Twenty Brånemark implants were placed with membranes (Gore-Tex Augmentation Material) as immediate or delayed implants in the extraction sockets of 15 patients. Membrane perforations through the mucous membrane occurred in 10 patients after 6 to 24 weeks and once after 2 weeks. Histologic examination of 15 tissue samples taken when the membrane was removed showed genuine bone regeneration in three patients, connective tissue regeneration with intermittent bone regeneration in eight patients, purely fibrous healing in two patients, and inflammatory granulation tissue in two patients. The high proportion of membrane perforations with immediate implants should be taken into account in the assessment and clinical application of this therapy principle. Keywords: extraction sockets, guided bone augmentation, implants, wound healing