What is the basis for recommending reversible treatments for TMD?
For more than three and one half decades some authors have recommended limiting treatments for Temporomandibular Disorders to only those that are reversible, including MPDS, TMJ, etc.1–8 In some articles the authors have even suggested or implied that a consensus has been reached that only reversible treatments are needed for all TMD treatment.9,10 It should not be surprising then that the concept of limiting TMD treatments to only reversible ones is wide-spread in private practices, since the dental profession has been fed this idea for so long.11 It has even been suggested in one recent article that applying an irreversible TMD treatment might be unethical.12 The level of coercion reached the level of ridiculousness in one Review of the Systematic Reviews in 2018.13 However, the real reason for limiting treatments to only reversible ones was revealed nearly three decades ago: A lack of understanding of the multiple etiologies of TMD and the inability to accurately diagnose with good sensitivity and specificity the many distinct conditions within the large category of TMD really drive the hesitancy towards definitive treatments.14
If I am guessing what is wrong with the patient and what treatment to use, then I should prefer to select a reversible treatment.
The possibility of developing precise diagnoses for TMD patients from only their reported histories and their clinical examinations is too slim in many cases. It was demonstrated several decades ago that the clinical information available from many TMD patients is just not sufficient to provide the necessary information needed for accurate diagnoses.15 This has recently been reinforced by the comprehensive finding that the RDC/TMD lacks validity and fails to accurately diagnosis many physical conditions primarily due to its low Axis I sensitivities.16,17 While some TMD cases are simple, many include the additional complication of having multiple etiologies.18 If the provider is not able to accurately ascertain a patient’s TMD conditions or the etiologies of them, a reversible approach to treatment superficially appears as a safer choice.
When an initial diagnosis of TMD remains tentative, selecting a treatment tends to be guesswork. Some might even say that due to the multifactorial nature of TMD, the complete diagnosis for a patient is unknowable.19 If that were true, the only approach left would be Trial & Error. Under that circumstance, certainly complete reversibility would have merit. The ability to reverse an unsuccessful TMD treatment and return the patient back to the starting point, no worse than prior to treatment, could be a savior for a clinician. After all, some have suggested that many TMD patients may be only suffering from somatization (Somatic Symptom Disorder), with only marginal physical problems.20
It has been suggested repeatedly that many TMD patients tend to spontaneously get better over time without any treatment or successfully adapt to their condition. Therefore, no treatment may even be preferred by those who have no confidence in producing any successful treatment. And lastly, there are those who advocate for self-management of TMD, letting the patients treat themselves.21 An insistence upon reversibility does seem rather odd considering most routine dental procedures are not at all reversible. Reversibility can only be seen as an indication of indecision.
What treatments are truly reversible?
Certainly, no treatment is safe from any need for reversibility. Self-treatment, which has also been advocated, includes little risk for the clinician. Self-treatment is usually applied as hot packs, cold packs, jaw exercises, pain suppression ointments, relaxation training and/or TENS for pain relief.22 Exercises can change muscle strength and consequently improve function or they may have no effect.23 All of these palliative treatments ignore the underlying condition that is the etiology of the patient’s symptoms and consequently are most appropriate when no actual diagnosis has been achieved.
In spite of the fact that occlusal appliances have long been shown to be the favorite and most commonly successful treatment for TMD, they are often guilty of changing the bite, at least when worn for an extended period of time. That can be seen as good or bad when considered in light of the trade-off between symptom relief and bite change. OSA appliances often change the patient’s bite, but may also preserve life. Physical Therapy seems more effective when applied to neck-related conditions than to jaw-related TMD conditions. The applications of pharmacological treatments for TMD have diverse outcomes as well. Over the counter pain medications are pretty safe short-term, but prescription drugs include many risks of adverse side effects as well as opioid addiction. Some authors have concluded that the palliative effects of clonazepam and capsaicin are effective for Burning Mouth Syndrome, cyclobenzaprine, a muscle relaxant, can reduce muscle pains (along with negative side effects), while NSAIDs, corticosteroid and hyaluronate injections can be effective for TMJ pain.24 None addresses the underlying etiology of the TMD condition.
Cognitive Behavioral Therapy (CBT) has been seen as harmless by many, although at least some TMD patients have been known to become very hostile towards a diagnosis of a psychosomatic illness.25 It has also been demonstrated that emotional factors are most often secondary to physical factors and not true etiologic factors.26 Consequently, little treatment of substance can be provided to a patient with TMD that does not include some risk of permanent changes in the bite, changes in the temporomandibular joints, changes in the function of the muscles of mastication or that does not also include some potential negative side effects.
What are some common irreversible treatments for TMD?
Occlusal adjustment is considered irreversible as one cannot put the removed enamel back onto the tooth. Of course, dentists routinely remove enamel every day when restoring mouths with crowns, on-lays, etc., so that cannot be by itself the objection. The real objection is that sense of uncertainty with respect to the prognosis of the treatment outcome.
There is at least one occlusal adjustment technique that has been shown to increase the prognostic factor considerably. It is applied only when a very definitive diagnosis is obtained through the application of T-Scan Computerized Occlusal Analysis System (Software Version 10, Tekscan, Inc., S. Boston, MA USA),27 This diagnosis is referred to as occluso-muscle disorder, a sub-diagnosis within the broad category of TMD involving pain in the muscles from a mal-occlusion. The method is normally only applied if the TMJs are known to be stable and well-functioning, because unstable TMJs cause instability of the occlusion. The subjective symptoms are muscle related, but the most important sign recorded with the T-Scan 10 is the presence of a prolonged time working side group function occlusion and consequently, a long disclusion time in lateral excursions.26,28–31
Since the T-Scan 10 measures both the relative force at each tooth and the timing of the contacts, any high and/or interfering contacts can be readily identified and reduced. Disclusion Time Reduction is accomplished through Immediate Complete Anterior Guidance Development32 and the primary goals are to create a cuspid-protected occlusion that discludes all posterior teeth during lateral excursions in less than half of a second and creates an even distribution of bite forces around the full arches when biting into the Maximum Intercuspation Position (MIP).33 In many cases just one or two interfering high spots are present necessitating minimal tooth reduction, but the degree of symptom resolution is not proportional to the amount of change in the occlusion. There are no reversible treatment options available to permanently correct a real mal-occlusion, only devices that temporarily separate the teeth.
When an appliance is indicated because of TMJ symptoms, most often in the form of unilateral or bilateral internal derangements, it is usually due to either an acute closed lock or poor adaptation of the joints to a chronic condition. The lucky patients that do adapt successfully to internal derangements over real time (years) eventually develop good-enough joint function without any treatment. Good-enough TMJ function is best recorded dynamically and non-invasively using Joint Vibration Analysis (JVA).34,35 A definitive determination of good-enough TMJ function is a contraindication for additional TMJ treatment. Patients that are not lucky or with less adaptable genes, develop degenerative joint disease. With the aid of sophisticated imaging, it is possible to better evaluate the patients’ TM joint morphology and develop a reliable diagnosis, treatment plan and prognosis. The treatments for internal derangements include appliances, orthodontics, arthrocentesis, TMJ arthroscopic or open joint surgeries, all of which are quite irreversible. There is no efficacious reversible treatment for dysfunctional TMJs. The alternative to treatment is to wait for perhaps decades until the condition reaches its endpoint, allowing the patient to suffer chronic pain in the meantime.
A more subtle TMD diagnosis involves the orthopedic relationship of the mandible to the maxilla. From a variety of etiologies (trauma, developmental anomalies, loss of molar support, etc.), the relationship of the mandible to the maxilla can become distorted. Common primary symptoms are masticatory muscle pains, ear pains, headaches, joint noises and sometimes a visually distorted physiognomy, but additional symptoms may also be present. This type of condition is typically treated with an appliance for phase one, followed by either orthodontics, reconstructive prosthodontics or by orthognathic surgery in phase two. In practice there is not even one reversible treatment available to correct a real maxillo-mandibular mal-relationship.
Are physical TMD treatments equivocal as suggested by some “randomized” TMD treatment studies?
The first common mistake in randomized TMD treatment studies has been a lack of a sufficiently definitive diagnosis.36,37 When study subjects are merely labeled as TM Disorder patients with no further definition, randomization of treatment guarantees that many, if not most of the patients, will receive a treatment inadequate or even inappropriate for their actual condition. The various non-palliative treatments used for TMD are each designed to treat specific conditions. When applied to an inappropriate condition, they are usually either ineffective or only partially effective. This lack of understanding has led to the widespread belief that TMD patients can only be managed, not successfully treated. None of the randomized TMD treatment studies have shown complete success unless the study group has been limited to very clearly defined subjects.
The second mistake is related to the extensive correlations that have been made between the presence of TMD symptoms and emotional disturbances; correlation is not the same as causation. The depressive symptoms that are associated with TMD most often appear to be secondary symptoms.26 The same can be said for many of the physical symptoms of TMD. Muscle pains in the absence of myopathy or neuropathy are most often secondary symptoms. To treat the patient effectively and for the long-term it is necessary to determine the primary condition that is causing the muscle to become painful. TMD patients only rarely present with myopathies or neuropathies. Ear pain, tinnitus and loss of hearing acuity in the absence of direct ear pathology are all secondary symptoms. (E.g. Tension headaches can be the result of constant temporalis muscle tension secondary to either a structural or an occlusal deficiency.)
The third and the most common mistake is the seeking of one treatment that will be effective for all TMD patients. Of course, palliative treatments can be applied to all TMD patients, but they do not correct anything, they only mask the problem at best. Due to the wide variety of conditions within the category TMD, it is not even imaginable that one physical treatment could be effective for every possible TMD condition. The lack of complete effectiveness for many physical TMD treatments is due to their application to TMD patients with undiagnosed conditions that are not appropriate for that treatment.
Cognitive Behavioral Therapy can be applied to any TMD patient and may even mitigate to some extent the symptoms for some, but it does not correct any of the physical conditions that most often exist. It is well understood in medicine that patients in physical pain, especially chronic pain, will usually develop depression and/or anxiety. When a TMD patient with a physically painful condition is tested for a Somatic Symptom Disorder (SSD) without first correcting their physical condition, the patient will register a false positive indication of somatization.
It is not the purview of the psychiatrist to eliminate all physical alternative explanations for patient’s painful symptoms. He/she must operate expecting that the referring practitioner has already done that. Only after a TMD patient has been determined to have no painful physical disease or dysfunction can a diagnosis of SSD be reliably assigned. Thus, to maximize successful treatment of all Temporomandibular Disorders, there is no alternative to starting with accurate physical diagnoses.
If the goal is merely any improvement in the levels of symptoms, a simple intraoral appliance may be the treatment of choice. However, it does not represent a definitive correction and weaning the patient off of the appliance just returns the patient to the situation that was symptomatic in the first place. For success in treating TMD, there is no substitute for accurate diagnosis.