Comparative Evaluation of 5% Carbohydrate-derived Fulvic Acid and Various Chelating Agents for Root Dentin Microhardness: An In vitro Study

Introduction: Successful endodontic therapy requires eliminating bacteria, debriding root canals and ensuring complete obturation to prevent reinfection. During cleaning and shaping, a smear layer forms, composed of dentine shavings, pulp remnants and microorganisms, which can compromise treatment success. Various solutions, including NaOCl, ethylenediaminetetraacetic acid (EDTA) and natural chelators such as chitosan and citric acid are used for smear layer removal. This study evaluates the effects of 5% carbohydrate-derived fulvic acid (CHD-FA), 17% EDTA and 20% citric acid on root dentin microhardness. Materials and Methods: A total of thirty human mandibular single-canal premolars with mature roots were chosen for this study. The samples were decoronated to achieve a standard working length of 15 mm. Canal patency was established using a 10 k file. The samples were sealed with sticky wax to create a vapour lock effect. Biomechanical preparation was carried out up to F3. The samples were divided into three groups according to the final irrigation protocol, with 5 mL of solution for each sample. Group 1: CHD-FA, Group 2: 17% EDTA and Group 3: 20% citric acid. The samples were split into two equal halves longitudinally. One section from each sample was mounted horizontally on acrylic resin. The microhardness of dentin was assessed using the Vickers microhardness testing. Results: Statistical analysis was conducted using the one-way ANOVA F -test and Tukey’s post hoc test. Group 1 exhibited the highest mean microhardness value, followed by Groups 2 and 3. All groups showed a highly significant difference from one another ( P < 0.001). There was no significant difference between Group 2 and Group 3 ( P = 0.024). The 5% CHD-FA had the least effect on the microhardness of dentin compared with 17% EDTA and 20% citric acid. Conclusion: Irrigants used for root canal irrigation not only reduces the smear layer but also decrease the microhardness of dentin.