Scanning Electron Microscopic Analysis of Smear Layer Removal in Root Canals by Ozonated Water

Objective:To observe the effect of ozonated water for smear layer removal on root canal.Methods:Forty human teeth with single root canal were randomly divided into five groups.Then each group was prepared with step-back technique.Five groups of irrigates were used:ozonated water,3% hydrogen peroxide and physiological saline,ozonated water and 1% NaClO,17% EDTA and 5.25% NaClO(positive control group),triple-distilled water(negative control group).After irrigating with different irrigation,the teeth were splited along long axis and the middle of canal wall was observed by scanning electron microscopy.Then data analysis was committed statistically.Results:The group with 17% EDTA plus 5.25% NaClO presented the most completed smear layer removal,but the dental tubule and canal walls were eroded.2.15mg/L ozonated water had potential for removing the smear layer,but the ability was better when combining with 1 % NaClO.The group with 3 % hydrogen peroxide plus physiological saline and the group with triple-distilled water nearly had no effect on smear layer removal,but the former was slightly better than the latter.Conclusion:2.15mg/L ozonated water has potential in removing the smear layer,and it has certain ability for the smear layer removal commbining with 1 % NaClO,especially without erosion on the root canal walls.