## 2 Materials and Methods
### Prosthetic Protocol  
Prior to surgery, all patients had their vertical dimension recorded by means of facial landmarks. Preliminary alginate impressions were taken to allow immediate loading. Immediately after surgery, provisional acrylic resin prostheses were refined intra-orally using self-curing polyurethane resin (Voco, Fort Mill, SC, USA). Within 24 h, the prostheses were placed with a torque spanner applying a torque of 15 N/cm. Intra-oral digital radiographies (DIGORA 2.5 Soredex software, Tuusula, Finland) were performed to assess the marginal adaptation of the prosthetic structure. Static and dynamic occlusion and contacts in centric relation were verified and modified using an articulating chart (Bausch 40 um articulating chart, Nashua, NH, USA). Centric and lateral contacts were limited to the inter-canine area and the passivity of the prosthesis was verified. Finally, a temporary material (Fermit, Ivoclar Vivadent, Naturno, Bolzano, Italy) was used to cover the screw access holes. After a period of about four months, necessary for the tissues to fully heal, definitive prosthetic procedures were begun using digital methods. The scan bodies (Sweden & Martina, Due Carrare, Padua, Italy), which replace the traditional impression coping, were joined in the same way as for traditional prosthetic techniques. The intra-oral scanner used for all patients was a Carestream CS 3600 (Version 3.1.0 Acquisition Software, Carestream Dental LLC, Atlanta, GA, USA). The Carestream system operates using the principle of structured light, transforming the three-dimensional geometry of the dental arches into a virtual model. The light source was initially held parallel to the occlusal plane, starting from the distal implant elements on the left side and moving towards the anterior implants of the contralateral quadrant; the source was then moved behind the distal implants on the left side, tilting it towards the palatal/lingual side. The occlusal plane was crossed towards the buccal side and the scanner was moved again from the scan starting point of the left side to the anterior implant of the right side, trying to keep it orthogonal to the occlusal plane. Subsequently, the image obtained was carefully analyzed and the incomplete areas were completed by further passes of the scanner. The same scanning procedure was performedon the contralateral side. Next, the operator scanned both the soft tissue and the provisional prosthesis with the analogues in place and then the scans were matched to each patient. The antagonist arch was scanned with the same procedure, followed by a scan of the buccal aspect of the patient's teeth in maximum intercuspation and the resulting 3D scans were exported in the standard tessellation format (.stl). The model of the provisional prosthesis, with implant analogues in place, was subsequently acquired extra-orally through the use of a laboratory scanner (Newway, Open Technologies, Rezzato, Italy) to verify the accuracy and precision of the intra-oral scan. In cases where differences were noted between the intra-oral and extra-oral scans, the restoration would be performed using the extra-oral scan as reference. All scanner scans were processed in the laboratory and returned after post-processing. The virtual images were evaluated for accuracy of detail and correct occlusal relationship. Once the virtual model was completed, with dental implants in place, the digital framework was fabricated using CAD Ultimate software (Exocad Software, Darmstadt, Germany). Subsequently, the titanium framework was machined and, at the same time, the prototype model was used to realize the final restoration. The final prosthesis was made based on the provisional prosthesis but with greater attention to aesthetic, functional and soft tissue details. Following the aesthetic assessment, the prosthetic restoration was finalized. The aesthetic tooth restoration material (Nacera Hybrid, Doceram Medical Ceramics GmbH, Dortmund, Germany) and soft tissue were added on top of the meso-structure.