Assessment of the Push-Out Bond Strength of Three Different Root-End Filling Materials in Retrograde Cavities Using Three Different Retro Preparation Techniques

BACKGROUND/AIMS: The aim of this study was to evaluate the push-out bond strength of root-end cavities filled with different retrograde filling materials.MATERIALS AND METHODS: Straight and single root canals of 180 maxillary incisor teeth were prepared, obturated, and randomly divided into nine groups (n=20 per group). In each group, one of the root-end cavity preparation techniques (drill, erbium:yttrium, aluminum-garnet laser, or ultrasonic retrotip) was applied and matched with a retrograde filling [ProRoot mineral trioxide aggregate (MTA), Tech Biosealer Root End, or Biodentine]. Three slices were sectioned from the root apex, and the middle ones were selected. They were placed in a universal testing machine, applying push-out force until bond failure occurred. The push-out bond strength values at bond failure were analyzed using KruskalWallis H test and post-hoc multiple comparison test (p<0.05).RESULTS: The bond strengths between the root-end cavities prepared with a bur, laser, and ultrasonic retrotip and the filling materials (MTA, Tech Biosealer Root End, and Biodentine) were determined to be statistically significantly different (p<0.05). The highest mean value occurred in the ultrasonic + Biodentine group, whereas the lowest mean value was seen in the bur + Tech Biosealer group. There were no statistical differences between the cavities prepared with laser and ultrasonic retrotip and filled with MTA and Biodentine (p>0.05). However, the mean bonding strength of Biodentine placed in cavities prepared with the drill was significantly higher than MTA and Tech Biosealer (p<0.05).CONCLUSION: In laser-prepared cavities, Tech Biosealer showed lower bonding strength compared to the other materials. Similarly, in ultrasonic retrotip prepared cavities, Biodentine and MTA showed better bonding, while Tech Biosealer showed a weaker bonding.