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Journal of Healthcare Engineering
Volume 2017 (2017), Article ID 4842072, 6 pages
Research Article

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System

1Clinical Translational Research Center for Dental Science, Seoul National University Dental Hospital, Seoul, Republic of Korea
2Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, Republic of Korea

Correspondence should be addressed to Man Yong Kim and Jong-Ho Lee

Received 3 March 2017; Revised 19 June 2017; Accepted 22 June 2017; Published 6 August 2017

Academic Editor: Rui Zhu

Copyright © 2017 Bo Kyun Sim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access hole for easy retrieval. This study aimed to introduce this modified design of the abutment screw, the concept of easy retrieval, and to compare the mechanical strengths of the conventional and hollow abutment screws by finite element analysis (FEA) and mechanical test. In the FEA results, both types of abutment screws showed similar stress distribution in the single artificial tooth system. A maximum load difference of about 2% occurred in the vertical load by a mechanical test. This study showed that the hollow abutment screw may be an alternative to the conventional abutment screws because this is designed for easy retrieval and that both abutment screws showed no significant difference in the mechanical tests and in the FEA.