title: Antimicrobial Activity of Photodynamic Therapy Against Enterococcus faecalis Before and After Reciprocating Instrumentation in Permanent Molars.
abstract: OBJECTIVE
  The present study sought to evaluate the antimicrobial activity against Enterococcus faecalis of photodynamic therapy applied before and after reciprocating instrumentation of permanent molars.
  
  
  BACKGROUND
  Apical extrusion of debris can cause flare-ups due to introduction of bacteria into the periapical tissues.
  
  
  METHODS
  Eighteen mesial roots from permanent mandibular molars were selected. The crowns were removed to obtain a standard root length of 15 mm. The included mesial roots had an angulation of 10°-40° and canals with independent foramina. The orifice of each mesiolingual canal was sealed with light-curing resin, and the working length was established visually, 1 mm short of the apical foramen. The roots were rendered impermeable and sterilized, and the mesiobuccal canals were contaminated with a standard strain of E. faecalis for 21 days. Specimens were randomly divided into three groups (n = 6): G1, photodynamic therapy performed before instrumentation and irrigation with 0.9% NaCl (saline) solution; G2, photodynamic therapy performed after instrumentation and irrigation with 0.9% NaCl; and G3 (control), instrumentation and irrigation with 2.5% NaOCl (sodium hypochlorite) solution. Canals were shaped with a WaveOne primary file (25.08) and irrigated with 0.9% NaCl. E. faecalis samples were collected before and after each procedure, and the results were analyzed using descriptive statistics and the Kruskal-Wallis and Wilcoxon tests.
  
  
  RESULTS
  Significant reductions in E. faecalis were observed when photodynamic therapy was performed before and after instrumentation of the root canal system (p < 0.05). Reciprocating instrumentation significantly reduced E. faecalis colonies in experimentally contaminated root canal systems (p < 0.05).
  
  
  CONCLUSIONS
  Photodynamic therapy was effective in removing E. faecalis from the root canal system, whether performed before or after reciprocating instrumentation.
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Sérgio Luiz
authors: SL
authors: Pinheiro
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Giuliana Rodrigues
authors: GR
authors: Azenha
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Yasmin Marialva
authors: YM
authors: Democh
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Daniela Camila
authors: DC
authors: Nunes
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Silvia
authors: S
authors: Provasi
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Giovana Masiero
authors: GM
authors: Fontanetti
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Danilo Antônio
authors: DA
authors: Duarte
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Carlos Eduardo
authors: CE
authors: Fontana
authors: School of Dentistry, Pontifícia Universidade Católica de Campinas-PUC-Campinas , Campinas, São Paulo, Brazil .
authors: Carlos Eduardo
authors: CE
authors: da Silveira Bueno
mesh_terms: D003786:Dental Pulp Cavity / Q000382:microbiology; D013293:Enterococcus faecalis / Q000528:radiation effects*; D006801:Humans; D010778:Photochemotherapy
keywords: endodontic treatment; photodynamic therapy; reciprocating instrumentation