Biomimetic remineralization of human dentin using promising innovative calcium-silicate hybrid “smart” materials

Introduction. The hypothesis was that experimental ion-leaching bioactive composites enhance remineralization of apatite-depleted dentin. Materials and methods. Calcium-aluminosilicate (wTC-Ba) or fluoride-containing calciumaluminosilicate (FTC-Ba) Portland-derived mineral powders were mixed with HTP-M methacrylate HEMA/TEGDMA/PAA-based resin to prepare experimental composites. Controls were Vitrebond and Gradia Direct LoFlo. Calcium- and fluoride-release, pH of soaking water, solubility and water uptake were evaluated in deionized water using material disks (8 mm diameter and 1.6 mm thick). The apatite-formation ability (bioactivity) and the ability to remineralize previously demineralized dentin were assessed by ESEM-EDX and FTIR after soaking in a phosphatecontaining solution. Human dentin slices (0.8 mm thickness) were demineralized in EDTA 17% for 2 h, placed in close contact with the material disks and immersed in a phosphate-containing solution (Dulbecco’s Phosphate Buffered Saline, DPBS) to assess the ability of the materials to remineralize apatite-depleted dentin. Results. Only the experimental materials released calcium and basified the soaking water (released hydroxyl ions). A correlation between calcium release and solubility was observed. FTC-Ba composite released more fluoride than Vitrebond and formed calcium fluoride (fluorite) precipitates. Polyacrylate calcium complexes (between COO− groups of polyacrylate and released calcium ions) formed at high pH.