Diederik Hentenaar

175 Summary patients with 67 posteriorly implants with a 5 year follow-up. Patients with single two-piece, platform-switched implants in between two natural teeth or adjacent to one natural tooth were included. Clinical parameters and standardized peri-apical radiographs taken at 1 month and 5 years after final crown placement were assessed. Clinical evaluation of the peri-implant soft tissue was performed 1 month (baseline) and 5 years after placement of the final implant crown. The sulcus bleeding index, the gingival/mucosal index and the probing depth were clinically recorded. Peri-implant bone level change was determined by measuring the distance from the implant reference point (most outside point of implant neck) to the level of bone-to-implant contact, at both the mesial and distal aspect of the implant. Radiographs were calibrated using the known dimensions of the implant as reference values. The difference in bone level between one month and five years after crown placement was calculated. A new measurement method was developed to analyse geometric values of the cervical crown contour. The inter and intra-examiner reliability (Cronbach’s a) was assessed showing an almost perfect agreement. Emergence angles were measured at 1, 2 and 3 mm above the implant shoulder. The linear correlation between variables was determined by calculating the Pearson correlation coefficient. The results showed no correlation between the mesial and distal cervical crown angles with peri-implant bone loss and soft-tissue health. It should however be noted that none of the implants showed signs of peri-implantitis. Therefore it was concluded that the cervical crown contour at platform-switched, posteriorly placed, two-piece implants showed no correlation with peri-implant marginal bone loss and soft-tissue health up to 5 year after implant placement. A