Out of 189 inserted implants in total, nine had to be explanted. Of these explantation took place in eight cases within the first five months, during the healing phase. In six cases explantation was performed because of increased implant mobility. One implant fractured around one week after the definitive prosthetic restoration. Out of the total of nine explantations the affected implant could be replaced successfully by a new one in six cases. The probability of survival remains stable at 93% after four explantations within the first half year after implantation. The data interpretation with regard to the Kaplan-Meier analysis was broken off in less than ten implants under risk (Fig. 7). In the reduced group of test subjects (n=44), which were assessed additionally according to the success criteria by Jahn and d‘Hoedt, it is shown that the greatest share of failures was caused by the criterion of pocket depth. The criteria «in situ», «percussion sound» and «vertical bone loss» followed (Fig. 8).