Journal of Oral & Facial Pain and Headache, 02/1996

A literature review concerning the relationships between motor vehicle accidents and temporomandibular disorders, whiplash, headache, neck pain, and litigation was undertaken. The review shows that many patients recover or resume work prior to settlement, but most unsuccessfully treated patients do not generally recover following the settlement of legal claims; the postinjury problems are not strictly psychologic. Litigating patients and non-litigating patients are often not dramatically different in most important regards (including pain and return to work), with litigating patients deserving the same treatment as other patients with chronic pain. It was found that postinjury neck symptoms and headaches can be persistent. Employment appears to be a better predictor of long-term outcome than compensation and litigation. In addition, limited consensus is available concerning prognostic factors. Patients with postinjury temporomandibular disorders tend to respond less well to treatment than do noninjury patients with temporomandibular disorders, as do litigating compared to nonlitigating temporomandibular disorders patients, but a cause and effect relationship is not known. The incidence of temporomandibular disorders following motor vehicle accidents may not be as high as has been claimed in whiplash cases. More research is required in the area of temporomandibular disorders, motor vehicle accidents, and litigation.

Previous studies have shown that characteristics of posttraumatic temporomandibular disorders (pTMD) differ considerably from those of nontraumatic or idiopathic temporomandibular disorders (iTMD). Both the rate of recovery and the amount of treatment required appear to be different for both groups. In this blinded study, 14 patients with iTMD and 13 patients with pTMD were examined. Patients submitted to a variety of reaction-time tests and neuropsychologic assessments to test their ability to cope with simple and more complex tasks with and without a variety of cognitive interferences. Clinical examination was used to assess signs of TMD. Eleven of the subjects (six iTMD, five pTMD) consented to a second phase of the investigation, whereby the patients were studied with single-photon emission computerized tomography (SPECT) using 99mTc-hexamethylpropyleneamineoxime (HMPAO). For simple and complex reaction-time tests, the pTMD group was significantly slower than the iTMD group (P .05 to P .001). Other neuropsychologic assessment tools such as the Consonant Trigram Test and the California Verbal Learning Test indicated that pTMD patients were more affected by both proactive and retroactive interferences and were more likely to perseverate on a single thought. In clinical examination, pTMD patients demonstrated greater reaction to muscle palpation than did iTMD patients (P .05). The SPECT results suggested that there were mild differences between the two populations, and further studies are required to confirm this finding. The results lend support to the concept that there are differences between pTMD and iTMD populations. It is suggested that although patients with pTMD may have some similarities to those with iTMD, the former population may benefit from being handled somewhat differently and should be assessed and treated using a more broad, multidisciplinary treatment paradigm. These results must be confirmed in studies of larger populations.

This study explored psychologic and physiologic factors differentiating patients with temporomandibular disorders (n = 23) from sex-, age-, and weight-matched asymptomatic control subjects. Each subject completed several standard psychologic questionnaires and then underwent two laboratory stressors (mental arithmetic and pressure-pain stimulation). Results indicated that patients with temporomandibular disorders had greater resting respiration rates and reported greater anxiety, sadness, and guilt relative to control subjects. In response to the math stressor, patients with temporomandibular disorders reacted with greater anger than did control subjects. There were no differences between patients with temporomandibular disorders and control subjects on pain measures or any other measured variable for the pressure-pain stimulation trial. In addition, there were no differences in electromyography levels between patients with temporomandibular disorders and control subjects. The results are discussed in terms of their implications for the etiology and treatment of this common and debilitating set of disorders.

Longitudinal changes of symptoms of temporomandibular disorders in 275 Japanese university students were investigated through use of questionnaires in 1990 and in 1994. A comparison of the 1990 responses with the 1994 responses revealed taht the prevalences of temporomandibular joint sounds, mouth opening restriction, and pain significantly increased from 28.7% to 49.8%, from 12.7% to 22.5%, and from 7.6% to 18.5%, respectively. The increase in the prevalence of symptoms mainly resulted for students who did not have symptoms of temporomandibular disorders at the first examination. Subjects who had been frequently aware of symptoms of temporomandibular disorders showed a tendency toward a decrease in their frequency of awareness. Although 66 students (24.0%) reported discomfort from symptoms of temporomandibular disorders during the period, only three (1.1%) visited medical facilities to receive treatment. These results suggest that symptoms of temporomandibular disorders evaluated through the use of questionnaires are longitudinally fluctuant, and that few students developed temporomandibular disorders.

This double-blind study evaluated the short-term effect of iontophoretic delivery of dexamethasone on the signs and symptoms of temporomandibular disorders in patients who had concurrent temporomandibular joint disc displacement without reduction and capsulitis. Twenty-seven patients with this clinical diagnosis were randomized to one of three groups: treatment group (dexamethasone sodium phosphate and lidocaine hydrochloride); control group (lidocaine hydrochloride); and placebo group (pH-buffered saline). Pretreatment and posttreatment data included items to calculate Helkimo's Anamnestic Dysfunction index, Helkimo's Clinical Dysfunction index, the Symptom Severity Index, and the Craniomandibular Index (CMI). The CMI is composed o the Dysfunction index (DI) and Muscle index. Analysis of variance showed no baseline differences on these measures between the three groups. Pretreatment and posttreatment values were compared with the paired t tests. Posttreatment, the treatment group had an increased mean maximal active mandibular opening of 6 mm (P = .02), increased mean lateral excursion of 1.2 mm to the noninvolved side (P = .05), and reduced mean DI scores of 0.51 to 0.39 (P = .01); no statistically significant decrease in pain symptoms was reported. Analysis of variance showed a significant difference in the DI scores (P = .04) between groups from pretreatment to posttreatment, with the treatment group showing the greatest improvement in the DI scoers relative to the other two groups. No other questionnaire items, exam items, or resultant indexes showed changes in any of the groups t P - .05. These results suggest that iontophoretic delivery of dexamethasone and lidocaine was effective in improving mandibular function, but not in reducing pain, in temporomandibular disorders patients who had concurrent temporomandibular joint capsulitis and disc displacement without reduction.

The case of a patient with bilateral preauricular pain and tinnitus is reported. Minimal relief was obtained with traditional temporomandibular disorders therapy, and complete relief was obtained after endodontic therapy. Pulpal conditions that can refer pain are discussed, and recommendations are made to help practitioners identify a possible pulpal etiology for symptoms and tests of temporomandibular disorders.