RESUMEN
OBJECTIVE: The objective was to compare the efficacy of three different lasers in disinfection of root canals inoculated with Enterococcus faecalis and Candida albicans biofilms. BACKGROUND: Endodontic space disinfection depends on the type of root canal irrigant used and the way it is delivered and agitated because irrigants have limited ability to reach all parts of root canal system. MATERIALS AND METHODS: Thirty single-rooted human teeth were selected. Root canals were instrumented and root surfaces were sealed using adhesive and the apical openings with adhesive and composite resin. Roots were fixed in Eppendorf tubes and sterilized in autoclave. The specimens were randomly divided into three experimental groups (n = 10) and inoculated with E. faecalis and C. albicans. After 7 days of incubation period, the number of E. faecalis and C. albicans colony-forming units (CFUs) was determined for each root canal. In the first experimental group, Er:YAG laser (0.3 W) with photon-induced photoacoustic streaming technique was used for root canal disinfection, in the second, Nd:YAG laser (1.5 W), and in the third, Er,Cr:YSGG (1.25 W) laser was used. After different root canal disinfection protocols, the number of E. faecalis and C. albicans CFUs was determined again for each root canal. RESULTS: Er:YAG and Er,Cr:YSGG lasers eradicated significant number of E. faecalis and C. albicans CFUs (p < 0.05), while Nd:YAG laser irradiation did not result in statistically significant reduction (p > 0.05). Er,Cr:YSGG laser eradicated significantly more microorganisms in comparison with Er:YAG laser (p < 0.05). CONCLUSIONS: Er,Cr:YSGG laser was the most efficient tool in eradication of E. faecalis and C. albicans biofilms.