Sealing off of a bone defect from the surrounding soft connective tissue by placement of a mechanical barrier (membrane), thereby creating a secluded space into which only cells from the walls of the bone defect can migrate. Expanded polytetrafluoroethylene (e‐PTFE) is the best documented membrane material for promoting bone healing and regeneration by encouraging the biologic or mechanic environment of the healing or regenerating tissues; however, resorbable collagen membranes are equal in value.