In the clinical assessment of a patient with temporomandibular disorder (TMD), which factor is considered the LEAST important in establishing a definitive TMD diagnosis?

The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and its successor, the DC/TMD, identify the most diagnostically relevant factors as: mandibular range of motion measurements, presence of joint sounds (clicking, crepitus), and muscle/joint tenderness on palpation. While pain history (onset, duration, aggravating factors) is important, the specific quality of pain (sharp vs. dull) has lower diagnostic specificity for TMD subtype classification compared to objective clinical findings. Most TMD pain is described as dull, aching, or pressure-type. The pain quality alone does not distinguish between myofascial pain, disc displacement, or degenerative joint disease.