Validation of the Portuguese version of the RDC/TMD Axis II questionnaire.

The present paper aimed at evaluating the validity of the Portuguese version of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II Questionnaire. The sample was comprised of 155 patients with signs and symptoms of Temporomandibular Disorders (TMD), evaluated at the Orofacial Pain Control Center, School of Dentistry, University of Pernambuco, Brazil, between July 2003 and February 2004. Data collection was performed with the following tools: the RDC/TMD Axis I (clinical evaluation and TMD classification), and Axis II (psychosocial evaluation), as well as specific questionnaires for evaluation of Oral Health Related Quality of Life, namely, Oral Impacts on Daily Performances and the Oral Health Impact Profile-14, considered to be gold standard criteria. Validity evaluation consisted of internal consistency evaluation by the Cronbach alfa reliability test, reliability and reproducibility estimated by the Kappa test and the Spearman's correlation, and concurring validation through Spearman's correlation. The Portuguese version of the RDC/TMD Axis II questionnaire was considered consistent (Cronbach alfa = 0.72), reproducible (Kappa values from 0.73 to 0.91, p < 0.01), and valid (p < 0.01). It was concluded that this version showed valid and reproducible results for the Brazilian population, thus paving the way for including Brazil in transcultural epidemiological studies on TMD.