Alveolar Ridge Preservation Using Allografts and Dense Polytetrafluoroethylene Membranes With Open Membrane Technique in Unhealthy Extraction Socket.

We evaluated the effectiveness of the open membrane technique using a high-density polytetrafluoroethylene (dPTFE) membrane with freeze-dried bone allografts in damaged sockets for alveolar ridge preservation (ARP). This retrospective study included 26 sites from 20 patients who had received ARP for the placement of dental implants. ARP was conducted using dPTFE membrane with allografts on the day of extraction without primary closure. When the membrane was removed after 4 weeks, the newly formed reddish tissue at the grafted site was checked (first outcome, clinical evaluation). Four months after membrane removal, a core biopsy was performed from the center of the grafted site before implant placement (second outcome, histomorphometric evaluation). Radiographic measurements of alveolar bone changes between implant prosthesis delivery and the 1-year follow-up were obtained (third outcome, radiographic evaluation). A total of 23 sites from 18 patients had no complications during the follow-up period. Three sites from two patients were excluded because of early membrane removal. Newly formed reddish tissue was found at 15 sites, and partially formed tissue was found at 8 sites. Although we were unable to harvest bone core from all sites, histomorphometric analysis in 11 patients indicated that the mean area of new bone was 28.48% ± 6.60%, that of the remaining graft particle was 27.68% ± 9.18%, and that of fibrous tissue was 43.84% ± 6.98%. The mean loss of marginal bone was 0.13 ± 0.06 mm at the mesial area and 0.15 ± 0.06 mm at the distal area, as assessed using radiographic evaluations. The results of this nonrandomized study suggest that this technique may be an appropriate procedure for ARP. Further studies with a control group and more subjectives can be designed based on this study.

The Role of Two Different Collagen Membranes for Dehiscence Defect Around Implants in Humans.

The aim of this study was to elucidate the role of 2 types of collagen membranes (cross-linked vs noncross-linked) used in conjunction with autogenous or allogenic bone followed by xenogeneic bone particles for dehiscence defect around implants in humans. Experimental groups were divided into 2 groups: Group CL (cross-linked, Ossix Plus, n = 24 implants, 16 patients) and Group NCL (noncross-linked, Bio-Gide, n = 25 implants, 18 patients). At the time of implant insertion and uncovery surgery, measurements of the dehiscence bony height, width, and surface area were made. Before applying the membrane to defects, guided bone regeneration was performed. Because it is difficult to measure the degree of exposure, early exposed cases were excluded from the result analysis. The mean percentage gain of the dehiscence defect and the mean marginal bone reduction value of follow-up radiograph did not show statistically significant differences between the 2 groups. Both membranes exhibited satisfactory results on dehiscence defects. As a result, our authors concluded the success of guided bone regeneration was performed simultaneously for dehiscence defects around the implant, regardless whether collagen membranes were cross-linked or noncross-linked.