Examination of the Bond Strength of Retrograde Filling in Teeth with Failed Apical Resection After Retreatment

Background/Objectives: The primary purpose of the study is to investigate the bond strength of apical fillings following retreatment in teeth with failed apical resection. Methods: After the preparation and obturation of the 120 human upper central and canine teeth, apical 3 mm was resected and separated into two main groups to prepare retrograde cavities using tungsten carbide burs or ultrasonic retro-tips. Each main group was separated into three subgroups according to retrograde filling material (Glass ionomer cement, MTA and Biodentine), and each subgroup was divided according to placement technique: manual condensation and indirect ultrasonic vibration. After the retrograde filling, retreatment procedures were performed, and 2 mm sections were removed from the apical filling and analyzed for push-out test. A Kolmogorov–Smirnov test was used to check the normal distribution of the data while Levene’s test was used to check the homogenity of group variances. The data were analyzed using three-way ANOVA. Results: The analysis of variance demonstrated a significant difference between cavities prepared with tungsten carbide and ultrasonic retro tips in push-out bond strength. Conclusions: There was no effect on the bond strength of the retrograde filling material and the placement technique of the material.