Comparison of antibacterial effects of ER:YAG, ER,CR:YSGG lasers and conventional technique on enterococcus faecalis and candida albicans

Endodontic therapy aims to disinfect root canal system from microorganisms. The inability of contemporary irrigation agents to completely disinfect root canals lead to investigation of new agents and techniques in recent years. The aim of the present study is to compare the antibacterial efficiency of alternative approaches for root canal disinfection including Er,Cr:YSGG ve Er:YAG lasers on Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans) to that of NaOCl. The peresent study included 140 single rooted human mandibular premolars with one root canal. After preparing and sterilizing, the samples were divided into two groups. Root canals in group 1 were contaminated with E. faecalis while root canals in Group 2 were contaminated with C. albicans. The root canal of each sample except negative control group was inoculated with 105 cfu/ml of microorganisms in order to achieve standardization. After 4 weeks incubation, all samples were randomly divided into 10 subgroups; Group 1A: Er,Cr: YSGG laser group (2 W, 20 Hz, 25 mJ, 25% water, 35% air, 12 sec, 4 repeat), Group 1B: Er:YAG laser (0.8 W, 20 Hz, 40 mJ, 5 sec, 5 repeat), Group1C: 5% NaOCl group (7 mL, 2 min), Group 1D: positive control group, Group 1E: negative control group, Group 2A: Er, Cr:YSGG laser group (2 W, 20 Hz, 25 mJ, 25% water, 35% air, 12 seconds, 4 repeat), Group 2B: Er:YAG laser (0.8 W, 20 Hz, 40 mJ, 5 sec, 5 repeat), Group 2C: 5% NaOCl group (7 mL, 2 min), Group 2D: positive control group, Group 2E: negative control group. After disinfection process, the culture of each sample was tested to determine cfu/ml values for before incubation and after 4-week incubation. According to the resuls, in both Er:YAG laser group and NaOCl groups, a significant reduction occurred in the number of microorganisms obtained from the root canal after disinfection process (p<0.05). On the other hand, in Er,Cr: YSGG laser group, this reduction was not significant (p>0.05). For the output power of 2W for Er.Cr:YSGG laser, contrary to NaOCl, the antimicrobial activity on E. faecalis and C. albicans was not found significant. Compared to the conventional method, the use of Er:YAG laser with NaOCl is thought as an inducing method to increase the success rate in the elimination of E.faecalis and C.albicans.