Evaluation of microleakage and bond strength of root-end filling materials performed with different methods

The aetiology of periapical lesions is microbial. İntra-radicular microorganisms cause an inflammatory and immune response within the periradicular tissues. The mean purpose of endodontic therapy is elimination of bacteria from root canal system and establishment an effective barrier to prevent further passage of microorganisms or their products to the periapical tissue. If root canal therapy fails, retreatment is indicated. However, retreatment is not always possible. Therefore, in some situations, endodontic surgery is necessary. The aim of this in-vitro study was to comparatively evaluate apical leakage of Mineral Trioxide Aggregate (MTA) and BioAggregate application with or without zirconia pins by using fluid filtration test method, and to assess bond strength of these experimental groups by using push-out test method. In this study, eigthy-six extracted single rooted, fresh human teeth were used. All teeth except positive control group were filled with gutta-percha and AH Plus root canal filling materials. Three teeth in the positive control group were filled only with gutta percha. The root apexes of teeth in negative control group were covered with three layers of nail polish. The apical 3 mm of the samples were resected by using diamond saw perpendicular to axis of teeth. The root-end cavities were prepared by using ultrasonic retro tips in 5 mm depth. The specimens were randomly divided into four groups of 20 samples. In group 1-2-3-4, root-end cavities were filled with MTA, BioAggregate, MTA and zirconia pin, BioAggregate and zirconia pin, respectively. Zirconia pins which were prepared at the same size of ultrasonic retro tip were placed into the root-end cavities with digit pressure after the cavities were fiiled with MTA or BioAggregate. The microleakage of samples were tested by using fluid filtration method and the bond strength of different four root-end filling groups were evaluated by using push-out test method. The data were evaluated by using SPSS, 17.0. One-way ANOVA and the Post Hoc Tukey HSD tests were used for the analysis of data. Statistically significant differences among the groups were set at p≤0.05. According to results of our apical leakage study; Group 4 showed lower apical microleakage mean value than the other groups. Statistically significant results observed only between group 1 and 4 (p=0,015). And, according to results of our push-out bond strength study; Group 4 showed higher bond strength mean value than the other groups. Statistically significant results observed between group 1 and 4 (p=0,005), and group 3 and 4 (p=0,003). The result of this in-vitro study showed that the sealing ability and bond strength of new developed bioceramic containing root-end filling material BioAggregate was as good as MTA. In addition, application of zirconia pin in root-end cavities showed better results than conventional root-end filling technique.