Reliability and validity of the DC/TMD Axis I

We thank the authors of the critical commentaries for their efforts and appreciation of our recommendations to improve the DC/TMD1. Drs. Schiffman and Ohrbach have mentioned the Standards for Reporting Diagnostic Accuracy (STARD) requirement to justify the use of computed tomography (CT) and magnetic resonance imaging (MRI) as a reference standard in the Validation Project. Yet the inclusion of a reference standard that does not show an association with the temporomandibular conditions under study cannot be the basis for reporting diagnostic accuracy. Without doubt, CT and MRI play an important role in specific TMD conditions to confirm temporomandibular joint (TMJ) inflammation in rheumatic disease, malignancy, or growth disorders. In nonspecific temporomandibular conditions, however, the role of imaging is less pronounced. We are convinced that this point will continue to be discussed as long as a proper reference standard for nonspecific temporomandibular conditions is lacking. Without an appropriate reference standard, it is not possible to report the sensitivity and specificity of the (R)DC/TMD tests. The most one can achieve at this point in time is to report the reliability of test results within and among examiners. Moreover, the risk of circularity in the Validation Project raises doubt over the presented diagnostic validity, as other authors have already pointed out.