Effect of blood contamination on the push-out bond strength of calcium-enriched mixture and white mineral trioxide aggregate in simulated furcation perforations in different debonding times

Abstract

Introduction: The aim of the present study was to compare of the effect of blood contamination on retention characteristics of white mineral trioxide aggregate (WMTA) and calcium-enriched mixture (CEM) in reconstructions of the furcation area. Materials &Methods: Furcal perforations, measuring 1.3 mm in diameter and 2 mm in height, were produced in 180 human mandibular first molars. The teeth were divided into 12 groups of 15. WMTA and CEM were used in groups 16 and 712, respectively, for perforation repair. In groups 1, 3, 5, 7, 9 and 11 the walls of the perforated area were contaminated with blood; normal saline was injected in the remaining groups. Instron test was carried out in groups 1, 2, 7 and 8 after 24 hours, in groups 3, 4, 9 and 10 after 72 hours and in the remaining groups 7 days after placement of the materials using a Universal test machine. In order to evaluate the failure modes, the samples were sectioned at furcation floor area, divided into two in the vertical direction and evaluated under a stereomicroscope at 40. Data were analyzed with multi-variate ANOVA and post hoc Tukey tests. Results: The highest (6.75 MPa) and lowest (1.77 MPa) bond strength values were recorded in groups 12 and 1, respectively. There were no statistically significant differences in bond strength between MTA and CEM (P<0.05). However, there were significant differences in bond strength between blood-contaminated and un-contaminated groups in both materials (P<0.05); time had exerted a significant effect on the bond strength of the study groups (P<0.05). Failure patterns were of the mixed type in all the samples. Conclusions: Resistance of both WMTA and CEM to displacement was similar and elapse of time from 24 hours to 7 days and contamination resulted in an increase and decrease in bond strength of these two materials to dentin, respectively