Bioactivity and Biocompatibility of light-curing resin-modified MTA

Objectives: light-curing resin-modified calcium-silicate cements (lc-MTA) were designed to obtain a fast setting root-end cement for root-end filling. It was hypothesized that lc-MTA are bioactive materials with properties comparable with calcium-silicate Portland cements and ProRoot MTA. Methods: the material was prepared by mixing an amount of calcium-silicate cement, HEMA/TEGMA, canphoroquinone and barium sulphate. The setting time and the solubility were tested according with ISO. Two experimental cements (lc-MTA and MTA) and ProRoot MTA were tested. The lc-MTA was light-cured for 120 seconds. The samples were immersed in simulated body fluid, SBF (DMEM or DPBS). The pH of soaking medium and the Calcium releasing from the cement were tested with ion selective electrodes. The bioactivity was investigated with Raman and ESEM/EDX analyses. The SaOS-2 cell viability on cements was assessed after 3 days of culture by Alamar blue test. Results: the setting time was 2 minutes for lc-MTA, 74 for MTA and 76 for ProRoot MTA. The solubility of lc-MTA was significantly reduced. A complex network of round-shaped precipitates (as sub-micron spherulites), covering the cement surface, mainly composed Ca and P was observed by ESEM/EDX after 24 hours of SBF immersion. Raman confirmed the presence of apatite bands (960 cm-1). Both MTA showed a lower amount of sub-micron spherulites deposits covering cement surface than lc-MTA. All cements exerted no acute toxicity in the cell assay systems. Conclusion: the study demonstrated the early and improved bioactivity of light-curing resin-modified MTA cements. The lc-MTA with very short setting time and adequate mechanical properties expand the range of clinical application of conventional MTA cements. Early in vitro bioactivity makes the lc-MTA cements an attractive alternative to conventional MTA cements as root-end repair materials