Long-Term Impact of New Calcium-Silicate-Based Sealer on Mineral Contents and Crystallinity of Radicular Dentin: An Ex Vivo Study

Introduction. This study aimed to evaluate the long-term impact of new calcium silicate-based sealer (HiFlow Bioceramic) compared to calcium hydroxide-based sealer (Sealapex) on mineral constituents and crystallinity of radicular dentin. Methods. Roots of multirooted maxillary molars were denuded their dentin from all covered cementum then longitudinally split. The dentin segments were divided into three groups covered with either HiFlow root canal sealer or Sealapex root canal sealer or kept untreated (control group). After complete setting of sealers, the radicular dentin of each group was stored in phosphate buffer solution or deionized water for 60 days and then examined with Fourier Infrared Spectroscopy, scanning electron microscope/energy dispersed X-ray and X-ray diffraction (XRD). Results. When the dentin was stored in phosphate buffer solution, compared with untreated dentin, Fourier transform infrared spectra showed insignificant increase in the amide I and phosphate, significant increase in carbonate area, and carbonate/phosphate ratio, while there was insignificant change in phosphate/amide I ratio of HiFlow-treated dentin, whereas Sealapex induced significant decrease in amide I area, phosphate area, and phosphate/amide ratio. Both sealers induced significant increase in crystallinity index and significant decrease in crystallinity percent. Energy dispersed X-ray showed decrease in calcium content by both sealers. The phosphate content was increased by HiFlow and decreased by Sealapex. Conclusions. The mineral composition and crystallinity of dentin were insignificantly changed by the long-term HiFlow treatment, whereas, markedly changes by Sealapex.