In Vitro Comparison of the Push-Out Bond Strength of RetroMTA, OrthoMTA, and ProRoot MTA

Different MTA brands may have different push-out bond strength (PBS) values in 10 minutes and 4 hours. Thus, this study aimed to compare the PBS of RetroMTA, OrthoMTA, and ProRoot MTA.  

In this in vitro, experimental study, 54 dentin discs with 2 mm diameter and a central lumen with 1.3 mm radius were used in each of the RetroMTA, OrthoMTA, and ProRoot MTA groups (18 discs for each group). The samples were wrapped in a moist gauze and incubated at 37°C and 100% humidity. The PBS was measured by a universal testing machine at a crosshead speed of 1 mm/minute after 10 minutes and 4 hours. The mode of failure was also categorized by using a stereomicroscope. The mean PBS of the three groups was compared using two-way ANOVA. The mode of failure was analyzed by the Chi-square test.

The interaction effect of time and material on PBS was not significant (P=0.227). At both time points, the PBS of the three groups was significantly different (P=0.001), and RetroMTA showed significantly higher PBS (P<0.014). However, the PBS of OrthoMTA and ProRoot MTA was not significantly different (P=0.695). The PBS of all materials at 4 hours was significantly higher than that at 10 minutes (P=0.001).

RetroMTA was superior to ProRoot MTA and OrthoMTA regarding the PBS after 4 hours.