Bacterial Microleakage at the Implant-Abutment Interface: An In Vitro Study

The objective of this study is to evaluate, in vitro, the microleakage of bacteria of 3 different implant connections for a period of 14 days. 60 dental implants (AoN) (n = 20) were distinguished into three groups, accordingly to the type of connection: External Hexagon (EH), Internal Hexagon (IH), and Cone Morse (CM) connection. All implants were inserted and fixed on sterile special vinyl support. Ten fixtures for each group were inoculated in the internal platform with 1.0 μL of Streptococcus oralis (SO) and the other ten with the same amount of Pseudomonas aeruginosa (PA). The penetration of bacterial suspension into the surrounding solution was determined by the observation of the turbidity of the broth. Five implants for each sub-group were randomly observed at SEM, to verify the correct fitting of the abutments. Considering the total of the samples analyzed, CM showed significantly lower bacterial contamination, with respect to IH. In particular, bacterial contamination was found in 45%, 55%, and 20% of EH, IH, and CM, respectively. Analyzing results for the type of inoculated bacteria, P. aeruginosa showed a higher ability to contaminate all the connections, with respect to S. oralis.