Assessment and further development of RDC/TMD Axis II biobehavioural instruments: a research programme progress report.

A symposium was held in Toronto, 2008, in which research progress regarding the biobehavioural dimension of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was presented. An extended workshop was held in April 2009 in which further recommendations were made from an expert panel, using the 2008 symposium material as a base. This paper is a summary of the 2008 symposium proceedings with elaborations based on further developments. Seven studies were conducted between 2001 and 2008, in which the following were investigated: (i) basic properties of Axis II instruments, (ii) reliability and criterion validity of Axis II instruments, (iii) expansion of predictors, (iv) metric equivalence of the depression and non-specific physical symptoms subscales in the RDC/TMD, (v) laboratory investigation of oral behaviours, (vi) field data collection of oral behaviours, and (vii) functional limitation of the jaw. Methods and results for each of these studies are described. Based on the results of these studies that have been published, as well as the direction of interim results from the few studies that await completion and publication, the biobehavioural domain of the RDC/TMD, as published in 1992, is reliable and valid. These results also provide strong evidence supporting the future growth of the biobehavioural domain as the RDC/TMD matures into subsequent protocols for both clinical and research applications.