Effects of the addition of nanoparticulate calcium carbonate on setting time, dimensional change, compressive strength, solubility and pH of MTA

AimTo evaluate nanoparticulate calcium carbonate (NPCC) using transmission electron microscopy and the effects of NPCC addition to MTA in regard to the setting time, dimensional change, compressive strength, solubility and pH. MethodologyThe experimental groups were G1 (MTA), G2 (MTA with 5% NPCC) and G3 (MTA with 10% NPCC). The tests followed ISO and ADA standards. The specimens in the dimensional change and compressive strength tests were measured immediately after setting, after 24h and after 30days. In the solubility test, rings filled with cement were weighed after setting and after 30days. The pH was measured after 24h and 30days. The data were analysed with the ANOVA, Tukey's and Kruskal-Wallis tests (=5%). ResultsThe setting time was reduced (P<0.05) in samples from G2 and G3 compared to G1. After 24h, the dimensional change was similar amongst the groups, and after 30days, G2 was associated with less alteration than G1 and G3. There was a difference in the compressive strength (P<0.001) after 24h and 30days (G1>G2>G3). The solubility test revealed a difference amongst the groups when the specimens were hydrated: G2>G1>G3 and dehydrated: G3>G2>G1. The pH of the groups was similar at 24h with higher values in each group after 30days (P<0.05), and G2 and G3 had similar mean pH values but both were higher than G1. ConclusionsNanoparticulate calcium carbonate had a cubic morphology with few impurities. The addition of nanoparticulate calcium carbonate to MTA accelerated the setting time, decreased compressive strength and, after 30days, resulted in lower dimensional change (G2), higher solubility and a higher pH.