The TMJ Association is a voluntary health organization collaborating with patientINFORM. Through patientINFORM, you can access important new scientific research articles pertaining to Temporomandibular Disorders and overlapping chronic pain conditions."patientINFORM is a program that brings together the publishers of the world's leading medical journals and the world's most trusted health organizations to provide patients and their caregivers with access to some of the most up-to-date, reliable and important research available about the diagnosis and treatment of specific diseases."
A recent article that appeared in Current Rheumatology Reviews by a Spanish and a Scandinavian author* underscores the complexity of temporomandibular disorders (TMD). The authors note that these painful conditions have been discussed for over 70 years without reaching consensus on either their causes or treatment. As a service to the research field they have reviewed the most recent studies for which there is valid scientific evidence relating to the epidemiology, symptoms, diagnosis, pathophysiology, and management of myofascial TMD, and making suggestions for future research. "Myofascial" refers to the fibrous tissue that sheathes the chewing muscles and other tissues associated with the TM joint. It is the more common form of TMD, as opposed to conditions confined to the joint itself, such as disc displacement.
The investigators conclude that TMD represents a complex and multifaceted pain disorder that may involve genetics, nervous system peripheral or central sensitization, and a range of psychological, behavioral and other variables. Most importantly, they emphasize that proper management of patients with myofascial TMD must be multimodal, including health care professionals besides dentists. Also, "Proper therapeutic interventions should see things from a personalized patient's point of view," they say, "including active listening, empathy, and addressing psycho-social issues," adding that "Patient-centered care involves shared decision making with mutual respect between clinicians and individuals."
Included in the management section of the paper is a table evaluating a range of treatment options, such as manual and physical therapies, psychological approaches, acupuncture and orthodontics, rating the strength or weakness of evidence for their effectiveness. While the article is lengthy and not written for the general reader, we believe that it will help those who live with TMD or care for a TMD patient in validating that the pain is real, that it is associated with a multitude of risk factors, that symptoms can vary and that patients deserve treatment that takes into consideration their unique set of clinical findings and history.
* Fernandez-de-Las-Penas C1, Svensson P., Myofascial Temporomandibular Disorder. Curr Rheumatol Rev. 2016;12(1):40-54.
Patients who develop symptoms of temporomandibular disorders (TMDs), face certain challenges when weighing the benefits and risks of new treatments. Because the TMD field is well known for having diverse opinions, different practitioners may offer a wide variety of treatment options for the same condition. Some of those options may be relatively conservative, while others are rather invasive. This difference is often represented as a choice between reversible and irreversible treatment. In a recent paper, Drs. Greene and Obrez have suggested a novel way of assessing the choice between the proposed treatments. Their paper, entitled “Treating temporomandibular disorders with permanent mandibular repositioning: is it medically necessary?” focuses on a central issue in the TMD treatment controversy: should the position of the lower jaw (mandible) be irreversibly changed as a part of treating these conditions?
It should be pointed out that no other joint in the human body can have its parts permanently repositioned except for the temporomandibular joint (TMJ). Therefore, no such controversy exists in orthopedic medicine. Indeed, like all other joints, the TMJ is constantly undergoing minor changes as we age. But because the arrangement of the teeth can be changed by a variety of dental techniques (bite adjustments, crowns and bridges, orthodontics, and even surgery), it is possible to substantially change the position of the lower jaw (condyle) relative to the skull (fossa).
In their paper, the authors argue that there already exists a lot of evidence that most TMD patients can be successfully treated without doing such invasive procedures. The new element they add to this discussion is described as homeostasis, which refers to the body’s ongoing attempts at maintaining a balance within the systems. In the case of the TMJs, this refers to the balance between the teeth, the muscles, and the joints. This represents a more biological concept that supports the clinical decision-making process. The authors then set up a series of six criteria to determine whether jaw repositioning can meet the test of being medically necessary:
1. The medical condition (i.e., mandibular malposition) is generally recognized as a valid health problem or a disease.
2. The diagnostic tests used to assess whether the patient has this condition are valid with acceptable specificity (getting a correct diagnosis) and sensitivity (avoiding a false positive diagnosis).
3. The patient’s condition will get worse unless a particular procedure is done.
4. The clinical procedure itself has specificity (proven value from good clinical studies) for addressing the patient’s particular problem.
5. The procedure is clinically effective according to evidence-based criteria (i.e., not just a placebo effect).
6. The disease or disorder cannot be resolved by performing a less invasive procedure, thus justifying the invasiveness of the clinical procedure based on its benefit-to-risk ratio.
Their conclusion is that criterion #1 above has not been met, since there is no valid diagnosis called “mandibular malposition.” Therefore, treating TMD with permanent jaw repositioning procedures does not meet these medical necessity criteria, and yet many practitioners may still continue to do some or all of those procedures. For TMD patients, this represents a danger of being over-treated with an irreversible therapy. Therefore, they would be wise to seek second opinions if this approach is being offered to them. If an oral splint is being proposed as part of their treatment, they should ask the dentist whether this will lead to bite-changing and jaw-repositioning procedures afterward.
As the authors state in their final paragraph: “In summary, we have concluded that permanent mandibular repositioning procedures do not fulfill any of the six criteria of medical necessity as the appropriate and medically acceptable treatments or management options for patients with various TMD conditions. This conclusion also has ethical implications, as discussed in the recent paper by Reid and Greene. According to ethical standards, a physician is expected to offer patients the best treatment options with the least risk possible, even if that approach results in less ideal financial returns for the practitioner.”
The authors, from University of Maryland's Schools of Dentistry and of Nursing, begin their article noting, "In general, women are more sensitive to pain than men, and a greater number of chronic pain syndromes are more prevalent in women, including irritable bowel syndrome (IBS) and temporomandibular disorder (TMD)." They comment that both these conditions occur primarily in premenopausal women with symptoms that fluctuate across the menstrual cycle, and that patients with IBS frequently report symptoms of TMD, while TMD patients frequently report IBS, chronic pelvic pain or fibromyalgia. Also noted is that the pain of IBS and TMD can be associated with or exacerbated by stress.
To facilitate research to understand these conditions and why they often overlap the researchers have developed a rat model. The model itself is complex. It involves first removing the ovaries of female rats. The estrogen normally produced by the ovaries was later replaced by injections of estradiol, a potent estrogen, at 4- day intervals. This was done to simulate the normal rise and fall in levels of the hormone, which is associated with fluctuations in the level of pain female patients experience over the menstrual cycle. Following ovariectomy, an injury was made to a chewing muscle in the rat to simulate TMD, and the animals were exposed to stress in the form of a "forced swim" test. In this test, the animal is placed in a water tank for a length of time in which it must swim to stay afloat. Using this model, the investigators were able to show that the rats exhibited chronic visceral hypersensitivity, including chronic abdominal pain -- a defining symptom of IBS -- which persisted in the animals for months. Further, they were able to demonstrate that estradiol was necessary for the transition from acute to chronic hypersensitivity. Animals subjected to muscle injury and the forced swim, but not injected with estradiol exhibited visceral hypersensitivity, but the effect was only transient, returning to normal levels over time. Other tests conducted with the model are consistent with the concept that in the transition from acute to chronic pain, the central nervous system undergoes central sensitization, a process by which the response of pain-activated cells is magnified and prolonged. The investigators conclude with the hope that their model will further progress in understanding overlapping pain conditions.
Source: Traub RJ Cao D-Y, Karpowicz J, Sangeeta P, Ji Y, Dorsey SG, Dessem D: A clinically relevant animal model of temporomandibular disorder and irritable bowel syndrome comorbidity. J Pain 15:956-966 2014.
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