IRRADIATION OF INFECTED ROOT CANALS WITH A DIODE-LASER IN-VIVO - RESULTS OF MICROBIOLOGICAL EXAMINATIONS

Background and Objective: It was shown in previous studies [1] that th e Nd:YAG laser can be used as an excellent tool for killing bacteria i n root canals. The present examinations were carried out with a high p ower diode laser in comparison with a conventionally treated control g roup. Study Design/Materials and Methods: In this in vivo study, 40 pa tients with infected root canals underwent diode laser treatment. To v erify the findings, microbiological tests were performed and the resul ts compared to those obtained with conventional antibacterial treatmen t. Results: The microbiological examination revealed streptococci at r elevant concentrations in 20 cases and staphylococci in 5 cases. Exten sive bacterial reduction was achieved in all cases by repeating laser treatment only once. Following the first irradiation, minimal streptoc occal growth was observed in 7 root canals and minimal staphylococcal growth in 2 root canals. The maximum log kill was 4.22 for streptococc i and 3.33 for staphylococci. In the control group, a maximum reductio n by only one log step could be achieved in 6 of 10 patients. Conclusi ons: Compared with the results achieved with the conventional bacteric idal technique in the control group, the high power diode laser seems to be highly suitable for killing bacteria in infected root canals. (C ) 1997 Wiley-Liss, Inc.