Evaluation of the Relation between Bond Strength of AH26 and Dorifill to Dentin and Gutta Percha and Their Apical Microleakages

Statement of problem: The sealing ability of different endodontic sealers has been evaluated using micro-leakage tests and/or measuring their bond strength (adhesion) to dentin and gutta percha. However, the micro-leakage studies do not determine the location of the micro-leakage. Therefore, to determine whether the micro-leakage occurs in the dentin-sealer or the gutta percha- sealer interfaces, the bond strength studies are required. The purpose of the present study was to measure the bond strength of AH26 and Dorifill to dentin and gutta percha and to compare their relationship with their apical micro-leakage values using electrochemical test. In this laboratory study, to evaluate the tensile strength of AH26 and Dorfill, the dentinal coronal surface of the twenty four extracted maxillary and mandibular first and second molars were used. Twenty four disk shape specimens of the gutta-percha were prepared. Two groups of sealers (AH26, Dorifill) were placed within the aluminum customized cylinders (n=48) and stabilized on the dentin and gutta-percha. The tensile strength of each sealer with dentin; and gutta- percha were measured separately by a universal testing machine (zwick) in four groups (12 samples in each groups). The data were analyzed using independent samples t-test. To evaluate the sealers’ apical leakages using electrochemical method, 36 maxillary and mandibular canines were used. The selected teeth randomly divided into 2 groups (16 sample in each group) and 4 teeth as control. After canal preparation, each group was filled with one of the sealers and gutta-percha using lateral condensation method. Measurment of current flow through the test system were recorded as a voltage drop across the 100-ohm resistance by a digital multimiter every 72 hour. The data were analyzed using Mann- Whitney test. the bond strength of AH26 to both dentin and gutta-percha was significantly stronger than Dorifill. AH26 had a significantly lower magnitude of apical microleakage than Dorifill the results of this study showed a direct relation between sealers’ bond strength to dentin and gutta-percha with their resistance to apical micro-leakages