Microleakage and mechanical behavior of conical vs. internal hexagon implant-abutment connection under a cyclic load fatigue test.

OBJECTIVE The aim of the present investigation was to evaluate, by an in vitro simulation, the mechanical behavior of the conical vs. internal hexagon under cyclic load and the microleakage of the prosthetic connection of the fixture. MATERIALS AND METHODS A standardized cyclic loading was performed considering the implant with conical connection (diameter 4 mm - length 10 mm) (CS) and internal hexagon connection (diameter 4 mm - length 10 mm) (IH). The toluidine blue infiltration has been evaluated with the paper cone test. RESULTS After a total of 5x104 loads, the screw has been removed and the abutment appears solid and stable to the implant fixture for CS, while the IH was unstable. There was no infiltration of the toluidine marker in the connection interfaces of CS implants, while the IH was positive to the paper cone test. CONCLUSIONS The study data showed that the conical connection showed higher stability compared to the internal hexagon connection under the loading and it is able to prevent bacterial microleakage. This effectiveness should be considered for the long-term maintenance of the peri-implant soft and hard tissues around the fixture.