Introduction: The aim of the present study is to evaluate comparatively the action of 0.2% chitosan, 4% propolis, 2.6 % NaOCl and 17% EDTA on human root dentin microhardness.
Methods: Twenty recently extracted single-rooted mandibular premolar teeth were selected. The roots were split longitudinally into 2 parts (40 specimens). The specimens were randomly divided into 4 groups and were treated with 0.2% chitosan, 4% propolis, 2.6 % NaOCl and 17% EDTA immediately after the initial baseline microhardness measurements. A standardized volume of 2 ml of each solution was used for 5 minutes. The reference microhardness values of untreated specimens were initially measured with a Vickers indenter under a 50-g load and a 10-second dwell time. Posttreatment microhardness values were obtained in the same manner as the initial ones. The decrease in microhardness was calculated as a percentage. Data were analyzed statistically by 1-way analysis of variance (P = .05) and the post hoc Tukey test for multiple comparisons at the same level of significance. Differences between pretreatment and post-treatment microhardness were statistically analyzed by using the t-test with a P value of .05
Results: After treatment, all solutions significantly decreased the microhardness of root dentin (P < .05) however both 0.2% chitosan, 4% propolis significantly decreased dentin microhardness compared to 2.6 % NaOCl and 17% EDTA.
Conclusion: All the tested irrigation decreased root dentin microhardness however the effect of either 0.2% chitosan or 4% propolis decreased root dentin microhardness more than 2.6% NaOCl or 17% EDTA.