In Vitro Evaluation of the Removal Force of Abutments in Frictional Dental Implants
The objective of the present work was to determine some force parameters for removal of an abutment from a dental implant in a frictional system (locking taper, 1.23 degrees). Ten implants of the same length (11 mm) and different diameters were selected, along with 10 straight abutments (13 mm length) with different diameters. Abutments were attached to implants without application of force. Fixation of the implant-abutment mount (IA) (repeated 1–5 times) was performed through the impact of a body weight (compression force, tapping) left from a known height. After each group of tappings, IA mounts were coupled with a tensile strength tester. The lowest removal value was found after the first tapping of mount #2 (83 N, implant diameter 3.3 mm/4.5 mm abutment diameter), and the highest removal value happened with mount #8 after the fifth tapping (420 N, 5.0 mm/5.5 mm). The force to remove IA mounts increased with the number of tappings and with the increase in abutment mass. Three activations (tappings) of the abutment were considered necessary to yield optimal stability, demonstrated by the large increase in removal force.
Figure 1. Schematic drawing of frictional implant used here. Threads are used for cover screws and temporary plugs, not for the implant abutment. Figure 2. The instrument used to tap the abutment against the implant, the first one being supported by its proper base.
Figure 3. Removal force values (N) as a function of the number of tappings. Figure 4. Removal force values (N) as a function of the mass (g) of the abutment.
Figure 5. Separated implant and abutment. Figure 6. Implant and abutment union.
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