Alveolar bone resorption can result from tooth loss, periodontal disease, or trauma. Guided tissue regeneration is used in an attempt to exclude tissues devoid of osteogenic potential from a bone defect or cavity and promote new bone growth to replace missing osseous structure. Many types of barrier membranes have been used, but none have been found to be ideal for every clinical situation. Macroporous membranes, such as expanded polytetrafluoroethylene, require primary closure and a second surgical procedure for their removal. Macroporous membranes can incorporate bacteria and may become infected if exposed in the oral cavity. Membranes manufactured of resorbable polymers require primary closure of the augmentation site and exhibit variable patterns of resorption, introducing a degree of unpredictability into the procedure. The use of high-density polytetrafluoroethylene membrane to promote deposition of bone for ridge augmentation in the oral cavity is described. Two clinical reports are presented. (Implant Dent 1995;4:21–26)