Which symptom is most characteristic of disc displacement with reduction (DDwR) compared to myofascial pain?

• A. Persistent muscle tenderness without joint noises.
• B. Intermittent numbness in the chin.
• C. A jaw joint click or intermittent noise during opening or closing is hallmark of DDwR.
• D. Significant bone pain.

Answer: (C)

A key distinction when evaluating TMD is the joint sound during movement. In disc displacement with reduction, the disc sits anterior to the condyle at rest but returns to its normal position during mouth opening, producing a characteristic jaw click or intermittent noise. This audible event reflects the dynamic disc–condyle interaction and helps separate it from myofascial pain, where pain and tenderness come from the muscles without joint sounds.

Persistent muscle tenderness without joint noises fits myofascial pain rather than disc displacement with reduction. Intermittent numbness in the chin suggests nerve involvement rather than a disc-to-condyle movement issue. Significant bone pain is not typical for disc displacement with reduction and would point to other pathologies.