Calcium aluminate cement-based compositions for biomaterial applications

Calcium aluminate cement (CAC) Calcium aluminate cement (CAC) is classified as a hydraulic binder presenting various advantages, such as fast hardening at room temperature and suitable rheological properties, when compared to traditional materials. Based on this, CAC has been investigated as an alternative biomaterial in order to overcome some drawbacks presented by commercial products usually applied in the dentistry (mineral trioxide aggregate=MTA and glass ionomer) and orthopedics (polymethyl methacrylate=PMMA) fields. In this work, the properties of CAC-based compositions containing different amounts of additives (i.e., alumina, zirconia, zinc oxide, hydroxyapatite, tricalcium phosphate, chitosan and collagen) were evaluated and the attained results were compared to those of MTA, PMMA and two glass ionomers (Meron and Vidrion F). The characterization of the selected materials comprised their particle size distribution, as well as the cold crushing strength, apparent porosity, pore size distribution and radiopacity. Plain CAC presented higher crushing strength than the commercial products used in dentistry and the blend of this cement with 4 wt% of additives (alumina, zirconia, zinc oxide, tricalcium phosphate or hydroxyapatite) resulted in improved mechanical performance when compared to PMMA (cement for bone repair). The addition of zinc oxide and hydroxyapatite to CAC also gave rise to samples with low porosity levels and smaller pore sizes after their contact with simulated body fluid solution over 7 days at 37 °C. Conversely, collagen and chitosan-containing compositions showed higher porosity and lower mechanical strength. Regarding the radiopacity results, the evaluated compositions presented better results than the commercial products, except for MTA.