Journal of Oral & Facial Pain and Headache, 02/1997

The articular disc of the temporomandibular joint was studied in fetuses (16 to 39 weeks of intrauterine life), infa nts (up to 4 months of age), dentulous adults (aged 30 to 39 years), and completely edentulous adults (aged 60 to 69 years) by scanning electron microscopy. The constituent bundles of collagen fibers were stratified and were oriented anteroposteriorly, laterolaterally, and obliquely in the middle portion of the disc. A ring of laterolateral bundles constituted the main feature of the thick posterior portion. In the anterior portion of the disc, the fibers were anteroposteriorly and obliquely oriented. On the superior and inferior surfaces of the disc, a thin layer of perpendicularly arranged collagen fibers covered the underlying, thick, laterolateral oriented collagen fibers.

The purpose of this study was to investigate normal physiologic tremor in jaw movement as a factor that may influence chewing performance more directly than either muscle activity or jaw displacement. Chewing performance was defined in terms of the reduction in food particle size after 15 chewing strokes. Data on chewing particle size and electromyographic activity were available for 24 asymptomatic adults from an earlier study. Jaw movements during chewing were recorded using electrognathography, and velocity and acceleration in three planes were determined. Power spectrum for acceleration was calculated during opening and closing phases of the chewing cycle. The frequency of the peak amplitude in the power spectrum represented physiologic tremor of the jaw. Tremor frequencies during both opening and closing phases of the chewing cycle were strong predictors of chewing performance. A multivariate model composed of variables derived from acceleration, together with electromyographic and jaw movement variables, produced a multivariate model that was able to predict chewing performance with an adjusted R2 value of .78.

There is a growing body of evidence that psychologic stressors can affect physical health and proneness to disease through depletion of the body's immune system. Relativ ely little research, however, has ivnestigated the pot ential immunoenhancing effect of stress-relieving strategies such as progressive muscle relaxation. This study e xplored the relationship between immune functioning and relaxation training with persons experiencing persistent facial pain. In a single experimental session, 21 subjects either received relaxation training or rested for an equivalent time period. S alivary immunoglobulin A, mood, pain, and tension levels were measured before and after relaxation and rest periods. Results indicated that a greater proportion of those receiving relaxation training had increases in secretion of salivary immunoglobulin A. These findings suggest that immunoenhancement may be another potential benefit of progressive relaxation training for perso ns with chronic pain conditions.

This study tested the hypotheses that electromyographic (EMG) activity at rest would be significantly greater for temporomandibular disorder (TMD) patients with myofascial pain than for nonpain control subjects, and that a cutoff score based on EMG values could be established to accurately separate the two groups. Fifty-four TMD patients diagnosed with myofascial pain and 54 nonpain control subjects who were matched for age and gender were examined. Both groups participated in an EMG scanning procedure in which the left and right frontalis, temporalis, and masseter muscles were examined. Results showed that the TMD group had significantly higher EMG activity at rest for three of the six sites examined. The application of a cutoff value that produced the smallest classification error nonetheless resulted in misclassification of about one third of the TMD and nonpain individuals. These data provide little support for the use of resting EMG data obtained via a scanning procedure in accurately distinguishing facial pain patients from nonpain control subjects.

Randomized clinical trials are recognized as providing the most rigorous evidence of treatment efficacy. For temporomandibular disorders, randomized clinical trails have been used to evaluate the efficacy of low-cost occlusal appliances or the adjunct use of cognitive behavioral interventions. However, noncompliance with treatment regimens and losses to follow up are common randomized clinical trial protocol violations that compromise the desired rigor or the trial. At times it is not clear to the investigator how to deal with these issues during the trial and at the data analysis phase. Often treatment efficacy is based on the compliant subjects, subjects who may no longer represent randomized groups or yield the desired fair estimate of treatment efficacy. This study focuses on management of compliance issues, the description and collection of data needed to obtain a more accurate assessment of treatment efficacy, and results particularly relevant to actual clinical practice and patient care decisions. These are applied to a randomized clinical trial evaluating the efficacy of a cognitive-behavioral intervention for temporomandibular disorders.

The clinical efficacy, side effect liability, and hormonal effects of two prototypic pharmacologic agents were evaluated for the management of chronic myogenous facial pain in a double-blind, randomized, controlled clinical trial. Thirty-nine subjects (35 women, 4 men) with daily or near-daily orofacial pain of at least 3 months' duration and tenderness to palpation of masticatory muscles participated. Patients were randomly allocated to one of four treatments: placebo, diazepam, ibuprofen, or the combination of diazepam and ibuprofen, Pain, mood, muscle tenderness, maximal interincisal opening, and plasma levels of B-endorphin were measured following 2-week baseline and 4-week treatment periods. Pain, as measured by a visual analog scale, was significantly decreased in the diazepam and diazepam plus ibuprofen groups but not for the ibuprofen or placebo groups. Analysis of variance showed a significant drug effect for diazepam but not for ibuprofen, indicating that pain relief was attirbutable to diazepam. No significant changes were noted in muscle tenderness, interincisal opening, or plasma B-endorphin level. This study supports the efficacy of diazepam in the short-term management of chronic orofacial muscle pain. The lack of effect following administration of an anti-inflammatory analgesic suggests that inflammation is not the basis for chronic muscle pain in the orofacial region, and that the analgesic effect of such medications is not sufficient for pain relief in this condition.

Recent recommendations regard musculoskeletal disorders of the masticatory system as dual-axis disorders, but little comparative data of psychologic factors across different pain populations are available. In this study, presenting psychologic factors across different pain populations are available. In this study, presenting psychologic profiles were assessed in 40 Australian and 42 Finnish patients diagnosed with temporomandibular disorders. Findings were compared with those of a group of Australian patients reporting acute dental pain and with reference to response to conservative management. The psychologic testing instrument incorporated cognitive, motivational/affective, and illness behavior variables, and it was based on validated general pain questionnaires (Coping strategies Questionnaire and Illness Behavior Questionnaire). This instrument was found internally reliable in the majority of its subscales in the group studies and provided comparable data to other pain populations. Significant differences in the presenting psychologic profiles were found according to nationality, type of pain suffered, and treatment outcome. Affective disturbance, hypochondriasis, lack of cognitive control, and feeling ill with symptoms were identified in discriminant function analysis as potential predictors of treatment outcome, and they correctly classified 79% of the Australian and 87% of the Finnish patients with temporomandibular disorders. It was concluded that psychologic profiles differed in the two nationalities and were related to treatment outcome. The concept of multiaxial assessment was supported.

The objective of this study was to assist clinicians in the diagnosis of the occipital neuralgia syndrome by describing its clinical characteristics. Bibliographies and clinical descriptions of occipital neuralgia syndrome were identified through a review of literature published between 1966 and 1993. A prospective case series was performed by the authors in a unviersity emergency department during a 1-year period. Patients with unilateral aching pain of the head, coupled with pain in the distribution of the occipital nerve, Tinel's sign, and relief of pain after local anesthetic injection, were included. Patients rated pain relief on a 10-point scale. Twelve patients met the criteria for occipital neuralgia and w ere included in the study. All patients reported at least 80% decrease of pain after injection, and 42% had complete relief. Clinical features, other than headache, that were common in patients included tinnitus in 33%; scalp paresthesia, 33%; nausea, 42%; dizziness, 50%; and visual disturbances, 67%. Occipital neuralgia is a benign extracranial cause of headache, and it may be confused with other more serious headache syndromes. Recognition depends on an understanding of the symptoms along with a careful history and physical examination. Local anesthetic injections produce significant relief of the headaches and can aid in the diagnosis of the syndrome.

This guide provides a method for evaluating permanent impairment due to injury of the temporomandibular joint (TMJ). Each author represents a major organization whose members treat displacement and joint degeneration, (2) range of motion, and (3) surgery. The rating values are comparable to those provided in the American Medical Association Guides to the Evaluation of Permanent Impairment for functional and disc-protected joints, so TMJ impairment values obtained by use of this guide can be combined with values for other impairments rated in accord with the AMA Guides. This guide for rating of TMJ impairment is intended for individualized application. A conservative attitude and sound clinical judgment are recommended.