Proliferation and differentiation parameters of human osteoblasts on titanium and steel surfaces

Commercially pure titanium (cpTi), titanium alloys, and steel are often use d for dental and orthopedic implants. In these applications titanium is con sidered the "gold standard." However, tissue reactions around titanium impl ants and the changing trend to leave orthopedic devices in the body have le d to a new examination of the preferred material. This in vitro study teste d the behavior of osteoblasts on cpTi, Ti-6Al-7Nb, and stainless steel with surface designs similar to clinical implants. After surface characterizati on by scanning electron microscopy and profilometry, cell proliferation and the differentiation parameters of alkaline phosphatase (ALP) activity and osteocalcin were measured. For all materials tested, the growth curves show ed a similar kinetic. On Ti-6Al-7Nb, ALP activity was significantly lower w hen compared with steel, and cpTi and did not change over the time. ALP act ivity increased moderately on steel and cpTi. Osteocalcin levels were highe r on both titanium materials than on steel. Based on undisturbed cell growt h and the relatively high alkaline phosphatase and osteocalcin levels, we s uggest that cpTi provides the best biocompatibility with regard to prolifer ation, in addition to more reliable early and late differentiation markers of human osteoblasts in vitro. (C) 2000 John Wiley & Sons, Inc.