Bacterial colonization of the internal part of two-stage implants. An in vivo study

This study aimed to investigate the presence of microorganisms in the inner thread of the fixture (endosteal implant part) of the Brånemark system. In 9 volunteers the apical part of 2 abutment screws that had been in place for 3 months was examined by means of differential phase-contrast microscopy. All screws harboured a significant quantity of microorganisms, mainly coccoid cells (86.2%) and nonmotile rods (12.3%). Motile organisms (1.3%) or spirochetes (0.1%) were only sporadically registered. A microbial leakage at the abutment/fixture interface probably is the most probable origin for this contamination.