CONDITIONS WHICH PROMOTE MINERALIZATION AT THE BONE-IMPLANT INTERFACE- A MODEL IN-VITRO STUDY

This in vitro study was an investigation of osteoblast functions on gl ass substrates modified with the bioactive peptide Arg-Gly-Asp-Ser (RG DS) in the absence and presence of recombinant human Osteogenic Protei n-1 (OP-1); control substrates were plain glass, glass modified with a mine groups, and glass modified with the non-adhesive peptide Arg-Asp- Gly-Ser. In serum-free cell culture medium, osteoblasts adhered in gre ater numbers (P < 0.1) to glass modified with RGDS, compared to adhesi on on all other substrate types tested in the present study. In the pr esence of serum proteins, osteoblasts adhered similarly to all substra te types examined, in the absence or presence of 100 ng ml(-1) OP-1. T he presence of 100 ng ml(-1) OP-1 inhibited (P < 0.1) 72 h proliferati on of sparsely seeded (2500 cells cm(-2)) cultures on all substrates e xamined in the present study. OP-1 (100 ng ml(-1)) promoted 21 day min eralization on all substrates examined; in addition, mineralization wa s further enhanced in osteoblast cultures grown on glass modified with the adhesive peptide RGDS. The present study establishes conditions w hich can be utilized in the design of dental/orthopaedic biomaterials which elicit timely, specific responses from surrounding bone tissue.