Aim: To evaluate the antibacterial effect of diode laser, associated or not with 2.5% sodium hypochlorite (NaOCl), against Enterococcus faecalis.
Materials and methods: Eighty dentin blocks were obtained from single-rooted human teeth and sterilized. Seventy were inoculated with 0.01 mL of fresh bacterial inoculum (within 24 hours of preparation from pure culture) standardized to 1 McFarland turbidity. Contaminated blocks were incubated for 7 days at 37°C in humid conditions. Ten uncontaminated samples were incubated at 37°C during the contamination period to serve as a negative control group, while 10 of the infected specimens served as a positive control group. The dentin blocks were randomly divided into eight experimental groups (n = 10 each) according to the method of decontamination: 2.5% NaOCl alone; 2.5% NaOCl + photodynamic therapy (PDT) with methylene blue/660 nm laser at 18 J for 180 seconds; 2.5% NaOCl + PDT with methylene blue/660 nm laser at 8 J for 80 seconds; methylene blue alone; PDT alone with methylene blue/660 nm laser at 18 J for 180 seconds; PDT alone with methylene blue/660 nm laser at 8 J laser for 80 seconds; positive control group; and negative control group. Microbial growth was evaluated by culture medium turbidity and microbial concentration was analyzed by UV spectrophotometry (adjusted to read at wavelength l = 600 nM).
Results: Root canals treated with laser alone at 18 J for 180 seconds had higher bacterial contamination compared with groups in which NaOCl was used, with or without laser irradiation at 18 J for 180 seconds (p < 0.05).
Conclusion: Photodynamic therapy with a 660 nm diode laser effectively reduced E. faecalis contamination. These findings can guide development of further studies in search of better alternatives for endodontic treatment.
Clinical relevance: Chemical and mechanical root canal preparation plays an essential role in reducing microbial burden. However, microorganisms present in areas not mechanically reachable by endodontic instruments. As an alternative to fix this problem, the laser can be applied.
Oliveira JC, Alves FR, Uzeda M, Rôças IN, Siqueira JF Jr. Influence of serum and necrotic soft tissue on the antimicrobial effects of intracanal medicaments. Braz Dent J 2010; 21(4):295-300.
Siqueira JF Jr, Rôças IN. Polymerase chain reaction-based analysis of microorganisms associated with failed endodontic treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004 Jan;97(1):85-94.
Estrela C, Sousa-Neto MD, Alves DR, Alencar AH, Santos TO, Pécora JD. A preliminary study of the antibacterial potential of cetylpyridinium chloride in root canals infected by E. faecalis. Braz Dent J 2012;23(6):645-653.
Estrela C Gonçalves AH, Decurcio DA, Borges AH, Estrela CR. Influence of strategies for sanitization on success of apical periodontitis therapy. Rev Odontol Bras Central 2012;21(56): 367-375.
Pécora JD. Estrela C Bueno MR, Porto OC, Alencar AH, Sousa-Neto MD, Estrela CR. Detection of root canal isthmus in molars by map-reading dynamic using CBCT images. Braz Dent J 2013 Nov-Dec;24(6):569-574.
Estrela C, Sydney GB, Figueiredo JA, Estrela CR. A model system to study antimicrobial strategies in endodontic biofilms. J Appl Oral Sci 2009 Apr;17(2):87-91.
Hülsmann M. Effects of mechanical instrumentation and chemical irrigation on the root canal dentin and surrounding tissues. Endod Topics 2013 Sep;29(1):55-86.
Haapasalo M, Shen Y, Qian W, Gao Y. Irrigation in endodontics. Dent Clin North Am 2010 Apr;54(2):291-312.
Trindade AC, De Figueiredo JA, Steier L, Weber JB. Photodynamic therapy in endodontics: a literature review retrieved no results. Photomed Laser Surg 2015 Mar;33(3): 175-182.
Konopka K, Goslinski T. Photodynamic therapy in dentistry. J Dent Res 2007 Aug;86(8):694-707.
Portenier I, Waltimo TM, Haapasalo M. Enterococcus faecalis— the root canal survivor and “star” in post-treatment disease. Endod Topics 2003 Nov;6(1):135-159.
Estrela C, Silva JA, de Alencar AH, Leles CR, Decurcio DA. Efficacy of sodium hypochlorite and chlorhexidine against Enterococcus faecalis—a systematic review. J Appl Oral Sci 2008 Nov-Dec;16(6):364-368.
AL-Ahmad A, Müller N, Wiedmann-AL-Ahmad M, Sava I, Hübner J, Follo M, Schirrmeister J, Hellwig E. Endodontic and salivary isolates of Enterococcus faecalis integrate into biofilm from human salivary bacteria cultivated in vitro. J Endod 2009 Jul;35(7):986-991.
Arias-Moliz MT, Ferrer-Luque CM, Espigares-García M, Baca P. Enterococcus faecalis biofilms eradication by root canal irrigants. J Endod 2009 May;35(5):711-714.
Rios A, He J, Glickman GN, Spears R, Schneiderman ED, Honeyman AL. Evaluation of photodynamic therapy using a light-emitting diode lamp against Enterococcus faecalis in extracted human teeth. J Endod 2011 Jun;37(6):856-859.
Stojicic S, Amorim H, Shen Y, Haapasalo M. Ex vivo killing of Enterococcus faecalis and mixed plaque bacteria in planktonic and biofilm culture by modified photoactivated disinfection. Int Endod J 2013 Jul;46(7):649-659.
Usha HL, Kaiwar A, Mehta D. Biofilm in endodontics: new understanding to an old problem. Int J Contemp Dent 2010 Dec;1(3):44-51.
Bago Juric I, Plecko V, Anic I, Plesko S, Jakovljevic S, Rocca JP, Medioni E. Antimicrobial efficacy of photodynamic therapy, Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm. Photodiagnosis Photodyn Ther 2016 Mar;13: 238-243.
de Gregorio C, Estevez R, Cisneros R, Paranjpe A, Cohenca N. Efficacy of different irrigation and activation systems on the penetration of sodium hypochlorite into simulated lateral canals and up to working length: an in vitro study. J Endod 2010 Jul;36(7):1216-1221.
Silva LA, Novaes AB Jr, de Oliveira RR, Nelson-Filho P, Santamaria M Jr, Silva RA. Antimicrobial photodynamic therapy for the treatment of teeth with apical periodontitis: a histopathological evaluation. J Endod 2012 Mar;38(3): 360-366.
Ok E, Ertas H, Saygili G, Gok T. Effect of photo-activated disinfection on bond strength of three different root canal sealers. Eur J Dent 2014 Jan;8(1):85-89.
Xu Y, Young MJ, Battaglino RA, Morse LR, Fontana CR, Pagonis TC, Kent R, Soukos NS. Endodontic antimicrobial photodynamic therapy: safety assessment in mammalian cell cultures. J Endod 2009 Nov;35(11):1567-1572.
Soukos NS, Goodson JM. Photodynamic therapy in the control of oral biofilms. Periodontol 2000 2011 Feb;55(1):143-166.
Bago I, Pleèko V, Gabriæ Panduriæ D, Schauperl Z, Baraba A, Aniæ I. Antimicrobial efficacy of a high-power diode laser, photo-activated disinfection, conventional and sonic activated irrigation during root canal treatment. Int Endod J 2013 Apr;46(4):339-347.
Eldeniz AU, Guneser MB, Akbulut MB. Comparative antifungal efficacy of light-activated disinfection and octenidine hydrochloride with contemporary endodontic irrigants. Lasers Med Sci 2015 Feb;30(2):669-675.
Schlafer S, Vaeth M, Horsted-BIndslev P, Frandsen EV. Endodontic photoactivated disinfection using a conventional light source: an in vitro and ex vivo study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010 Apr;109(4):634-641.
Fonseca MB, Júnior PO, Pallota RC, Filho HF, Denardin OV, Rapoport A, Dedivitis RA, Veronezi JF, Genovese WJ, Ricardo AL. Photodynamic therapy for root canals infected with Enterococcus faecalis. Photomed Laser Surg 2008 Jun;26(3):209-213.
Pinheiro SL, Schenka AA, Neto AA, de Souza CP, Rodriguez HM, Ribeiro MC. Photodynamic therapy in endodontic treatment of deciduous teeth. Lasers Med Sci 2009 Jul;24(4):521-526.
Garcez AS, Fregnani ER, Rodriguez HM, Nunez SC, Sabino CP, Suzuki H, Ribeiro MS. The use of optical fiber in endodontic photodynamic therapy. Is it really relevant? Lasers Med Sci 2013 Jan;28(1):79-85.
Queiroga AS, Trajano VN, Lima EO, Ferreira AF, Queiroga AS, Limeira Fa Jr. In vitro photodynamic inactivation of Candida spp by different doses of low power laser light. Photodiagnosis Photodyn Ther 2011 Dec;8(4):332-336.
Vaziri S, Kangarlou A, Shahbazi R, Nazari Nasab A, Naseri M. Comparison of the bactericidal efficacy of photodynamic therapy, 2.5% sodium hypochlorite, and 2% chlorhexidine against Enterococcous faecalis in root canals; an in vitro study. Dent Res J (Isfahan) 2012 Sep;9(5):613-618.
Filipov I, Markova K, Boyadzhieva E. Efficiency of photoactivate disinfection on experimental biofilm—scanning electron microscopy results. J IMAB 2013 Oct;19(4):383-387.