Caroliene Meijndert

23 Single implants in the aesthetic region preceded by local ridge augmentation Study groups To reconstruct the local bone defects, three treatment modalities were applied: • Chin bone; • Chin bone combined with a resorbable Guided Bone Regeneration membrane (Bio-Gide®, Geistlich, Wolhusen, Switzerland); • Bio-Oss® spongiosa granules (0.25–1.0 mm, Geistlich, Wolhusen, Switzerland) in combination with a Bio-Gide® GBR membrane. Patients were randomly assigned to one of the three treatment groups using a balancing procedure aiming at an equal distribution of variables that may interfere with the outcome of the study, being age, gender and location of the single-tooth defect (Zielhuis et al., 1990) ( Table 1 ). The study was approved by the Medical Ethical Committee; written informed consent was obtained from all patients. Table 1. Characteristics of the study group at the start of the study. Chin bone (gr1) Chin bone + Bio-Gide® (gr2) Bio-Oss® + Bio-Gide® (gr3) Total Number of participants 31 31 31 93 Mean age in years at the time of implant surgery (range) 33.3 (18-59) 34.6 (18-63) 32.2 (18-63) 33.3 (18-63) Gender (male/female) 15/18 16/15 15/16 44/49 Tooth gap position (I 1 /I 2 /C/P 1 ) 21/7/1/2 21/7/1/2/ 21/9/0/1 62/24/2/5 Surgical and restorative procedures All augmentation procedures were performed under local anaesthesia. In groups 1 and 2, monocortical chin bone grafts were harvested and fixed on the perforated receptor site with a titanium screw. In group 2, the chin bone graft was covered by a Bio-Gide® GBR membrane. In group 3, Bio-Oss® spongiosa granules were placed on the perforated cortical bone of the receptor site and were also covered with a Bio- Gide® GBR membrane. Three months after the augmentation procedure with chin bone (groups 1 and 2) and 6 months after augmentation with Bio-Oss® (group 3), Straumann Standard Plus implants (Institut Straumann AG, Basel, Switzeland) were placed. All implants had a standard body diameter of 4.1 mm and were uncovered 6 months after insertion. An impression was taken during the surgical procedure at the time the implant was placed. A temporary crown was custom made in the laboratory by the dental technician. The temporary crown consisted of a titanium temporary post (RN synOcta® 2