Accuracy of two forms of infrared image analysis of the masticatory muscles in the diagnosis of myogenous temporomandibular disorder.

The aim of the present study was to assess the accuracy of two forms of infrared image analysis (area and extension) of the masseter and anterior temporalis muscles in the diagnosis of myogenous temporomandibular disorder (TMD). A cross-sectional study was carried out involving 104 female volunteers from the university community. Following the application of the Research Diagnostic Criteria for Temporomandibular Disorders, the volunteers were divided into a TMD group (n = 52) and control group (n = 52), and evaluated using infrared thermography. The area and extension of the masseter and anterior temporalis muscles were measured on the images. The receiver operating characteristic (ROC) curve was used to determine diagnostic accuracy (area under the curve), best cutoff point, sensitivity and specificity. A significant difference in skin temperature between groups was only found in the measurement of the area of the left anterior temporalis muscle (p = 0.011). The area under the ROC curve was less than the reference values for all muscles evaluated in the analyses of area and extension. Thus, neither method of infrared thermography tested for the quantification of the masseter and anterior temporalis muscles (analysis of area and extension) is consistent with the RDC/TMD for the diagnosis of myogenous TMD in women.