## 2 Materials and Methods  
A 58-year-old woman with no problematic medical history (ASA 1) presented to the dental office with the chief complaint of dental pain, tooth mobility, and unsatisfactory esthetics (Figure 1). The clinical and radiographic examination revealed several missing teeth, bleeding, plaque, and periodontal disease (Stage IV, Grade C). The patient did not report any articular or muscular symptoms. The preliminary treatment plan focused on the periodontal chart and non-surgical periodontal treatment in both arches. After re-evaluations and a diagnostic wax-up, different possible definitive treatments were discussed with the patient, including risks, benefits, and costs. The patient wished to rehabilitate only the upper arch through a full-arch implant-supported FDP. Cone beam computed tomography was prescribed to plan the implant placements. The presented study was performed in private  
Figure 1: Initial clinical situation. practice, in accordance with the Declaration of Helsinki of 1964, as revised in 2013, as Good Clinical Research Practice requires. The operator asked the patient to give full and informed consent before inclusion within the protocol. In the first surgery step, all teeth except elements 13 and 23 were extracted and dental implants (Tapered Screw-Vent Implant, Zimmer Biomet, Conegliano, Italy) in locations 16, 14, 12, 22, 24, and 16 were placed. Teeth 13 and 23 were prepared with an abutment tooth to support a temporary prosthesis realized by using the diagnostic wax-up. After 4 months, temporary abutments were screwed into the implants, the temporary prosthesis was relined using the abutment teeth as support, and elements 13 and 23 were extracted. After a 1-month period to allow for the healing of the soft tissue, the digital impressions were performed using the IOS (iTero Align, Align Technology, Tempe, AZ, USA). Six scan-bodies (Gentek, Zimmer Biomet, Conegliano, Italy) were tightened with a special screwdriver (Zimmer Biomet, Conegliano, Italy) and a manual torque-controlled ratchet (15 Ncm), and 10 full-arch digital implant impressions were acquired according to the manufacturer's instructions (Figure 2). After scanning the antagonists, a buccal scan with teeth in maximum intercuspation position as a bite registration was performed. During scanning, a dry field was maintained using a dental aspirator. The implant-supported temporary prosthesis was acquired to transfer the vertical dimension, shape, and occlusal morphology to the definitive prosthesis [5]. The 10 STL files were uploaded to CAD software (Exocad, Exocad DentaCad, Darmstadt, Germany) to design the frameworks. Successively, 10 titanium frameworks were realized with a 5-axis milling machine (Zfx in-house 5X, Zimmer Biomet, Conegliano, Italy) (Figure 3). Figure 3: Occlusal view of the 10 milled frameworks. Figure 2: **(A)** Occlusal view of the clinical situation before digital impression. **(B)** Occlusal view of the intraoral digital impression. Moreover, a traditional impression by using coping pick-up and the open tray technique was used to realize a master model [15]. The passive fit was assessed by the Sheffield test, screwing each framework onto the mouth of the patient. According to this test, the framework presented a passive fit when one screw on the distal abutment was completely tightened without creating a gap among the other framework-implant interfaces. If the fit was not sufficient, the superstructure was lifted when a screw was tightened, creating a gap at the level of one or more abutment analogs [21,22] (Figure 4). In addition, the frameworks were screwed onto the master model to measure the interface among frameworks and implants by using a digital microscope (AM7915 MZL, Dino-Lite Microscope, Almere, The Netherlands) at 150\(\times\) magnification (Figure 5). For each framework, we obtained 6 measurements. The average of the 6 measurements was considered as the overall misfit value for the framework. Descriptive statistical analysis was performed. Average and standard deviations were calculated.