In vitro reactions of human osteoblasts in culture with zirconia and alumina ceramics

The biocompatibility of two implantable materials, zirconia and alumina cer amics, was investigated in vitro using human osteoblast cell cultures. The viability of osteoblast cells with the materials was evaluated by the methy lthiazole sulfate test that revealed an absence of any cytostatic or cytoto xic effect. Cell proliferation kinetic and total protein synthesis in osteo blasts with zirconia or alumina were similar to that observed in control ce lls cultured on glass coverslips. Light and scanning electron microscopic e xaminations showed an intimate contact between osteoblasts and the substrat es; well-spread cells were observed on the surfaces of both materials. Adhe sion ability and morphological characteristics were preserved in osteoblast cultures with these substrates. Moreover, immunohistochemical staining in osteoblasts with zirconia and alumina showed the capacity of these cells to elaborate the extracellular matrix composed of types I and V collagen, ost eocalcin, osteonectin, bone sialoprotein, and cellular fibronectin. Finally , DNA image cytometry and interphase silver-nucleolar organizer regions qua ntification were applied as complementary biocompatibility tests to detect any changes in DNA synthesis and cell proliferation, respectively The resul ts showed that neither material altered cell ploidy or cell growth rate in accordance with the absence of any inducing effect on DNA synthesis or prol iferation. (C) 1999 John Wiley & Sons, Inc.