Microbial leakage and marginal fit of the implant-abutment interface.

Two-stage implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues. These gaps between the components are inevitable, and their clinical significance has so far been mostly neglected by both manufacturers and clinicians. The aim of the study was to determine whether there is microbial leakage at the implant-abutment interface. Thirteen different implant-abutment combinations were subjected to an in vitro experiment, in which the penetration of bacteria (Escherichia coli) was observed for 10 assemblies of each type. All implant systems presented microbial leakage. When the Frialit-2 implant was supplied with a silicon washer, there were fewer cases of leakage. The width of the marginal gap between the prefabricated components, measured with a scanning electron microscope, was less than 10 microns in all systems.

A 10-year follow-up study of IMZ and TPS implants in the edentulous mandible using bar-retained overdentures.

This study presents data related to 136 patients who were treated with 300 implants in the edentulous mandible anterior to the mental foramina. Two implant systems were used: the titanium plasma-sprayed screw implant (TPS) and the intramobile cylinder implant (IMZ) in three different modifications. The longest observation time was 11 years, with a mean of 5.7 years. Patients were recalled for regular clinical examinations once every 6 months. After prosthesis placement, only a few implant losses were recorded, although critical states could be found according to periodontal standards. This led to the definition of success criteria according to clinically tolerable bone loss or pocket-probing depths. The 5-year survival rate considering the implant loss was greater than 90% for all implant systems and was lowest for the new type IMZ 3.3. Selecting a vertical bone loss of 4 mm or more as failure criterion reduced the survival rates, which then ranged from 83% to 97% (according to the implant system) for the 5-year interval. The mean annual bone-level change was identified individually for each implant using a linear-regression model.