A 71-year-old man consulted us in July 2018 with a complaint of discomfort around an implant in the anterior mandible. The teeth from the left mandibular canine (i33) to the right mandibular central incisor (i41) had been restored by two internal connection-type implants and cemented-type fixed prostheses 7 years earlier. The left mandibular central incisor (i31) had a 7-mm-deep pocket and bleeding on probing. Gingival recession had occurred on the buccal side and the keratinized gingiva was insufficient (Fig. 1A, Table 1). Periapical radiographs revealed radiolucent bone defects along the marginal bone of i31. After initial non-surgical treatment, surgical therapy was performed. After removing the prostheses, a flap was raised to expose the bone defect surrounding i31. A full-thickness mucoperiosteal flap, from the mesial to distal adjacent teeth, was raised under local anesthesia. Supra-alveolar and horizontal bone loss was observed buccal and lingual to the implant following granulation tissue removal. The patient was diagnosed with a Class II peri-implantitis defect, as described previously (Fig 1B).¹⁰ The surface of the implant was cleaned using a rotary titanium brush (R-Brush, NeoBiotech) at 8000 rpm for 30 s per thread (Fig. 1C). Following 50 mg/mL tetracycline cotton pellet application for 90 s, the implant surface was washed with saline solution. Porcine bone mineral (THE Graft, Purgo, Seoul, Korea) and a titanium-reinforced polytetrafluoroethylene membrane (PM1424, B&Medi, Seoul, Korea) were applied to the implant surface, and a bone tack (truFIX, ACE Surgical Supply, Brockton, USA) was fixed on the buccal side of the implant. To augment the thin gingiva, subepithelial connective tissue (15 × 10 mm) obtained from the palatal surface was positioned above the membrane and sutured. The tissue healed and remained intact without membrane exposure. Six months following GBR, the site of the bone defect was favorable for membrane removal surgery (Fig. 1E). The previously removed prostheses were reinstalled (Fig. 1F). Clinical and radiographic parameters, as described previously,^10,12 were recorded at baseline and at the 2-year follow-up. These parameters were the bone defect shape, modified plaque index (mPI), modified sulcus bleeding index (mSBI), the mean probing depth at 6 sites around the implant (PD), and the distance from the implant shoulder to the first bone-to-implant contact (DIB). The mPI, mSBI, PD, and DIB of i31 decreased from 1.5 to 0.25, 1.5 to 0.5, 7 mm to 3 mm, and 5.7 mm to 1.3 mm, respectively, over two years (Table 1).

A 71-year-old man consulted us in December 2019 for discomfort in relation to the implant in the left posterior mandible (i36, i37), which had been placed 9 years earlier. The left posterior mandibular teeth were restored by placing two internal-type implants and cemented-type fixed prostheses on the mandibular first and second molars. The posterior splinted implant (i37) had a 9-mm-deep pocket with suspected circumferential bone loss and exudate through the buccal gingival sulcus (Fig. 2A). Periapical radiographs showed vertical, radiolucent bone loss along the marginal bone of i37. Following non-surgical treatment, surgical therapy comprising a mucoperiosteal flap and removal of granulation tissue was performed. Circumferential bone loss (Class Ie) was observed around the implant (Fig. 2B). Similar to Case 1, a rotary titanium brush was used to clean the implant surface (Fig. 2C). Tetracycline was applied, and a cover screw was placed. The implant was covered with porcine bone mineral (THE Graft, Purgo) and a resorbable membrane (Ossixplus, Datum Dental, Lod, Israel), and the flap was sutured (Fig. 2D). Healing was observed at the site of the bone defect when the flap was raised again 5 months later (Fig. 2E). Vestibule deepening was performed using a partial-thickness flap, and a healing abutment was connected and sutured. The previously removed prostheses were reinstalled with a wider embrasure for easier cleaning (Fig. 2F). Clinical and radiographic parameters were measured and recorded. The mPI, mSBI, PD, and DIB of i37 decreased from 1.5 to 0.5, 2 to 0.5, 8.8 mm to 3 mm, and 4.3 mm to 1.7 mm, respectively, over two years (Table 1).

A 66-year-old man visited us in November 2018 with a chief complaint of discomfort with respect to the right anterior maxillary implant. Five implants were placed in the right maxillary first premolar (i14), canine (i13), and central incisor (i11), and the left central incisor (i21) and canine (i23), followed by cemented-type fixed prostheses on all teeth from the right first premolar to the left canine. i13 and i14 had a 10-mm-deep pocket with exudate at the buccal gingival sulcus (Fig. 3A). Periapical radiographs revealed marginal bone loss surrounding i13 and i14. Following non-surgical therapy, surgical treatment comprising a mucoperiosteal flap and removal of granulation tissue was performed. Significant exposed portions (4-5 threads) were observed at both implants (Fig. 3B). The implants were cleaned with a rotary titanium brush (Fig. 3C) and treated with tetracycline cotton pellets followed by placement of porcine bone mineral (THE Graft, Purgo). Since the cover screws for the implants could no longer be acquired, cover screws from another manufacturer (Osstem, Seoul, Korea) were fixed with an acellular dermal matrix (Megaderm, L&C Bio, Seoul, Korea) to cover the implant threads (Fig. 3D). Two months later, 2 mm and 1 mm of the crestal areas of i13 and i14, respectively, were exposed (Fig. 3E). The previously removed prostheses were reinstalled. No bleeding was observed upon probing, and the patient reported no discomfort (Fig. 3F). The patient was kept on regular follow-up thereafter. Clinical and radiographic findings were recorded (Table 1). The mPI, mSBI, PD, and DIB of i13 and i14 decreased from 0.75 to 0, 1 to 0, 9.3 mm to 3 mm and 9.8 mm to 3 mm, 6.2 mm to 2.8 mm, and 9.2 mm to 3.4 mm, respectively, over two years.