Accuracy of the digital implant impression with splinted and non-splinted intraoral scan bodies: A systematic review

Introduction: Accurate implant impressions are crucial for successful prosthetic rehabilitation. Digital impressions using intraoral scanners (IOS) have emerged as an alternative to conventional techniques. Various factors influence the accuracy of digital implant impressions, including scan body design, scanning protocol, and splinting techniques. Aim and Objective: To evaluate the difference between splinted and nonsplinted scan bodies in the accuracy of digital impressions for single or multiple implants by measuring distance and angular deviations between superimposed digital impressions. Materials and Methods: PRISMA guidelines were followed in this systematic review. Electronic databases were searched for relevant studies published up to January 2024. Inclusion criteria encompassed clinical trials, in vivo and in vitro studies on scan bodies in partially or fully edentulous arches. Two reviewers independently assessed abstracts, titles and full texts. Data extraction included distance deviation, angular deviation, trueness, and precision measurements. Discussion: Most studies found that scan body splinting improved the accuracy of digital implant impressions, particularly for complete-arch cases. Splinting techniques varied, including light-cured resin, pattern resin, dental floss, and custom-made splints. Factors such as the inter-implant distance, number of implants and choice of IOS also influenced accuracy. However, some studies reported no significant improvement or even negative effects of splinting on accuracy. Conclusion: Splinting scan bodies generally improves the accuracy of digital implant impressions, especially for complete-arch cases. It enhances the stitching process in digital workflows and provides more stable reference points. However, the effectiveness may vary depending on the specific clinical situation, scanning protocol, and IOS used. Further research is needed to establish standardized protocols and evaluate long-term clinical outcomes of digitally fabricated implant restorations based on splinted scan body impressions. Keywords: Digital implant impression, intraoral scanner, scan body, splinting