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The influence of stiffness of implant‐abutment connection on load‐deflection ratios of a screw‐retained stiff cantilever beam. 3‐ D measurements in vitro
Author(s) -
Cassel Björn,
Lundgren Dan,
Karlsson Dan
Publication year - 2013
Publication title -
clinical oral implants research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.407
H-Index - 161
eISSN - 1600-0501
pISSN - 0905-7161
DOI - 10.1111/j.1600-0501.2012.02563.x
Subject(s) - cantilever , deflection (physics) , abutment , materials science , implant , stiffness , beam (structure) , welding , screw thread , composite material , structural engineering , optics , mechanical engineering , engineering , physics , medicine , surgery
Abstract Aim The purpose of this in vitro study was to investigate the influence of degree of stiffness of implant‐abutment connection of a Brånemark implant system on load‐ deflection ratios in three dimensions of the beam‐end of a screw‐retained stiff cantilever beam when subjected to vertically directed loads. Material and methods Two different implant‐abutment connections were tested; welded and screw‐retained. One of the abutments ( E sthetiCone 2.0; N obel B iocare AB ) was screwed with a torque force of 20 N cm and then laser welded around its entire periphery to one of two Brånemark implants (welded unit). This unit and the other implant were tightly screwed into each of two pre‐threaded holes in a steel plate so that the implants became submerged in the plate. The remaining abutment was thereafter screwed to its implant with a torque force of 20 N cm (screw‐retained unit). A cantilevered gold beam of 6 mm height and width comprising a gold cylinder ( N obel B iocare AB ) was attached to each abutment with a slotted, flat headed, prosthetic gold screw (torque force 10 N cm). A force transducer, synchronized with a 3‐ D motion analysis system, was glued on the upper surface of each beam‐end 19.4 mm from the implant, to register the loads transferred from a specially built loading device. The beam‐ends were stepwise subjected to vertically directed loads from 14.9 to 40.3 N and the vertical and horizontal deflections of the beam‐ends were registered with the 3‐ D motion analysis system. Results For load 14.9–40.3 N the vertical ( z ‐axis) deflections of the beam‐end were for the welded implant‐abutment connection reduced with 18–46% compared with the screw‐retained unit. After maximal loading (40.3 N) the horizontal counter‐clockwise rotation of the beam around the screw joints ( y ‐axis rotations) was reduced with 61% for the welded connection. The horizontal movements of the beam‐end along the x ‐axis ( x ‐axis deflections) were reduced with 49% at maximal loading. Conclusion It was concluded that increased implant‐abutment stiffness will substantially reduce both vertical and horizontal deflections of a screw‐retained stiff cantilever beam subjected to vertically directed loads.