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The International Journal of Prosthodontics



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Int J Prosthodont 30 (2017), No. 6     17. Nov. 2017
Int J Prosthodont 30 (2017), No. 6  (17.11.2017)

Page 542-544, doi:10.11607/ijp.5286, PubMed:29095962

Preload, Coefficient of Friction, and Thread Friction in an Implant-Abutment-Screw Complex
Wentaschek, Stefan / Tomalla, Sven / Schmidtmann, Irene / Lehmann, Karl Martin
Purpose: To examine the screw preload, coefficient of friction (COF), and tightening torque needed to overcome the thread friction of an implant-abutment-screw complex.
Materials and Methods: In a customized load frame, 25 new implant-abutment-screw complexes including uncoated titanium alloy screws were torqued and untorqued 10 times each, applying 25 Ncm.
Results: Mean preload values decreased significantly from 209.8 N to 129.5 N according to the number of repetitions. The overall COF increased correspondingly. There was no comparable trend for the thread friction component.
Conclusion: These results suggest that the application of a used implant-abutment-screw complex may be unfavorable for obtaining optimal screw preload.