Temporomandibular disorders (TMD) often result in pain and masticatory dysfunction, despite a range of treatments. As several studies have shown that stimulation of the primary motor cortex can provide analgesia in patients with refractory central pain, this study assessed the effect of high definition transcranial direct current stimulation (tDCS) in patients with pain-related TMD.

Subjects were 24 female adults with chronic myofascial TMD pain, all with daily, chronic pain and dysfunction for at least one year. Pain was measured with a Visual Analogue Scale (VAS), the Short Form of the McGill Pain Questionnaire and Pain Trek, as well as pain-free mouth opening. All subjects underwent 20-minute sessions of active or sham 2 mA HD-tDCS at the M1 stimulation area, five times per day. The primary outcome measure was a pain VAS decrease of 50% or greater from week one to week six.

At week six, nine of 13 in the active group and three of 11 in the sham group achieved a greater than 50% decrease in VAS pain (P＝0.04). There was a significant difference in the change in pain free opening of the mouth from week one to week three (P<0.01), but not at week six (P＝0.24).

This study of female patients with chronic temporomandibular disorders found that high definition transcranial direct current stimulation can produce meaningful, long-term pain relief.