Modification of mineral trioxide aggregate. Physical and mechanical properties

To evaluate the physical and mechanical properties of two cements with a similar chemical composition to mineral trioxide aggregate and to attempt to improve their properties by producing a composite material.

Two cement types were used: a mixture of calcium sulpho-aluminate cement and Portland cement (CSA) and calcium fluoro-aluminate cement (CFA) in conjunction with an admixture to improve the handling characteristics. Cements were mixed with an inert filler to produce cement composite. The setting time of the cements was evaluated using an indentation technique. The flexural and uni-axial compressive strengths and solubility of the cements and cement composites were evaluated. The properties of the materials were compared with proprietary brand glass-ionomer cement.

The setting time of the CSA and CFA cements was less than 6 min. The use of an admixture to improve the handling properties tended to retard setting. CSA was stronger then CFA in both compression and flexure (P < 0.001). Addition of granite increased the flexural strength of both cements but reduced the compressive strength (P < 0.01). CFA absorbed more water then CSA. Addition of granite reduced the water uptake of both cements.

Both CSA and CFA cements had adequate setting times and compressive strength values when compared with proprietary brand glass-ionomer cement. CSA was superior to CFA and had more promise as a prospective dental material.