the underlying mechanism for what is termed central sensitization likely starts at the periphery, not central and treating at the periphery has certainly been the most effective.

12. The belief that technology can assist in the diagnosis and treatment of TMD should be abandoned

In today’s computerized world this is probably the most incomprehensible myth of all. Within just the past half-century we have seen miraculous technological innovations applied to dental diagnosis (MRI, CBCT, Computer-aided diagnosis, etc.) that were not even dreamed about a century ago. To completely abandon the use of all technology in the pursuit of more accurate TMD diagnoses seems to be a “head in the sand” approach. Some authors have actually railed against treating TMJ internal derangements because they believe that no treatment is ever necessary (e.g. “…each person’s current temporomandibular joint position is biologically ‘correct’.”).³³ That sort of illogic along with a philosophy of “not invented here” explains why some so ardently oppose including computer technology in the TMD diagnostic process.

EXECUTIVE SUMMARY

TMD is always plural because it is a category not a diagnosis. Occlusion is often a factor, but not the only one. Macro-trauma, especially during youth, is often an etiologic factor as a trigger for a disorder that develops later in life. While the history and clinical examination are important, they are usually insufficient by themselves to lead to accurate TMD diagnoses, but by adding modern technological devices, an accurate diagnosis and effective treatment plan can be obtained. It is a backwards approach to place diagnosis after failed “conservative treatment.” Finding and eliminating the causal factors of patients’ TMD are the only ways to achieve lasting positive results. The psychosocial correlates of pain are routinely secondary to physical conditions that when treated successfully, also relieve them. Limiting TMD to palliative treatments most often also limits success to a temporary status. Most successful dental treatments are irreversible, because that is usually what is required to correct the underlying mal-condition. Long-term success treating chronic pain first requires identifying the etiologies, which usually stem from peripheral inputs to the CNS. The abandonment of technology in today’s world is a fool’s errand. It is far more rewarding not to be one.

Correspondence

Ben Sutter bsutterdmd@AOL.com owns a private referral dental practice in Eugene, OR with a focus on TMD. John Radke is the Chairman of the Board of Directors for BioResearch Associates, Inc.