## 2 Materials and Methods  
Three analogue models were created by placing Straumann BLX 4.0 mm \(\times\) 12 mm implants (Institut Straumann AG, Basel, Switzerland) in an edentulous acrylic mandible with artificial gingiva (Institut Straumann AG, Basel, Switzerland). Implant placement was performed by an experienced operator, ensuring parallel alignment and insertion torques ranging from 45 to 60 Ncm (Figure 1). Subsequently, 4.6 mm straight abutments (Institut Straumann AG, Basel, Switzerland) were connected to the implants using a torque of 35 Ncm. To determine implant position, the Carames Classification (CC)--which considers the patient's clinical information as the cornerstone of the therapeutic decision-making process--was applied. Based on the degree of resorption and the quantity of available bone (in terms of height and width) in both jaws, the CC defines five classes of bone atrophy, each associated with three therapeutic options. In this study, the models were fabricated according to class I of the CC (CCI), which represents the least severe bone resorption. Based on this classification, three physical models were created, each simulating one of the three therapeutic options proposed for this classification: Option A was 6 implants (2 anterior implants placed in the lateral incisor positions, 2 implants placed in the premolar region, anterior to the mental foramen, and 2 implants placed in the first molar positions); Option B was 4 implants (2 anterior implants placed in the canine positions, anterior to the mental foramen, and 2 posterior implants placed in the first molar positions); and Option C was 4 implants (2 anterior implants placed in the lateral incisor positions and 2 distal implants positioned in the premolar region, anterior to the mental foramen). Considering the posterior bone availability and the favorable anterior region with higher bone density, two fixed full-arch rehabilitation options (Options A and B) and one removable full-arch option (Option C) are proposed [31]. The three models were scanned using a high-precision industrial 12-megapixel scanner GOM Atos Compact Scan 12M (Zeiss, Oberkochen, Germany) (Figure 2), resulting in three corresponding digital reference models (Figures 3-5). A total of 90 digital impressions were subsequently obtained, with 30 impressions for each of the three implant distribution types. Of these, 10 were captured using the IO Trios 3 scanner (3 Shape, Copenhagen, Denmark), 10 with the IO Mediti i500 scanner (Medit, Seoul, Republic of South Korea), and 10 using photogrammetry technology with the PICdental system (PIC dental, Spain) (Figure 6). For digital impressions using the industrial scanner and the IOSs, mono CARES (r) Scanbodies were employed for 4.6 mm screw abutments (PEEK/TAN, Straumann, Basel, Switzerland), with a tightening torque of 10 Ncm. For digital impressions with photogrammetry, PIC transfers (PIC dental, Madrid, Spain) were utilized, also tightened to 10 Ncm (Figure 6). All scans were performed in accordance with the manufacturers' recommended protocols to ensure standardization between the two IOS systems. The scanning sequence included the occlusal surfaces first, followed by the lingual and buccal surfaces. For the photogrammetry system, scanning was also carried out following the manufacturer's guidelines. All scanners were calibrated prior to use, and the master model was scanned 10 consecutive times with each scanner. To maintain consistency, temperature and humidity were controlled, and all scans were conducted under standardized laboratory conditions by a single experienced operator. Figure 4: Digital reference model for CCI Option B.  
Figure 5: Digital reference model for CCI Option C.  
Figure 3: Digital reference model for CCI Option A. The digital impressions were then processed through a standard laboratory workflow and imported into Exocad software 3.1 (Exocad GmbH, Darmstadt, Germany) for the generation of digital implant replicas.