To evaluate the physical and biological properties of a novel calcium silicate-based self-adhesive resin cement (TheraCem) by comparison with a traditional self-adhesive resin cement (UniCem 2) and a resin-modified glass-ionomer cement (FujiCEM 2).pH of the cements was measured with moist pH strips. Antimicrobial activity was evaluated by a modified disk diffusion assay. Calcium release of TheraCem in water or lactic acid was measured with an ion selective pH meter for 56 days. Shear bond strength of the cements to zirconia after incubation in water or lactic acid for 7 days was assayed according to ISO 29022:2013, and the fractured surface of zirconia and cement were observed with a stereomicroscope and a scanning electron microscope, respectively.TheraCem started with an acidic pH value of 4.0 and stabilized at pH 9.0, whereas the other two cements remained acidic. TheraCem and FujiCEM 2 displayed antimicrobial activity, but not UniCem 2. Calcium release was observed from TheraCem, which was higher in lactic acid than in deionized water. TheraCem showed highest shear bond strength to zirconia among the three cements, which was not impaired by incubation in lactic acid. In contrast, bond strength of UniCem 2 and FujiCEM 2 decreased significantly under the acidic condition. Consistently, scanning electron micrographs demonstrated marginal degradation of UniCem 2 and FujiCEM 2, but not TheraCem, samples in the acid. The results suggest that TheraCem had features that would help reduce or prevent secondary caries.The new calcium silicate-based self-adhesive resin cement, TheraCem, had an alkaline pH and could be desirable in clinical applications with advantages such as bond strength and stability, antimicrobial activity, as well as calcium release.
