Evaluation of the photodynamic therapy on root decontamination and modulation of the immuno-inflammatory response and healing of the periodontal tissues: a randomized controlled clinical study in humans

Abstract

The purpose of this study is to evaluate the adjunct effect of the photodynamic therapy (PDT) to scaling and root planning (SRP).Methods: Fifteen patients with diagnosis of chronic periodontitis, presenting bilaterally lower molars with class III furcation lesions and scheduled for extraction, will be included in the study. Each par of teeth will be randomly assigned to control and test groups (CGr and TGr, respectively). In the CGr, the conventional procedures of the SRP will be performed and in the TGr, the SRP will be associated to PDT, using a laser source with wavelength of 660nm and a phenothiazine photosensitizer. Subgingival plaque samples and gingival crevicular fluid (GCF) samples will be collected at baseline and 7, 21 and 42 days post-therapy. Counts of 40 subgingival species will be determined using checkerboard DNA-DNA hybridization and the amounts and concentrations of interleukin (IL)-; matrix metalloproteinase (MMP)-8, receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OP), and transforming growth factor-1 (TGF) in the GCF will be measured by enzyme-linked immunosorbent assay (ELISA). At 42 days (6 weeks) post-initial therapy, flap surgery plus SRP and flap surgery plus SRP+PDT will be performed in the CGr and TGr, respectively. At 7 and 21 days post-surgery, subgingival plaque samples and gingival crevicular fluid (GCF) samples will also be taken. At 21 days post-surgery, the newly formed granulation tissue will be collected and stored in a tube containing RNAlater® and the teeth will be extracted. The quantitative polymerase chain reaction (Real-Time PCR) will evaluate the expressions of genes: tumor necrosis factor; (TNF) IL-1;, IL-4, IL-10, MMP-2, MMP-8, RANKL, OP, type I and III collagens (Col I and III), osteocalcin (OCN), osteopontin (OPN), alkaline phosphatase (ALP), bone sialoprotein (BSP), TGF, platelet-derived growth factor (PDGF), and basic fibroblast growth factor (FGF-2). The Mann-Whitney U test and the Wilcoxon signed rank test will be used in the statistical analyses (a significance level of 5% will be used for all statistical analyses). (AU)