Cavitational effects in aqueous endodontic irrigants generated by near-infrared lasers.
BACKGROUND
Laser-generated pressure waves may have application for removing debris and smear layers from root canals. Past work has employed middle infrared erbium lasers. The present study examined whether near infrared 940 and 980 nm diode lasers (Biolase Ezlase and Sirona Sirolaser, respectively) could induce cavitations in aqueous media.


METHODS
Laser energy was delivered into a capillary tube using a 200 microm fiber, and the formation of cavitations observed with a microscope. In the first part of the study, a range of laser parameters were trialled to establish conditions which form cavitations within 5 seconds of the commencement of laser irradiation. The second part of the study compared cavitation in distilled water, aerated tap water, degassed distilled water, ozonated water, 3 and 6% hydrogen peroxide using panel setting of 2.5 W/25 Hz for the Sirolaser, and 4 W/10 Hz for the Ezlase.


RESULTS
Both diode laser systems could induce cavitation in water-base media by the formation and implosion of water vapour. Laser power played a more important role than pulse frequency or pulse interval. Optimal laser-initiated cavitation occurred when weak (3%) peroxide solutions were used as the target irrigant, rather than water.


CONCLUSIONS
This phenomenon has potential for enhancing debridement in endodontics.
Hmud
Raghad
R
The University of Queensland School of Dentistry, Brisbane, QLD, Australia.
Kahler
William A
WA
George
Roy
R
Walsh
Laurence James
LJ
D003646:Debridement / Q000379:methods*; D054023:Lasers, Semiconductor; D045423:Microbubbles; D012388:Root Canal Irrigants / Q000528:radiation effects*; D018915:Root Canal Preparation / Q000379:methods*; D016369:Smear Layer
D012388:Root Canal Irrigants