A scanning electron microscopic study on cleaning effectiveness of root canal irrigation with chlorine dioxide.

Objective:To evaluate the cleaning effectiveness of chlorine dioxide solution used as root canal irrigant.Mathod:Thirty recently extracted premolar teeth with a single root canal were divided randomly into six equal groups(SA,SB,SC,UA,UB,UC).After cutting affdental crowns,all the root canals were instrumented using a conventional step back technique with stainless steel endodontic instruments.The fore three groups were irrigated by syringe using alternately 3%H2O2 and 0.9% saline(group SA),1%NaOCl(group SB) or 0.1% ClO2(groupSC);The other groups were irrigated by ultrasonic using distilled water(group UA),1% NaClO(group UB),0.1%ClO2(group UC).All the roots were split longitudinally and prepared for SEM observation,the presence of debris and smear layer was evaluated from photomicrographs taken in the apical,middle and cervical thirds of the canals,scores were compiled separately.statistical analysis was carried out.Result:Among the syringe irrigation groups,statistical analysis showed that group SC had significantly less debris and smear layer on root canal walls compared with group SA(P 0.05),but had no significant difference in debris and smear layer compared with group SB(P 0.05);Among the ultrasonic irrigation groups,there was no significant difference between the three groups for debris(P 0.05),group UC had significantly less smear layer in compared with group UA,but had no significant difference from group UB(P 0.05).Conclusion:Chlorine dioxide can be used as irrigant of root canals during preparation,the cleaning effectiveness of 0.1% ClO2 to root canals is better than using alternately 3% H2O2 and 0.9% saline,similar to that of 1%NaOCl,and it is more effective combined with ultrasonic irrigation.