Ozone Water To Remove The Root Canal Smear Layer Effect And Cytotoxicity Of Experimental Research

Recent years, the ozonated water has been used as a new kind of root canal irrigation for its good effect on destroying bacteria and viruses. But the criterion to appraise a type of root canal irrigation is not only based on the ability to sterilize, but also considered the ability of removing the smear layer on the root canal walls by it and other biocompatibility. These present studies focus on the ability of removing smear layer and cytotoxicity of ozonated water.Objective:(i) to investigate the changes in concentration of ozonated water at various intervals(ii) to compare the effectiveness of smear layer removal between ozonated water and commonly used root canal irrigants(iii) to study the biocompatibility of the various irrigants and to compare their cytotoxicity on L929 cell by MTT method.Methodology: Six Samples are taken at an interval of 5 minutes in the next 30 minutes, when ozone gas is released into water from an ozone generator. Ozone water concentration curves were plotted according to the results measured by iodimetry at six different points. Five groups of irrigants like 17% EDTA and 5.25% NaClO,2.15mg/L Ozonated water, 2.15mg/L Ozonated water and 1% NaClO, 3% hydrogen peroxide, triple-distilled water was used during the stepback preparation of 40 single canalled human teeth (further divided into five different groups). After irrigating, the teeth were spit along its long axis and middle of the canal wall was observed through scanning electron microscopy followed by statistical analysis. L929 cells were cultured in vitro. The cells were exposed to 2.15mg/L ozonated water, 3%hydrogen peroxide, the mixture of 17% EDTA and 5.25% NaClO at 1:1 ratio, and the mixture of 1% NaClO and 2.15mg/L ozonated water at1:1 ratio for 6 hours, 12 hours and 24 hours respectively and the triple-distilled water was taken as the control group. The MTT assay was done to evaluate the cytotoxicity.Results:Concentration of the Ozone solution is directly proportional to the working time of the Ozonizer. The concentration of Ozonated water reaches the maximum of 2.15mg/L at 20 minutes and gradually decreases thereafter. The group that used 17% EDTA plus 5.25% NaClO as irrigant, showed the maximum smear layer removal, but the dental tubule and canal walls were eroded. Using 2.15mg/L ozonated water as an irrigant has the potential to remove the smear layer, but its efficiency is increased when combined with 1 % NaClO. The group with 3 % hydrogen peroxide and the group with triple-distilled water nearly showed no effect on smear layer removal, but the former appears to be slightly better than the latter. The cytotoxicity of each root canal irrigants evaluated by means of MTT, indicated that the ozonated water has nearly no cytotoxicity when compared to other irrigations, whose toxicity increases with time.Conclusion: 2.15mg/L ozonated water has the potential to remove the smear layer with no erosion of the canal walls, and its efficiency increases when combined with 1 % NaClO. Its biocompatible, with reduced cytotoxicity when compared with other clinically used irrigants .So ozonated water shows a future prospective root canal irrigant for its advantages such as easy to manufacture, cheap, antimicrobial effect and biocompatibility.