Comparing TMD diagnoses and clinical findings at Swedish and US TMD centers using research diagnostic criteria for temporomandibular disorders

The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) guidelines, originally developed in the United States, were translated and used to classify TMD patients on physical diagnosis (Axis I) and pain-related disability and psychologic status (Axis II) in a TMD specialty clinic in Sweden. The objectives of the study were to determine if such a translation process resulted in a clinically useful diagnostic research measure and to report initial findings when the RDC/TMD was used in cross-cultural comparisons. Findings gathered using the Swedish version of the RDC/TMD were compared with findings from a major US TMD specialty clinic that provided much of the clinical data used to formulate the original RDC/TMD. One hundred consecutive patients were enrolled in the study. Five patients with rheumatoid arthritis and 13 children or adolescents were excluded. The remaining 82 patients participating in the study comprised 64 women and 18 men. Group I (muscle) disorder was found in 76% of the patients; Group II (arthralgia, arthritis, arthrosis) disorder was found in 25% and 32% of the patients in the right and left joints, respectively. Axis II assessment of psychologic status showed that 18% of patients yielded severe depression scores and 28% yielded high nonspecific physical symptom scores. Psychosocial dysfunction was observed in 13% of patients based on graded chronic pain scores. These initial results suggest that the RDC guidelines are valuable in helping to classify TMD patients and allowing multicenter and cross-cultural comparison of clinical findings.