Microleakage of the prosthetic abutment/implant interface with internal and external connection: In vitro study

Abstract

ObjectiveThis study determined the degree of marginal microleakage of the abutment-implant interface on platforms with Morse taper connection and external connection.

Materials and methodsFor this in vitro study, 42 implants, 21 with external connection and 21 with Morse taper connection, were used, immersed in acrylic resin cylinders. Each implant was joined by a prosthetic abutment screw tightened at different degrees, forming the six study groups: (1) External connection, manual tightening (2) External connection, 20 Newton (N) tightening (3) External connection, 30N tightening (4) Morse taper connection, manual tightening (5) Morse taper connection, 20N tightening (6)Morse taper connection, 30N tightening. All samples were subjected to load cycling and thermocycling. Then, they were submerged in a solution of 0.2% methylene blue for 24h. Finally, the microleakage was measured via 20x optical microscopy in each study group, average was obtained, and Mann-Whitney test was applied.

ResultsStatistically significant differences (P<0.001) were found between the levels of microleakage presented in the Morse taper connection implants (1.48) and external connection implants (2.8) in all three types of tightening. Microleakage levels decreases when increasing torque is applied to the screws.

ConclusionMorse taper connection implants showed lower levels of microleakage than external connection implants; also, it was observed that microleakage decreases in the way torque increases.