Irradiation of infected root canals with a diode laser in vivo: results of microbiological examinations

Abstract

Background and objective: It was shown in previous studies [1] that the Nd:YAG laser can be used as an excellent tool for killing bacteria in root canals. The present examinations were carried out with a high power diode laser in comparison with a conventionally treated control group.

Study design/materials and methods: In this in vivo study, 40 patients with infected root canals underwent diode laser treatment. To verify the findings, microbiological tests were performed and the results compared to those obtained with conventional antibacterial treatment.

Results: The microbiological examination revealed streptococci at relevant concentrations in 20 cases and staphylococci in 5 cases. Extensive bacterial reduction was achieved in all cases by repeating laser treatment only once. Following the first irradiation, minimal streptococcal growth was observed in 7 root canals and minimal staphylococcal growth in 2 root canals. The maximum log kill was 4.22 for streptococci and 3.33 for staphylococci. In the control group, a maximum reduction by only one log step could be achieved in 6 of 10 patients.

Conclusions: Compared with the results achieved with the conventional bactericidal technique in the control group, the high power diode laser seems to be highly suitable for killing bacteria in infected root canals.