Neuromuscular Dentistry - A Discipline of Physiologic Dentistry

by Clayton A. Chan, DDS, MICCMO

For the past forty three years, dentistry has enjoyed an exciting evolution in the delivery of care. Technological advances have predominantly driven this evolution. Scientific advances have resulted in dental materials as technological break throughs using bio-instrumentation that have completely changed our perspectives on how dentist diagnose, manage and treat their cases. Technological advances have also allowed us to go beyond visualizing occlusal relationships solely from an anatomic perspective.

The early years from 1967 to 1977 gave insights and appreciation for the intellectual and courage of Dr. Bernard Jankelson (the Father of Neuromuscular Dentistry) single handedly challenged the dental occlusionist establishment with science and technology we now may take for granted and is available today.  Dr. Jankelson fight for new technology and new paradigmns to dental occlusal treatment brought to light the dogmas, scepticisms and epic confrontations from various levels of the profession.

After Dr. Jankelson's death in 1987, battles erupted in the American Dental Association and U.S. Food and Drug Administration.  By 1986 the scientific foundation for neuromuscular concepts and techniques were firmly ground in scientific literature and the technology was recognized as safe and effective for the purposes intended by the American Dental Association Council on Scientific Affairs.  The clinical techniques which continue to be advocated by his son Drs. Robert Jankelson, James F. Garry and Clayton A. Chan and others (through 2005) have been found to be precise, predictable and successful inspite of some continued attacks from those who ignore the documented science.  Neuromuscular clinicians who have endorsed this philosophy, approach and use of technology today continue to be attacked by leaders whose status and livelihood depended upon the defense of the scientifically indefensible, by third party carriers intent on denial of payment, by IME's whose livelihood depend on dential of patient claims, and by psycho-social academics whose research funding depended upon adherence to a particular TMD paradigmn.

The Neuromuscular Paradigm
New knowledge and understanding of the influences of occlusal proprioception on the human body requires intimate knowledge of the histological, anatomic and physiologic realm of the neuromuscular complex. The dentist should not only be the caretakers of the dentition, but of the health of all the structures innervated by and/or associated to the trigeminal nerve. Understanding the physiologic mechanisms of the stomatognathic system allows simplified clinical procedures that can be applied in all facets of dentistry including the TMD dentist, orthodontic dentist and restorative dentist to treat his/her patients with greater precision and predictability. Neuromuscular principles of occlusion are not new to the profession, but further builds on past gnathological concepts on which our present dental profession is based on. The use of scientific instrumentation has been used to objectively quantify and validate physiologic discoveries to occlusion. This new knowledge and training confirmed with advanced technology allows the restoration of pathologic dentitions to stable healthy dentition previously unattainable for function, self preservation and aesthetics.
 Our profession is now realizing the significance and importance of objectivity, especially when transitioning from academic knowledge to clinical treatment for our patients when: 1) an optimal bite is needed to begin a diagnosis for eventual treatment, 2) the importance of bite management during the phase I stabilization stage and finalizing the orthodontic and/or restorative phase II stage, and 3) finishing the bite to meet the physiologic parameters of stability and dental health.

Today’s dental practitioners are recognizing the necessity to incorporate the latest biomedical technology into their contemporary dental practice. As dental science has evolved and new discoveries are being made through the aid of computer technologies greater responsibilities, capabilities and opportunities for the dental profession are being realized.

Physical, physiologic and biologic laws that govern articular and neuromuscular function at all structural levels of the human body apply to the masticatory apparatus. Generic biologic and physiologic principles that apply to all articular, muscular, neural and central nervous system organs are better realized and understood through the use of computerized Myotronic instrumentation that enhances the clinicians perspective of what is truly physiologic occlusion. Clinicians are recognizing the potential and effectiveness of applying the above mentioned neuromuscular principles to TMD, orthodontic and restorative dentistry. Myotronic instrumentation is able to deliver the reality of these profound NM concepts especially in the clinical setting. These concepts are unfortunately missed by many practitioners.

Five basic principles of occlusion that the physiologically minded clinician realizes when desiring optimal masticatory stability:

1. Acknowledges the multifaceted Musculoskeletal Occlusal Signs and Symptoms.

2. Identifies an optimal starting point for diagnosis and treatment “PHYSIOLOGIC REST” (Homeostasis) - without manual intervention.

3. Recognizes a physiologic mandibular opening and closing NM TRAJECTORY along an isotonic path for STABILITY at a terminal contact position.

4. MICRO-OCCLUSION- Eliminates the afferent and efferent noxious proprioceptive stimuli of occlusion during mandibular closure with FREEDOM OF ENTRY and EXIT.

5. Can accurately OBJECTIVELY MEASURE and RECORD muscle and postural responses of the mandible in establishing an occlusion before, mid and after treatment.

Many do not see the power of micro-occlusion, the importance of finding an optimal NM trajectory, starting from physiologic rest, the importance of removing mandibular torque, the importance of proprioception as it relates to the trigeminal system. These are the ingredients for an “optimal bite” many treating clinicians have been searching for to bring long term stability and success in their dentistry. Many have either over look these principles or gave up too quickly to relinquish their role of being a treating “dentist”, to other adjunctive modalities, because they did not see the connection of these points to their clinical problems. In short they got distracted from perfecting their main role of what they were licensed to do, being a dentist dealing with all the issues relating to the trigeminal nerve and THE BITE (Occlusion).

Thousands of clinicians all around the world have found that by applying these profound neuromuscular principles first that they are able to effectively get the results of some of the most challenging TMD, orthodontic and restorative patients who present with numerous musculoskeletal occlusal signs and symptoms, involving cranio-mandibular, neurovasomuscular/cervical/occlusal dysfunction.

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What is Neuromuscular Occlusion?
Neuromuscular occlusion is discipline of dentistry based upon minimizing the need for muscle ACCOMODATION as the patient closes into a STABLE CENTRIC OCCLUSION.

These concepts are predicated upon the ability to:
  • Objectively measure muscle function
  • Correlate it to an optimal physiologic position and function of the temporomandibular joints and
  • Correlate it to an optimal resting posture and function of the masticatory muscles.
What is Neuromuscular Dentistry?
Neuromuscular Dentististry NMD) is a protocol utilizing diagnostic instrumentation to OBJECTIVELY quantify, verify and measure biophysiologic responses  of the masticatory and cervical system.  It takes into consideration the status and influences of MASTICATORY MUSCLES.

How is an Optimal Physiological Mandibular Position Determined?
Instrumentation is used objectively measure and records muscle activity via electromyography (EMG), before, during and after muscle relaxation using low frequency TENS.  Spastic muscles are physiologically relaxed via ultra low frequency TENS (transcutaneous electroneural stimulation) to compare normal versus abnormal muscle activity.  The clinician is able to visualize a physiologic mandibular rested position via Jaw Tracking (or Computerized Mandibular Scanning CMS) instrumentation in the frontal and sagittal planes.

A bite registration is taken via Jaw Tracking, TENS and synchronous real time EMG recordings to capture an optimal physiologic maxillo-mandibular relationship in 6

A bite relationship is taken with the patient sitting up and relaxed.  No manual manipulation is required neither do we touch the patient's jaw when taking the recording, which would induce potential pathology. A light weight sensor array is used with a magnet to record and track mandibular position in space both frontally and sagittally.

After the patient's mandible is relaxed and monitored for low muscle activity (EMGs) and bite registration material is used to record that maxillo-mandibular relationship. The neuromuscular clinician is able to visualize this relationship on the computer monitor and access if the jaw trajectory is correct as well as on frontal open and closing path.  Optimal resting EMGs are also identified and observed "simultaneously" to establish the best position.

All jaw torque, skews, strain, distortions are minimized to prevent further jaw mis-alignments from abnormal jaw joints pathology, hyper muscle tension, mal aligned and worn teeth as well as  abnormal head postures.  Guesswork is eliminated.  Establishing this "physiologic relationship" versus working within a "habitual" acquired bite position is what neuromuscular dentistry is about. 

Dental training is required to understand how to properly interpret and assess the objective data.  

Patient must understanding that there are various levels of training, skills and experience that there dentist has acquired to master these principles and techniques.  

Neuromuscular dentistry is comprehensive and address the complete postural issues of the head, neck, mandibular position, muscle activity status, the joint position all which in turn impact the occlusal position and relationship of the teeth. Based on these objective and scientific recordings do we consider our beginning starting point to diagnosis and treat.


The following 13 points must be considered in understanding what “Neuromuscular Dentistry” is REALLY ABOUT. These points have been adapted from the writings of Dr. Robert Jankelson who has pioneered the clinical use of computerized Myotronic instrumentation along with his father Dr. Bernard Jankelson (the Father of Neuromuscular Dentistry).
  1. Physical, physiologic and biological laws that govern articular and neuromuscular function at all structural levels of the human body apply to the masticatory apparatus. A rigid mechanistic concept of masticatory function is not consistent with generic physiologic knowledge.
  2. The TMJ and intercuspal masticatory articulations are a continuum of the entire body posture articulation. Anatomic and/or physiologic changes at any postural level require compensatory neuromuscular accommodation.
  3. Clinical dysfunction and symptoms occur when the need for structural and physiologic accommodation exceeds the ability of the organ system to accommodate.
  4. Compression of anatomic structures is a generic medical model of pathophysiology, pain and dysfunction. Decompression of impinged anatomic structures is the medical therapeutic model.
  5. General laws of homeostasis support the desirability of analysis of maxillo-mandibular posture from optimal muscle relaxation. Relaxation is good in the postural state. Muscle tension is bad in the postural state.
  6. Good laws of homeostasis and entropy support physiologic closure along an isotonic path of closure to terminal intercuspation.
  7. Relaxation of masticatory muscles prior to diagnosis and therapeutic procedures is a fundamental neuromuscular paradigm.
  8. Ultra Low Frequency TENS (Myomonitor) is a well established and scientifically documented adjunct to facilitate masticatory muscle relaxation.
  9. Objectively measuring occlusal function/dysfunction is consistent with scientific methodology. If the following three questions are answered affirmatively the measurement devices have scientific and clinical validity.
      • Can you measure a given physiologic function?
      • Are you measuring that physiologic parameter accurately?
      • Does that information add to the diagnostic information to assist diagnosis and treatment?
  10. Electromyography (EMG) is a safe and efficacious technique to monitor muscle at rest and in function.
  11. The medical and dental literature supports lowering EMG postural activities as objective data of improved muscle relaxation state which is a universal therapeutic medical objective.
  12. Increased isometric force in the intercuspal position as a desirable objective is consistent with all generic physiologic and medical models of kinesthesia.
  13. Mandibular malposition and occlusal dysfunction can initiate or contribute to temporomandibular disorders (TMD). TMD is a multi etiologic musculoskeletal dysfunction having common pathologic characteristic of all musculoskeletal disease. 
Appreciation is extended to all treating clinician’s who have realized the realities of the importance of a thorough diagnosis and understanding of this complex system in order to bring treatment to a finalize stage of postural/cervical/occlusal stability, muscular balance, dental aesthetics for the patient seeking comfort and satisfaction.

Supportive Scientific References

Supportive Scientific References:

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2. MacGregor RJ. Neural and Brain Modeling, San Diego, Academic Press Inc., 1987.

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5. King EE, Minz B, and Bigelow. The effect of the brain stem reticular fomation on the linguomandibular reflex. J. Comp Neurology 102(3):565, 1955.

6. Jankelson B, et al. Kinesiometric Instrumentation: A New Technology. J. Am Dent Assoc, 90:834-840, April 1975.

7. Hunnam AG et al, The Kinesiographic measurement of jaw displacement, J of Prosth. Dent. Vol 44:88-93, July 1980.

8. Moller, E Clinical electromyography I dentistry. Int Dental J. 19:250-266, 1969.

9. Mannheimer JS and Lamp GN. Clinical Transcutaneous Electrical Nerve Stimulation. 5th Ed. Philadelphia FA Davis Co. 1985.

10. Kasman GS, Cram JR and Wolf SL. Clinical Application sin Surface Electormyography. Gaithersburg, Maryland, Aspen Publishers Inc. 1998.

11. Soderberg GL. Ed. Selected Topics in Surface Electromyography for Use in Occupational Setting: Expert Perspectives, U.S. Dept of health and Human Services. DHHS Pub No 91-100, March 1992.

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14. Konchak P., et al. Freeway space measurement using mandibular Kinesiograph and EMG before and after TENS. The Angle Orthodontist, pp. 343-350 Oct 1988.

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19. Rodbard S and Pragay EB. Contraction frequency, blood supply and muscle paoin. J. Of Applied Physioloyg. Vol 24, No. 2 Feb, 1968.

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21. Wilkie DR, Ibid.

22. Lasagna M and Orlandi C. Ibid.

23. Thomas, NR Utilization of electromyographic spectral analysis in the diagnosis and treatment of craniomandibular dysfunction. Neuromuscular Dentistry Anthology Vol. V, Hickmanm DM Ed. Pp. 159-170, 1999.

24. Mohl ND et al, Devices for the dianosis and treatment of temporomandibular disorder: Part III: Thermography, ultrasound, electrical stimulation and electromyographic feedback. J. Prosthet Dent 63(4) 472-477, 1990.

25. Lund JP et al. Use of electronic devices in the diagnosis and treatment of temporomandibular disorders, J. Canadian Dent Assoc. 55(9):749-750. 1989.

26. Dinham R. Treatment of tic douloureux with Jankelson Myo-monitor. J Hawaii Dent Assoc, Vol III, 1970.

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28. Wessberg GA et al. Transcutaneous electrical stimulation as an adjunct in the management of myofascial pain dysfuncti0n syndrome. J of Prosth Dent. Vol 45, No 3, March 1981.

29. Panteleo T and Prayer-Galletti F et al. An electromyographic study in patients with myofacial pain dysfunction syndrome. Bull. Gr int. Rech., sc Stomat. Et Odont. Vol 26 pp 167-179, 1983

30. Konchak P and Thomas N et al. Ibid. 1988.

31. Choi B. On the mandibular position regulated by Myo-monitor stimulation. J Japenses Prosthetic dent. Vol 17 pp 73-96, 1973.

32. Jenkelson B et al. Neural condiction of the Myo-monitor stimulus: a quantitative analysis. J Prosth Dent Vol 34 No. 3 pp 245-253, Sept 1975.

33. Baker LL. Clinical uses of neuromuscular electrical stimulation. In; Nelson RP and Currier DP, eds Clinical Electrotherapy, 2nd ed. Norwalk, CT, Appleton and Lange pp 143-170, 1991.

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35. Currier DP. Neuromuscular stimulation for improving muscular strength and blood flow and influencing changes. In Nelson RP and Currier DP eds. Clinical Electrotherapy. 2nd ed. Norwalk, CT. Appleton and Lange pp 171-200, 1991.

36. Morrissey MC. Neuromuscular electrical stimulation in the rehabilitation of orthopedic injury. Phy Ther Pract. 1:20-29, 1992.

37. Kasman GS, Cram JR and Wolf Sl. SEMG triggered neuromuscular electrical stimulation. In: Clinical Applications in Surface Electromyography, Aspen Pub. Pp 193-211, 1998.

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39. Moller E. Clinical electromyography in dentistry. Int. Dent. Journal. 19:250-266, 1969.

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44. Gossman MR, Sahrman SA and Rose SJ. Review of the length associated changes in muscle: experimental evidence and clinical implications. Phys Ther. 62:1791-1808, 1982.

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48. Cooper, BC. Craniomandibular disorder. In: Cooper BC and Lucente FE, eds. Management of Facial, Head and Heck Pain. Philadelphia: WB Sauders; pp153-254, 1989.

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