Evaluation of Screw Loosening and Removal Force of Original and Compatible Implant-Abutment Connection (Tissue Level): In Vitro Study

 

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Abstract

Objective

Screw loosening in dental implant prosthetics can lead to serious issues. Various factors contribute to screw loosening, including prosthesis design, misalignment between the prosthesis and abutment or between the abutment and implant, insufficient screw tightening force, excessive biomechanical loading, the material and design of the screw, chewing forces, and parafunctional habits.

Materials and Methods

This study evaluated three implant systems (SNUCone, Dentis, and Implant Swiss) along with their original and compatible abutments. The implants were mounted in acrylic blocks measuring 20 × 6 × 10 mm, and the abutments were connected to the fixtures with a torque of 30 N/cm. The samples were subjected to a chewing simulator with a load of 90 N and 10,000 cycles, and the amount of screw loosening was measured. Subsequently, the removal torque of the abutments was recorded using a universal testing machine. The data were analyzed using analysis of variance and Tukey's post hoc test.

Results

According to the study results, the screw loosening torque of abutments is significantly influenced by the type of abutment and implant. Among the groups with Implant Swiss fixtures, the Implant Swiss abutments had the highest loosening torque, with an average of 27.24 N/cm, whereas in SNUCone fixtures, Dentis abutments showed the lowest loosening torque. Similarly, in Implant Swiss fixtures, Dentis abutments recorded the lowest loosening torque, with an average of 23.86 N/cm. In SNUCone implants, Dentis abutments had the lowest loosening torque, averaging 23.86 N/cm. The removal torque required for abutments did not significantly differ across the different implant systems.

Conclusion

According to the study findings, the screw loosening torque of abutments varies depending on the type of abutment and implant. Implant Swiss abutments exhibited the highest loosening torque, while SNUCone abutments showed the lowest. The highest average abutment removal torque was observed in the Implant Swiss implant with the SNUCone abutment, and the lowest was in the Dentis implant with the Implant Swiss abutment. The abutment type has a limited effect on this parameter, which may be influenced by other factors such as the overall design of the implant systems.

Publication History

Article published online:
03 June 2025

© 2025. European Dental Research and Biomaterials Journal. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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