In order to determine the degree of bone regeneration after removal of radicular cysts using guided bone regeneration (GBR), a prospective, controlled and randomized clinical study was performed. Thirty patients with radicular cysts were divided into three groups. One group, the control group (n = 10 patients), was treated by enucleation and primary closure. The other two groups were treated by enucleation and primary closure but GBR was used in addition, using a resorbable membrane (n = 10) and a nonresorbable membrane (n = 10). The membranes were fixed with nonresorbable Memfix System® screws. The residual volume and the density of the newly formed tissue was measured by computer-assisted tomography and computer-assisted digital image analysis before enucleation and three and six months postoperatively. No statistical significance was found in density and residual volume between the three treatment groups after six months. These results suggest that GBR using membranes does not contribute to increased bone regeneration.