A prospective randomized study comparing two techniques of bone augmentation: onlay graft alone or associated with a membrane

Two techniques of ridge augmentation using onlay bone graft alone or associated with a non-resorbable membrane have been previously described. This prospective, randomized study compared these two techniques at 6 months, in terms of bone gain, resorption and quality obtained at edentulous sites. Osseous measurements were taken using stents, callipers and Cr-scans. Membrane exposure occurred at one site, 4 weeks after placement. Endosseous implants were successfully placed at all grafted sites. The mean graft thickness for all subjects was 4.7 mm (range: 2.3-6.2 mm). Overall mean resorption was 1.5 mm (range: 0-4.6 mm) whereas overall mean width gain was 3.2 mm (range: 0.8-6.2 mm). Six months following surgery the membrane group experienced significantly less bone resorption than the graft alone group (P <0.01). Width augmentation did not differ significantly between the two groups. In conclusion, combining a membrane with an onlay graft demonstrates less bone resorption with a minimal risk of complications. Longer follow-up is needed to confirm the benefits of using a non-resorbable membrane.