A new approach to demonstrate cellular activity in bone formation adjacentto implants

Bone tissue repeatedly formed in titanium 6-aluminum 4-vanadium rabbit bone harvest implants was collected in vivo at various times between 12 days an d 5 weeks. Qualitative and quantitative examinations on undecalcified thin sections were performed in the light microscope. The amount of bone tissue was calculated on routinely stained sections. Alkaline (ALP) and acid phosp hatase (ACP) enzyme activities were investigated. We also performed immunoh istological detection of bone matrix proteins. Increasing bone density as w ell as an increasing mineralization of the tissue was observed in the biops ies with increasing time. The ALP and ACP activities were similar at short times (12 days and 2 weeks). With increasing time the ALP activity was stro nger than that of ACP. The results from the immunohistochemical detection o f osteonectin, osteopontin, bone sialoprotein, and collagen I and II demons trated changes in the tissue differentiation with time. The tissue formatio n in the canal became more mature with time of ingrowth, as observed with t he various techniques used in this study. Owing to these methodical develop ments, undecalcified ground sections may be used for detailed analysis of v arious phases of tissue formation in close proximity to implants. (C) 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 51, 280-291, 2000.