[Response of osteoblast cultures to titanium, steel and hydroxyapatite implants].

The biocompatibility of bone implants and substitutes is usually tested on cell-lines only, despite a different and more relevant behaviour on primary osteoblasts as final targets can be expected. "Osteoblast-like" cell line (MC3T3-E1) and fresh human osteoblasts (HOB), cultured from cancellous bone grafts from the iliac crest were used for the study. Three different clinically used biomaterials were compared regarding biocompatibility: titanium, steel and hydroxyapatite (Bio-Oss). "Osteoblast-like" cell line and fresh human osteoblasts (5x104) were seeded on the three bone implants. Cell proliferation and osteocalcin synthesis were determined 1, 3, 7, and 10 days after the cells were plated on the biomaterials. All experiments were performed in five times (pro culture double measurements). HOB proliferation on hydroxyapatite was decreasing after 3 days, whereas cells from "Osteoblast-like" cell line showed comparable proliferation to the control group. The most interesting observation was the significant decrease of the osteocalcin levels (in conditioned medium) of "osteoblast like" cells and HOB on HA (Bio-Oss). We conclude that HA disturbs the proliferation and osteocalcin synthesis of HOB.