The Cleaning Effectiveness Of Three Irrigation Methods For Enterococcus Faecalis Biofilm On Root Canal In Vitro

Objective:This study was designed to compare the clearning efficiency for Enterococcus faecalis biofilm in root canals between Erbium-doped yttrium aluminum garnet?Er:YAG?laser of shock wave-enhanced emission photoacoustic streaming?SWEEPS?mode,Photon Induced Photoacoustic Streaming?PIPS?mode and Passive Ultrasonic Irrigation?PUI?.Methods:330 freshly extracted mandibular single premolars were collected from the outpatient department of Shanxi Provincial People's Hospital from February 2018 to October 2018.Conventional methods were used shaping root canals,the smear layers were removed.After sterilization,the model of Enterococcus faecalis infection was established in vitro.330 roots were randomly divided into 8 groups?n=40?,respectively,A₁ group SWEEPS-Er:YAG laser with 3%NaClO?SWEEPS+NaClO group?,A₂ group SWEEPS-Er:YAG laser with 0.9%saline?SWEEPS+saline group?,B₁ group PIPS-Er:YAG laser with 3%NaClO?PIPS+NaClO group?,B₂ PIPS-Er:YAG laser with 0.9%saline?PIPS+saline group?,C₁ group Passive Ultrasonic Irrigation?PUI?with 3%NaClO?PUI+NaClO group?,C₂ group Passive Ultrasonic Irrigation?PUI?with0.9%saline?PUI+saline group?as the experimental group,D₁ group 3%NaClO group and D₂ group 0.9%saline group were the control groups.After irrigation,the bacterial clearing effectiveness were qualitatively observed through a scanning electron microscope,and the rate of bacterial reduction was quantitatively determined by the plate bacterial counting method,and all data were statistically analyzed by a Mann-Whitney U test.Results:1)The amount of E.faecalis was significantly decreased in SWEEPS+NaClO group,SWEEPS+saline group,PIPS+NaClO group,PIPS+saline group,PUI+NaClO group,PUI+saline group and NaClO group?P<0.05?.2)The comparison of bacterial reduction rate before and after irrigation in each group.When using the same irrigation solution,the bacterial reduction was SWEEPS+NaClO group>PIPS+NaClO group>PUI+NaClO group>NaClO group;SWEEPS+saline group>PIPS+saline group>PUI+saline group>saline group.The difference between the each two groups was statistically significant?P<0.05?.3)When using the same irrigation method,The bacterial reduction was SWEEPS+NaClO group>SWEEPS+saline group;PIPS+NaClO group>PIPS+saline group;PUI+NaClO group>PUI+saline group;NaClO group>saline group.The difference between the each two groups was statistically significant?P<0.01?.Conclusion:Among the above three irrigation methods,the clearning efficiency of SWEEPS-Er:YAG laser irrigation was significantly better than that of PIPS-Er:YAG laser and Passive Ultrasonic Irrigation.The SWEEPS-Er:YAG laser is the optimal irrigation strategy.