Microbial penetration along the implant components of the Brånemark system. An in vitro study

This study examined in vitro the existence of microbial leakage along the components of the Brånemark implant system. Thirty-two implant/abutment assemblies were installed in a liquid blood medium previously inoculated with oral micro-organisms. To examine the leakage at the implant-abutment interface, 16 assemblies were partially immersed. The remaining 16 were completely immersed to observe the leakage at both the implant-abutment and abutment-prosthesis interface. After 7 days of anaerobic incubation, the micro-organisms in the internal part of the implants were collected and incubated on blood agar plates in anaerobic conditions. Micro-organisms were found in the completely immersed assemblies and at lower numbers in the partially immersed implants, indicating that bacterial leakage at both levels seems to exist. Several penetrating bacteria have been associated with peri-implantitis. The clinical importance of this bacterial leakage is not yet well understood. Although the longevity of the Brånemark implants is well documented, this bacterial leakage might play a role in peri-implantitis, both in the etiology as well as in the treatment.