Comparative study of three different membranes for guided bone regeneration of rat cranial defects

The purpose of the study was to compare the efficacy of a non-resorbable polytetrafluoroethylene (e-PTFE) membrane (Gore-Tex(R)) versus a resorbable polyglactin membrane (Vicryl(R)) and a newly designed collagenic membrane for enhancing bone regeneration on rat skull defects. The study was conducted on 30 adult Wistar rats. On each animal, two symmetrical, 6 mm wide, full-thickness, skull defects were created in the parietal regions. The right defect was chosen as the experimental site and the left one was left empty as a control. Each experimental site was covered by an inner and outer membrane. The 30 rats were divided into three groups: In group 1 (n=10), a non-resorbable polytetrafluoroethylene (e-PTFE) membrane was used. In group 2 (n=10), a resorbable polyglactin 910 membrane was used. In group 3 (n=10), a collagen membrane processed from avian eggshell was used. In each group, the animals were euthanized at 60 days. The harvested specimens mere processed for contact radiography and standard histological examination. The results were assessed by a Fisher's exact test. In group 1, partial bone healing was observed in seven out of 10 animals and complete in three out of 10 animals (P<0.001). In group 2, no or minimal bone healing was observed in seven out of 10 animals and partial bone healing was observed in three out of 10 animals. In group 3, no or minimal bone healing was observed in nine out of 10 cases and partial bone healing in only one animal. In conclusion, only the non-resorbable e-PTFE membrane group exhibited a favourable result in this study. This study suggests that the structure of the membrane is at least as important as its composition.