Physicochemical Properties, Biocompatibility, and Bioactivity of Calcium Silicate-Based Sealers

Objectives: New calcium silicate-based endodontic sealers have been developed. Neo MTA Plus® (NMTAP) is a recent bioceramic material, which the indications include vital pulp therapies, root apexification, root repair, root-end filling and sealing of root canals. MTA Fillapex (MTAF) is a resin MTA-based root canal sealer. AH Plus (AHP) is a gold standard epoxy resin–based sealer due its excellent physicochemical properties. This study evaluated the physicochemical properties, cytotoxicity, cell bioactivity and bioactive potential of NMTAP and MTAF, compared with AHP.

Methods: Setting time, flow and solubility were evaluated based on ISO-6876. pH was evaluated in different periods. Radiopacity was evaluated by radiographic analysis in mmAl. Volumetric change was evaluated in micro-CT after 7 and 30 days of immersion in distilled water. Biocompatibility was evaluated by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and neutral red (NR) assays, and the cell bioactivity was evaluated by alkaline phosphatase (ALP) and alizarin red (ARS) assays. The bioactive potential was evaluated by scanning electron microscopy (SEM). Physicochemical and ARS data were analyzed by ANOVA and Tukey tests; cell viability and ALP by ANOVA-two-away and Bonferroni post-test (α=0.05).

Results: MTAF presented the highest setting time, flow, solubility, and volumetric change (P<0.05). NMTAP showed the highest values of pH (P<0.05). NMTAP and MTAF presented the lowest radiopacity (P>0.05). MTAF had the highest cytotoxicity in all dilutions and lower ALP activity than the control group at 1 and 7 days (P<0.05). NMTAP induced similar ALP activity (P>0.05) at all periods, and higher formation of mineralized nodules when compared to the control group (P<0.05). ARS values were similar between MTAF and the control group (P>0.05). NMTAP showed bioactive potential in SEM analysis.

Conclusions: In conclusion, NMTAP had biocompatibility, bioactivity, and bioactive potential, but low values of flow and radiopacity. MTAF showed low bioactivity and radiopacity besides high cytotoxicity, solubility, and volumetric reduction.