Guided bone regeneration is a new technique that evolved following the guided tissue regeneration procedure for regeneration of lost periodontium. The objective of guided bone regeneration is to promote bone formation in osseous deformitites either before or in conjunction with endosseous implant placement. Osseous defects consist mainly of extraction sited, dehiscences or fenestrations, and localized ridge deformitites. In addition, bone defects may either provide natural spacemaking or be nonspacemaking. A plethora of publications indicate that the guided bone regeneration technique can be used successfully in all types of defects. Nonspacemaking defects usually require bone graft materials to assist in space maintenance and enhance bone formation. Fixation pins are also used, either with or without graft material, in this regard. The scientific literature on guided bone regeneration was review by a task force to determine techniques proven to increase predictability relative to successful patient outcomes and to develop specific evidence based diagnostic and treatment decision trees.