Comparative Evaluation of Root Dentin Microhardness after using Different Standard Irrigating Solutions and Stevia Leaf Extract- An In vitro Study

Abstract

Introduction: Success in endodontic therapy largely depends on mechanical and chemical debridement of the root canals by using instruments and effective irrigating solutions which are not only important for cleaning and disinfecting the root canals, but also, are capable of altering the chemical and structural properties of dentin. As the microhardness test is sensitive to surface changes of tooth structure, it is useful in making a correlation between irrigating solutions and root dentin microhardness. Aim: To evaluate the effect of different standard irrigating solutions at standard concentrations and Stevia leaf extract (2.5%) on the microhardness of root canal dentin. Materials and Methods: This is an in-vitro comparative study where forty intact single rooted teeth were selected and decoronated to get an apico-coronal length of 10 mm and were randomly divided into four groups as per the irrigant used; Group 1 (control): Irrigation with Normal saline, Group 2: Irrigation with 2.5% Sodium Hypochloride (NaOCl) followed by 17% EDTA, Group 3: Irrigation with 2.5% Stevia extract solution, Group 4: Irrigation with SmearClear solution. They were prepared using ProTaper Universal Rotary Files with intermittent irrigation with the respective irrigating solution. The teeth were then embedded in acrylic resin and subjected to Vicker’s Hardness test and the data obtained were analysed using one way ANOVA test. p<0.05 was taken to be statistically significant. Results: At 500 microns, Vickers Hardness Number (VHN) value was less than at 1000 micron, but was not statistically significant, (p>0.05). Between the groups, the control group showed the highest microhardness at 500 and 1000 microns, namely, 51.27±4.36 VHN and 53.60±5.12 VHN, respectively. Group 3 and 4 showed a comparable reduction in microhardness with Group 3 showing slightly better results (47.98±4.34 VHN and 48.89±5.26 VHN, respectively) as compared to Group 4 (47.36±5.50 VHN and 48.62±5.84 VHN, respectively). Group 2 showed the least value (36.60±5.71 VHN and 37.11±5.82 VHN, respectively). Conclusion: Within the limitations of this study, teeth irrigated with normal saline showed least reduction in microhardness followed by irrigation with Stevia leaf extract solution, SmearClear and Hypochlorite followed by EDTA.