In personal injury trials the role of trauma, particularly cervical whiplash, in the causation of TemporoMandibular Dysfunction (TMD) continues to be debated between dental experts for plaintiff and defence. Nontraumatic TMD is common and psychological factors well-researched. As with the neck, research on whiplash of the jaw joint tends to polarise between believers and non-believers.
The prolific (believer) researchers at the University of Saskatchewan School of Dentistry compared1 randomly selected patients having a history of trauma with matched nontrauma patients. Patterns of symptoms were distinctly different: trauma patients had significantly more numerous and widespread painful syndromes, whereas sufferers without history of trauma tended to have more problems of jaw-joint function.
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POINT The characteristic symptom profile differs between patients with and without a history of trauma |
Experimental studies2 on healthy volunteers found no support for the theory that temporary failure of reflex jaw closure leaves the TM joint vulnerable to mandibular whiplash. The researchers tried to overcome the protective mechanism by sudden, unexpected stretching of the muscles closing the jaw, but the resting position was reflexly restored within one-sixth of a second, whether the jaw was originally relaxed or clenched. As with cervical whiplash simulations, however, the role of preparedness ( see article on Kinematics) remains unanswered.
In a very large personal series3 derived from practice exclusive to temporomandibular disorders, a researcher into prognosis explored the role of emotional factors. Although stress and psychological dysfunction were accompanied by greater severity of initial symptoms, they had no significant relationship to treatment outcome.
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POINT Psychological factors amplify symptoms but do not worsen treated prognosis |
Copyright © 2008 Electronic Handbook of Legal Medicine