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The RCDSO 2018 Draft TMD Guidelines on Neuromuscular Occlusion

RCDSO 2018 Draft TMD Guidelines (Page 6): The concept of “neuromuscular occlusion” is based on the diagnostic value of electromyography for TMDs and treatment is based on the use of electrical stimulation of the muscles of mastication to establish appropriate occlusal positioning. Controlled studies suggest that there is a wide range of results and inconsistent findings using electromyography, which minimize its usefulness as a diagnostic test for TMD. Specifically, differences between TMD patients and healthy controls were not consistent. Regarding the clinical efficacy of TMD treatment based on electrical stimulation of the muscles of mastication, there is insufficient data from well controlled studies to rule out a placebo effect. Until properly controlled studies are available, there is insufficient evidence to support the clinical use of these techniques.

Myotronics Response to the Above Statement

Neuromuscular occlusion is a stable maxillo-mandibular position of dental occlusion arrived at by isotonic contraction of relaxed masticatory muscles, achieved by stimulation of those muscles, with a Dental TENS, on a trajectory (arc) beginning at a muscularly rested mandibular position. NM occlusion is in harmony with relaxed, healthy muscles and properly functioning temporomandibular joints.

Studies published in peer reviewed journals, including two randomized controlled studies, substantiate that the establishment of a neuromuscular occlusion, facilitated by the use of a Dental TENS, provides improved mandibular and masticatory function in a large group of TMD patients with notably significant reduction or resolution of symptoms. ^(1-4)

The Peer-Reviewed Studies the RCDSO Did Not Cite

Cooper 1997: Bioelectric Instrumentation in TMD Documentation and Management

Cooper B: The role of bioelectric instrumentation in the documentation of management of temporomandibular disorders. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 83(1): 91-100.

 Abstract

Temporomandibular disorders (TMDs) can affect the form and function of the temporomandibular joint, masticatory muscles, and dental apparatus. Electronic measurement of mandibular movement and masticatory muscle function provides objective data that are defined by commonly accepted parameters in patients with TMDs; these data can then be used to design and monitor therapy and enhance treatment therapy. In this study, data on 3681 patients with TMD are presented, including electronic test data on 1182 treated patients with TMDs. Electronic jaw tracking was used to record mandibular movement and to compare the presenting and therapeutic dental occlusal positions. Electromyography was used to analyze the resting status of masticatory muscles and occlusal function at presentation and after therapeutic intervention. Transcutaneous electrical nerve stimulation therapy relaxed masticatory muscles and aided in the determination of a therapeutic occlusal position. The data show a positive correlation between the clinical symptoms of TMD and the presenting occlusion, accompanied by muscle activity. A strong positive correlation also appears to exist between a therapeutic change in the dental occlusion to a neuromuscularly healthy position with use of a precision orthotic appliance and the significant relief of symptoms within 1 month and at 3 months.

Cooper and Kleinberg 2008: Neuromuscular Orthosis Treatment in 313 TMD Patients

Cooper B, Kleinberg I: Establishment of a temporomandibular physiological state with neuromuscular orthosis treatment affects reduction of TMD symptoms in 313 patients. J Craniomandib Pract 2008; 26(2): 104-117.

Abstract
The objective of this investigation was to test the hypothesis that alteration of the occlusions of patients suffering from temporomandibular disorders (TMD) to one that is neuromuscularly, rather than anatomically based, would result in reduction or resolution of symptoms that characterize the TMD condition. This hypothesis was proven correct in the present study, where 313 patients with TMD symptoms were examined for neuromuscular dysfunction, using several electronic instruments before and after treatment intervention. Such instrumentation enabled electromyographic (EMG) measurement of the activities of the masticatory muscles during rest and in function, tracking and assessment of various movements of the mandible, and listening for noises made by the TMJ during movement of the mandible. Ultra low frequency and low amplitude, transcutaneous electrical neural stimulation (TENS) of the mandibular division of the trigeminal nerve (V) was used to relax the masticatory muscles and to facilitate location of a physiological rest position for the mandible. TENS also made it possible to select positions of the mandible that were most relaxed above and anterior to the rest position when the mandible was moved in an arc that began at rest position. Once identified, the neuromuscular occlusal position was recorded in the form of a bite registration, which was subsequently used to fabricate a removable mandibular orthotic appliance that could be worn continuously by the patient. Such a device facilitated retention and stabilization of the mandible in its new-found physiological position, which was confirmed by follow up testing. Three months of full-time appliance usage showed that the new therapeutic positions achieved remained intact and were associated with improved resting and functioning activities of the masticatory muscles. Patients reported overwhelming symptom relief, including reduction of headaches and other pain symptoms. Experts consider relief of symptoms as the gold standard for assessment of effectiveness of TMD treatment. It is evident that this outcome has been achieved in this study and that taking patients from a less to a more physiological state is an effective means for reducing or eliminating TMD symptoms, especially those related to pain, most notably, headaches.

Weggen, Schindler, and Hugger 2011: Myocentric vs. Manual Methods of Jaw Position Recording

Weggen H, Schindler H, Hugger A: Effects of myocentric vs. manual methods of jaw position recording in occlusal splint therapy — a pilot study. Journal of Craniomandibular Function 3 (2011), No. 3: 177-203.

 Abstract

Occlusal splint therapy is a central element of the treatment of temporomandibular disorders (TMD). However, little has been reported about the effect of transcutaneous electrical nerve stimulation (TENS)-based methods of myocentric jaw position recording on the effect of splint therapy. In this randomized clinical trial, 40 patients with myofascial pain of the jaw muscles were treated with occlusal splints fabricated using bimanual manipulation (Michigan group, n = 20) or myocentric jaw position recording (myocentric group, n = 20) for determination of centric vs. myocentric relation. Therapeutic effects were evaluated based on the change in pain symptoms and the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) procedure after 4 and 12 weeks of treatment. The extent of change in mandibular position was determined by condymeter measurements and magnetic kinesiography as well as by comparison with a healthy control group. Twelve weeks of wearing the respective splints at night resulted in the significant relief of symptoms in both groups, as determined based on subjective pain reports and visual analog scale (VAS) scores. Group comparison revealed that the VAS scores were significantly lower in the myocentric group. Myocentric positioning of the mandible led to mandibular position changes of similar extent in TMD patients and healthy controls. The use of TENS to establish myocentric relation for splint therapy is therapeutically effective and achieves a greater reduction in pain. Furthermore, TENS treatment alone also has a significant pain-relieving effect

Weggen, Schindler, Kordass, and Hugger 2013: Clinical and EMG Follow-Up of Myofascial Pain Patients

Weggen T, Schindler HJ, Kordass B, Hugger A: Clinical and electromyographic follow-up of myofascial pain patients treated with two types of oral splint: a randomized controlled pilot study. Int J Comput Dent. 2013, No. 16(3): 209-24.

Abstract

Increased resting electromyographic activity (EMG), reduced EMG during maximum voluntary clenching, and a shift to lower frequencies of the mean/median power frequency (MPF) of the EMG power spectrum have been reported for patients with temporomandibular disorder pain. It is unclear, however, whether these electrophysiological phenomena can be correlated with symptom improvement during the follow-up of myofascial pain patients in treatment. The objective of this study was to monitor the therapeutic effects of two different splint concepts (standard method and a complex splint procedure assisted by transcutaneous electrical nerve stimulation, TENS) for a period of 12 weeks, by use of clinical outcome criteria and EMG recordings. We tested the hypotheses that both measures evaluated will change in parallel during treatment and that the different splint concepts will result in no outcome differences between the variables studied. For two randomly selected groups, each containing 20 non-chronic myofascial pain patients, the clinical course after splint insertion was documented over a period of 12 weeks on the basis of pain and pain on palpation ratings, in parallel with EMG recording. Baseline values were monitored for matched healthy subjects. Although there was no correlation between the course of symptom improvement and significant changes in EMG data, MPF differed significantly (p < 0.05) between healthy subjects and patients. The therapeutic effects of splints of different clinical complexity differed significantly (p < 0.05) between the patient groups, in favor of the complex oral appliances, and substantial (p < 0.001) but temporary pain relief was achieved by additional TENS. For non-chronic myofascial TMD pain patients treated with splints, the course of symptom improvement is not paralleled by significant changes in EMG data. MPF can, however, be used to distinguish between healthy subjects and patients. Splints of different clinical complexity differ in their therapeutic effects in non-chronic myofascial TMD patients, and substantial temporarily limited pain relief can be achieved by additional muscle stimulation by TENS.

The Same Pattern Across Borders

The RCDSO 2018 Draft Guidelines were not an isolated regulatory event. The same dismissal of EMG-based diagnostics and TENS-guided splint therapy appears in the AAOP’s 2019 application to the American Dental Association — including the explicit attack on surface EMG and jaw tracking on pages 22 and 91 of that application — and in the ADA’s subsequent recognition of Orofacial Pain as a dental specialty on March 31, 2020. The Canadian guideline language and the American specialty application are not coincidental; they are two regional expressions of the same institutional pattern. The structural and historical analysis is examined in Dentistry Without Occlusion: A Profession Redefining Itself Out of Its Foundation →.

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