Leakage at the implant-abutment junction (IAJ) is a major contributing factor for periimplant inflammatory reactions.
1 Gaps and cavities between the implant and the abutment acting as a bacteriological reservoir have been described.
2 The presence of a gap between implant and abutment may cause unfavorable stress distribution on connection components, implant, and crestal periimplant bone.
3 Microbial colonization of this microgap may result in bone resorption.
2 Implant manufacturers aim to reduce the leakage by reducing the mobility of the implant-abutment connection by constructing physically tight connections with a high level of precision in a submicrometer range.
1 Very little data regarding the analysis of the microleakage at the IAJ of different implant-abutment connections are present in the literature
1 Leakage within a short storage time (5 minutes)
To evaluate, in vitro, the leakage observed in internal hexagon and Morse taper implant-abutment connections.
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.
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.
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.