Three-Dimensional Accuracy of Surgical Guides for Static Computer-Aided Implant Surgery: A Systematic Review

Background: The purpose of this study was to evaluate the dimensional accuracy of surgical guides for static computer-aided implant placements processed using milling or 3D printing. Methods: A comprehensive literature search was performed on electronic databases inclusive of PUBMED, SCOPUS, Cochrane Database of Systematic Reviews, EBSCO host Research Databases, and Web of Knowledge were searched without restriction to date. Studies investigating the surgical guides fabricated by milling or 3D-printing, comparing them with their computer-aided design model, and reporting outcome measures about the accuracy of the internal/external surface, the angular deviation of the sleeves, and the vertical or horizontal deviations of the sleeves' access were included. Results: From 1928 retrieved records, 33 studies were selected; 11 out of them fulfilled the eligibility criteria. All studies analyzed printed surgical guides, while only two studies analyzed both printed and milled templates. Studies were very heterogeneous in methodology and equipment; moreover, different parameters were used for accuracy measurements which made their results not comparable and quantitative synthesis not feasible. Conclusion: There is no clear evidence to address which manufacturing technology provides surgical guides with better accuracy, although milling might achieve better results, at least in terms of reduced variation. For additive technologies, several factors could influence accuracy. Since this issue has sensible clinical implications, future studies are encouraged.