Effect of 5.25%NaOCl Irrigation on the Microhardness of Root Dentin with Two Different Types of Instrumentation
Huang Li, Peng Bin Dept. of Endodontics, Hospital of Stomatology, Wuhan University, Wuhan 430079, China
Objective: To compare root-dentin microhardness after instrumentation with two types of files and irrigating with 5.25% sodium hypochlorite. Methods: Twenty-nine roots were involved in this experiment. 8 roots with the pulp extirpated followed irrigation only. 16 roots were instrumented with stainless steel K files and rotary nickel-titanium files respectively, each followed with irrigation. 5 roots had the pulp extirpated as the contrast. The roots were sliced and root-dentin microhardness was measured. Results: Sodium hypochlorite irrigation decreased root-dentin microhardness. Significant differences were found between the microhardness at depths of 500 μm and 1 000 μm from the pulp-dentin interface in all roots. Instrumentation with SS K file affected dentin microhardness significantly to a lesser extent than instrumentation with Ni-Ti files did. Conclusion: Instrumentation and NaOCl irrigation affect microhardness of dentine. Ni-Ti instrument decreases the influence of irrigation on root canal dentin microhardness.
【CateGory Index】： R781.05