Science of Computerized Mandibular Scanning (CMS)

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Optimized Myo-Trajectory Chan Protocol

The following list below is a partial list of the large body of supportive evidence documenting the use and efficacy of Mandibular Tracking in the Diagnosis and Treatment of TMD/ MSD.

Progress in the field of mandibular tracking was limited by the capability of available instrumentation. As early as 1931 Hildebrand used cinematography of a moving reflective point to track mandibular movement (Hildebrand, G.Y. 1931). Cineflourography was used by Klatsky in 1941 (Klatsky, 1941) and was followed by Kurth’s use of stroboscopic photography in 1942 (Kurth, 1942). Mechanical tracking has also been used by several investigators throughout the history of mandibular tracking in dentistry (Boswell, 1951). The interference of mechanical tracking devices with normal mandibular function was a common problem. The first use of electronic recording techniques to record occurrence and duration of occlusal contacts during mastication was reported in 1953 (5). Brewer and Hudson later used miniaturized make or break switches to study tooth contact (Brewer et. al., 1961). Adams and Cannon developed instrumentation to trace actual movement patterns of the mandible during functional and parafunctional movements (Adams et. al, 1964, Cannon et. al., 1964).

K7 Bite Recording Tools - GNM

In 1975 Jankelson defined the requirements and criteria for a mandibular tracking system that would provide reliable quantitative and reproducible data. The criteria are:

  1. The relationship of the mandible to the maxilla must be determined in three dimensions.
  2. Data output must be continuous to permit analysis of the dynamic components of mandibular function.
  3. The system cannot encroach on the occlusal plane so as to interfere or alter proprioception.
  4. To avoid unnatural proprioceptive input and minimize mechanical limitations on mandibular movement, no supporting structures or wires should protrude from the mouth.
  5. The practical use of the system requires that setup time be minimal and htat the system be self contained.
  6. Measurement in the vicinity of the occlusal plane should be accurate to within .1 mm.
  7. The system should be widely available and operable by dental personnel (Jankelson et. al., 1975).

Belser and Hannam demonstrated that an early model Myo-tronics Kinesiograph was capable of recording incisal point movement to within .3 mm anywhere within the envelope of chewing (Belser et. al., 1985). The same authors have used this instrumentation in other scientific studies, demonstrating their confidence in the capability and accuracy of this modality (Belser et. al., 1986).

Today’s Mandibular Kinesiograph is a computerized electronic measuring device that can track mandibular movement with .1 mm plus or minus accuracy in three simultaneous planes as well as precisely measuring opening and closing velocity.

The value of this measurement capability to the clinical dentist responsible for establishing a predicatable and accurate occlusal position diagnostically and therapeutically is self evident. The ability to record, measure and capture and desired occlusal position transcends occlusal philosophy.

The value of coreelative data utilizing the MKG was emphasized in an AADR 1983 report by Bigelow, Slagle, and Chase, Department of Oral and Maxillofacial Surgery, University of Tennessee, entitled “Evaluation of Internal Derangement of TMJ with Mandibular Kinesiograph/Arthrography” (Bigelow et. al., 1983). The report stated:

“Arthography has established the increasing frequency of internal derangement of the TMJ. Jankelson et al have developed the Mandibular Kinesiograph (MKG) to characterize abnormalities of the TMJ. This study demonstrates a positive correlation between patients with stages of internal derangements and diagnostic MKG tracings. 20 patients were examined in this study. Historical, physical and radiographic criteria were used to diagnose patients with internal derangement of the TMJ. Arthrography was then performed to evaluate the extent of abnormalities. Patients were grouped according to the presence of clicks on opening, closing or both. Also on arthrography findings: normal, anterior dislocation with reduction, or anterior dislocation without reduction. Velocity tracing of the MKG were compared concerning characteristic and morphologic patterns. The velocity tracings were classified according to the irregularities in the opening and closing velocities. Correlations occur between velocity tracings and the arthrogram presentation of internal derangement which resulted in reduction or nonreduction during jaw excursions. Patients with arthrographic diagnosis of internal derangement without reduction demonstrated MKG tracings of impaired vertical opening deviation toward the affected side and characteristic irregularities in the velocity tracing. Patients with reduction showed only deviation to the affected side. MKG evaluation appears to be a reliable means to diagnose internal derangement of the TMJ.”


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