Caroliene Meijndert

63 Bone level tapered implants in the maxillary aesthetic zone − smoking; − a history of radiotherapy to the head and neck region; − use of bisphosphonates less than 10 years ago. Surgical phase One day before implant placement, the participants started antibiotic therapy (amoxicillin 500mg, 3 times daily for 7 days, or clindamycin 300 mg, 4 times daily for 7 days in case of an amoxicillin allergy) and a 0.2% chlorhexidine mouth rinse, twice daily for 7 days. Although it acknowledged that implant placement in healed sites probably does not require antibiotic therapy, it was expected that a substantial number of patients would need a local bone augmentation because of limited thickness of the buccal bone wall. For this reason antibiotics were prescribed for all included patients. All the participants’ surgeries were performed by the same, experienced, surgeon (GMR). After administering local anaesthesia, a mid-crestal incision with a divergent relieving incision was made at the distal side for a small muco-periosteal flap elevation. The implant position was dictated by a (semi-guided) surgical template and the implant bed was prepared following the manufacturer’s drilling guidelines. All the participants received a Straumann Bone Level Tapered implant (SLActive ® , Roxolid ® , Ø 3.3mm and 4.1mm, Institut Straumann AG, Basel, Switzerland) according to the pre-operative planning. The implants were placed 3 mm apically of the prospective gingival margin of the future restoration. The reason for this was to take fully advantage of the biologic width to create a natural emergence profile with individually designed abutments. Next to this, the implants were placed somewhat palatally of the center of the former tooth root to have at least 2 mm of buccal bone thickness, whether or not reached with an additional bone augmentation procedure. When the bone wall thickness facially to the implant was < 2 mm, a local bone augmentation was performed with a 1:1 mixture of xenogenic bone (Cerabone®, Botis Biomaterials GmbH, Zossen, Germany) and autologous bone chips collected during implant bed preparation, which was covered with a collagen membrane (Jason®, Botis Biomaterials GmbH, Zossen, Germany) and secured with interrupted sutures (5-0 ethilon, Johnson&Johnson Gateway, Piscataway, USA). Wound healing and suture removal were checked after two weeks. A partial removable denture (RPD) was provided to wear until the day of abutment connection. Prosthetic phase The implants were uncovered three months after insertion, with the use of a soft- tissue punch technique. An open tray impression was made with a vinylpolysiloxane 4