An implantable screw system for maintaining horizontal and/or vertical space during bone grafting procedures is provided, the screw comprising: a contoured head having a region adapted to support soft tissue and permit bone growth; a threaded shaft and a tip adapted to penetrate bone tissue; and where one screw contains a threaded chamber for engaging a second screw for additional space maintenance; wherein the screw(s) comprises cortical bone material. Methods of implanting one or more screws during bone grating procedures are disclosed.