The association between wear facets, bruxism, and severity of facial pain in patients with temporomandibular disorders.

STATEMENT OF PROBLEM: It is unclear whether patients with temporomandibular disorders (TMD) who report high levels of bruxism have more severe signs and symptoms of TMD and more advanced tooth wear than patients with TMD who report lower levels of bruxism. PURPOSE: The purpose of this study was to determine whether there was a significant association between tooth wear, the parafunctional oral habit of bruxism, temporomandibular joint (TMJ) pain, and muscle pain severity in a TMD population. MATERIAL AND METHODS: A total of 84 subjects previously diagnosed with TMD, according to the Research Diagnostic Criteria for TMD (RDC/TMD) and who met 10 specific inclusion/exclusion criteria underwent a thorough multiaxial examination and classification recommended by the National Institute of Dental and Craniofacial Research (NIDCR). Measurement of tooth wear facets by use of a 4-point scale were graded in 10 zones on mandibular casts. One calibrated examiner performed all scoring. Bruxism was assessed in a standardized pretreatment questionnaire and in the dental history and interview (RDC/TMD) to indicate how frequently (0 = never to 3 = very often) subjects performed a list of oral habits, which included bruxism. The Kappa reliability coefficient (range from: -1.0 to 1.0) was used to correct for chance agreement, and was computed for each of the 10 study sites designated for rating. Subjects were also compared for muscle and joint pain. Muscle pain was a summed measure derived from the dental examination findings (range 0 to 20), calculated from the presence or absence of pain induced by palpation of 20 predetermined muscle sites. Similarly, joint pain was a summed measure of the presence or absence of pain in the TMJs induced by palpation of the joints on the outer surface and in the external auditory canal in 5 different positions of the mandible. A Pearson product-moment correlation was used to compute the summed severity of tooth wear and the subjects' age. Analysis of covariance was used to determine whether the number of wear facets was significantly higher in patients with TMD who reported a history of bruxism, compared with patients with TMD who reported no or minimal bruxism, after controlling for the effect of age. Multivariate analysis of variance was used to determine whether the number of painful muscles of mastication and joint sites on standardized examination were significantly higher in patients with TMD with a history of bruxism (alpha=.05). RESULTS: In the population tested, tooth wear was modestly correlated with age (r =.40, P<.001). Of the 84 subjects studied, 11.9% reported no bruxing activity, 32.1% reported some or occasional bruxing activity, and 47.6% had frequent bruxism activity; the remaining 8.4% were eliminated from analysis because they provided inconsistent responses. Bruxism activity was not correlated with muscle pain on palpation and was inversely associated with TMJ pain on palpation. Tooth wear was not significantly correlated with bruxism, TMJ pain, or muscle pain. CONCLUSIONS: In this TMD population, tooth wear factors did not differentiate patients with bruxism from those without. The amount of bruxism activity was not associated with more severe muscle pain and was associated with less pain in the TMJ on palpation.

Relation of jaw sounds and kinematics visualized and quantified using 3-D computer animation.

The management of jaw pain or temporomandibular disorders (TMD) has been controversial regarding temporomandibular joint (TMJ) sounds and their implication regarding TMD prognosis. 3-D computer animation was used to visualize and quantify the internal mechanics of natural mandibular motion synchronized with TMJ sounds. Mandibular movements of four TMD patients and two healthy subjects were recorded using CCD cameras and reflective markers. Sounds were recorded with electret microphones. Magnetic resonance imaging was used to create 3-D geometric models. Visualization of the internal anatomy, mandibular condyle and glenoid fossa, revealed that the condyle initially rotated within the fossa and then moved out of the fossa along, and well beyond, the articular eminence. Power in the opening sound recordings after the condyle moved out of the fossa was significantly greater than when the condyle was within the fossa (p<0.001). The louder opening sounds were often classified as TMJ clicks, implying that clicks occur after the condyle moves out of the fossa. The 3-D computer animation should help resolve the implication of TMJ sounds regarding TMD prognosis by providing visualization and quantization of the TMJ internal mechanics during sound production.

Differential treatment responses of TMD patients as a function of psychological characteristics.

A number of studies have reported that psychological factors play a significant role in TMD. Several studies have identified subgroups of patients based on their responses to psychological assessments; however, none of these studies have reported on the clinical utility of classifications of TMD patients on these various measures. In this study, the differential response of 133 TMD patients classified within 3 psychosocial-behaviorally based subgroups to a conservative, standardized treatment was examined. The treatment consisted of the combination of an intra-oral appliance, biofeedback, and stress management. Follow-up assessments were conducted 6 months after treatment termination. The results demonstrated that overall as a group patients significantly improved and maintained improvements on physical, psychosocial, and behavioral measures (P < 0.0001). Comparisons across patient subgroups, however, revealed differential patterns of improvement on the outcome measures. Most notably, reliable change indices demonstrated that the patients classified into a subgroup characterized by the greatest degree of psychological distress (Dysfunctional) demonstrated significantly greater improvements on measures of pain intensity (P < 0.001), perceived impact of TMD symptoms on their lives (P < 0.001), depression (P < 0.01), and negative thoughts (P < 0.001), compared with groups characterized by greater interpersonal problems (Interpersonally Distressed) and those patients who appeared to be the least disabled by TMD (Adaptive Copers). These data provide support for the clinical utility of a psychosocial-behavioral classification system and suggest that in future research individualizing treatments and outcome measures based on patient characteristics may improve treatment efficacy and outcome evaluation.

An empirical taxometric alternative to traditional classification of temporomandibular disorders.

A number of investigators have suggested that the generic classification temporomandibular disorders (TMD) may consist of several subsets of patients. Two primary factors are to be significant in discriminating subgroups, namely, presence or absence of TM joint abnormalities and psychological characteristics such as traits, maladaptive behavioral patterns, and gross psychopathology. Few attempts, however, have been made to integrate psychosocial and behavioral parameters in order to identify a taxonomy of TMD patients and, subsequently, to examine the differentiation of subgroups on oral dysfunction/structural abnormalities (OD/SA). The primary purpose of this paper was to develop and cross-validate an empirically derived classification system of TMD patients. The first study identified three unique subgroups of TMD patients, labeled 'dysfunctional,' 'interpersonally distressed,' and 'adaptative copers.' A second study cross-validated and confirmed the uniqueness and accuracy of the taxonomy. Subsequent analyses were performed that demonstrated that these groups were not distinguishable on the basis of any measures of OD/SA. The taxonomy identified is compared and contrasted with other reported subgroups of TMD patients and the implications of this classification system for treatment of TMD patients are discussed.