Bacterial leakage in external hexagon implants with and without the interposition of a sealing-connector.

PURPOSE: To investigate whether the interposition of a sealing-connector was able to reduce the bacterial leakage in external hexagon implants. METHODS: 20 implants with external hexagon connection were used. Ten Test implant-abutment assemblies were connected with the interposition of a sealing-connector molded in the exact shape of the two opposed surfaces. Ten Control implant-abutment assemblies were connected with no sealing-connector interposed. Two types of bacteria were introduced into the internal portion of the implant, before placing the connector. The study lasted 28 days. RESULTS: All control specimens, seeded with P. aeruginosa (PA) and A. actynomycetemcomitans (AA), showed contamination of the culture medium, indicative of microbial leakage. In the Test specimens, three instances of contaminated specimens were found in the samples seeded with PA and two contaminated specimens in the ones seeded with AA, for a total of five contaminated samples out of 10. The use of the sealing-connector was able to prevent bacterial leakage in half of the samples (50%). The leakage in both groups occurred mainly in the last week of the experiment. Probably, a longer period, under the conditions of this experiment, is necessary for the migration of the bacteria, and, furthermore, an observation period of 7 or 14 days may not be enough to show microbial contamination. CLINICAL SIGNIFICANCE: Using an interface under in vitro non-loading experimental conditions, could sometimes (50%) prevent bacterial microleakage and thus possibly the risk of peri-implant site infection. Moreover, less bone resorption and the maintenance of soft tissues and esthetics might be achieved in those cases where bacterial leakage does not occur.