Abstracts of Select Studies and Articles that have used Myotronics Equipment.

Some of the uses described in the following studies may not have been reviewed or presently accepted by the U.S. FDA.

Jankelson, Bernard, (1978) The Myo-monitor: Its use and abuse (I). Quintessence International No. 2: Report 1601, pp 47-51.

SUMMARY – The Myo-monitor transcutaneously stimulates the motor branches of the Vth and VIIth cranial nerves, relaxes the associated musculature, and then records an occlusal position that is compatible with a continued state of relaxation. Additional techniques have been developed for taking denture impressions (or relining old dentures) functional occlusal diagnosis, occlusal adjustment, and treatment of TMJ and MPD syndrome.

Hickman, David, M., Cramer, Richard, Stauber, William T. (1993) The effect of four jaw relations on electromyographic activity in human masticatory muscles. Archs Oral Biol 38:3, pp 261-264.

SUMMARY – Significant differences were found in the electromyographic (EMG) activation between the masseter and temporalis muscles for the leaf gauge(LG), manually manipulated (CR) and neuromuscular (NM) bite positions during maximal static clench.The LG position consistently demonstrated the lowest EMG activity, while the NM position displayed the highest degree of muscle activity. Similarly, the ratio of the masseter/temporalis EMG activity during maximal clench was lower for the LG and CR positions and highest for the NM position. These data indicate that the NM position produced the greatest total muscle recruitment, with more masseter involvement during maximal clench, and enabled the subjects to generate greater clenching forces in the NM position as compared to the LG and CR positions.

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

SUMMARY – 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.

Jankelson, Robert (1990) Analysis of maximal electromyographic activity of the masseter and anterior temporalis muscles in Myocentric and Habitual Centric in Temporomandibular Joint and Musculoskeletal Dysfunction. Front. Oral Physiol., Karger, Basal, Vol. 7, pp 83-97

SUMMARY – A computer review of maximal bite integrated EMG values for 46 consecutive patients referred to a clinical practice for treatment of TMJ/MSD was analyzed for data correlation. The 46 patients included 37 females and 9 males. The average ages of the patients were 42 and 46 years, respectively, for females and males. The patients all displayed 3 or more of the standardized symptoms in the Kinnie-Funt TMJ profile [23]. Only those patients with EMG/CMS profiles indicating a positive rationale for orthosis therapy were selected. This meant that the patients had either an excess of 2.0 mm of freeway space, or had an anterior/posterior discrepancy between neuromuscular and habitual trajectory of closure that precluded selective grinding of the teeth.

(1) Analysis of 46 temporomandibular joint/musculoskeletal dysfunction patients showed masseter EMG activity significantly lower than anterior temporalis EMG activity during maximal bite to habitual occlusion. Since the masseter muscle is the primary force muscle, while the anterior temporalis is the primary posturing muscle, this appears to be a consistent finding in temporomandibular joint/musculoskeletal dysfunction patients with nonoptimal occlusion.

(2) The combined integrated EMG in the symptomatic temporomandibular joint/musculoskeletal dysfunction patient is significantly diminished when the patient maximally occludes in the habitual occlusion as opposed to the myocentric position. Restoration of the occlusion to a neuromuscular myocentric resulted in a 72.2% improvement in motor unit recruitment. The marked increase in motor unit recruitment and the significant reduction in the number of symptoms as reported by the patients in this study, suggests that the myocentric position is a more efficacious functional position for motor muscle recruitment than the existing habitual occlusion in the musculoskeletal dysfunction patient.

(3) The study supports previous studies showing reduced EMG activity during maximal bite in temporomandibular joint and musculoskeletal dysfunction patients. Therefore, integrated EMG of maximal function appears to be a reliable, quantitative modality to identify functional disorders of the masticatory system.

(4) Integrated EMG of maximal bite effort can be used as a quantitative means to monitor patient progress. There appears to be a significant correlation by the increase in maximal EMG activity of the masseter and anterior temporalis, and the reduction in the number of patient-reported symptoms.

(5) Providing a neuromuscular myocentric occlusal position for the temporomandibular joint/musculoskeletal dysfunction patients allowed markedly increased motor unit recruitment during maximal bite. The increase in function correspondingly resulted in concomitant reduction in the patient symptom index.

(6) Treatment to the myocentric position resulted in significantly more symmetrical recruitment of masseter and anterior temporalis motor units. The temporomandibular joint/musculoskeletal dysfunction patient appears to have a greater asymmetry of muscle function during maximal bite to the habitual occlusal position. Restoration of the temporomandibular joint/musculoskeletal patient to a neuromuscular myocentric position resulted in significant improvement of muscle recruitment and symmetry.

To conclude, this study of 46 consecutive clinical dysfunction patients confirmed the findings of Moller, Erikkson, Sheikholeslam, Riise, Molin, Pruim, Jarabak, Kydd, Bigland, Lous, Prayer-Galletti, Pantaleo and others in support of maximal bite EMG analysis for diagnosis and temporomandibular joint/musculoskeletal dysfunction.

The restoration of the dysfunctional patient to a neuromuscular myocentric occlusion results in significantly increased function and synergy of the anterior temporalis and masseter muscles.

Coy, Richard E., Flocken, John E., Adib, Fray (1991) Musculoskeletal Etiology and Therapy of Craniomandibular Pain and Dysfunction. Cranio Clinics Intl, Williams and Wilkens, Baltimore, pp 163-173.

SUMMARY – The investigators sent questionnaires and guidelines for submission of case histories to Fellows of the International College of Craniomandibular Orthopedics, who are geographically dispersed over the United States. The practitioners were requested to supply data and case histories on patients who were treated specifically for Craniomandibular pain or dysfunction. Sixty-eight case histories received from 20 practitioners that met the study guidelines were included.

Electronically derived measurement provides an objective quantitative database for diagnosing the existence and extent of myostatic contracture and skeletal malrelation. Compilation of the electronically derived data, correlated with the subjective evaluations of both patient and therapist, establish the existence of significant skeletal malrelation of the mandible to the cranium and consequent myostatic contracture in the pain and dysfunction population. The data reported in these case histories indicate that a common measurable etiology is responsible for the many ostensibly diverse manifestations of craniomandibular pain and dysfunction. The diagnostic validity and usefulness of the electronically derived quantitative data are supported by the correlative subjective perception by the patient of alleviation of symptoms in response to the correction of skeletal malrelation and the consequent reduction of muscle tension (table 7). The course of treatment provides rapid initial palliation followed by long-term resolution as a result of orthopedic correction of skeletal malrelation.

The data clearly established that in the patient population under study:

  1. The average electromyograph activity with the patient at rest decreased substantially in the left and right anterior temporalis and masseter muscles after treatment.
  2. The average electromyograph activity with the patient clenching increased substantially in the left and right anterior temporalis and masseter muscles after treatment.
  3. Following the orthopedic correction of skeletal malrelation, over half of the patients had complete alleviation of symptoms, with the remaining patients experiencing a substantial reduction in the number of their symptoms.

The continuing positive responses to this noninvasive treatment based on quantitative as well as subjective diagnosis indicate the need in every case of craniomandibular pain or dysfunction to rule in or rule out musculoskeletal dysfunction as the most common underlying etiologic factor in most aspects of craniomandibular pain and dysfunction.

In cases in which the data rule out existing musculoskeletal dysfunction as a possible etiology, the patient may then be referred to other appropriate specialties such as neurology, otolaryngology, orthopedics, or psychiatry with the assurance to that specialty that the etiologic possibility of musculoskeletal dysfunction has been explored and ruled out.

Dickerson, William G., Chan, Clayton A., Mazzocco, Michael W. (2000) Concepts of Occlusion, The Scientific Approach: Neuromuscular Occlusion, Signature ,Vol. 7, No. 2; pp 14-17.

SUMMARY – The neuromuscular occlusal approach is based on the precepts of science. We now have scientific instrumentation that can record and verify the observations and symptoms presented by our patients. Neuromuscular dentistry is the science-based philosophy that has brought further understanding of muscle physiology into clinical dentistry. Many of the questions have now been clearly answered, allowing the neuromuscular dentist to investigate further, opening doors that were previously closed in the realm of dental diagnosis and treatment.

The authors believe that everyone is trying to accomplish the same thing – that which is best for our patients. They are happy for everyone who is comfortable with what he or she is doing. For those clinicians uncomfortable with their occlusal expertise, however, and also for those with open minds and the desire to learn as much about the stomatognathic system as possible, this aspect of dentistry may be as transforming as it has been for the authors.

Lynn, Jack M., Mazzocco, Mike W., Miloser, Stephen J., Zullo, Thomas, (1992) Diagnosis and Treatment of Craniocervical Pain and Headache based on Neuromuscular Parameters, American Journal of Pain Management, 2:3, pp 143-151.

SUMMARY – There is increasing evidence supporting the premise that hypertonicity within facial muscles is an etiologic factor for some chronic headache patients. This muscular hypertonicity is the result of neuromuscular imbalances within the head and neck. Through the analysis of electromyograph (EMG) data, it is possible to construct an intraoral orthosis which creates neuromuscular balance and subsequently relieves the pain.

This study attempted to identify (i) the relationship of EMG-measured dysfunction to reported craniocervical pain and (ii) the effectiveness of EMG-based orthoses on reversing myospastic conditions. Results of the study (N=203) indicate a significant (p<.0001) decrease in muscular myospasm at rest and a significant (p<.0001) increase in muscular activity during function following treatment with EMG-based orthoses. Reported craniocervical pain was significantly reduced. Results of this study support the hypothesis that creation of a physiologic neurovasomuscular envelope of craniocervical motion allows reduction of muscular hypertonicity resulting in reduction of pain. Furthermore, utilization of electromyography is a valuable tool during assessment and treatment of chronic facial pain patients.

Cooper, BC, Parameters of an Optimal Physiological State of the Masticatory System: The Results of a Survey of Practitioners Using Computerized Measurement Devices. J. Craniomandibular Practice, 22:3, pp. 220-233, July 2004

SUMMARY – While bioelectronic instruments have been available for nearly 30 years to assist dentists in day-to-day evaluations of patient’s masticatory systems, little guidance has been published to support physiological norms or ideals. An electronic questionnaire was developed and administered to an international group of dentists familiar with the use of bioelectronic instrumentation. Respondents were asked to provide feedback on the norms or ideal parameters of jaw movement, masticatory muscle function with electromyography, and joint sounds through electrosonography that they use in guiding evaluation and treatment of patients with temporomandibular disorders, neuromuscularocclusion, and orthodontics. Surveys were collated to determine areas of consensus. Out of 150 surveys, 55 responses were received from dentists representing nine different countries. Sixty percent of the respondents reported treating more than 150 cases in the past five years using bioelectronic testing. While experience ranged from 2-30 years with the different types of devices, average experience was longer with mandibular/jaw tracking (mean 15.3 years) and electromyography (mean 14.1 years) than with electrosonography (mean 7.0 years). Parameters proposed as norms or ideals for electromyographic rest and clench values, and mandibular tracking (velocity, freeway space, and trajectory to closure) were very consistent. Although a smaller number of respondents reported utilization of electrosonography, their criteria for data significance and tissue-type genesis of joint sounds were consistent. While the intra-patient variability may limit the use of bioelectronic instruments, the current study demonstrates that through decades of experience, dentists have independently arrived at very consistent definitions of an ideal physiology that can be used to guide treatment.

Cooper, BC,Kleinberg, I, Establishment of a temporomandibular physiological state with neuromuscular orthosis treatment affects reduction of TMD symptoms in 313 patients. J. Craniomandibular Practice, 2008; 26(2) 104-115

SUMMARY – 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.