Clinical outcomes of GBR procedures to correct peri-implant dehiscences and fenestrations : a systematic review

Objectives. To analyze the clinical outcomes of endosseous implants following guided bone regeneration procedures (GBR) to correct dehiscence/fenestration defects associated with implant placement. Methods/ Search strategy A Medline search was performed for human studies published in English focusing on GBR procedures for the correction of dehiscence/fenestration defects associated with the placement of screw-shaped titanium implants. The selected studies had to include at least 10 consecutively treated patients with a minimum follow-up of 12 months after the start of prosthetic loading. The clinical outcome in terms of complication rate of the GBR procedure, implant survival, and stability of marginal soft tissues around implants were evaluated. Results. Seven publications were included in this review. A total of 238 patients received 374 implants. Defects were treated with resorbable or non-resorbable membranes, in association with or without graft materials. Patients were followed for 1 to 10 years after the start of prosthetic loading. In the postoperative period, 20% of the non-resorbable membranes and 5% of the resorbable ones underwent exposure/infection. However, in the majority of cases a complete or almost complete coverage of the initial defect was obtained. The overall survival rate of implants, irrespective of type of membrane and grafting materials, was 95.7% (range: 84.7-100%). No significant modifications of probing depth and/or variation of clinical attachment level around implants were observed during the follow-up period. Conclusion. Despite the favorable results obtained, it was difficult to draw significant conclusion as far as the more reliable grafting material and membrane barrier for the correction of dehiscence/fenestration defects are concerned, due to the limited sample of patients and the wide variety of grafting materials and membranes, used alone or in combination. Moreover, due to the lack of randomized clinical trials, it was impossible to demonstrate that such augmentation procedures are really needed to allow the long-term survival of implants.