Microbiological evaluation of bacterial and mycotic seal in implant systems with different implant-abutment interfaces and closing torque values

The aim of this study was to evaluate the possible leakage of 3 species of bacteria (Streptococcus sanguinis, Fusobacterium nucleatum, and Actinomyces odontolyticus) and of Candida albicans and Candida glabrata in osseointegrated implants with different implant-abutment interface (IAI) geometry. Two groups of implants, (1) implant-abutment unit with a tube-in-tube interface and (2) implant-abutment unit with a flat-to-flat interface closed with different torque values, were compared in the study. In the first phase, the implants were assembled and cultured in vitro for 7 days. The implants and abutments were disconnected and samples were taken and cultured. In the second phase, the internal part of each implant was inoculated with 0.1 µL of microbial broth and then connected to the respective abutments. Afterward, medium samples were taken and cultured. The group 1 implants were more resistant to colonization than those of group 2 (P < 0.05). The intragroup difference was significant between the implant-abutment units assembled with the recommended torque values and those with lower torque values (P < 0.01) for both the groups. IAI geometry influences both bacterial and yeast colonization inside the implants as well as the torque value used to connect abutments to implants.