In vitro evaluation of tooth-colored yttria stabilized zirconia ceramics

Effects of MoCl3 and NiCl2, originally incorporated as coloring agent, on the cellular response of3 mol% yttria stabilized zirconia (3Y-TZP) ceramics was investigated. MoCl3 and NiCl2-MoCl3incorporated, tooth-colored 3Y-TZP ceramics were produced through cold isostatic pressing at100 MPa followed by pressureless sintering at 1450°C for 2 h. Aging was performed on thesintered ceramics using distilled water in a reactor at 134°C at 2.3 bar pressure for 2 h. Thephases developed during different stages of processing were identified by X-ray diffraction(XRD) analysis. In vitro cell culture studies were carried out using L929 fibroblast cell line. Thecell viability and proliferation studies revealed that none of the specimens showed cytotoxicitywith respect to coloring. Confocal laser scanning microscope (CLSM) analyses suggested thatall of the specimens exhibited good in vitro cytocompatibility. Enhancement in cell attachment,adhesion, and proliferation was observed in all specimens via scanning electron microscope(SEM) analysis. Although the coloring process did not improve the proliferationperformance of the aged specimens, the incorporation of transition metals enhanced thein vitro performance of 3Y-TZP ceramics