Osseointegrated dental implants placed into adequate bone enjoy a high success rate. However, placing implants into resorbed alveolar ridges can result in fixtures that are not optimally positioned or must be placed in insufficient bone, thus reducing their rate of success. Recently, techniques for bone regeneration developed for use around teeth have been applied to implant dentistry. Guided Tissue Regeneration (GTR), also called Guided Bone Regeneration (GBR), uses thin membranes which act as barriers to soft tissue ingrowth. This approach for regenerating bone around implants is described in detail in this paper. Initial approaches and modifications are covered as are specific details of current techniques.