Journal of Oral & Facial Pain and Headache, 03/1996

Cadaver material was used in this study to correlate sequential sagittal and coronal T1-weighted magnetic resonance images against anatomic detail. Magnetic resonance imaging (MRI) was found to accurately represent soft tissues in normal and deranged joints. In contrast to previous reports, MRI was found to accurately represent the discal-retrodiscal junction and did not appear to give false positive findings for disc displacement. Magentic resonance imaging provided good images of bony outline, particularly in coronal views. Difficulties in interpretation arose when different adjoining tissues produced the same MR image; the central tendon of the lateral pterygoid muscle can appear as an extension of the disc, imaging as a distorted and displaced disc. In anatomic sections, a medial hernia sac in the lower joint space was seen as a constant indicator of the medial component of disc displacement; however, this was not evident in sagittal and coronal T1-weighted images. Fibrocartilaginous remodeling of the articular surface projecting into a discal perforation presented the same image as normal discal tissue. Because discs are often thinned over the lateral pole, it is difficult to determine whether discal tissue is present between the articular surfaces when MRI is at its present resolution. Subcortical bone spaces may be misinterpreted as areas of avascular necrosis and osteochondritis dissecans. It is recommended that an imaging sequence of the TMJ include a mid-condyle image and lateral, central, and medial sagittal images; however, the lateral sagittal image is the most difficult to interpret.

To better understand pathologic processes associated with arthritis of the temporomandibular joint (TMJ), detailed information on the innervation of TMJ tissues in normal as well as arthritic joints is needed. The aim of this study was to describe the normal innervation of the sheep TMJ in preparation for using this animal as a model for the study of the effects of arthritis on joint innervation. The macroscopic and microscopic appearance plus the distribution of neural structures within the TMJ were examined using fluorescence histochemistry (glyoxylic acid), immunohistochemistry (calcitonin gene-related peptide), silver, and gold chloride techniques. Joints from 10 mature merino sheep were studied. Calcitonin gene-related peptide-immunoreactive nerve fibers were found in the capsule and the synovial membrane, but not in the disc. Nerve bundles and single nerve fibers in the capsule, synovial membrane, and the peripheral 2 to 3 mm of the disc were stained by glyoxylic acid. Ruffini, paciniform-type, and Golgi organ nerve endings plus free nerve endings were located in the capsule, with the highest density of nerve endings occurring at the site of attachment of the disc to the capusle. The highest density of neural structures (using gold chloride) was in the posterior part of the joint. The highest density of autnomic fibers (using glyoxylic acid) was in the anterior capusle. The highest density of sensory fibers (using calcitonin gene-related peptide) was in the synovial and subsynovial tissues of the anterior capsule. These results confirm the existence of autonomic and sensory nerves in the capsule, synovial membrane, and peripheral disc in healthy adult sheep.

This study examined the effects of the intensity, quality, and duration of odotogenic pain on the incidence, pattern, and clinical characteristics of pain referral in the orofacial region. Four hundred consecutive patients reporting with posterior toothache to the dental emergency clinic were included. Patients completed a standardized clinical questionnaire consisting of a numerical rating scale for pain intensity and chose verbal descriptors from a list of adjectives describing the quality of their pain. In addition, patients indicated sites to which pain referred by drawing on a mannequin of the head and neck. Pain intensity was found to significantly affect the prsence of referred pain (P .005). However, neither duration nor quality of pain influenced the incidence of referred pain. Finally, pain referral occurred in vertical laminations as indicated on mannequin drawings, but these were not found to be diagnostic because of extensive horizontal overlap. The association of intensity and referral is attributed to central nervous sytem hyperexitability causing expansion of receptive fields and spread and referral of pain.

The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) guidelines, originally developed in the United States, were translated and used to classify TMD patients on physical diagnosis (Axis I) and pain-related disability and psychologic status (Axis II) in a TMD specialty clinic in Sweden. The objectives of the study were to determine if such a translation process resulted in a clinically useful diagnostic research measure and to report initial findings when the RDC/TMD was used in cross-cultural comparisons. Findings gathered using the Swedish version of the RDC/TMD were compared with findings from a major US TMD specialty clinic that provided much of the clinical data used to formulate the original RDC/TMD. One hundred consecutive patients were enrolled in the study. Five patients with rheumatoid arthritis and 13 children or adolescents were excluded. The remaining 82 patients participating in the study comprised 64 women and 18 men. Group I (muscle) disorder was found in 76% of the patients; Group II (arthralgia, arthritis, arthrosis) disorder was found in 25% and 32% of the patients in the right and left joints, respectively. Axis II assessment of psychologic status showed that 18% of patients yielded severe depression scores and 28% yielded high nonspecific physical symptom scores. Psychosocial dysfunction was observed in 13% of patients based on graded chronic pain scores. These initial results suggest that the RDC guidelines are valuable in helping to classify TMD patients and allowing multicenter and cross-cultural comparison of clinical findings.

The aim of this study was to evaluate the prevalence and need for treatment of temporomandibular disorders (TMD) in students living in Bauru, Brazil. The role of occlusal and emotional factors was also addressed. The presence and severity of TMD was determined by using a self-reported anamnestic questionnaire composed of 10 questions regarding common TMD symptoms. The symptoms were transposed into a severity classification according to the number and frequency of positive responses. Occlusalevaluation included an analysis of retruded contact position, intercuspal position, anterolateral guidance, and nonworking side contacts during mandibular movements. Palpation of the muscles and temporomandibular joints were performed to detect clinical signs of TMD. A chi square test was used to compare clinical and occlusal data with the presence and severity of TMd. A total of 0.65% of the subjects had severe TMD symptoms, 5.81% had moderate symptoms, and 34.84% had mild symptoms. Those with severe and moderate symptom levels were interpreted to be in need of treatment. Symptoms were found significantly more frequently in females than in males (P .01). Self-reported emotional tension and parafunctional habits demonstrated strong associations with should be reconsidered, and reversible and conservative procedures should be the first choice for managing TMD patients.

The aim of this study was to assess possible gender differences regarding the reporting of pain, somatic complaints, and anxiety in a group of patients suffering from temporomandibular disorders (TMD). The group consisted of 40 females and 13 males who received conservative TMD treatment comprising counseling, muscle exercises, and a stabilization splint. Before and 2 years after treatment, the patients answered three questionnaires (McGill Pain Questionnaire [Norwegian version] including a six-point scale, the Present Pain Intensity; a Somatic Complaints Questionnaire; and the trait part of Spielberger's State-Trait Anxiety Inventory). Before treatment, females reported greater persent pain intensity than did males. Two years after treatment, females reported less sensory and emotional pain than at the initial stage; males presented no reduction in these pain scores. There were no gender differences at either stage regarding somatic complaints or anxiety level scores.

Surface electromyography of the masseter and electrocardiogram recordings of heart activity during sleep were performed on nine subjects who suffer from an oral motor dysfunction (bruxism) during sleep. Signals were monitored in the subject's home sleeping environment over 4 consecutive nights. A total of 36 nights of data were analyzed to perform the following: (1) describe the nature and magnitude of total masseter muscle electrmyographic activity above a minimum threshold of 3% of each subject's indivudally established maximum voluntary contraction level; and (2) describe electrocardiograph rate changes (using the R-R interval) that occurred in relation to these electromyographic elevations. From these data, criteria for detection of bruxism events were established and combined into a fully automated event detection algorithm. The mean number and duration of the detected bruxism events are reported. The underlying logic for the criteria selected, and what effect other possible criteria would have on the separation of abnormal from normal motor events, is also presented and discussed.