The feasibility of regeneration and attachment of periodontal ligament and alveolar bone after surgical treatment of periodontal defects is documented in the literature. This article presents four cases of clinical and radiographic evidence showing apparent new attachment after root isolation with expanded polytetrafluoroethylene (PTFE) periodontal material, following the principle of guided tissue regeneration. Combination one-, two-, and three-wall angular bony defects of molars and incisors were exposed and root planed. A skirt of PTFE periodontal material was sutured into place and removed after 6 weeks in situ. Reductions in probed pocket depths and gain in bone-fill, as revealed by radiography, were achieved in every case. Maximum regeneration of alveolar bone was 6 mm in the two-wall angular defect of a first molar; minimum gain in bone height was 3 mm.