IRCT201512251760N44 IRCT 2016-02-23 Vice chancellor for Research, Babol University of Medical Sciences Assessment of the effect of photodynamic therapy on treatment of moderate-to-severe periodontitis Assessment of the effect of photodynamic therapy on treatment of moderate-to-severe periodontitis 2015-12-22 anticipated 30 Complete https://irct.ir/trial/1308 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Other design features: Groups based on all parameters (including PPD, CAL, BOP and plaque index) and with regard to the inclusion and exclusion criteria will be mentioned in the same building. All calculations weeks, third, sixth and twelfth after treatment by a clinicians will no longer do. Blindness study done. 2-3 Chronic periodontitis. Intervention 1: Control groups: This group will be under scaling/root planting (SRP) treatment. Intervention 2: Intervention group 1: In this group, Photo-dynamic Therapy will be used. Intervention 3: Intervention group 2: A combination of Photodynamic Therapy and SRP will be used in this group. Treatment processes of Photodynamic Therapy will be done immediately after SRP. The light-sensitive material used in the study (manufacturer: CMS Dental, Denmark) contains 10 milligrams per milliliter methylene Blue (16, 18, and 19) that will be directly applied inside the periodontal pockets for at least 60 seconds. Then, using PhotoSan system (manufactured by the same company) and by means of a 15-mm perio-tip located inside each periodontal pocket, all surfaces of the tooth are exposed for at least 30 seconds and the pocket is rinsed. Given the uniform distribution of light in this system, it will be possible to distribute it throughout the periodontal pockets.