## 2 Materials and Methods  
The overall experimental workflow is summarized in Figure 1.  
A maxillary model (Dentition, Nissin Dental Products, Kyoto, Japan) was scanned using a tabletop scanner (T500, Medit, Seoul, Korea), and the created study model was exported as files in Standard Tessellation Language (STL) format. The STL was imported into dental CAD software (Exocad DentalCAD, Exocad, Darmstadt, Germany). The lateral incisor, first premolar, and first molar of the model were removed to create a modified model in the form of an edentulous ridge. Five maxillary master models were printed using a 3D printer (Form 2, Formlabs, Somerville, MA, USA) and light-cured resin (standard gray resin, Formlabs). Screw-typed bone-level implants (10 mm long and diameter of 4.1 mm; [PERSON], Basel, Switzerland) were placed where teeth were removed at different levels: Normal bone level, submerged 1.5 mm, submerged 3.0 mm, submerged 4.5 mm, and submerged 6.0 mm. The direction of the internal antirotation structure of the fixture was unified to keep the direction of the ISB the same as that of the implant in the buccal direction (Figures 2 and 3). Figure 1: Overall experimental workflow of this study, showing the scanning procedure and the scanners used. Prior to scanning, all scanners were calibrated according to the manufacturers' instructions. One tabletop scanner (T500, Medit) and the following three oral scanners were used: TRIOS 3 (3 Shape, Copenhagen, Denmark), i500 (Medit), CS3600 (Carestream, Atlanta, GA, USA) (Table 1). In order to reduce errors in the fastening direction of each ISB (SC-BLR, Geomedi, Gyeonggi-do, Korea), the flat surfaces of all ISBs were aligned to face the buccal direction. The scan was started from the occlusal surface of the posterior teeth of the model, the anterior teeth were scanned last, and comparison data were generated by scanning eight times for each scanner. After completing the scanning of all experimental groups, T500 reference data (T500-REF) were created using the tabletop scanner as the last step. In order to reduce errors associated with shortening of the exposed length of the ISB during the scanning process, the area around the implant was removed with denture burs from the models of all groups, adjusted to expose the entire ISB, and then scanned eight times. Figure 3: An ISB (implant scan body) was connected to each master model and scanned. The exposed length of the ISB varied with the implant level. Figure 2: Designed and printed master model. In order to reproduce the position of the implant in the virtual model, the scanned ISB image was loaded into dental CAD software. The library for the ISB with the same shape as the scanned ISB was selected, and this library was first overlapped manually by clicking on a flat surface. Then, the two images were again superimposed to the optimal position using the best-fit matching function provided by the software. Abutment library data (RC-022.4325, Straumann) were automatically generated based on the location of the scanned ISB image. The replaced file was saved in STL format (Figure 4). This process was applied to all scanned files. For analyzing the scan data, 3D analysis software (Geomagic Control X, 3D Systems, Rock Hill, SC, USA) was used to compare all STL files obtained from the tabletop scanner and the intraoral scanners with reference scan STL files. After loading the reference data, the abutment regions were divided using an auto segmentation tool to analyze only the abutment area. This software was used to align the remaining comparison scan files using a best-fit algorithm that overlapped the shortest distance based on the reference data, and then the accuracy errors of the positional reproduction of the abutment library data were evaluated in three dimensions. To obtain data form tooth position, each model was analyzed three times in order of lateral incisor, first premolar, and first molar.