Temporomandibular joint disorders' impact on pain, function, and disability

The aim of this study was to determine the association between more advanced stages of temporomandibular joint (TMJ) intra-articular disorders ("TMJ intra-articular status"), representing a transition from normal joint structure to TMJ disc displacement with and without reduction (DDwR and DDwoR) to degenerative joint disease (DJD), and patient-reported outcomes of jaw pain, function, and disability ("TMD impact"). This cross-sectional study included 614 cases from the RDC/TMD Validation Project with at least one temporomandibular disorder (TMD) diagnosis. TMJ intra-articular status was determined by 3 blinded, calibrated radiologists using magnetic resonance imaging and computed tomography as one of normal joint structure, DDwR, DDwoR, or DJD, representing the subject's most advanced TMJ diagnosis. TMD impact was conceptualized as a latent variable consisting of 1) pain intensity (Characteristic Pain Index from the Graded Chronic Pain Scale [GCPS]), 2) jaw function (Jaw Functional Limitation Scale), and 3) disability (Disability Points from GCPS). A structural equation model estimated the association of TMJ intra-articular status with the latent measure TMD impact as a correlation coefficient in all TMD cases (n = 614) and in cases with a TMD pain diagnosis (n = 500). The correlations between TMJ intra-articular status and TMD impact were 0.05 (95% confidence interval [CI], -0.04 to 0.13) for all TMD cases and 0.07 (95% CI, -0.04 to 0.17) for cases with a pain diagnosis, which are neither statistically significant nor clinically relevant. Conceptualizing worsening of TMJ intra-articular disorders as 4 stages and characterizing impact from TMD as a composite of jaw pain, function, and disability, this cross-sectional study found no clinically significant association. Models of TMJ intra-articular status other than ours (normal structure → DDwR → DDwoR → DJD) should be explored.

Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders

There is a need to expand the current temporomandibular disorders' (TMDs) classification to include less common but clinically important disorders. The immediate aim was to develop a consensus-based classification system and associated diagnostic criteria that have clinical and research utility for less common TMDs. The long-term aim was to establish a foundation, vis-à-vis this classification system, that will stimulate data collection, validity testing and further criteria refinement. A working group [members of the International RDC/TMD Consortium Network of the International Association for Dental Research (IADR), members of the Orofacial Pain Special Interest Group (SIG) of the International Association for the Study of Pain (IASP), and members from other professional societies] reviewed disorders for inclusion based on clinical significance, the availability of plausible diagnostic criteria and the ability to operationalise and study the criteria. The disorders were derived from the literature when possible and based on expert opinion as necessary. The expanded TMDs taxonomy was presented for feedback at international meetings. Of 56 disorders considered, 37 were included in the expanded taxonomy and were placed into the following four categories: temporomandibular joint disorders, masticatory muscle disorders, headache disorders and disorders affecting associated structures. Those excluded were extremely uncommon, lacking operationalised diagnostic criteria, not clearly related to TMDs, or not sufficiently distinct from disorders already included within the taxonomy. The expanded TMDs taxonomy offers an integrated approach to clinical diagnosis and provides a framework for further research to operationalise and test the proposed taxonomy and diagnostic criteria.

Human temporomandibular joint and myofascial pain biochemical profiles: a case-control study

Neurobiological mechanisms of human musculoskeletal pain are poorly understood. This case-control study tested the hypothesis that biomarkers within temporomandibular muscle and joint disorders (TMJD) subjects' masseter muscles or temporomandibular joint (TMJ) synovial fluid correlate with plasma biomarker concentrations. Fifty subjects were recruited and categorized into TMJD cases (n=23) and pain-free controls (n=27) at the University of Minnesota School of Dentistry. Prior to specimen collection, pain intensity and pressure pain threshold masseter muscles and the TMJs were assessed. We collected venous blood; biopsied masseter muscle; and sampled TMJ synovial fluid on the subjects' side of maximum pain intensity. We assayed these tissues for the presence of nerve growth factor (NGF), bradykinin (BK), leukotreine B(4) (LTB(4) ) and prostaglandin E(2) (PGE(2) ), F(2) -isoprostane (F(2) I) and substance P (SP). The data was analyzed using Spearman Correlation Coefficients. We found that only plasma concentrations of bradykinin statistically correlated with synovial fluid concentrations (ρ=-0·48, P=0·005), but no association was found between pain intensities. The data suggests that biomarkers used to assess TMJD need to be acquired in a site-specific manner. We also discovered that F(2) I concentrations were associated with muscle pain intensity and muscle pressure pain threshold (PTT) (β=0·4, 95%CI: 0·03-0·8) and joint PPT (β=0·4, 95%CI: 0·07-0·8) suggesting that muscle oxidative stress is involved in myofascial pain and that F(2) -I may be a biomarker for myofascial pain.

Reliability and validity of Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) with proposed revisions

  The research diagnostic criteria for temporomandibular disorders (RDC/TMD) have been employed internationally since 1992 for the study of temporomandibular muscle and joint disorders (TMD). This diagnostic protocol incorporates a dual system for assessment of TMD for Axis I physical diagnoses as well as Axis II psychological status and pain-related disability. Because the reliability and criterion validity of RDC/TMD had not yet been comprehensively characterised, the National Institute of Dental and Craniofacial Research funded in 2001 the most definitive research to date on the RDC/TMD as a U01 project entitled, 'Research Diagnostic Criteria: Reliability and Validity'. The results of this multi-site collaboration involving the University of Minnesota, the University of Washington, and the University at Buffalo were first reported at a pre-session workshop of the Toronto general session of the International Association of Dental Research on 2 July 2008. Summaries of five reports from this meeting are presented in this paper including: (i) reliability of RDC/TMD Axis I diagnoses based on clinical signs and symptoms; (ii) reliability of radiographic interpretations used for RDC/TMD Axis I diagnoses; (iii) reliability of self-report data used for RDC/TMD Axis I diagnoses; (iv) validity of RDC/TMD Axis I diagnoses based on clinical signs and symptoms; and (v) proposed revisions of the RDC/TMD Axis I diagnostic algorithms.

Psychometric properties of the modified Symptom Severity Index (SSI)

The psychometric properties of the modified Symptom Severity Index were investigated to assess the relationships among dimensions of pain in temporomandibular disorders (TMD). The 15-item instrument is composed of ordinal scales assessing five pain dimensions (intensity, frequency, duration, unpleasantness and difficulty to endure) as experienced in three locations (temple, temporomandibular joint (TMJ), masseter). In 108 closed-lock subjects, Cronbach's alpha was used to measure internal consistency resulting in 31 of the 105 pair-wise comparisons >or=0.71. Multilevel exploratory factor analysis was used to assess dimensionality between items. Two factors emerged, termed temple pain and jaw pain. The jaw pain factor comprised the TMJ and masseter locations, indicating that subjects did not differentiate between these two locations. With further analysis, the jaw pain factor could be separated into temporal aspects of pain (frequency, duration) and affective dimensions (intensity, unpleasantness, endurability). Temple pain could not be further reduced; this may have been influenced by concurrent orofacial pains such as headache. Internal consistency was high, with alphas >or=0.92 for scales associated with all factors. Excellent test-retest reliability was found for repeat testing at 2-48 h in 55 subjects (Intra-class correlation coefficients = 0.97, 95%CI 0.96-0.99). In conclusion, the modified Symptom Severity Index has excellent psychometric properties for use as an instrument to measure pain in subjects with TMD. The most important characteristic of this pain is location, while the temporal dimensions are important for jaw pain. Further research is needed to confirm these findings and assess relationships between dimensions of pain as experienced in other chronic pain disorders.

Randomized effectiveness study of four therapeutic strategies for TMJ closed lock

For individuals with temporomandibular joint (TMJ) disc displacement without reduction with limited mouth opening (closed lock), interventions vary from minimal treatment to surgery. In a single-blind trial, 106 individuals with TMJ closed lock were randomized among medical management, rehabilitation, arthroscopic surgery with post-operative rehabilitation, or arthroplasty with post-operative rehabilitation. Evaluations at baseline, 3, 6, 12, 18, 24, and 60 months used the Craniomandibular Index (CMI) and Symptom Severity Index (SSI) for jaw function and TMJ pain respectively. Using an intention-to-treat analysis, we observed no between-group difference at any follow-up for CMI (p > or = 0.33) or SSI (p > or = 0.08). Both outcomes showed within-group improvement (p < 0.0001) for all groups. The findings of this study suggest that primary treatment for individuals with TMJ closed lock should consist of medical management or rehabilitation. The use of this approach will avoid unnecessary surgical procedures.

Pressure-pain thresholds and MRI effusions in TMJ arthralgia

It has been suggested that MRI-depicted effusions identify patients with TMJ arthralgia. The Research Diagnostic Criteria (RDC) propose a pressure-pain threshold (PPT) of 1 pound for the identification of TMJ arthralgia. The hypotheses in this study were that: (1) there is no association between MRI-depicted effusions and TMJ arthralgia, and (2) a PPT of 1 pound does not discriminate between subjects with and those without arthralgia. Thirty females with TMJ disc displacement with reduction were divided into two groups based on the presence or absence of the self-report of TMJ pain. Bilateral TMJ PPTs and MRIs were obtained. Increasing palpation pressure from 1 to 3 pounds increased the sensitivity for identifying arthralgia from 22% to 100%, with a corresponding decrease in the specificity from 100% to 81%. The sensitivity and specificity of effusions for identifying arthralgia were 85% and 28%, respectively. These results suggest that the use of palpation pressures greater than 1 pound is a valid test for TMJ arthralgia. However, TMJ effusions lack adequate specificity for identifying TMJ arthralgia and were not associated with pain.

The relationship between clinical and MRI findings in patients with unilateral temporomandibular joint pain

BACKGROUND

With the advent of magnetic resonance imaging, or MRI, clinicians and researchers have sophisticated techniques by which to assess the anatomy of the temporomandibular joint, or TMJ. Imaging is indicated when the results will affect the patient's care beyond that which can be gained from a complete clinical assessment. One of the primary indications for treatment of patients with temporomandibular disorders, or TMDs, is jaw pain, including TMJ pain. Therefore, it is necessary to assess whether MRI-depicted TMJ findings are associated with TMJ pain. This study assessed the relationship between TMJ pain and clinical and MRI findings.

METHODS

Subjects consisted of 85 patients with unilateral jaw pain in the area of the TMJ. The contralateral, nonpainful TMJ served as the matched control. All patients underwent a complete stomatognathic examination that included palpation of both TMJs. No care was given and no anti-inflammatory medications were prescribed until bilateral MRIs were obtained within one week.

RESULTS

The authors found significant relationships between the side of reported jaw pain and the patient's report that palpation of the TMJ was painful and between the side of reported pain and the presence of MRI-detected effusions. The authors found no relationship between the side of reported pain and the presence of a disk displacement, or DD, or between the presence of effusions and DD on either side of the jaw.

CONCLUSION

Although MRI-depicted effusions of the TMJ were associated with reports of TMJ pain, there was a high level of false-positive and false-negative findings. The results indicate that palpation of the TMJ is more accurate than MRI-depicted effusions in identifying the TMJ as the source of pain for patients with unilateral jaw pain.

CLINICAL IMPLICATIONS

The results of this study suggest that palpation of the TMJ is superior to MRI in identifying the joint as the source of pain. Therefore, the most cost-effective and valid test to determine if the TMJ is a source of jaw pain is a complete clinical assessment.

Temporomandibular joint iontophoresis: a double-blind randomized clinical trial

This double-blind study evaluated the short-term effect of iontophoretic delivery of dexamethasone on the signs and symptoms of temporomandibular disorders in patients who had concurrent temporomandibular joint disc displacement without reduction and capsulitis. Twenty-seven patients with this clinical diagnosis were randomized to one of three groups: treatment group (dexamethasone sodium phosphate and lidocaine hydrochloride); control group (lidocaine hydrochloride); and placebo group (pH-buffered saline). Pretreatment and posttreatment data included items to calculate Helkimo's Anamnestic Dysfunction index, Helkimo's Clinical Dysfunction index, the Symptom Severity Index, and the Craniomandibular Index (CMI). The CMI is composed of the Dysfunction index (DI) and Muscle index. Analysis of variance showed no baseline differences on these measures between the three groups. Pretreatment and posttreatment values were compared with the paired t tests. Posttreatment, the treatment group had an increased mean maximal active mandibular opening of 6 mm (P = .02), increased mean lateral excursion of 1.2 mm to the noninvolved side (P = .05), and reduced mean DI scores of 0.51 to 0.39 (P = .01); no statistically significant decrease in pain symptoms was reported. Analysis of variance showed a significant difference in the DI scores (P = .04) between groups from pretreatment to posttreatment, with the treatment group showing the greatest improvement in the DI scores relative to the other two groups. No other questionnaire items, exam items, or resultant indexes showed changes in any of the groups at P < or = .05. These results suggest that iontophoretic delivery of dexamethasone and lidocaine was effective in improving mandibular function, but not in reducing pain, in temporomandibular disorders patients who had concurrent temporomandibular joint capsulitis and disc displacement without reduction.

Treatment alternatives for patients with masticatory myofascial pain

Alternative therapies are used by many people, and the dental literature has reported that some alternative therapies are comparable to splint therapy in the effective treatment of masticatory myofascial pain. The authors review the efficacy of alternative therapies and discuss their clinical implications. This review is intended to help dental practitioners to select alternative therapies they can use with or instead of splint therapy for treating patients who have a primary diagnosis of myofascial pain.

The relationship between level of mandibular pain and dysfunction and stage of temporomandibular joint internal derangement

Temporomandibular joint internal derangement (TMJ ID) is the most common intra-articular TM disorder and can progress from TMJ ID with reduction to TMJ ID without reduction. It is not known whether this anatomical progression is associated with increasing levels of mandibular dysfunction. The objective of this study was to determine whether the level of clinically detectable mandibular dysfunction was related to the stage of TMJ ID. Two clinicians examined 42 subjects prior to bilateral TMJ arthrographic evaluation. The level of mandibular dysfunction was calculated by Helkimo's Clinical Dysfunction Index (Di) and the Craniomandibular Index (CMI). Statistical analysis revealed that the level of mandibular dysfunction as determined by the Di and CMI was not related to the arthrographic presence or absence of TMJ ID. Therefore, the clinician cannot assume that the level of mandibular dysfunction is directly related to the absence or presence of TMJ ID. Epidemiologically, the CMI and Di can be used only for estimation of the degree of mandibular dysfunction, since they do not provide direct information on a specific TM disorder.

The relationship of occlusion, parafunctional habits and recent life events to mandibular dysfunction in a non-patient population

This study investigated the association between occlusion, oral habits and stress relative to the level of mandibular dysfunction in the total population and in specific diagnostic subgroups (normal, joint disorder, muscle disorder and joint/muscle disorder). A total of 269 nursing students were given a questionnaire and examination. The questionnaire included items to calculate an oral habit index and a social readjustment rating scale. The examination included items to calculate an occlusal index, two craniomandibular indices and a diagnostic criteria for specific subgroups. In the total population there was a positive association between mandibular dysfunction and three postulated risk factors. The total population was then divided into diagnostic subgroups. There was a positive association between the degree of mandibular dysfunction and parafunctional habits for normals, muscle disorders and joint/muscle disorders. There was a positive association between mandibular dysfunction and occlusion for normals only. Finally there was a positive association between mandibular dysfunction and stress for muscle disorders only. The results suggest that associations between postulated aetiologic factors and mandibular dysfunction vary depending on whether the subjects have a muscle and/or joint disorder. Since all associations were weak, other possible risk factors need to be investigated.

The prevalence and treatment needs of subjects with temporomandibular disorders

A cross-sectional study of prevalence of temporomandibular joint (TMJ) internal derangements, muscle disorders, and associated TM signs and symptoms was completed on 269 female nursing students. The prevalence of specific stages of internal derangements of the TMJ and muscle disorders was estimated, using established diagnostic criteria. The levels of dysfunction and symptomatology associated with each diagnosis were estimated with previously established indexes. When subjects with symptoms were asked if they had previous treatment for a TMJ problem, 6.7% responded positively. When subjects with symptoms who had not had treatment were asked why they had not sought treatment, most responded that it was not a problem or they could live with the symptoms. Thus, most subjects with clinically detectable dysfunction are functioning adequately without significant symptoms and do not need treatment.

Clinical vs. arthrographic diagnosis of TMJ internal derangement

Internal derangements of the temporomandibular joint (TMJ) have gained increased recognition as a potential source of pain and dysfunction of the masticatory system. The objective of this study was to evaluate the reliability of clinicians in predicting an arthrographic diagnosis of articular disc position in a typical patient population presenting for TMJ arthrographic evaluation. Two clinicians utilized a brief history, clinical examination (including evaluation of mandibular movement and TMJ auscultation), and tomographic TMJ imaging in evaluating 60 patients. The radiologist subsequently performed the arthrographic procedures on 102 TMJs (18 unilateral and 42 bilateral). Diagnostic agreement was determined for all possible diagnostic categories including: normal disc position, TMJ internal derangement with reduction, TMJ internal derangement without reduction/acute, TMJ internal derangement without reduction/chronic, and osteoarthrosis. The significance of the diagnostic agreement between the clinicians and arthrography was evaluated with a Kappa Statistical Test, which showed good reliability. For epidemiological studies, it was concluded that clinical and tomographic evaluation would provide sufficient reliability for determination of the presence and stage of TMJ internal derangement. However, in a specific clinical situation, a difficult diagnostic problem may require the use of arthrography, depending on the impact of the diagnosis on subsequent treatment decisions.

The craniomandibular index: validity

The CMI appears to be valid for use in clinical studies, but users must be aware of its numerous potential errors and its associated strict methodologic guidelines to ensure accuracy and reproducibility of results. The subjective nature of some items demands that the same rater who is unaware of the management status of the patient perform both evaluations. If multiple raters are used, it is recommended that the raters discuss all items, and compare scoring of demonstration subjects before the study and use a pressure algometer for muscle palpation.

Reliability of a craniomandibular index

The Craniomandibular Index (CMI) was developed to provide a standardized measure of severity of problems in mandibular movement, TMJ noise, and muscle and joint tenderness for use in epidemiological and clinical outcome studies. The instrument was designed to have clearly defined objective criteria, simple clinical methods, and ease in scoring; it is divided into the Dysfunction Index and the Palpation Index. Inter-rater reliability (three raters) and intra-rater reliability (19 patients examined twice by one rater) were tested to determine whether the instrument has operational definitions sufficiently precise to allow for consistency in use between different raters and with one rater over time. Intraclass Correlation Coefficient for inter-rater reliability was 0.84 for the Dysfunction Index, 0.87 for the Palpation Index, and 0.95 for the CMI. Correlation for intra-rater reliability was 0.92 for the Dysfunction Index, 0.86 for the Palpation Index, and 0.96 for the CMI. These results support the reliability of the CMI for use in epidemiological and clinical studies. Users are cautioned about the subjectivity of numerous items within the CMI and the strict methodological guidelines that must be followed in order to assure accuracy and reproducibility of results.