The concept of osseointegration and bone matrix expression.

Osseointegration has been defined as the direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant. To date, this concept has been described by descriptive histological and ultrastructural criteria but not by biochemical means. This review evaluates the basic science work performed on this concept and then applies the concept to the principle of osseous healing. Specific studies are cited where alterations in the healing response are due to clinical management of implant placement and how studies of surface properties may lead to further insights on implant design and prognosis. In addition, a review of bone expression as a function of in vitro stress applications is given. This is followed by an indepth review of the collagens and noncollagenous proteins, described to date, within isolated bone matrix. It is this collagenous matrix (especially type I) that is described as being close to and oriented with a glycoprotein component next to the implant surface. In turn, the large family of noncollagenous proteins are important in mediating bone proliferation, matrix accumulation, orientation, mineralization, and turnover. This section is followed by a discussion of specific growth factors as they may relate to osseous healing around an implant.