## 2 Material and Methods  
The sample was divided into three groups (n = 10) based on the printing angulation: 0, 45, and 90-degrees (G1, G2, and G3). The reference STL file was obtained from a maxillary model with an internal hex connection implant placed in the left central incisor position. A scan body (ZI SCV 3.7 ref. 52.020, Dess, Barcelona, Spain) (Figure 1) was torqued to the implant at 15N following the manufacturer's recommendations. The model was digitized by a laboratory scanner (Aidite A-IS Pro, Aidite Tech. Co., Qinhuangdao, China). The STL was exported to a design software program (Autodesk Meshmixer 3.5, San Francisco, CA, USA) for mesh closure and zoning. Then, it was imported to another CAD software program (DentalCAD 3.0 Galway, Munich, Germany) for the offset setting. A diameter of 0.06 mm was set, corresponding to the diameter of the analog and its radial compensation. The STL file was laminated with a 3D print pre-processing software program (Chitubox(r), V.1.9.4 CBD-Tech, Shenzhen, China) (Figure 2) [27; 28; 29]. Figure 1: Reference model, (**a**) sagittal view, (**b**) frontal view. Figure 2: Printing orientation representations (0, 45, and 90 degrees). All models were printed under controlled environmental conditions using the LCD printer (Phrozen, Sonic Mini 4K, Hsinchu, Taiwan), and the platform was calibrated before printing, according to the manufacturer's recommendations. Likewise, the printing parameters were predetermined following the resin manufacturer's suggestions (Phrozen Water Washable Dental Model Resin PHP-RS1000 WWDM, Phrozen, Hsinchu, Taiwan). A layer thickness of 50 \(\mu\) was established, with an exposure time of 35 s per layer set in the initial ones and 6 s in the rest. There was no need for holes for resin ejection, and they were printed with three angulations: 0, 45, and 90 degrees. For each build angle, ten models were printed. All models were printed with the same new-branded resin bottle and the same printer, using the same printing and post-processing protocol, except for the printing orientation, depending on the study group. The same operator trained in 3D printing carried out all the manufacturing. After printing the models, they were post-processed. The models were placed in water for 15 min to remove excess impression material. Then, they were left for 15 min in the curing camera (Anycubic Wash&Cure 2.0 Shenzhen Anycubic Technology Co., Shenzhen, China). The support of all printed models was removed using a specific tool from the same manufacturer. All the models were stored in a dry area away from the light and without changes in temperature and humidity. The implant analogs were manually inserted in the offset and screwed with a hexagonal 1.20 mm screwdriver and retained by friction. The scan body was manually placed and screwed. Scan powder (Vanishing Spray, SCANTIST 3D, Aztech Technologies, Singapore) was applied, and each analog's position was digitized by a laboratory scanner (Aidite A-IS Pro, Aidite Tech. Co., Qinhuangdao, China). The laboratory scanner was calibrated previously according to the manufacturer's recommendations. This manufacturer reports an accuracy of under 10 microns. The accuracy analysis was performed using a specific reverse engineering software program (Geomagic Control X, v. 2020, 3D Systems, Rock Hill, SC, USA). The STL file from which all the models of the different groups to be evaluated were printed was the reference model with which the discrepancies of the experimental group files were measured. First, the reference STL was imported, and the mesh area corresponding to the scan body surface was selected. Subsequently, the experimental STL was imported. It was automatically superimposed by the best-fit alignment method, and the mesh area of the scan body surface was selected and compared with the reference one. A color map was obtained from the 3D comparison of the selected area (Figure 3). This process was carried out on each of the STLs of each of the 0-, 45-, and 90-degrees groups.