The endosteum is the tissue lining the medullary cavity of bone. It is composed of a single layer of osteoprogenitor cells and a small amount of connective tissue. In dentistry and oral surgery, the endosteum is generally where an implant is placed prior to a patient receiving a prosthesis. An endosteal implant is placed in the bone of the jaw and acts as a new artificial root which will anchor the restoration. For some patients, an alveolar bone graft or other type of bone graft is required to build up the area before the endosteal implant can be placed. Following the implant surgery, healing and osseointegration must occur prior to the dental prosthesis being affixed. Though endosteal implants can come in several different materials, titanium is most frequently used due to its strength, durability, corrosion-resistance, and biocompatibility. Endosteal implants are available either as screw-type (or cylinder) or blade.