Proliferation and osteogenic differentiation of osteoblast-like cells obtained from two techniques for harvesting intraoral bone grafts

The aims of our study were to verify the presence of viable osteoblasts in samples of bone tissue obtained by drilling or from cortico-cancellous bone blocks and to assess their growth and differentiation capacities. Bone tissue samples were processed independently and cultured in Dulbecco's modified Eagle medium, in a CO2 incubator at 37 A degrees C. The proliferative capacity of osteoblasts was determined by spectrophotometry (MTT) at 24 and 48 h of culture. Cell cycle was analysed by flow cytometry. Cell differentiation was studied by red alizarin staining of nodules formed in mineralisation medium and by analysis of alkaline phosphatase activity. In comparison to bone block-derived osteoblasts, the proliferative capacity was greater at 24 and 48 h of culture (P < 0.001) in the drilling-derived osteoblasts, which showed significantly increased G2/M (P = 0.014) and S (P < 0.001) phases in the cell cycle study. The number of mineralised nodules was proportional to the incubation time, with no differences between the two types of sample, which also did not significantly differ in alkaline phosphatase activity. Superior autograft material is obtained by harvesting particulate bone from low-speed drilling fragments than from a cortico-cancellous bone block. These results suggest that bone obtained from low-speed drilling is a simple and effective alternative to the classic procedure for obtaining bone tissue.