Efficiency of pulsed Er,Cr:YSGG laser induced photoacoustic streaming as a cavity disinfectant against streptococcus mutans
Author(s): Rand Kareem Jassim* and Hussein Ali Jawad
Abstract
Aim: the goal of this study was to determine the antibacterial effectiveness of photon induced photo acoustic streaming using Er, Cr:YSGG laser at short pulse duration against heavily colonized teeth with streptococcus mutans in vitro. Material and Methods: in this study we used twenty eight extracted third molars free of caries, cracks, restoration and other defects. In order to conduct the tooth cavity model test, cylindrical cavities were prepared in the flat occlusal dentin of the teeth. The teeth were stored at 37°C for 72 hours in a broth culture of Streptococcus mutans allowing bacterial invasion. The teeth were then distributed into four groups of seven teeth (14 cavity preparations). The cavities in the first group were left untreated as a control. In the second group the chlorhexidine gluconate–based cavity disinfectant were applied according to the manufacturer’s instructions. The erbium, chromium doped yttrium –scandium –gallium garnet laser (0.25 W,15 Hz, 1% air, 15 water) at short pulse duration ( 60 µ sec) applied to the experimental cavities of the third group. Lastly the experimental cavities in the fourth group both chlorhexidine and laser were applied (chlorhexidine used first then the laser) with the same parameter used above. The teeth were kept in saline for 72 hours. The colony forming unit was counted after collecting standardized amount of dentin chips. Result: The results were analyzed by ANOVA, Dunnett t and LSD tests. There was statistically a significant difference in the streptococcus mutans count before and after the treatment (P<0.05). In terms of antibacterial efficiency, photon induced photo acoustic streaming by Er,Cr:YSGG laser with 2% Chlorhexidine was found to be the most efficient disinfection method (47841.14286 ), followed by, photon induced photo acoustic streaming using Er,Cr:YSGG laser alone(47821.71429), 2% Chlorhexidine -gluconate based cavity disinfectant alone(45391.42857) respectively. conclusion: the result of this in vitro study showed that, photon induced photo acoustic streaming by pulsed erbium, Chromium doped yttrium scandium gallium garnet laser (0.25 W,15Hz,1% air, and 1% water ) at short pulse duration (60 µ sec) effective in lowering the number of the recovered bacteria, especially when used to together with chlorhexidine - gluconate based cavity.