Comparative Evaluation of the Push-out bond strength of Nano-formulations of MTA and Portland cement.

Abstract

Purpose: To investigate and compare the push-out bond strength of nano-formulation of ProRoot MTA (NPMTA) and Portland cement (NPC) with commercially available ProRootMTA (PMTA) and Portland cement (PC) aiming to develop a new root-end filling/ perforation repair material. Methods: Forty root-dentin slices prepared from freshly extracted single-rooted teeth were randomly allocated into four groups (n = 10) according to the tested cements: PMTA, PC, NPMTA and NPC. The root canal lumens were instrumented and filled with the test materials. The Universal testing machine was used for push-out bond strength evaluation. The maximum force employed at the time of dislodgment was recorded and the specimens were inspected under scanning electron microscope at x25 magnification to detect the nature of the bond failure. Kruskal–Wallis test was applied for the comparison between the groups. Mann-Whitney U test was used for pairwise comparison. Results: The mean push-out bond strength ± standard deviation values of PMTA, PC, NPMTA and NPC were 1.33 ± 0.4, 0.91 ± 0.34, 1.1 ± 0.39 and 2.22 ± 0.43 respectively. There was no statistically significant difference between the means of PMTA, PC and NPMTA (p=0.529) but the mean of NPC was significantly higher than the three groups (p=0.012). Under stereomicroscope PMTA, PC and NPMTA groups showed a majority of adhesive failure, while NPC showed a majority of mixed type failure. Conclusions: The force needed for NPMTA displacement is similar to PMTA and PC and significantly lower than the force required for NPC displacement.