Доклади на Българската академия на науките Comptes rendus de l’Acad´ emie bulgare des Sciences Tome 72, No 1, 2019 MEDICINE Oral medicine EFFECT OF DIODE LASER TREATMENT ON THE LEVEL OF IL-6 IN THE GINGIVAL CREVICULAR FLUID IN PATIENTS WITH CHRONIC PERIODONTITIS Theodora Bolyarova, Raya Grozdanova * , Gergana Micheva, Maria Dencheva ** , Tsvetelina Velikova *** (Submitted by Academician B. Petrunov on July 17, 2017 ) Abstract The aim of this trial was to determine the efficacy of Diode Laser Therapy (DLT) as an adjunct to scaling and root planing (SRP) in periodontal therapy on the basis of clinical measurements and level of IL-6 in gingival crevicular fluid (GCF). The study involved 40 patients with moderate chronic periodontitis, ran- domly assigned into two groups. The first group (test group) included 20 pa- tients to whom the procedure SRP and additional application of DLT (808 nm) has been performed. The second group (control group) included 20 pa- tients treated only by SRP procedure. In both groups the treatment has been applied in four visits twice a week. The clinical parameters of Hygiene index (HI), Bleeding on probing (BOP), Probing pocket depth (PPD), and Clinical attachment level (CAL) were measured at baseline and 1 month after treat- ment. Detection of IL-6 levels in GCF was conducted before treatment and four weeks after treatment completion. One month after treatment both groups showed significant improvements with regard to clinical parameters HI and BOP compared to baseline. The tendency of reduction in proinflammatory cytokine IL-6 level in GCF, recorded one month after treatment in the test group only, not in the control group showed the additional beneficial effects of DLT applied as an adjunct to SRP in the treatment of chronic periodontitis. Key words: chronic periodontitis, diode laser, interleukin-6 This study was supported by Grant No B01/8/21.12.2012 from the National Science Fund of Bulgaria – “Therapeutic efficacy of laser-assisted photoactivation disinfection in dentistry”. DOI:10.7546/CRABS.2019.01.17 130