Computerized Electro-diagnostic Instrumentation



nvented by Dr. Bernard Jankelson and further developed and perfected by his son Dr. Robert R. Jankelson (Myotronics/ Normed, Inc. Tukwila, Washington).

A variety of other techniques have been developed to diagnose TMJ diseases and disorders including mandibular jaw tracking, surface electromyography and sonography. The use of computerized electro-diagnostics is a more sophisticated approach to accurately and objectively define and treat TMJ/ TMD. In the past these technologies were not available thus resulting in erroneous conclusion, misdiagnosis, and misguided treatments.

Although there are some opponents that say that there is inadequate evidence to support the use and effectiveness of such diagnostics instrumentation, it is clear that they are misinformed and do not understand how the instrumentation can be used and implemented to aid in the diagnosis and treatment of TMJ.

  1. Computerized Mandibular Scanning (CMS)

    Computerized Mandibular Scanning is a more complex assessment of mandibular function using biomedical instrumentation which measures Accurate Light Weight Sensor to Record Jaw Movement the rotational movement in the frontal and sagittal planes thus confirming a neuromuscular dysfunction. The computerized mandibular scanner measures jaw movement (both qualitatively and quantitatively in several dimensions) to within 0.1 millimeters of accuracy. With a magnetic tracking device and sensor array, it projects the data on a calibrated computer monitor.

    The CMS measures jaw movement is far more accurate than the eye, making it possible to document characteristics of mandibular motion considered significant to evaluate jaw function. It also identifies the amount of free space, the swallowing pattern, and the quality of the occlusion, and substantiates the presence of disc derangements and their prognosis for reduction. It is a multi-dimensional assessment of torquing movements used to differentiate between contributing factors of a pathologic position to a non-pathologic position on opening and closing of the mandible. It is used in conjunction with EMG recordings.

    Graphic recording of opening/ closing paths of jaw movements from the side and front views can be analysed to assess abnormal mandibular paths of movement. The speed at which the jaw can open and close is also simultaneously recorded.

    Jaw Movement can be Accurately Recorded and Measured Range of Mandibular Motion can be Measured to identify Joint Pathology
               Sagital/ Frontal views of jaw movement Range of Motion can be measured accurately

    The literature supports the efficacy of mandibular tracking in the diagnosis and treatment of TMJ/ MSD.
      There are over 22 controlled published studies that further support the rationale for mandibular jaw tracking.

      There are 25 additional supporting referenced studies confirming the same.

      There are numerous other studies that document the clinical efficacy and validity of computerized mandibular scanning.
  2. Electromyography (EMG)

    Surface electromyography is a series of tests to more specifically delineate and define hypertonic musculature in the compromised TMJ patient. Surface Sensors Measures the Physiologic Muscle Activity These series of tests are necessary to differentially diagnose between intra-capsular interference (mensical or otherwise) and extra-capsular interference (influence of the surrounding hypertonic muscular matrix) so as to determine the predominant dysfunctions. Surface electrodes are placed over the muscles which in turn send impulses to the recording instrument. Defining the etiology of the TMJ patient's predominate neuromuscular dysfunctions will preclude misdirected palliative treatment regimens.

    Surface electromyography (EMG) utilizes eight channels monitoring the right and left posterior temporalis muscles, right and left anterior temporalis muscles, right and left masseters, and right and left anterior digastric muscles. A clinical hands-on muscle palpation examination is not able to quantify and objectively record muscle hypertonicity with out subjective intervention.

    Muscles of the face and jaw can be recorded to determine hyperactive muscle activity and/ or resting muscle activity. A strained jaw position can effect muscle activity. The objective is to determine the optimal resting jaw position at physiologic rest that harmonizes with resting EMG levels.

    Hyperactivty of Strained Muscles Before Treatment Calm Rested Muscles after Treatment
       Hyperactive/ Strained Muscles Calm/ Rested Muscles

      There is a broad body of literature that supports the physiologic basis for using surface EMG as an aid in assessment of muscle function/ dysfunction. (38 + studies support this ending with Lynn et al, 1992).

      There is substantial evidence based upon controlled studies that confirm that surface EMG is reliable and reproducible. (18 studies ending with Dean et al., 1992).

      87 studies verifying the use, safety, and efficacy of EMG to monitor masticatory muscle function/ dysfunction.

      "In summary, based on well controlled empirical and clinical studies that have been conducted in several universities over the past three decades throughout the world, there is unequivocal evidence to strongly support the use of EMG for the evaluation and diagnosis of temporomandibular disorders." - Robert Jenkelson, D.D.S.

  3. Sonography

    Sonography utilizes a kinesograph to measure intracapsular TMJoint sounds against normalized data, Measures and Records Joint Sound when Opening and Closing the Mouth duration of these sounds, exact location of the occurrence of these sounds during jaw opening/ closing, or lateral excursions, and a spectral frequency analysis of the sound. Without this information, one could not restore function free of intracapsular interference resulting in decreased muscle tenderness on palpation, an increased range of motion free of restrictions and resolve patient complaints of pain). A pair of ultrasensative transducers are held in place by a lightweight headset over the temporomandibular joints. Vibrations from each joint during opening and closing of the mandible are monitored by the transducers, amplified and inputted into a computer for display, analysis and data storage. The joint sounds are analy
    zed by the computer in terms of amplitude and frequencies present relative to occurrence in the opening and closing cycles. It is a valuable adjunct used in conjunction with other clinical diagnostic modalities to confirm such conditions of joint pathology.

    Sound vibration recordings when the jaw is opened and closed.

    High Frequency Recordings indicating Joint Pathology Low Frequency Recording indicating Normal Joints
    Joint Pathology Normal Quite Joint

  4. TENS (Transcutaneous Electro Neural Stimulation)

    Transcutaneous electrical nerve stimulation is a specific therapy for the treatment and resolution of pain related to
    neurological and myofacial conditions. It does this by delivering a mild electronic impulse through the nerves that control the masticatory and facial muscles. The rhythmic pulsing relaxes the muscles and therefore allows us to determine the correct relation of the mandible to the cranium. It also relieves pain and trismus of the muscles of the face caused by spasms and tension. In addition, it propels the mandible through space to a position which is most compatible with a relaxed musculature. This procedure involves the placement of electrodes bilaterally in the preauricular area anterior to the right and left ears, just lateral to the coronoid notch. The current emanating form the electrodes stimulate the motor divisions of the fifth and seventh cranial nerves. The TENS pulse rate is once every 1.5 seconds (low frequency). It mimics the natural pulsing action of the body somewhat like a massage. The effectiveness of the TENS therapy is documented by EMG recordings.

    Although the use of TENS is a mode of treatment it can be used most effectively when used in conjunction with CMS and EMG recordings simultaneously in objectively documenting and diagnostically gathering information before, during and after treatment.

      The efficacy of low frequency TENS in the diagnosis and treatment of TMJ/ MSD has been clearly confirmed in the published literature. It is clear and unequivocal that low frequency TENS (.05 Hz - 10 Hz) is both safe and efficacious for muscle relaxation and pain control. It is clear that low frequency TENS has a high degree of specificity when utilized for craniofacial pain. (Over 44 internationally published studies support and confirm this fact).

    There is more than adequate confirming evidence to support the effectiveness of such diagnostic instrumentation as verified and confirmed by the American Dental Association (ADA) and the Food and Drug Administration (FDA).

      The American Dental Association's Council on Scientific Affairs has awarded surface electromyography (SEMG), Computer Mandibular Scanning (CMS), and Sonography its "Seal of Acceptance", as diagnostic aids in the management of temporomandibular disorders.

        (Report on Acceptance of TMD Devices, ADA Council on Scientific Affairs, JADA, Vol. 127, November 1996)

      The U.S. Food and Drug Administration has granted 510k status to each of these mentioned devices for use in the diagnosis and management of TMD in my practice.

    This reflects that the U.S. Government and the dental profession acknowledges the safety and efficacy of the devices as recording and measuring devices used in the diagnosis and management of TMD and orofacial pain.


    Go to: MYOTRONICS/NOROMED for more about this high technology company.

    They can also be reached at:

    15425 - 53rd Ave
    S Tukwila, WA  98188
    (206) 243-4214 - Fax: (206) 243-3625 . . All rights reserved.