Standardised testing of bone-implant surfaces using an osteoblast cell culture system. II. Titanium surfaces of varying degrees of roughness

The effect of titanium surfaces with different degrees of roughness on oste oblast proliferation and differentiation was investigated using a standardi sed cell culture system. Human foetal osteoblasts (hFOB 1.19) were cultured on polished (Ti pol), sandblasted (Ti sb) and sandblasted/heat treated (Ti sb-ht) titanium surfaces for 17 days. Cell culture quality polystyrene (Ps ) was used as a control. Cell number and viability were determined for asse ssment of proliferation. Alkaline phosphatase activity, collagen I and oste ocalcin production were measured as parameters for osteoblast differentiati on. In the early phase, higher proliferation values were measured on Ti pol. Ho wever, on Ti sb and Ti sb-ht higher proliferation was found in the late pha se. The activity of the early differentiation marker alkaline phosphatase w as higher on Ti pol. No differences were seen for the late differentiation parameters collagen I and osteocalcin. The test system permits the influence of the surface structure on the dynam ics of the osteoblast development cycle to be determined. The larger surfac e area of rough materials leads to an initially delayed, but then prolonged cell proliferation. This model correlates with recent in vivo findings, an d confirms the use of rough surfaces for implants in direct contact with bo ne, even at the cellular level.