Guided bone regeneration procedures were carried out around 1,503 implants, including 237 that were noted in a previous publication, using Gore-Tex membranes over deminerali zed freeze-dried bone allograft, freeze-dried bone allograft, an equal combination of htese, or demineralized freeze-dried bone allograft combined with equal parts of resorbable tricalcium phosphate. Comparison of findings at the time of clinical reentry and preoperative photographs and measurements yielded an overall success rate of 97.0% in the treatment of dehisced or fenestrated implants or fixtures placed in immediate extraction sockets. Success was defined as the presence of regenerated hard tissue covering all previously exposed implant surfaces (complete success) or as the presence of two threads or 2 mm or less of residual dehiscence (partial success).