Effects of Transcranial Direct Current Stimulation (tDCS) on Patients With Chronic Orofacial Pain

Inclusion criteria: * Male and female between 18 and 75 years old * Clinic history of previous orofacial and/or dental surgery * Chronic orofacial pain for more than a year measurable by the VAS more than 3 . * Pain not responsive to pharmacological treatment (analgesic, anti inflammatory, opiaces, antidepressant drugs and physiotherapy modalities) Outcome measures: Subjects will be assessed before the beginning of the treatment (T0), after tDCS (T1) and after one month of stimulation(T2) . In the two weeks prior to T0 the patient will be asked in a questionnaire to report daily the level of pain, anxiety and state of mind using the VAS. This period of observation is necessary for the patient to get used to these measures and to underline possible intra-subject changing. • Clinic scales -Visual Analogue Scale (VAS): it is one of the most used between scales for pain evaluation \[18\] RDC/TMD AXIS I: diagnostic classification for temporomandibolar disfunction. RDC/TMD AXIS II: behavioral questionnaire (7 questions about chronic pain severity) which evaluates chronic pain following the graded scale for chronic pain. * Symptoms Checklist-90-R scales (SCL 90-R): Depression and anxiety assessment for non-specific physical symptoms * electrical pain threshold: The Digitimer High Voltage Stimulator model DS74 provides high voltage pulses of constant current up to 100mA, pulses are of short duration and the output current is variable ranging between 0 and 100mA. The Digitimer is used to evaluate the pain perception threshold by applying electrical stimulation to the index finger to a pulse duration of 200 ls. The initial current applied is 0mA and increases of 0.1 mA until the subject feels pain. * Oral Health Impact Profile 49 (OHIP 49): provides a measure of social impact of oral disorders by providing a comprehensive measure of dysfunction, discomfort and disability resulting from the oral cavity conditions. The OHIP-49 is based on the adaptation of the World Health Organization classification. * Pain detect Questionnaire Pressor pain threshold