Frequently Asked Questions
About Neuromuscular Dentistry (3/4)
WHAT Is Jaw Tracking?
"Jaw tracking" is one of the modalities used by Neuromuscular Dentists. It is used to precisely identify the relationship of the mandible to the skull and to study mandibular movement dynamically. While a number of devices have been promoted for this purpose, the one that is least cumbersome and does not affect the patient's function is one that utilizes a tiny magnet affixed to the mandibular incisors. Sensors track the path of the mandible in three dimensions by sensing magnetic field changes - a science developed by Myotronics.
WHY Is Jaw Tracking Data So Valuable?
The data produced through jaw tracking has three important roles. First, is to permit the dentist to study mandibular action dynamically by recording and replaying traces representative of the mandibular path of opening and closing. This can reveal, in a highly precise fashion, a number of anomalies otherwise difficult to discern. One example is a sudden slowdown of mandibular velocity, invisible to the eye but often an alert to a clicking joint. Second, the jaw tracking device records the relationship of the mandible to the skull with great precision, information useful in the diagnostic process, and in taking a neuromuscular bite registration. The third application of jaw tracking is to record and verify that patient's closure to centric occlusion is on a neuromuscular (physiologic) trajectory.
Cooper, DC, The role of bioelectronic instrumentation in the documentation and management of temporomandibular disorders. J. Oral Surg. Oral Med. Oral Pathol. 83:1 pp. 91-100, 1997
Lynn, J. Computerized Mandibular Motion Analysis: A Physiologic perspective. Computers in Clinical Dentistry, Quintessence Books, pp. 79-93, 1991
Mazzocco, MW, Hickman, DM, "Space" The Final Frontier: Use of neuromuscular measurements in Clinical Treatment, Anthology Intl Coll. of Carniomandib. Orthopedics, Vol. VI, pp. 3-14, 2003
WHY Use Myotronics Jaw Tracking?
Myotronics developed this science in 1971 and has led the way in its improvement ever since. The Myotronics patented "sensor array" at four ounces is the lightest available, assuring that the patient will not become tired and that the sensing module does not interfere with mandibular function. The unit is remarkably free of interference from inadvertent patient movement or nearby metal objects. The software makes operation simple and provides powerful capabilities in evaluation and patient education.
WHAT Is Surface Electromyography (SEMG)?
SEMG is the study of muscle status (activity) using surface electrodes, as opposed to invasive needle EMG which only measures a single muscle fiber. SEMG picks up tiny signals coming through the skin that are representative of the average of multiple fibers of a given muscle. The data is obtained through surface electrodes much like EKG electrodes, amplified, and sent to the computer where it is displayed. The Myotronics system permits study of up to eight channels of SEMG simultaneously.
WHY Use Surface Electromyography?
SEMG is the only way that the dentist can accurately measure and record muscle status and function. Palpation is subjective at best, has little consistency from one dentist to another, and provides no objective documentation. SEMG allows the dentist to measure and record objective data concerning muscle status. The information can be invaluable as an aid in occlusal diagnosis and is highly useful in patient education. SEMG also enables studies of muscle function - showing precise timing and activation patterns of various muscle groups. This information is adjunctive to the occlusal diagnosis and is not otherwise available.
Hickman, DM, Cramer, R, Stauber, WT, The effect of four jaw relations on electromyographic activity in human masticatory muscles. Archs. Oral Biology, 38:3 pp. 261-264, 1993
Jankelson, RR, Analysis of maximal electromyographic activity if the masseter and anterior temoralis muscles in Myocentric and Habitual Centric in temporomandibular joing and musculoskeletal dysfunction. Front. Oral Physiol., Karger, Basil Vol. 7, pp. 83-87, 1990
Thomas, N. Utilization of electromyographic spectral analysis in the diagnosis and treatment of craniomandibular dysfunction. Int. Coll. Of Craniomandib. Orthoped. Anthology, Vol. V, pp. 159-170, 1999
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Dr. Molly Rodgers, General Dentist - Providing services in cosmetic dentistry to the area of Edmonton Alberta, Canada.
