ABSTRACT: 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??m) followed by ITERO ELEMENTS 5D® (31.4??m), i-500® (32.2??m), TRIOS 3® (36.4??m), CS 3600® (36.5??m), PRIMESCAN® (38.4??m), VIRTUO VIVO® (43.8??m), RUNEYES® (44.4??m), EMERALD S® (52.9??m), EMERALD® (76.1??m), OMNICAM® (79.6??m) and DWIO® (98.4??m). With the nurbs/nurbs method, the best results were obtained by ITERO ELEMENTS 5D® (mean error 16.1??m), followed by PRIMESCAN® (19.3??m), TRIOS 3® (20.2??m), i-500® (20.8??m), CS 3700® (21.9??m), CS 3600® (24.4??m), VIRTUO VIVO® (32.0??m), RUNEYES® (33.9??m), EMERALD S® (36.8??m), OMNICAM® (47.0??m), EMERALD® (51.9??m) and DWIO® (69.9??m). 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.