Comparative analysis of microbial reduction using photodynamic therapy in bovine teeth infected with Enterococcus faecalis – an in vitro study

  • Janaina Guzzo Zechin School of Dentistry, Pontifical Catholic University of Rio Grande do Sul.
  • Liviu Steier Warwick Dentistry, Warwick Medical School, Warwick, United Kingdom.
  • Giampiero Rossi-Fedele School of Dentistry, Pontifical Catholic University of Rio Grande do Sul.
  • Grasiela Longhi Gründling School of Dentistry, Pontifical Catholic University of Rio Grande do Sul.
  • Daniela Sá School of Biosciences, Pontifical Catholic University of Rio Grande do Sul.
  • Amanda Guwzinski School of Biosciences, Pontifical Catholic University of Rio Grande do Sul.
  • Alessandra Cesar Trindade School of Dentistry, Pontifical Catholic University of Rio Grande do Sul.
  • Matheus Albino Souza a School of Dentistry, Pontifical Catholic University of Rio Grande do Sul.
  • Silvia Dias de Oliveira School of Biosciences, Pontifical Catholic University of Rio Grande do Sul.
  • Jose Antonio Poli de Figueiredo School of Dentistry, Pontifical Catholic University of Rio Grande do Sul.
Keywords: Biofilm, Bovine teeth, Enterococcus faecalis, Photodynamic therapy


Objective: To evaluate the use of optic fiber and different pre-irradiation times (PIT) in phototherapy with LED for the root canal disinfection of bovine teeth infected in vitro with Enterococcus faecalis.
Methodology: The teeth were incubated for 60 days and divided into six groups according to disinfection protocol: Group 1 – distilled water; Group 2 – 1 minute PIT and no optic fiber; Group 3 – 1 minute PIT and optic fiber; Group 4 – 5 minute PIT and no optic fiber; Group 5 – 5 minute PIT and optic fiber; Group 6 – 2% sodium hypochlorite. Microbiological test (CFUs counting) and scanning electron microscopy (SEM) were performed to evaluate the effectiveness of proposed treatments.
Results: SEM analysis of canal wall, in the three thirds, revealed group 6 had the best results, whereas microbiological results revealed that group 6 had the best results. No differences in disinfection of root canals were found when optic fiber was used for photodynamic therapy. Conclusion: Photodynamic therapy should not be used alone in the disinfection of root canals, but it may be valuable as a complement for disinfection performed using different cleaning methods.


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Original Article