Effect of Calcium Hydroxide Mixed with Different Vehicles on the Push-Out Bond Strength of Mineral Trioxide Aggregate

The aim of this in vitro study was to evaluate the effect of calcium hydroxide mixed with different vehicles on the push-out bond strength of mineral trioxide aggregate.
The study was conducted on 80 extracted single-rooted human maxillary incisor teeth who secrowns had been removed. The root canals were instrumented and divided into 4 groups according to the vehicle of the calcium hydroxide paste: Group I – distilled water; Group II – propylene glycol; Group III – 0.2% chlorhexidine; Group IV – control. After placement ofthe root canal dressings, the teeth were washed with EDTA and sodium hypochlorite and sealed with MTA. After 7 days, the push-out test was carried out using a universal testing machine. Data were analyzed with one-way ANOVA and gomes-howell tests.
The maximum and minimum bond strength values were recorded in the propylene glycol and distilled water groups, respectively. There was significant differences in push out bond strength between chlorhexidine and propylene glycol groups (P=0.015). There were significant differences in resistance to dislodgement between group control - propylene glycol (P=0.032) and group control-chlorhexidine (P=0.012).
Placement of propylene glycol before placement of MTA in root canal improves the push-out bond strength of this material.