© 2002 American Dental Association
Background. Research is needed to assess the validity of the Clinical Diagnostic Criteria for Temporomandibular Disorders, or CDC/TMD. The authors conducted a prospective, double-blind study to determine whether applying the specific CDC/TMD diagnosis of TMJ internal derangement, or ID, type III would demonstrate good agreement with diagnoses obtained by MRI.
Methods. The study comprised 138 TMJs in 69 subjects who had a clinical diagnosis of unilateral TMJ ID type III (disk displacement without reduction). The authors obtained bilateral sagittal and coronal MRIs to establish the corresponding diagnosis of disk-condyle relationship.
Results. For the CDC/TMD interpretations, the positive predictive value of ID type III for disk displacement without reduction was 86 percent, and for the presence of an ID it was 91 percent. The overall diagnostic agreement for ID type III was 78.3 percent with a corresponding value of 0.57. Most of the disagreement was due to false-positive interpretations of an absence of ID.
Conclusions. The results suggest that using CDC/TMD for ID type III is predictive for the presence of an ID but is not sufficiently reliable for determining disk displacement without reduction. Parameters other than the functional disk-condyle relationship may need to be addressed to account for the biological plausibility of this entity.
Clinical Implications. A clinical TMJ-related diagnosis of ID type III may need to be supplemented by evidence from an MRI to determine the functional disk-condyle relationship. Investigation of longitudinal evidence, including risk factors, history and response to treatment, appears to be warranted.
The measurable and reproducible set of Clinical Diagnostic Criteria for Temporomandibular Disorders, or CDC/TMD, for the most common forms of TMD was published in 1992 to provide a standardized definition of diagnostic sub-goups of patients with orofacial pain and TMDs.1 Each criterion refers to a particular examination and interview item, and each item is accompanied by specifications on how to perform the diagnostic procedure.2
A clinical temporomandibular joint–related diagnosis of internal derangement type III may need to be supplemented by evidence from a magnetic resonance image.CDC/TMD was developed in an attempt to form a common set of working criteria for classifying subjects in TMD epidemiology and treatment studies. It classifies the most common forms of TMD into the main diagnostic subgroups of masticatory muscle disorder; temporomandibular joint, or TMJ, internal derangement, or ID; and TMJ degenerative joint disease. To verify that these disorders and diseases represent distinct entities, data supporting decisive differences in the areas of pathogenesis, treatment and prognosis are essential.3 Validating the masticatory muscle disorder subgroup may be difficult because of the lack of available definitive diagnostic procedures or of "biological gold standards" that may define some pathological changes.4–6 TMJ imaging techniques, on the other hand, can be used to validate the diagnostic criteria for TMJ ID and TMJ degenerative joint disease. Magnetic resonance imaging, or MRI, is the most accurate imaging modality for identifying TMJ disk positions and may be regarded as the "gold standard" for disk position identification purposes.7 A study of observer variation when the classification system proposed by Tasaki and colleagues8 is used has shown a low level of intraobserver and interobserver variability.9
We conducted this prospective, double-blind study to determine whether applying the specific CDC/TMD diagnosis of TMJ ID type III would demonstrate good agreement with diagnoses obtained by MRI.