Abstract
Adding modern technology to clinical diagnostic methods instead of replacing them, represents an improvement in patient care, because objective bio-physiologic measurements enhance the information obtained from the patient report of symptoms and the clinical observations made during a patient examination. Combining multiple tests has universally been acknowledged to enhance diagnostic sensitivity and specificity. The increased objectivity of bio-physiologic measurements that represent quantifiable data for diagnostic purposes also adds value to treatment monitoring and/or outcome assessments. The most recent evidence suggests that the emotional aspects of temporomandibular disorders (TMD), are more the result of pain and dysfunction than the cause. This chapter discusses several dental technologies that are now available that provide objective bio-physiologic measurements of masticatory functions. Bio-physiologic measurements have the capacity to provide detailed, objective analysis. Each diagnostic technology is illustrated with an example of its output data, recorded from both an asymptomatic subject, as well as a patient with masticatory dysfunction. Of significance when considering employing these instruments is that a dentist can use these technologies to improve the initial diagnostic accuracy, and also to verify the degree of success after rendered treatment. Finally, recommendations are provided that dental medicine should accept the use of modern digital technology as an indispensable part of modern clinical practice, and that resistance to its implementation should no longer inhibit its widespread clinical use.
TopIntroduction
There are three types of data collection methods used in healthcare to gather information for research, for diagnostic purposes, or to monitor treatment outcomes. They are given in Table 1.
Table 1.| Healthcare Data Collection | Type of Data |
| • Self-Report (Patient History) | Subjective |
| • Observation (Clinical Examination) | Subjective/Objective |
| • Bio-Physiologic Measurement (BPM) | Objective/Subjective (Interpretation) |
Of the above three methods, Biophysiologic Measurement is the most quantifiable (e.g. blood pressure, heart rate, range of motion), since it incorporates modern measurement equipment, and currently takes full advantage of the latest advances in computer technology. Despite the advantages of incorporating digital technology in dental practice, resistance within the dental community discounts the application of technology to dental diagnosis and treatment monitoring (Reid and Greene, 2013; Greene, Klasser & Epstein, 2010; Greene, 2010a; Greene, 2010b). In the 21st century, this resistance is surprising, especially considering that there exists a myriad of evidence-based information, published studies, and extensive dental literature, that demonstrates the efficacy of various technologies for specific dental applications.
However, at closer inspection, some published literature that appeared in1969 proposed a psychosocial and stress-related theoretical epidemiology of what was termed “Myofascial Pain Dysfunction Syndrome” (MPDS), that to date, has long fueled the debate as to the need, or lack thereof, to employ measurement technology when diagnosing Temporomandibular Disorders (TMD) (Laskin, 1969; Greene, Lerman, Sutcher & Laskin, 1969; Laskin,1970). The promulgated biopsychosocial etiology minimizes the role that a breakdown of the masticatory structures plays in the appearance of Temporomandibular Disorder symptoms, thereby eliminating the need to measure physical and structural function. This stress-related epidemiologic theory was further perpetuated into the early 1990s, when the so-called “Research Diagnostic Criteria” was first postulated as a valid method to diagnose TMD (Dworkin and LeResche, 1992). The ongoing belief within the dental profession that TMD is caused by emotional stress, explains why some clinicians and authors still resist using any bio-physiological measurements in clinical diagnosis. The “biopsychosocial” theorists’ rejection of virtually all physical diagnostic measurement is based in their (incorrect) assumption that TMD has no causative physical structural basis.
It is interesting to note that resistance to technology-aided TMD diagnosis is maintained philosophically, despite there being a complete lack of reproducible physical data to support these biopsychosocial theories. Alternatively, the dental literature does contain many studies that detail the benefits that technology offers to patients who present with Temporomandibular Disorders, some of which will be described within this chapter. While scientific honesty requires acknowledging conflicting or competing theories, that can be very difficult for some people to do.
Key Terms in this Chapter
Joint Vibration Analysis System (JVA): A device for recording and analyzing vibrations emanating from the Temporomandibular joints during movements. The unit of pressure, equivalent to loudness, is the Pascal, which is defined as 101.97 grams of force spread over a one-meter area.
Bio-Physiologic Measurement: The measurement of any physiologic processes, usually for the purpose of evaluating its function. Also referred to as biometrics.
Opening Angle: The angle as measured from the horizontal of the departure from centric occlusion while chewing (e.g., the normal frontal plane angle is approximately 65 to 95 degrees).
Electromyograph (EMG): A device for measuring the electrical activity associated with skeletal muscle contractions. The unit of measure is the microvolt, one millionth of a volt.
Research Diagnostic Criteria: A scheme designed to diagnose all TMD conditions as if they were somatized pain conditions irrespective of actual etiology. Introduced in 1992 and extensively studied, it has never been successfully validated.
Jerk: The third derivative of position (in calculus) or the rate of change of acceleration can give a good indication of smoothness of chewing. Excessive transitions between acceleration and deceleration produce jerkiness. Smooth masticatory function averages 3.6 transitions/cycle and perfectly smooth function is 2.0 transitions/cycle.
Electrognathograph (EGN): A magnet-based incisor-point jaw movement recorder. Records in three dimensions (frontal, coronal and sagittal planes) the path and speed of the lower incisors during various activities.
Maximum Lateral Width: The width of the frontal pattern of function in gum-chewing is normally about 5.5 mm (+/- 1.25 mm). Most types of dysfunction tend to narrow the frontal pattern, but a worn-flat occlusion increases the width of the pattern.
Average Chewing Pattern (ACP): The mean frontal, coronal and sagittal patterns of a patient’s chewing movements, calculated from a complete mastication sequence.
Dysthymia: A neurotic, chronic depression. A mood disorder with the same cognitive and physical symptoms as depression, but less severe with longer-lasting symptoms.
Terminal Chewing Position (TCP): The end-point of bolus crush where the distance from centric occlusion is minimal. Normally this value in a small fraction of one millimeter.
Myofascial Pain Dysfunction Syndrome (MPDS): A term coined in 1970 under the theory that painful conditions of the masticatory system are primarily due to emotional stresses rather than physiologic causes.
Immediate Complete Anterior Guidance Development (ICAGD): A method of coronoplasty utilizing the T-Scan to detect and remove prolonged in time, excursive friction present in all excursive movements.
Closing Angle: The angle is measured from the horizontal as the mandible approaches centric occlusion while chewing (e.g., the normal frontal plane angle is approximately 45 to 75 degrees).
Irritable Bowel Syndrome (IBS): A condition of unknown etiology causing disruption of lower intestinal function and discomfort, but without evidence of inflammation.
Temporomandibular Disorders (TMD or TMJD): An umbrella term referring to any one or more of at least 38 distinct pathologic conditions within the head and neck area. It is always a plural term and never represents a diagnosis.
Turning Point (TP): The most open position in the chewing cycle where opening transitions to closing. The dimension varies with the size of the bolus. For one stick of gum the mean value is about 16 or 17 mm.