STATEMENT OF PROBLEM: The precision and accuracy of intraoral scanners for complete arch implant scanning is questionable as it is affected by the absence of anatomic features, the presence of large homogenous areas, and the lack of clear reference points, all of which create inherent errors in the image stitching process by the scanner software program. PURPOSE: The purpose of this in vitro study was to test a newly designed scan-aid apparatus for evaluating the effect of geometric heterogeneity and additional reference points on the time efficiency and scanning precision of complete arch implant scanning. MATERIAL AND METHODS: A total of 60 scans (20 per group) were performed using an intraoral scanner in 3 different clinical simulations: 2 parallel implants, 4 parallel implants, and 4 implants
2 anterior implants in parallel axial orientation
and 2 distal implants with a 30-degree posterior inclination. The scanning procedure was alternated between scanning with the scan-aid apparatus (test groups
4IP+, 4IA+, 2IP+) and without (control groups
4IP-, 4IA-, 2IP-). A 3-dimensional (3D) inspection software program was used to assess scan precision. Test group scans were compared with a reference scan for repeatability, with and without the scan-aid apparatus. One scan per group was the reference
the others were superimposed by using a best-fit algorithm. The 3D standard deviations were recorded for repeatability analysis. To assess time efficiency, the total scanning time, actual scanning time, and time lost were measured. A paired t test was used to compare means between the groups (α=.05). RESULTS: Precision was significantly higher in the test groups using the scan-aid apparatus than in the control groups (P<
.05). Furthermore, scanning with the scan-aid apparatus was significantly more time efficient (P<
.05). CONCLUSIONS: Additional reference points and geometric heterogeneity using a scan-aid apparatus significantly improved the precision and time efficiency of complete arch implant scanning.