Journal of Oral & Facial Pain and Headache, 02/1995

The masseter muscles of six nonbruxing subjecs (five men, one woman) and six bruxing subjects (four men, two women) were assessed during chewing by nuclear magnetic resonance spectroscopy (31P-NMR). The NMR spectra were collected on a GE Sigma 1.5T whole body magnet with a double-tuned 31P/1H surface coil. Two-minute trials of rest/chewing/rest were completed three times. Averaged spectra of inorganic phosphate, phosphocreatine, and three adenosine 5' triphosphate peaks were collected in each trial. Bruxing subjects had a lower concentration of total phosphate during chewing significantly less than control subjects. The pH levels during rest and during chewing were similar in both controls and bruxers. These preliminary results suggest that bruxing subjects exhibit an altered phosphate metabolism pattern during chewing as compared to nonbruxing subjects.

Interleukin - 6 - dependent mouse hybridoma cell line KD83 used to test the biologic activity of interleukin-6 in synovial fluid from 37 patients with temporomandibular disorders. The results showed taht the interleukin-6 level was greater than 100 U/mL in 13 of 18 patients with degenerative joint disease and in five of 12 patients with temporomandibular disc displacement. However, the interleukin-6 level was less than 100 U/mL (range, 20 to 75 U/mL) in all patients with masticatory muscle disorder. It has been found that degenerative joint disease tends to have acute and chronic stages, and interleukin-6 activity was probably related to the acute stage in the patients. Histologic studies of the synovium from several patients with degenerative joint disease showed a variable degree of hyperplasia of the synovial lining cells and chronic inflammation in five of eight specimens. Immunostaining studies clearly showed the presence of significantly more HLA-DR-expressing cells (human leukocyte antigen-D-related) in synovium. Although it is unlikely that immune responses play an important primary role in initiating synovial inflammation and cartilage destruction, immune reactions may be one important factor in the maintenance and severity of some patients with temporomandibular disorders.

Ongoing pain, intermittent sharp pain, or intermittent dull aching pain around the teeth can evoke the suspicion of tooth pathology. However, when no dental cause can be found clinically or radiographically, the differential diagnosis involving neuropathic pain and pulpal pathology is still a chalenge. Neuropathic fcial pains are still too often misdiagnosed as tooth pain of dental origin, resulting in unnecessary dental extraction or endodontic therapy. The purpose of this study was to determine if electronic thermography was able to differentiate neuropathic acial pains presenting as toothache from pulpal pathology. electronic thermography was used to compare asymptomatic subjects and subjects with neuropathic facial pains. Asymptomatic subjects and subjects with trigeminal neuralgia, pre-trigeminal neuralgia, and pulpal pain without periapical pathology showed no thermographic difference in the territory of the pain complaint when compared to the opposite nonpainful side. Patients with sympatheticaly maintained traumatic trigeminal neuralgia (atypical odontalgia) and half of the group with sympathetically independent traumatic trigeminal nueralgia presented with hot thermograms. The other half of the patients with sympathetically independent traumatic trigeminal neuralgia displayed cold thermograms in the area of their pain complaints. Electronic thermography was the least selective test for the group showing cold thermogram patterns (80% agreement with the thermographic characterization criteria). These data suggest that electronic thermography may be helpful in differentiating neuropathic pains from pulpal pathology.

A retrospective investigation of 257 patient records from a university-based facial pain center for patients with temporomandibular disorders examined the natural history patients with temporomandibular disorders for consultation and treatment of their complaints. Data were obtained on a variety of demographic variables, referral patterns, types of providers seen for consultation, and the types of diagnostic tests ordered by these providers. Results showed that patients with temporomandibular disorders see more than three providers prior to their referral to a tertiary care center, that a considerable proportion of those providers are physicians, that patients reported undergoing a variety of diagnostic tests, and that patients reported receiving a variety of diagnoses for their condition. Results also showed that patients who initially consulted a physician were somewhat more likely to be referred to another physician, while patients who consulted a dentist were highly likely to be referred to another dentist.

This study was designed to investigate stresses in the TMJ clenching in patients with skeletal discrepancies in the vertical direction. A three-dimensional model of the mandible including the TMJ was used for finite element analysis for the stresses. The model, referred to as a standard model, consists of 2,088 modes and 1,105 solid elements, comprising the cortical and cancellous bones, articular disc and cartilage layer, and periodontal ligament. The standard model was modified by varying the gonial and mandibular plane angles to simulate vertical discrepancies between the maxilla and mandible observed in open and deep bites. Stresses were analyzed on the surfaces of the condule, the glenoid fossa, and the articular disc, and the values were compared to those found with the standard model. Stresses increased substantially for the condule, the glenoid fossa, and the articular disc with greater gonial and mandibular plane angles, and those changes were more obvious in association with the divergent mandibular plane. Thus, the nature of stress distributins in the TMJ was substantially affected by vertical discrepancies of the craniofacial skeleton. It is also suggested that these changes in stresses produce a lack of biomechanical equilibrium in the TMJ, which may have some association with tempromandibular disorders.

This study investigated the relationship between forward head posture and temporomandibular disorder symptoms. Thirty-three temporomandibular disorder patients with predominant complaints of masticatory muscle pain were compared with an age-and gender-matched control group. Head position was measured from photographs taken with a plumb line drawn from the eiling to the lateral mallelus of the ankle and with a horizontal plane that was perpendicular to the plumb line and that passed through the spinous process of the seventh cervical vertebra. The distances from the plumb line to the ear, to the seventh vertebra, and to the shoulder were measured. Two angles were also measured: (1) ear-seventh cervical vertebra-horizontal plane and (2) eye-ear-seventh cervical vertebra. The onlly measurement that revealed a statistically significant difference was angle ear-seventh cervical vertebra-horizontal plane. This angle was smaller in the patients with temporomandibular disorders than in the control subjects. In other words, when evaluating the ear position with respect to the seventh cervical vertebra, the head was positioned more forward in the group with temporomandibular disorders than in the control group.

Progression of degenerative joint disease is dependent on the underlying pathologic and/or reactive processes involved that, in general, compromise tissue adaptability. A review of clinical and experimental literature relating to degenerative joint disease is presented. Epidemiology, pathogenesis, diagnosis, treatment, and prognosis are described with particular emphasis given to the temporomandibular joint. This article describes factors affecting the temporomandibular joint remodeling/degeneration parity and presents rationale for approaches to diagnosis and treatment.

The aim of the present investigation was to study the interexaminer reliability of orthopedic tests and palpation techniques routinely used in the clinical diagnosis of disorders of the masticatory system. The tests were performed by a dentist and a physiotherapist, who both used the tests routinely when examining patients with temporomandibular disorders. Seventy-nine patients participated in this study. In the analysis, percentage agreement, intraclass correlation, and Cohen's kappa were used. The interexaminer reliability of the tests measuring maximal active mouth opening and registration of clicking during active mouth opening was high. The interexaminer reliability was fair for the tests measuring the intensity of pain during active movements and moderate for tests recording joint sounds (k=0.47 to 0.59). There was high interobserver agreement on several items of the traction and translation tests, although the kappa values were low. The interexaminer reliability of the multitest scores for compression was substantial for joint sounds (k=0.66) and fair for pain (k=0.40). The interexaminer reliability of the multitest scores for muscle palpation and joint palpation was moderate (k=0.51) and fair (k=0.33), respectively. It can be concluded that most variables determined during active movements can be measured with satisfactory reliability, whereas variables for other tests are not measured with the same reliability on the basis of the kappa scores. The main symptoms of temporomandibular disorders can be evaluated reliably with multitest scores. It is recommended that clinicians calibrate their techniques regularly to improve the reliability of results in daily practice.

Thirty subjects seeking treatment for masticatory muscle pain at a university based TMJ clinic were randomly assigned to soft-splint, palliative-treatment, and no-treatment groups. After 4 to 11 weeks of treatment, subjects were evaluated for changes from their baselinelevels of symptoms, maximum pain-free opening, pain thresholds measured by a pressure algometer, and occlusal contacts. With the use of the multivariate analysis of variance and analysis of covariance, the results suggest that the soft-splint group had statistically significant improvement (p.01), the palliative-treatment group had improvement that was not statistically significant, and the no-treatment group had a slight aggravation of symptoms. The soft-splint group had fewer occlusal contact changes assessed with shimstock sompared to the palliative-treatment and no-treatment groups. The findings of this study suggest that the soft splint is an effective short-term treatment for reducing the signs and symptoms of masticatory muscle pain in patients, and the soft splint does not cause occlusal changes.