Retrospective Analysis of the Outcome of Ridge Preservation with Anorganic Bovine Bone Mineral: Marginal Bone Level at Implants Placed Following Healing of Grafted Extraction Sockets

The objective of this study was to investigate marginal bone level (MBL) changes as the primary outcome of implants placed following healing of extraction sockets treated with ridge preservation, compared to implants placed following unassisted healing. A total of 268 patients (contributing 572 implants) treated from April 2005 to March 2013 were included in this retrospective study. Following estimation of the overall success rate of implants placed in the practice, 129 patients (contributing 222 implants) met the inclusion and exclusion criteria to be further evaluated. Of these, 78 patients (contributing 105 implants) received ridge preservation procedures, which entailed placement of anorganic bovine bone mineral covered with polytetrafluoroethylene membrane. The other 51 patients (contributing 117 implants), with healed sites without history of bone grafting, served as controls. Digital radiographs were taken at the time of implant placement and during follow-up visits. The mean follow-up period for ridge preservation sites was 33.6 months (range: 7.5 to 61.5 months) and for healed sites was 36.3 months (range: 6 to 91.2 months). The survival rate of implants in sites following healing of ridge preservation was 97.3%, compared to 98.5% in the nongrafted healed sites. The mean MBL changes during the observation period were 0.11 and 0.07 mm on the mesial and 0.06 and 0.06 mm on the distal aspects of the ridge preservation and healed sites, respectively (P > .05). The mean crestal bone remodeling during the observation period was 0.63 and 0.45 mm on the mesial and 0.48 and 0.12 mm on the distal aspects in the ridge preservation and healed sites, respectively (P < .05). The results of this study demonstrated stable MBL and survival of implants placed in sites following ridge preservation with xenograft as well as nongrafted healed sites.