Use of the research diagnostic criteria for temporomandibular disorders for multinational research: Translation efforts and reliability assessments in The Netherlands

Aims: To outline the steps taken to conduct and to culturally adapt Dutch translations of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) history questionnaire, clinical examination form, and verbal instructions to the patients, and to assess the reliability of the clinical examination. Methods: For the linguistic translation from English into Dutch, the forward and back-translation approach was followed. For cultural adaptation, an expert panel reviewed the translation, and a pretest was performed on a small clinical sample. Examiner training and calibration were carried out, and the clinical reliability of a "gold standard examiner" and 3 clinicians was assessed on 18 symptomatic TMD patients and 6 asymptomatic controls. The order of the examinations was based on a quasi-random Latin square design. Intraclass correlation coefficients (ICCs) were calculated to assess the overall interexaminer reliability of the clinical examination. Results: A linguistically valid and culturally equivalent translation of the RDC/TMD into Dutch resulted from the above-outlined procedure. As for the clinical reliability, the ICC values obtained could mostly be considered "excellent" or, less frequently, as "fair to good." Poor reliability was found only for some of the palpation tests. For uncommon diagnoses (disc displacement without reduction and without limited mouth opening; osteoarthritis), no reliable ICC value could be calculated. Conclusion: The mode described by the authors for preparing clinical sites for RDC/TMD-based research is a feasible one.