Techniques for locating the screw access hole in cement-retained implant-supported prostheses: A systematic review

Abstract

Statement of problem: Different techniques for retrieving cement-retained implant-supported prostheses have been described to minimize damage to the prostheses. Nevertheless, a classification of the described techniques remains ambiguous.

Purpose: The purpose of this systematic review was to review and classify the described techniques for recording and locating the screw access hole in cement-retained implant-supported prostheses.

Material and methods: A bibliographic search was completed on MEDLINE/PubMed, Web of Science, Scopus, and Cochrane databases. A manual search was also conducted. The articles that described or evaluated techniques for recording and locating the screw access hole of cement-retained implant-supported prostheses were included. Two investigators independently assessed the quality assessment of the studies using the Revised Cochrane risk of bias tool for randomized trials. A third examiner was consulted to resolve the lack of consensus.

Results: A total of 30 articles were included. The different methods were classified according to whether the screw access hole location was registered before or after cementation. The precementation techniques were classified into 4 subgroups: identification marks, photographic records, digital files, and precementation screw access hole location guides. The postcementation techniques were subdivided into 2 subgroups: radiographic records and postcementation screw access hole location guides.

Conclusions: Different techniques have been proposed to facilitate the location of the screw access hole in cement-retained implant-supported restorations. Although the evidence is scarce, studies seem to ascertain that some techniques, such as the use of drilling guides, orientation with cone beam computed tomography images, or holes made in the metal framework, can increase the retrievability of cement-retained implant-supported prostheses and decrease complications in the location of the screw access hole. The proposed classification summarizes precementation and postcementation techniques and provides a tool to decide the most suitable for each specific clinical situation.