Evaluation of the bactericidal potential of 2780-nm ER,CR:YSGG and 940-nm diode lasers in the root canal system

Successful endodontic therapy relies on chemomechanical debridement. Laser-assisted irrigation techniques are available for debridement. However, there are limited studies demonstrating the effectiveness of dual lasers for root canal disinfection. Hence, the aim of the present study is to determine if laser activation irrigation using the Er,Cr:YSGG and 940-nm diode laser is as effective as positive pressure needle irrigation using sodium hypochlorite (NaOCl) and ethylenediamine tetraacetic acid (EDTA). Fifty-two caries-free premolars were divided into six groups: G1, sterile water via positive pressure irrigation; G2, EDTA and NaOCl via positive pressure irrigation; G3, sterile water and the Er,Cr:YSGG cleaning and disinfection step; G4, sterile water and the Er,Cr:YSGG cleaning and disinfection step followed by disinfection with the 940-nm diode; G5, sterile water and the Er,Cr:YSGG cleaning step followed by a disinfection step with the Er,Cr:YSGG and diode laser together; and G6, negative controls. S1 samples were validated in both negative and positive control groups via culturing. All teeth, except the negative controls, were inoculated with Enterococcus faecalis. S2 sampling after treatments was completed and tested for bacterial presence via culturing and SEM and CLSM analysis. The data demonstrated that the traditional irrigation group (G2) and the dual laser group (G5) showed the greatest percentage decrease in bacterial counts from the S1 to the S2 group. The data demonstrates that the combination of the Er,Cr:YSGG and 940-nm diode laser wavelengths is safe and more effective than either laser alone and is comparable to needle irrigation with sodium hypochlorite and EDTA.