LONG-TERM EVALUATION OF NON-SUBMERGED ITI-IMPLANTS .1. 8-YEAR LIFE TABLE ANALYSIS OF A PROSPECTIVE MULTICENTER STUDY WITH 2359 IMPLANTS

In the present multi-center study, non-submerged ITI implants were pro spectively followed to evaluate their long-term prognosis in fully and partially edentulous patients. In a total of 1003 patients, 2359 impl ants were consecutively inserted. Following a healing period of 3-6 mo nths, the successfully integrated implants were restored with 393 remo vable and 758 fixed restorations. Subsequently, all consecutive implan ts were documented annually up to 8 years. At each examination, the cl inical status of all implants was evaluated according to predefined cr iteria of success. Therefore, the data base allowed the evaluation of 8-year cumulative survival and success rates for 2359 implants. In add ition, cumulative success rates were calculated for implant subgroups divided per implant type, implant length, and implant location. Furthe rmore, the actual 5-year survival and success rates could be determine d for 488 implants. During the healing period, 13 implants did not suc cessfully integrate, whereas 2346 implants fulfilled the predefined cr iteria of success. This corresponds with an early failure rate of 0.55 %. During follow-up, 19 implants were classified as failures due to se veral reasons. In addition, 17 implants (approximate to 0.8%) demonstr ated at the last annual examination a suppurative periimplant infectio n. Including 127 drop out implants (= 5.4% drop out rate) into the cal culation, the 8-year cumulative survival and success rates resulted in 96.7% and 93.3%, respectively. The analysis of implant subgroups show ed slightly more favorable cumulative success rates for screw type imp lants (> 95%) compared to hollow-cylinder implants (91.3%), and clearl y better success rates for mandibular implants (approximate to 95%) wh en compared to maxillary implants (approximate to 87%). The actual 5-y ear survival and success rates of 488 implants with 98.2% and 97.3%, r espectively, were slightly better than the estimated 5-year cumulative survival and success rates of 2359 implants indicating that the appli ed life table analysis is a reliable statistical method to evaluate th e long-term prognosis of dental implants. It can be concluded that non -submerged ITI implants maintain success rates well above 90% in diffe rent clinical centers for observation periods up to 8 years.