An in vitro investigation concerning the bacterial leakage at implants with internal hexagon and Morse taper implant-abutment connections.

PURPOSE To evaluate, in vitro, the leakage observed in internal hexagon and Morse taper implant-abutment connections. MATERIALS Ten specimens with internal hexagon and 10 with Cone Morse connection were used. The inner parts of 5 implants, per group, were inoculated with Pseudomonas aeruginosa (PS) suspension and 5 implants, per group, with Aggregatibacter actinomycetemcomitans (AA). The penetration of bacterial suspension into the surrounding solution was determined by observation of turbidity of the broth. RESULTS In the internal hexagon implants, bacterial contamination was found in 2 of 5 implant-abutment assemblies seeded with the PS, and in the assemblies seeded with AA, the contamination was found in 3 samples, with a total of leaked assemblies in this group in 5 of 10. In the Cone Morse implants, bacterial contamination was found in 2 of 5 implant-abutment assemblies seeded with the PS, whereas in the assemblies seeded with AA, no contamination was found, with a total of leaked assemblies in 2 of 10. CONCLUSION The data support a not significantly higher permeability to bacterial leakage and a lower infiltration rate of screw-retained abutment connections when compared to Cone Morse taper internal connections.