Effect of different concentrations of propylene glycol on the physical-chemical properties of MTA

Aim: This study evaluated the effect of different concentrations of propylene glycol (PG) on the dimensional change (DC), compressive strength (CS), solubility and pH of MTA.

Methodology: Groups were formed according to the proportion of distilled water (DW) and PG in MTA manipulation: G1 (100% DW); G2 (80% DW+20% PG); G3 (50% DW+50% PG); G4 (20% DW+80% PG). The tests were guided by ISO and BSI standards. DC and CS tests were performed after 24 h and 30 days of samples storage in water. In the solubility test, rings filled with the cements were weighed after setting and after 7 days. The pH was measured after 3 and 24 h, and 30 days. The data were analyzed with the ANOVA, Tukey’s and Paired t tests (a=5%).

Results: After 24 h and 30 days, the DC and CS were similar among groups, except the CS for G3 in 30 days. After 7 days, G1 gained weight when hydrated, differing from G3 and G4 (p<0.05). When weighed dehydrated, G2 was different from the other groups (p<0.05). After 3 h, G1 had lower pH values in comparison with G2, G3 and G4 (p<0.05). At the 24-h period, G2 had higher pH values than G1 and G2 (p<0.05). After 7 days, there was no difference among groups.

Conclusions: PG did not affect the MTA dimensional change and compressive strength (except for G3). However, PG reduced MTA solubility (G2) and increased its pH after 3 hours.