Background The literature has not yet validated the use of intraoral scanners (IOSs) for full-arch (FA) implant impression. Hence, the aim of this in vitro study was to assess and compare the trueness of 12 different IOSs in FA implant impression. Methods A stone-cast model of a totally edentulous maxilla with 6 implant analogues and scanbodies (SBs) was scanned with a desktop scanner (Freedom UHD®) to capture a reference model (RM), and with 12 IOSs (ITERO ELEMENTS 5D®; PRIMESCAN® and OMNICAM®; CS 3700® and CS 3600®; TRIOS3®; i-500®; EMERALD S® and EMERALD®; VIRTUO VIVO® and DWIO®; RUNEYES QUICKSCAN®). Ten scans were taken using each IOS, and each was compared to the RM, to evaluate trueness. A mesh/mesh method and a nurbs/nurbs method were used to evaluate the overall trueness of the scans; linear and cross distances between the SBs were used to evaluate the local trueness of the scans. The analysis was performed using reverse engineering software (Studio®, Geomagics; Magics®, Materialise). A statistical evaluation was performed. Results With the mesh/mesh method, the best results were obtained by CS 3700® (mean error 30.4 μm) followed by ITERO ELEMENTS 5D® (31.4 μm), i-500® (32.2 μm), TRIOS 3® (36.4 μm), CS 3600® (36.5 μm), PRIMESCAN® (38.4 μm), VIRTUO VIVO® (43.8 μm), RUNEYES® (44.4 μm), EMERALD S® (52.9 μm), EMERALD® (76.1 μm), OMNICAM® (79.6 μm) and DWIO® (98.4 μm). With the nurbs/nurbs method, the best results were obtained by ITERO ELEMENTS 5D® (mean error 16.1 μm), followed by PRIMESCAN® (19.3 μm), TRIOS 3® (20.2 μm), i-500® (20.8 μm), CS 3700® (21.9 μm), CS 3600® (24.4 μm), VIRTUO VIVO® (32.0 μm), RUNEYES® (33.9 μm), EMERALD S® (36.8 μm), OMNICAM® (47.0 μm), EMERALD® (51.9 μm) and DWIO® (69.9 μm). Statistically significant differences were found between the IOSs. Linear and cross distances between the SBs (local trueness analysis) confirmed the data that emerged from the overall trueness evaluation. Conclusions Different levels of trueness were found among the IOSs evaluated in this study. Further studies are needed to confirm these results.

Objectives To assess the trueness of a solid index (SI) in the full-arch (FA) implant impression, and to compare it with that of two intraoral scanners (IOSs). A type-IV gypsum model of a completely edentulous patient with 8 implant scanbodies (SBs) was scanned with a desktop scanner (7Series®) to obtain a reference virtual model (RVM), and with two IOSs (CS 3700® and Emerald S®). Five scans were taken with each IOS. Based on the RVM, an SI (custom tray consisting of hollow cylinders connected by a bar) was fabricated and used to capture a physical impression of the model; from this, a second gypsum model was derived and scanned with a desktop scanner (D15®). The SI-derived and the IOSs-derived models were superimposed onto the RVM, to evaluate trueness. Results The overall mean trueness was 29 μm (± 26) for the SI-derived model, versus 42.4 μm (± 14.7) for CS 3700® and 52.2 μm (± 4.6) for Emerald S®. Despite its limitations (in vitro design, a limited number of models evaluated, RVM captured with a desktop scanner) this study supports the use of SI for FA implant impressions. Further studies are needed to confirm this evidence.