Diagnostic Tests

An accurate diagnosis requires a reasonably reliable and reproducible diagnostic protocol that screens for multiple causes of facial pain. The history and physical examination remain critical to developing a differential diagnosis. Although advocated by some clinicians, the use of sonography, electromyography, myomonitor- ing, and kinesiology has little to offer for the diagnosis of TMD [13, 14]. Although the use of MRI of the TMJ to diagnose disc displacement or degenerative joint disease is reasonable, these pathological entities may not be responsible for pain and reduced function unless suggested by the history and clinical examination [15]. Disc displacements occur in nearly one third of asymptomatic and healthy subjects [16]. Imaging studies are necessary if the patient has failed to respond to conservative treatment for intra-articular disorders, and TMJ surgery is being considered.

The original Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) is the most widely used diagnostic protocol for researchers and clinicians to diagnose common diagnostic subsets of TMD [17]. The RDC/TMD diagnostic protocol is divided into Axis I that consists of the history and physical exam and Axis II which assesses related psychosocial dysfunction and psychological distress. In 2014, the RDC/TMD was renamed to the Diagnostic Criteria of Temporomandibular Disorders (DC/TMD) and was revised to present new evidence-based Axis I and Axis II diagnostic criteria for the 12 common TMDs [18]. Sensitivity and specificity values have been established for 10 of the 12 diagnostic subsets of TMD. Diagnostic protocols with a sensitivity of > .70 and specificity of > .95 are considered satisfactory. Currently only five of the ten subsets of TMD have diagnostic protocols with adequate sensitivity and specificity. The remaining five subsets of TMD do not have diagnostic protocols with satisfactory sensitivity and specificity values. The DC/TMD is intended for immediate implementation in clinical and research settings. Incorporating the DC/TMD criterion along with

Table 2.1 Diagnostic subset of TMD with sensitivity and specificity [14]

clinical reasoning and experience will guide the clinician to make an accurate diagnosis of TMD, including intra-articular pathology that may benefit from surgical intervention. (Table 2.1)

The diagnostic subsets of TMD are not mutually exclusive, and it is not uncommon to have patients with more than one diagnosis [19, 20]. The DC/TMD diagnostic criteria are based on the patient having singular Axis I diagnosis rather than multiple diagnostic subsets of TMD. Future versions of the DC/TMD will need to identify patients who meet criteria for multiple diagnostic subtypes. Failing to identify a patient with more than one subset of TMD may also result in treatment failure. It behooves clinicians to seek concurrent diagnostic subsets of TMD and other sources of facial pain in all patients.