compressive strength of mineral trioxide aggregate with propylene glycol

introduction: the aim of this study was to evaluate the effect of adding propylene glycol (pg) to mineral trioxide aggregate (mta) liquid with volume ratio of 20% on the compressive strength (cs) of mta in two time periods (4 and 21 days) after mixing. methods and materials: four groups of steel cylinders ( n =15) with an internal diameter of 3 and a height of 6 mm were prepared and mta (groups 1 and 2) and mta+pg (80% mta liquid+20% pg) (groups 3 and 4) were placed in to the cylinders. in groups 1 and 3 the cs was evaluated after 4 days and in groups 2 and 4 after 21 days. data were calculated using the two-ways anova. the level of significance was set at 0.05. results: the highest (52.22±18.92 mpa) and lowest (4.5±0.67 mpa) of cs was obtained in 21-day mta samples and 4-day mta+pg specimen, respectively. the effect of time and pg were significant on the cs ( p <0.05). mixing mta with pg significantly reduced the cs; but passing the time from 4 to 21 days significantly increased the cs. conclusion: considering the limitations of this study, pg had a negative effect on cs of mta.