The effect of antimicrobial photodynamic therapy in the treatment of experimental periodontitis. A biochemical and microbiological study in dogs

Author(s)

Rafael Ramos de Oliveira

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2009-11-30

Examining board members

Arthur Belem Novaes Junior; Alvaro Francisco Bosco; Alberto Consolaro; Jamil Awad Shibli; Mario Taba Junior

• Advisor: Arthur Belem Novaes Junior

Abstract

The purpose of this study was to evaluate the effect of a single application of antimicrobial photodynamic therapy (aPDT) on microbiological profile and cytokine pattern in dogs. Periodontal disease was induced by placing 3.0 silk ligatures around the mandibular pre-molars bilaterally during 8 weeks. The dogs were randomly treated with aPDT using a dye/laser system, scaling and root planning (SRP) or with the association of treatments (SRP+aPDT). Plaque samples were collected at baseline, 1, 3 and 4 weeks and the mean counts of 40 species were determined using DNA-DNA hybridization. Gingival biopsies were removed and the expression of tumor necrosis factor alpha (TNF-α), receptor activator of NF-kB ligand (RANKL), osteoprotegerin (OPG), matrix metalloproteinase (MMP-1), interleukin (IL) 6, IL-10 and total bacterial load by analysis of 16S rRNA gene were evaluated through RealTime PCR. The results shows that the levels of the majority of the species were reduced one week post therapy for all treatments, however, an increase in counts of Prevotella intermedia (P =0.00), Prevotella nigrescens (P =0.00) and Tannerella forsythia (P =0.00) was observed for aPDT and SRP+aPDT. After 4 weeks a regrowth of Porphyromonas gingivalis (P =0.00) and Treponema denticola (P =0.00), was observed for all treatments, also a strikingly reduction of counts on counts of Aggregatibacter actinomycetemcomitans was observed for the aPDT (P =0.00). For the cytokine pattern the results were similar for all treatments and it was observed a reduction in the expression of cytokines and bacterial load throughout the study. Our results suggest that SRP, aPDT in a single application and SRP+aPDT affects different bacterial species and have similar effects on the expression of cytokines evaluated during the treatment of ligature-induced periodontitis. (AU)