Journal of Oral & Facial Pain and Headache, 01/1994

Specialized roles for the different components of the retrodiscal tissues have been previously postulated. This study compared the histologic features of the retrodiscal tissues of temporomandibular joints, taken from human cadavers, in the open and closed position; it was concluded that the primary role of these components was to provide a volumetric compensatory mechanism for pressure equilibration. This mechanism was still active in joints that demonstrated disc displacement and degenerative changes. Elastin was found in the upper and lower strata of the retrodiscal tissues, as well as in the central zone. The concept of an elastic upper stratum that has a recoil mechanism to control disc movement was not supported by this study, as the upper stratum was folded on itself in the closed position and only became stretched near maximal opening.

To evaluate the clinical course of temporomandibular joint osteoarthrosis and internal derangement, 99 patients who had received nonsurgical treatment for temporomandibular problems were reexamined 30 years after the original treatment. Results were compared with information obtained from patients' clinical examinations before and a few years after the original treatment as well as information from the clinical examination of 35 control subjects. During the first years after treatment, the main signs of temporomandibular joint osteoarthrosis and internal derangement decreased significantly. In the next three decades, very few changes were noticed. Clicking and crepitus were the most common remaining signs. These signs, however, did not appear to be bothersome to the patients. It was concluded that the disorders in question eventually reach a state of quiescence.

The accuracy and reliability of the TMJ Scale were originally determined in cross-validation studies on large, research-based patient samples. It had been assumed that the demographic characteristics and test responses of these research-based samples would be representative of the clinical population in which the TMJ Scale would ultimately find use. The present study on more than 10,000 patients that were evaluated for temporomandibular disorders in clinical practice demonstrates that the test scores, demographic variables, and the patterns of symptom severity that characterize the original TMJ Scale research sample accurately represent the general temporomandibular disorder patient population in which the TMJ Scale is now being used. The results suggest a high degree of confidence in the clinical efficacy of this assessment tool. The overall symptom severity of temporomandibular disorders was found to be normally distributed in the patient population. Women with temporomandibular disorders report a higher level of severity of all physical and psychological symptoms than men. This may explain the high female-to-male ratio in patients seeking treatment. However, a higher percentage of male temporomandibular disorder patients has clinically significant psychological and stress-related problems than do women. The severity and prevalence of symptoms associated with joint dysfunction and range of motion limitation are lower in older age groups, and the overall symptom severity of temporomandibular disorders is not higher in older age groups. However, the severity and prevalence of symptoms associated with joint dysfunction are greater in groups in which temporomandibular disorders have existed for longer durations, although pain levels do not follow this trend. There is also an association between time duration of the temporomandibular disorder and the severity of psychological problems and chronicity. Patients with chronic problems are symptomatically more impaired than those with acute problems.

An immunohistochemical investigation for the neurospecific markers S-100 protein and protein gene product 9.5 was carried out on 12 healthy temporomandibular joint discs and capsules that were taken at autopsy from human adults. Large nerve trunks in the joint capsule and posterior disc ligament, as well as small nerve bundles and single nerves in almost all parts of the capsule, were heavily stained by anti-S-100 antiserum. The S-100 immunoreactive chondrocytes were also detected in the disc. Antiprotein gene product 9.5 similarly evidenced nerve fibers in the capsule and posterior disc ligament, and it also labeled a few small nerve bundles and a number of single fibers in the peripheral portions of the disc. No corpuscular or specialized endings were encountered in the specimens. These results give new support to the existence of a rich innervation of the human temporomandibular joint capsule and disc that should be further characterized with regard to type, function, and neuropeptide content.

Comprehensive evaluation of mandibular function requires a broader assessment of the head, neck, and jaws than is normally performed. Examining only the teeth and periodontium will fail to assess problems in muscles and joints, which should be considered in the management plan. Recognition of function-related symptoms is important in the prediction of treatment outcomes. Stress-induced muscle tension and traumatic oral habits may be linked with reported symptoms of headache, earache, and temporomandibular joint problems, and the significance of these symptoms should be assessed through detailed clinical examination.

Single photon-emission computerized tomography scintigraphy was used to examine 250 patients who previously had temporomandibular joint sounds auscultated and recorded with a Doppler machine. Patients were divided into four groups based on the presence of joint sounds: no sound, reciprocal clicks, reciprocal clicks with crepitus, and crepitus. Statistically significant differences between the groups and the single photon-emission computerized tomography scintigraphy results were determined. There was no correlation between these results and the no sound and crepitus groups, but significant correlation was established between positive results and crepitant joints with reciprocal clicks and noncrepitant clicking joints.

Chronic habitual chewers usually present with a lack of passive laterotrusive range of mandibular motion at maximum intercuspation, and many have some form of mandibular asymmetry. This study attempted to discover mechanisms that may be responsible for this association and proposes a system by which such persons can be classified based on physiognomy and patterns of mandibular deviation. The influence of facial biotype and altered head posture on the selection of a preferred chewing side was also analyzed.

This study established a method of detecting temporomandibular joint sounds based on signal-to-noise ratios. After comparing the temporomandibular joint signals obtained from three different sites over the skin, the articular eminence was found to be the best site for detecting temporomandibular joint sounds; this site provided the highest mean amplitude in the time domain waveform. However, using an electret condenser microphone at the intra-auditory meatus provided a broader, 20-decibel signal-to-noise bandwidth, which resulted in minimized artifacts. This method may be useful for recording temporomandibular joint sounds in the differential diagnosis of various temporomandibular joint conditions using spectral analysis.

Clinical, electromyographic, and kinesiographic methods were used to evaluate 35 female patients presenting with craniomandibular disorders. Twenty-six similarly aged, symptom-free women served as controls. Clinical assessments showed that the patients demonstrated a higher prevalence of bruxism than did the controls. Electromyographic results suggested that the rest activity of patients' elevators was significantly greater than that of the controls. Kinesiographic measurements showed that the patient group demonstrated greater vertical and anterior posterior movements from rest to centric occlusion than did the control group, and both the average and maximum opening velocities were smaller in patients than in controls.

Most surgical and nonsurgical treatments of painful temporomandibular joint internal derangements are primarily directed toward relief of pain and dysfunction; correction of disc displacement is increasingly of lesser or no concern. However, internal derangements are variably progressive and, in some patients, cause condylar deformity with secondary deficiency of the mandible. If data support the hypothesis that condylar deformity and growth retardation can result from a displaced disc, and, conversely, that a normally positioned disc permits normal growth and maintains condylar mass, a goal of any treatment for reducing disc displacement should include reestablishment of a normal disc/condyle relationship. Functional appliance therapy for the deficient mandible may be most effective in those patients that present with a normal disc/condyle relationship; if a reducing disc is present, such therapy may be most effective only when the appliance advances the condyle to a position beneath the disc.