Effect of Blood Contamination on Push-Out Bond Strength of Mineral Trioxide Aggregate Mixed with Different Liquids

Mineral trioxide aggregate (MTA) as a retrograde filling is always in contact with blood in the periradicular area during apical surgery. The purpose of this study was to investigate the effect of blood contamination on the push-out bond strength of MTA mixed with sterile water, local anesthetic, and 5% CaCl2. Thirty middle thirds of mandibular premolar roots were randomly assigned into three groups of ten. Group 1: MTA mixed with sterile water. Group 2: MTA mixed with local anesthetic (2% lidocaine HCl). Group 3: MTA mixed with 5% CaCl2. Each group was then divided into two groups: group A, in which specimens were contaminated by blood, and group B, in which specimens were not contaminated by blood. Specimens were stored in an incubator with a temperature of 37 °C for 72 h, subjected to a push-out test, and observed under a stereo-microscope at a magnification of 40× to determine the nature of the bond failure between MTA and dentinal walls. The data were analyzed using two-way analysis of variance and Tukey’s post hoc test with a 5% significance level. The results show that blood contamination reduced the push-out bond strength of MTA mixed with either sterile water, local anesthetic, or 5% CaCl2 (P < 0.05). The predominant failure in each group was a mixture of adhesive and cohesive types. MTA mixed with local anesthetic produced the lowest push-out bond strength, and MTA mixed with 5% CaCl2 had the greatest push-out bond strength.