Abstract
Background: Increased Dentin Brittleness means it is weaker and more liable to fracture under occlusal forces which adversely affects the strength of the tooth, the prognosis of the endodontic treatment, and the life time of the tooth under the occlusion forces. Irrigation solutions have different effects on the micro hardness and the micromorphology of the root canal dentin. Aim: The current study was done to evaluate the effect of two different nano irrigating solutions on the dentin microhardness. Materials and methods: Sixteen intact human maxillary incisors with mature apices were decoronated, after cleaning and shaping all the roots were longitudinally split by using Isomet. To get total of 32 root halves. Each root half was horizontally embedded in auto polymerized acrylic resin exposing the most dentin surface. Each root half was given a number and distributed into four equal groups. Group I Nano Magnesium oxide, Group II Chlorhexidine loaded chitosan nano particles, Group III 5.2% Sodium hypochlorite followed by 17% EDTA and Group IV Saline. Each half was immersed in the tested solution for 5 min. The microhardness of the root dentin was assessed by vicker's microhardness indenter Results: Group III shoed statistically significant reduction in dentin microhardness compared to other groups. Conclusion: CHX+CSNPs and MgO are suitable endodontic solutions because of their lower toxic effect on microhardness in comparison to 5.25NaOCL + 17% EDTA.