Bioactivity and marginal adaptation of a novel light-curing MTA cement

Objectives: a calcium-silicate MTA (Mineral Trioxide Aggregate) cement have been modified by adding HEMA and TEGDMA resin to obtain an experimental light-curing resin-modified root-end filling material (LC-MTA). The hypothesis of the study was that the innovative LC-MTA cement possess bioactivity properties compareble to ProRoot MTA (DentSply, USA). Methods: HEMA, TEGDMA and photo-activator were added to a tricalcium-silicate/dicalcium-silicate powder. Extracted single-rooted human teeth were instrumented with ProTaper rotary instruments and filled with single-cone gutta-percha technique. Apex was sectioned and a root-end cavity was created by ultrasonic instruments. Root-end fillings were made using ProRoot MTA or the experimental light-curing cement. All samples were then aged in simulated body fluid solution DPBS (Dulbecco's Phosphate Buffered Saline) at 37°C for 24 hours and 1 month. Surface morphology and marginal adaptation of cements were evaluated by ESEM. Bioactivity was evaluated by EDX, Raman and FTIR analyses after 24 hours and 1 month of ageing. Results: ESEM analysis of aged samples revealed a good marginal adaptation of both cements. EDX showed Ca and Si peaks on fresh samples, and Ca and P peaks on 24-hours and 1-month aged samples. Diffuse deposits of apatite spherulites were detected on the surface of both aged cements. Apatite deposits filled the margin of the restoration and coated the root dentin surface. Raman and FTIR analyses displayed calcium hydroxide bands on 24-hours aged samples and apatite bands on aged samples of both cements. Conclusions: the study confirmed the optimal marginal adaptation and the bioactivity of ProRoot MTA and LC-MTA cements. Resin-modified MTA kept the ability to form superficial apatite deposits that improve marginal sealing ability