Comparing methods for diagnosing temporomandibular joint disk displacement without reduction.

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 K 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.