Reduced thermal threshold in patients with Temporomandibular Disorders.

BACKGROUND: Many studies have demonstrated the presence of somatosensory modulation changes at different sites in patients with temporomandibular disorders (TMDs) using different modalities. However, the neck area, a well-know condition related to TMD, remains unexplored. OBJECTIVE: To assess the thermal pain threshold in patients with TMD and controls at cephalic and extra-cephalic areas, including the neck. METHODS: Twenty female patients with TMDs diagnosed by the Research Diagnostic Criteria for TMD (RDC/TMD) and twenty age-matched controls underwent a first interview about neck pain and disability (NDI questionnaire). A blinded evaluator assessed the thermal pain threshold for cold (CPT) and heat (HPT) stimuli in accordance with an ascending method of limits of the Quantitative Sensory Testing at the following sites: periorbital, masseter, cervical posterior and ventral forearm. The groups were compared using a t-test with alpha = 5%. RESULTS: Patients with TMDs reported pain at higher temperature for cold stimuli in all sites (P < 0.05) and at lower temperature for heat stimuli in the right periorbital site (P < 0.05) than controls. Pain and disability due tothis symptom were reported more often in the TMD group (P < 0.05). CONCLUSION: Patients with TMD have pain modulation changes in the neck area as well, especially for cold stimuli, associated with higher disability and a higher report of neck pain than controls. These findings reinforce the evidence regarding the relationship between TMDs and neck pain.