References:TEMPORO MANDIBULAR 1997, PIN Volume 4, Issue 2

1. AUTHOR	Kolbinson-D-A, Epstein-J-B, Senthilselvan-A, Burgess-J-A.
INSTITUTION	Department of Diagnostic and Surgical Sciences, University of Saskatchewan, College of Dentistry, Saskatoon, Canada.
TITLE	A comparison of TMD patients with or without prior motor vehicle accident involvement: initial signs, symptoms, and diagnostic characteristics.
SOURCE	J-Orofac-Pain 1997 Summer, VOL: 11 (3), P: 206-14, ISSN: 1064-6655.
ABSTRACT	The role of trauma in the etiology of temporomandibular disorders (TMD)is controversial. The objectives of this study were to compare presenting signs,symptoms, and diagnoses in patients who had motor vehicle accident trauma related TMD to patients who had nontrauma related TMD. Files of 50 trauma and 50 matched nontrauma TMD patients were reviewed. Information concerning presenting pain, temporomandibular joint (TMJ) and related symptoms, examination findings, and diagnoses was recorded. Posttraumatic TMD patients reported higher facial (P = .006) and headache (P = .0001) pain ratings, neck symptom frequency (P < .01), ear related symptoms (P = .02), sleep disturbance (P < .001), and occupational and avocational disability frequencies (P < .0001). They had greater masticatory muscle (P < .001), neck muscle (P < .001), and TMJ tenderness (P = .01) scores and myofascial pain (P = .006) and arthralgia/capsulitis (P = .008) diagnoses. The nontrauma group had more subjective (P = .02) and objective (P = .05) TMJ crepitus and higher self reports of parafunctional jaw habits (P = .05). Trauma may be an important etiologic factor for some TMD --patients. Author.

2. AUTHOR	Christensen-L-V, McKay-D-C. E
TITLE	Reflex jaw motions and jaw stiffness pertaining to whiplash injury of the neck.
SOURCE	Cranio 1997 Jul, VOL: 15 (3), P: 242-60, ISSN: 0886-9634
ABSTRACT	Because a so called mandibular whiplash injury requires the absence of short latency jaw closing reflexes in order to explain the postulated mechanism of injury (excessive jaw opening); the authors studied the presence and absence and more importantly, the kinematics (duration, displacement,velocity, acceleration) of monosynaptic and possibly, polysynaptic myotatic (stretch) reflexes in the jaw elevator muscles. In six healthy adults jaw jerk maneuvers were elicited through a brisk tap on the chin, and surface electromyography identified elevator reflexes while translational electrognathography identified the kinematics of the reflexes. The maneuvers -were done while maintaining the rest position (3% MVC) and moderate clenching of the teeth (30% MVC). Electromyography was also used to identify phasic elevator excitations during a passive brisk neck extension maneuver. A sudden and unexpected elongation of the jaw elevators released autogenic reflex responses that, in conjunction with augmented tissue elasticity (stiffness), elevated the mandible into centric occlusion within approximately 150 milliseconds. In 86% of trials, the responses occurred regardless of the prevailing resting and clenching contractile activities. There was no evidence of a depressor force that consistently would and could anchor the mandible in a position of extreme or moderate depression, the theoretical linchpin of the mandibular whiplash injury. It was concluded that the mandibular locomotor system is very efficient in maintaining the rest and intercuspal positions of the mandible. his study found no evidence corroborating he mechanism claimed to release a so alled mandibular whiplash injury. Author.

3. AUTHOR	Steed-P-A.
TITLE	Etiological factors and temporomandibular treatment outcomes: the effects of trauma and psychological dysfunction.
SOURCE	Funct-Orthod 1997 Aug-Oct, VOL: 14 (4), P: 17-20, 22, ISSN: 8756-3150.
ABSTRACT	This paper examines the effect of trauma and psychological dysfunction as etiological factors in temporomandibular disorder (TMD). It employs a thoroughly validated measurement system, the TMJ Scale, to determine the effects of traumatic temporomandibular joint injury as well as pretreatment stress and psychological dysfunction levels upon presenting symptom levels. It also addresses these parameters for the eventual treatment outcome. During the course of the study, 754 patients were evaluated at the author's practice, which is limited to the diagnosis and Phase I treatment of temporomandibular dysfunction. Of those individuals, 693 (91.9%) were found to have clinically treatable temporomandibular disorders. At the time of this study, 201 consecutive patients (29%) have completed treatment and were deemed to have reached Maximum Medical Improvement (MMI). The validated measurement system of the TMJ Scale was readministered to this post treatment population. Data analysis revealed that trauma patients did not differ from nontrauma patients in initial symptom levels, nor in levels of symptom improvement (with the exception of a higher palpation pain level reported by the trauma patients). Stress and psychological dysfunction were predictive of higher initial symptom perception levels, but were not significantly related to treatment outcomes. These findings have important implications for practitioners in the field of temporomandibular studies. If it can be confirmed that psychological variables have no impact on treatment outcome, it would be difficult to justify the now frequently employed classifications and major emphasis placed on psychological treatment for temporomandibular patients. Author.