Caroliene Meijndert

84 Chapter 5 bone wall was <2 mm (Grunder et al., 2005), a 1:1 mixture of autologous bone (from the drills) and bovine bone (Cerabone®, Botiss Biomaterials GmbH, Zossen, Germany) was augmented. The augmented area was covered with a collagen membrane (Collprotect®, Botiss Biomaterials GmbH, Zossen, Germany). Immediately following implant placement, an implant-level open tray impression was made with a vinylpolysiloxane precision impression material (Provil Novo, Medium fast set, Kulzer Mitsui Chemical Group, Germany) (HJAM). The impression was sent to the dental laboratory which then manufactured a screw-retained provisional restoration. The provisional restoration consisted of a platform-switched titanium stock temporary abutment with an acrylic resin restoration. The participants received the provisional restoration on the day the implant was placed. The screw of the provisional restoration was torqued to 25 Ncm. After 3 months, an impression was made for the construction of a definitive crown. Definitive porcelain fused to zirconia restorations were cemented onto individualized zirconium abutments with a platform-switched, internal conical connection (zirconium CARES Ò abutment) or designed as screw-retained restorations with a titanium base (Variobase Ò for single crowns AS, Straumann AG, Basel). In both cases, the implant screws were tightened with a torque of 35 Ncm. Oral hygiene instructions were given after installing both the provisional and the definitive restorations. Evaluation Clinical, radiographic, photographic and patient-centred outcomes were assessed before implant placement (T pre ), one month after definitive restoration placement (T 1 ) and 12 months after definitive crown placement (T 12 ). All the assessments were done by the same observer (CMM). Outcome measures At removal of the failing tooth, the size of the labial bone wall defect was measured and the origin of the donor bone (donor site), used to preserve the alveolar ridge, was noted. − At implant placement , it was noted if the thickness of the labial bone wall was insufficient, being <2 mm (Grunder et al., 2005), and additional augmentation was needed. − Implant stability. Implant stability was analysed by measuring the initial fixation (Implant Stability Quotient: ISQ) using an Osstell™ mentor device (IntegrationDiagnostics AB, Gothenburg, Sweden) (Sim & Lang, 2010; Sennerby