The purpose of this study is to confirm histologically whether a new attachment can be obtained around a tooth by guided tissue regeneration using bioresorbable barrier. The test tooth was a maxillary molar with an intrabony pocket. At reentry 5 months after periodontal surgery, a hard, whitish, blood-free tissue was found to fill the original defect. Histologic analysis revealed presence of new bone, cementum, and periodontal ligament compatible with the expected histologic result of guided tissue regeneration techniques with barrier membrane.