Bond strength of adhesive systems to mineral trioxide aggregate with different time intervals.

The aim of this study was to compare the shear bond strengths of various adhesive systems to white mineral trioxide aggregate (WMTA) with different time intervals. Two hundred cylindrical acrylic blocks with a hole (4-mm diameter and 2-mm height) were prepared. The holes were filled with WMTA, and the specimens were allocated into 5 groups. Forty specimens were stored for 4, 24, 48, 72, and 96 hours at 37°C and 100% humidity. Each group was divided into 4 subgroups: group 1, All-Bond SE (Bisco Inc, Schaumburg, IL); group 2, All-Bond 3 (Bisco Inc); group 3, One-Step Plus (Bisco Inc); and group 4, control. After the application of adhesive systems, composite resin (Aelite, Bisco) was applied over the WMTA. Shear bond strengths were measured using a universal testing machine, and the data were subjected to 1-way analysis of variance and the Scheffé post hoc test. There was a significant difference between the 4-, 24-, 48-, 72-, and 96-hour measurements in all of the adhesive systems (P < .001). Among all time intervals, group 3 showed significantly higher bond strengths to WMTA than the other groups (P < .001). Groups 1 and 2 were similar (P = .365). It was concluded that if a longer waiting time can be practiced after the mixing of WMTA, higher shear bond strength measurements can be obtained. Also, when WMTA was used with total-etch adhesive systems, it showed better shear bond strength.