ABSTRACT
Objective: The objective of this study was to compare the torque and detorque values of screw
intermediates of external hexagon, internal hexagon, and Morse taper implants in single
restorations before and after mechanical cycling. Materials and Methods: The study sample was divided into three groups (n = 10) as follows: group EH - external hexagon implant, group IH - internal hexagon
implant, and group MT - Morse taper implant. Universal abutments were screwed on the
implants, and metal crowns were cemented onto the abutment. The samples were submitted
to a mechanical testing of 1 million cycles, with a frequency of 8 cycles per second
under a 400 N load. The application and registration of the screw torque (T0) and
detorque (T1) values of the intermediate were performed before and after the test.
The results were statistically evaluated by analysis of variance (ANOVA) and Tukey′s
test (α = 0.05). Results: There was no difference between the values of T0 and T1 in the intra-group samples.
However, the inter-group difference in T0 between the EH (12.8 N cm) and MT (18.6
N cm) groups and in T1 between the EH (10.4 N cm) and IH (13.8 N cm), EH and MT (19.4
N cm), and MT and IH (P = 0.001) groups were significant. The MT group showed a lower variation of T0 and
T1. Conclusion: The internal implants, particularly MT, showed better stability in these cases when
used for single restorations.
Key words:
Dental implant - dental prosthesis - dental prosthesis retention - fatigue
