Biofilm removal by 6% sodium hypochlorite activated by different irrigation techniques




To compare the removal of biofilm utilizing four irrigation techniques on a bovine root canal model.


Fifty dentine specimens (2x2 mm) were infected with biofilm. The samples were then adapted to previously created cavities in the bovine model. The root canals were irrigated twice with 2 mL of 6% sodium hypochlorite for 2 minutes (4 minutes total). Following initial irrigation, the different treatment modalities were introduced for 60 s (3 x 20 s intervals). The evaluated techniques were needle irrigation, endoactivator, passive ultrasonic irrigation and laser activated irrigation (photon induced photoacoustic streaming). The controls were irrigated with distilled water and conventional needle irrigation. Subsequently, the dentine samples were separated from the model and analyzed using a scanning electron microscope (SEM). Fifteen operative fields were scanned per block and SEM pictures were captured. Two calibrated evaluators examined the images and collected data using a 4-degree scale. Non-parametric tests were used to evaluate for statistical significance among the groups.


The group undergoing laser-activated irrigation using photon induced photoacoustic streaming exhibited the most favorable results in the removal of biofilm. Passive ultrasonic irrigation scores were significantly lower than both the endoactivator and needle irrigation scores. Sonic and needle irrigation were not significantly different. The least favourable results were found in the control group.


Laser activation of 6% sodium hypochlorite significantly improved the cleaning of biofilm infected dentine followed by passive ultrasonic irrigation.


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