Hypersensitivity to mechanical and intra-articular electrical stimuli in persons with painful temporomandibular joints.

This study tested whether persons with TMJ arthralgia have a modality-specific and site-specific hypersensitivity to somatosensory stimuli assessed by quantitative sensory tests (QST). Forty-three healthy persons and 20 with TMJ arthralgia participated. The QST consisted of: sensory and pain detection thresholds and summation threshold to intra-articular electrical stimulation, tactile and pin-prick sensitivity in the TMJ area, pressure-pain threshold and tolerance on the lateral side of the TMJ and on the finger. Persons with TMJ arthralgia had lower pain detection and summation thresholds (P < 0.001), higher ratings of tactile and pin-prick stimuli (P < 0.05), and markedly lower pressure thresholds on the TMJ and finger (P <0.001) than did healthy individuals. Correlation analysis revealed associations between several QST and clinical pain measures. This study provides new evidence of sensitization of the TMJs as well as central nociceptive pathways. QST may facilitate a mechanism-based classification of temporomandibular disorders.