Accuracy of Complete-Arch Digital Implant Impressions with and Without Modular E-Chain Splinting: An in vitro Study

Abstract

Background and Objectives: The long-term success of full-arch implant-supported restorations depends on the precision of the impression-making process. Intraoral scanners (IOS) offer clinical advantages, yet capturing accurate complete-arch impressions in edentulous patients remains challenging due to cumulative stitching errors and limited stable landmarks. This study evaluated a novel stabilization method—the modular E-chain splinting technique—for improving digital impression accuracy. Materials and Methods: A prospective in vitro study was conducted using a standardized PMMA mandibular edentulous model in an “All-on-Four” configuration with four Noris implants (3.75×10 mm). Intraoral scan bodies (Noris C9010) were attached and 15 digital scans were acquired using Dentsply Sirona Primescan, both with and without modular E-chain splinting. STL files were compared against a laboratory reference scan (Dentsply Sirona inEos X5) using Geomagic Studio 12. Linear (x, y, z axes), angular, and distance deviations were measured. Statistical analysis was performed using IBM SPSS v25 (independent student t-test, p < 0.05). Results: Modular E-chain splinting significantly improved all measured accuracy parameters (p < 0.001). Mean linear deviations were reduced along all three axes (x: 1.12 vs. 1.19 μm; y: 2.15 vs. 2.24 μm; z: 2.55 vs. 2.61 μm). Angular deviation improved from 0.33° to 0.32°. Distance deviation decreased from 1.49 to 1.39 μm, and the global measure of linear absolute error (GMLAE) reduced from 2.01 to 1.94 μm. Conclusions: Modular E-chain splinting significantly enhances the accuracy of complete-arch digital implant impressions. This technique is time-efficient, passive, and clinically adaptable. Further in vivo studies are warranted to validate these findings in oral conditions.