Cleaning Effectiveness of Chlorine Dioxide Soluation Used as Root Canal Ultrasonic Irrigant

Objective To evaluate the cleaning effectiveness of chlorine dioxide soluation used as root canal ultrasonic irrigant.Methods Thirty recently extracted premolars with a single root canal were divided into three equal groups after cut crown(A,B,C).All root canals were instrumented by hand with stainless steel endodontic instruments using a conventional step back technique,and irrigated by ultrasond using distill water(group A),1.0% NaOCl(group B),0.1% ClO2(group C).All roots were split longitudinally and prepared for SEM observation,the presence of debris and smear layer was evaluated,the numbers of visible open dentinal tubules were counted respectively from photomicrographs taken in the apical,middle and cervical thirds of the canals,and the mean scores and numbers were compiled separately.Values obtained were tabulated and statistical analysis was carried out using One-Way ANOVA.Results Statistical analysis showed that there was no significant difference among the three groups for debris(P0.05),but there was significant difference among the three groups for smear layer and the numbers of visible open dentinal tubules(P0.01),both group B and group C had significantly less smear layer(P0.01)and more visible open dentinal tubules compared with group A(P0.01),but group B had no significant difference in smear layer and the numbers of visible open dentinal tubules from group C(P0.05).Conclusion Chlorine dioxide has a good cleaning effectiveness used as ultrasonic irrigant of root canals during preparation,the cleaning ability of 0.1% ClO2 to debris and smear layer is better than using distill water,similar to that of 1.0% NaOCl.