title: Photodynamic therapy associated with conventional endodontic treatment in patients with antibiotic-resistant microflora: a preliminary report.
abstract: BACKGROUND
  This study reports the antimicrobial effect of photodynamic therapy (PDT) combined with endodontic treatment in patients with necrotic pulp infected with microflora resistant to a previous antibiotic therapy.
  
  
  METHODS
  Thirty anterior teeth from 21 patients with periapical lesions that had been treated with conventional endodontic treatment and antibiotic therapy were selected. Microbiological samples were taken (1) after accessing the root canal, (2) after endodontic therapy, and (3) after PDT.
  
  
  RESULTS
  All the patients had at least 1 microorganism resistant to antibiotics. PDT used polyethylenimine chlorin(e6) as a photosensitizer and a diode laser as a light source (P = 40 mW, t = 4 minutes, E = 9.6 J). Endodontic therapy alone produced a significant reduction in numbers of microbial species but only 3 teeth were free of bacteria, whereas the combination of endodontic therapy with PDT eliminated all drug-resistant species and all teeth were bacteria-free.
  
  
  CONCLUSIONS
  The use of PDT added to conventional endodontic treatment leads to a further major reduction of microbial load. PDT is an efficient treatment to kill multi-drug resistant microorganisms.
authors: Centro de Pesquisa e Pós-Graduação São Leopoldo Mandic, Campinas, SP, Brazil. garcez.segundo@terra.com.br
authors: Aguinaldo S
authors: AS
authors: Garcez
authors: Silvia C
authors: SC
authors: Nuñez
authors: Michael R
authors: MR
authors: Hamblim
authors: Hideo
authors: H
authors: Suzuki
authors: Martha S
authors: MS
authors: Ribeiro
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000528:radiation effects; D002735:Chlorophyllides; D015169:Colony Count, Microbial; D003131:Combined Modality Therapy; D003786:Dental Pulp Cavity / Q000382:microbiology* / Q000528:radiation effects; D003790:Dental Pulp Necrosis / Q000150:complications / Q000382:microbiology / Q000628:therapy*; D004203:Disinfection / Q000379:methods; D018432:Drug Resistance, Multiple / Q000528:radiation effects; D006801:Humans; D053685:Laser Therapy / Q000379:methods; D054023:Lasers, Semiconductor; D008875:Middle Aged; D010485:Periapical Periodontitis / Q000150:complications / Q000382:microbiology / Q000628:therapy*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011094:Polyethyleneimine / Q000627:therapeutic use; D011166:Porphyrins / Q000627:therapeutic use; D019233:Retreatment; D012390:Root Canal Therapy / Q000295:instrumentation / Q000379:methods*; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D002735:Chlorophyllides; D017319:Photosensitizing Agents; D011166:Porphyrins; C062985:phytochlorin; D011094:Polyethyleneimine