Objective:To study the efficiency and biosafety of Electrochemical advanced oxidation processes(EAOP)in dental bleaching,and conduct preliminary application.Methods:Indigo carmine and coffee were used as the indicator to assess the effi-cacy of EAOP.High resistance meter was used to measure the resistance of the tooth to verify the safety of the working voltage.Twenty wisdom teeth after tooth extraction were collected,dyed and bleached in vitro to verify the bleaching efficiency.Subsequent-ly,the bleached teeth were examined by scanning electron microscopy,hardness testing,and bacterial adhesion experiments to as-sess surface damage.To determine its cytotoxicity,cells were co-cultured with electrolyte.Initial samples of bleaching tray was prepared,and its durability were verified.Results:The EAOP could bleach indigo carmine within 10 min and coffee within 90 min at an operating voltage of 8 V.The resistance at the groove of the tooth socket was(3.4±1.2)MΩ,and the theoretical calculated current was less than 3 μA.The efficiency of EAOP tooth bleaching was slightly lower than that of traditional office bleaching and higher than that of home bleaching.Compared with the traditional bleaching method,scanning electron microscopy showed that EAOP had less demineralization effect on tooth surface.The tooth hardness before and after bleaching had no statistical difference(P=0.912).The bacterial adhesion test after tooth bleaching showed that EAOP method could reduce about 60％bacterial adhe-sion(P＜0.001).The cytotoxicity test showed that EAOP electrolyte had no obvious toxic effect.The durability test shows that the bleached denture still has good bleaching effect after 20 h of use.Conclusion:Compared with the traditional bleaching method,EAOP bleaching had excellent tooth bleaching effect,little effect on tooth damage,high safety,and the related bleaching devices had good durability.

Objective:To study the efficiency and biosafety of Electrochemical advanced oxidation processes(EAOP)in dental bleaching,and conduct preliminary application.Methods:Indigo carmine and coffee were used as the indicator to assess the effi-cacy of EAOP.High resistance meter was used to measure the resistance of the tooth to verify the safety of the working voltage.Twenty wisdom teeth after tooth extraction were collected,dyed and bleached in vitro to verify the bleaching efficiency.Subsequent-ly,the bleached teeth were examined by scanning electron microscopy,hardness testing,and bacterial adhesion experiments to as-sess surface damage.To determine its cytotoxicity,cells were co-cultured with electrolyte.Initial samples of bleaching tray was prepared,and its durability were verified.Results:The EAOP could bleach indigo carmine within 10 min and coffee within 90 min at an operating voltage of 8 V.The resistance at the groove of the tooth socket was(3.4±1.2)MΩ,and the theoretical calculated current was less than 3 μA.The efficiency of EAOP tooth bleaching was slightly lower than that of traditional office bleaching and higher than that of home bleaching.Compared with the traditional bleaching method,scanning electron microscopy showed that EAOP had less demineralization effect on tooth surface.The tooth hardness before and after bleaching had no statistical difference(P=0.912).The bacterial adhesion test after tooth bleaching showed that EAOP method could reduce about 60％bacterial adhe-sion(P＜0.001).The cytotoxicity test showed that EAOP electrolyte had no obvious toxic effect.The durability test shows that the bleached denture still has good bleaching effect after 20 h of use.Conclusion:Compared with the traditional bleaching method,EAOP bleaching had excellent tooth bleaching effect,little effect on tooth damage,high safety,and the related bleaching devices had good durability.

0.05).The effect on dispelling edema,shortening wound-healing time and reducing exudate was better in group A than that in group B(P