Abstract
AIM: The aim of this study was to evaluate the microhardness of human dentin by using four irrigating solutions. Materials and Methodos: A total of 40 extracted mandibular premolars were selected and sectioned horizontally in the middle third of the root. Forty specimens of 4 mm thickness were embedded in acrylic resin and polished. Four test groups, each group containing ten specimens were immersed in respective irrigating solution and subjected to vicker's microhardness test at T0, T2 and T5min. STATISTICAL ANALYSIS: The data obtained were analyzed using the one way ANOVA followed by Tukey HSD method with ap=0.05 as the level for statistical significance. RESULTS: Suggested that there was no statistically significant difference in mean values between four experimental irrigating solutions. CONCLUSION: Mixture of Tetracycline isomer i.e. Doxycycline, Citric acid and a Detergent (Tween 80) MTAD not altered the microhardness of root canal dentin significantly and seems to be an appropriate irrigating solution, because of its harmless effect on the microhardness of the root canal dentin.