Osseointegration Vs. Biointegration
In 1985, dePutter observed that there are two ways of implant anchorage or retention: mechanical and bioactive. Mechanical retention refers to the metallic substrate systems such as titanium alloy. The retention is based on the undercut forms such as vents, slots, dimples, screws etc and involves direct contact between the dioxide layer on the base metal and bone with no chemical bonding. Bioactive retention is achieved with bioactive materials such as hydroxyapatite (HA), which bond directly to the bone, similar to ankylosis of natural teeth. Bone matrix is deposited on the HA layer as a result of physicochemical interaction between the collagen of bone and the HA crystals of the implant.