title: Effect of the concentration of phenothiazine photosensitizers in antimicrobial photodynamic therapy on bone loss and the immune inflammatory response of induced periodontitis in rats.
abstract: OBJECTIVE
  Antimicrobial therapy can suppress periodontal pathogens and increase the effectiveness of conventional mechanical treatment. The aim of this study was to assess bone loss and the immune inflammatory response of rats under the influence of two photosensitizing agents (MB and TBO) at two different concentrations in antimicrobial photodynamic therapy (aPDT), used as an adjuvant therapy in the treatment of periodontitis.
  
  
  METHODS
  Periodontitis was induced in the mandibular first molars of 162 rats. The animals were divided into nine groups: G1 - scaling and root planing (SRP); G2 - SRP plus 100 μg/mL of methylene blue (MB); G3 - SRP plus 10 mg/mL of MB; G4 - SRP plus 100 μg/mL of toluidine blue (TBO); G5 - SRP plus 10 mg/mL of TBO; G6 - SRP plus 100 μg/mL of MB and laser; G7 - SRP plus 10 mg/mL of MB and laser; G8 - SRP plus 100 μg/mL of TBO and laser; and G9 - SRP plus 10 mg/mL of TBO and laser. Six animals from each group were euthanized 7, 15, or 30 d after treatment. Bone loss (BL) in the furcation region was evaluated using histomorphometric and immunohistochemical analyses to detect the receptor activator of nuclear factor-Κappa B ligand (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP).
  
  
  RESULTS
  There was significantly less BL in animals treated with aPDT using low concentrations of MB and TBO at 7, 15 and 30 d. Immunohistochemical analysis revealed decreased RANKL and increased OPG in the aPDT groups and decreased TRAP-positive cells in G6 and G8.
  
  
  CONCLUSIONS
  aPDT, using low concentrations of MB and TBO, was the most effective adjuvant therapy to SRP, acting indirectly as a downregulator of the molecular mechanisms that control bone resorption in periodontitis.
authors.affiliation: Group for the Research and Study of Laser in Dentistry, Division of Periodontics, Department of Surgery and Integrated Clinic, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil; Master Course, Dental School of Barretos, University Center of the Educational Foundation of Barretos, Barretos, São Paulo, Brazil.
authors.forename: V G
authors.initials: VG
authors.lastname: Garcia
authors.forename: M
authors.initials: M
authors.lastname: Longo
authors.forename: E C
authors.initials: EC
authors.lastname: Gualberto Júnior
authors.forename: A F
authors.initials: AF
authors.lastname: Bosco
authors.forename: M J H
authors.initials: MJ
authors.lastname: Nagata
authors.forename: E
authors.initials: E
authors.lastname: Ervolino
authors.forename: L H
authors.initials: LH
authors.lastname: Theodoro
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D016301:Alveolar Bone Loss / Q000188:drug therapy* / Q000276:immunology; D000818:Animals; D003131:Combined Modality Therapy; D003238:Connective Tissue / Q000473:pathology; D012534:Dental Scaling / Q000379:methods; D007527:Isoenzymes / Q000032:analysis; D028022:Low-Level Light Therapy / Q000295:instrumentation; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage; D009504:Neutrophils / Q000473:pathology; D010010:Osteoclasts / Q000473:pathology; D053244:Osteoprotegerin / Q000032:analysis; D010518:Periodontitis / Q000188:drug therapy* / Q000276:immunology; D010640:Phenothiazines / Q000008:administration & dosage*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D053245:RANK Ligand / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D016745:Root Planing / Q000379:methods; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors; D014048:Tolonium Chloride / Q000008:administration & dosage
chemical_list: D007527:Isoenzymes; D053244:Osteoprotegerin; D010640:Phenothiazines; D017319:Photosensitizing Agents; D053245:RANK Ligand; C506032:Tnfrsf11b protein, rat; D014048:Tolonium Chloride; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; C031637:phenothiazine; D008751:Methylene Blue
keywords: alveolar bone loss; lasers; periodontitis; photochemotherapy