Objective: The purpose of this study was to assess whether recalibration of examiners would improve the reliability of gathering clinical findings and related diagnoses of temporomandibular disorders (TMD) in accordance with the Research Diagnostic Criteria for TMD (RDC/TMD).
Material and methods: Two clinicians independently examined a total of 48 symptomatic and asymptomatic subjects according to the RDC/TMD on two occasions: examination 1 (E1). Aarhus, Denmark (n=24; 18 female, ages 18-59 years); examination 2 (E2). Malmö, Sweden (n=24; 18 female, ages 18-86 years). The clinicians were calibrated in the use of the RDC/TMD Axis-I examination on the day before E1. Six months later, they were recalibrated on the day before E2. Intra-class correlation coefficients (ICCs) were used to examine the inter-examiner reliability of the two clinicians on the two occasions (E1, E2).
Results: The intra-class correlation coefficients of vertical range of jaw motion differed little between E1 and E2. At E2, all other examination components consistently improved in reliability relative to E1. Similar improvements were seen for the frequently occurring RDC/TMD clinical diagnoses: Ia. Myofascial pain [ICC = 0.83 (E1) and 1.00 (E2)], IIa. Disk displacement with reduction [ICC = 0.26 (E1) and 0.64 (E2)], and IIIa. Arthralgia [ICC = 0.16 (E1) and 0.73 (E2)].
Conclusion: Recalibration considerably improved inter-examiner reliability for assessing RDC/TMD clinical variables and diagnoses, which are critically dependent on reliable assessment of clinical signs; improvement was most marked when initial inter-examiner reliability was low. Final inter-examiner reliabilities after recalibration were all associated with acceptable to excellent levels.