Comparative changes in microvasculature and bone during healing of implant and extraction sites.

The acquisition and maintenance of biological fixation of dental implants are achieved by a rapid and regenerative response of the recipient tissues, especially the vascular and osseous elements. This sequential response is described from initial osteogenesis through remodeling up to 20 weeks after implantation in Macaca fuscata monkeys. The sequential changes in the microvasculature and bone formation in three-dimensional bone-vasculature microcorrosion casts are studied by means of a plastic injection method devised by the author. Micrographs derived from microcorrosion casts reveal that all soft tissues (blood vessels walls, marrow, collagen fiber cells and the like) have been digested, leaving spaces once occupied by these elements, bone, and polymeric material that filled the blood vessels at death. The effects of biomaterial choice, general implant configuration, and interface configuration and material were sequentially analyzed. The effects of one- and two-stage healing variables were not analyzed. The Macaca fuscata monkeys were used for SEM examination of both bioinert and bioactive dental implant materials. The objective of this paper is to describe osseous healing at an implant interface, and compare it with osseous healing in tooth extraction sockets by use of a similar research approach in identical animal models.