The bactericidal effect of a Genius® Nd:YAG laser

Purpose: To evaluate the 'in vitro' bactericidal effect of the Nd:YAG laser (Genius, MOlsgaard Dental, Copenhagen, Denmark) on six periodontal pathogens. Methods: Suspensions of six different periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum and Parvimonas micra) were prepared in small Eppendorff tubes, and exposed to a Nd: YAG laser for five different periods of time. Laser settings used: Power 6 Watt (on a scale of 1-12 W), Frequency 50 Hz, Pulse duration 250 mu s. After exposure to the laser, aliquots of the suspensions were spread on blood agar plates for bacterial counting. Results: After 5 s of laser exposure, there was a decrease in total colony forming units for all six selected microorganisms. After 15, 30 and 45 s, no viable bacterial cells could be retrieved. Conclusion: In this 'in vitro' model, 15 s of Nd: YAG laser use was found to be effective for total killing of the six tested periodontal pathogens.