Purpose: To describe a technique intended to transfer of the intermaxillary and occlusal relationships in a fully digital environment from a complete denture to an implant-supported 3D-printed hybrid prosthesis (an acrylic resin complete fixed dental prosthesis supported by implants). Methods: In edentulous cases, the physiological mandibular position should be determined before the immediate loading procedures. In some cases, the use of interim removable prostheses for a few weeks could be useful to test the new occlusion in centric relation and to verify the prosthetic project. When the correct intermaxillary relationships are achieved, it is difficult to transfer them from the provisional to the final prostheses, as impressions or scans of edentulous arches do not have reference points for intermaxillary records. This paper presents a complex case and the technique used to transfer information from a complete denture to an implant-supported prosthesis with a digital workflow. A prosthetic stent has been used to scan the edentulous mandibular arch and to record the intermaxillary relation. Results: The delivery of the hybrid implant-supported prostheses was carried out with no problems and minimal occlusal adjustments. The patient was extremely satisfied with the treatment and the situation remained stable at the 1-year follow up. Conclusions: The approach described in the present article predictably maintains prosthetic information and allows the delivery of a final implant-supported restoration with the same occlusal relationship as the one tested with the provisional diagnostic dentures.

To compare the 2D and 3D positional accuracy of four guided surgical protocols using an analysis of linear and angular deviations. DICOM and .STLs files obtained from a CBCT and a digital impression were superimposed with software to plan implant position. Fifty-six patients were subdivided into 4 groups: FGA group (template support [Ts]: teeth [T]; bed preparation [Bp]: fully guided [FG]; implant insertion [Ii]: 3D template [3Dt]; device [D]: manual adapter [MA], FGM group (Ts: T; Bp: FG; Ii: 3Dt; D: fully guided mounter [FGM]), PG group (Ts: T; Bp: FG; Ii: manual; D: none) and MS group (Ts: mucosa; Bp: FG; Ii: 3Dt; D: FGM). The position of 120 implants was assessed by superimposing the planned and final position recorded with a digital impression. In FGA group, 3D deviations were 0.92 ± 0.52 mm at the implant head and 1.14 ± 0.54 mm at the apex, and the angular deviation (ang. dev.) was 2.45 ± 1.24°. In FGM group, were 0.911 ± 0.44 mm (head) and 1.11 ± 0.54 mm (apex), and the ang. dev. was 2.73 ± 1.96°. In PG group, were 0.95 ± 0.47 mm (head) and 1.17 ± 0.488 mm (apex), and the ang. dev. was 3.71 ± 1.67°. In MS group, were 1.15 ± 0.45 mm (head) and 1.42 ± 0.45 mm (apex), and the ang. dev. was 4.19 ± 2.62°. Ang. dev. of MS group was different from the other groups (P < 0.05). Guided surgery showed a sufficient accuracy.

Background: Recently, intraoral scanning (IOS) has been proposed as a new tool to evaluate the accuracy of static computer-assisted implant surgery (s-CAIS); however, further research is needed to improve the precision of IOS for full-arch impressions. The purpose of the study was to assess the accuracy of s-CAIS in an edentulous patient either in vivo or in vitro with two different evaluation techniques and to investigate if their results are comparable. Methods: A patient with terminal dentition was selected and four implants were placed using s-CAIS with a bone-supported stackable template. Segmentation used for designing a template was 3D printed, and then four implants were placed in the model following the same protocol as for s-CAIS. The model then underwent cone beam computed tomography (CBCT) and laboratory scanning to evaluate its accuracy. Data were uploaded to specific software, and accuracy values were automatically generated. Results: A statistical analysis was not attempted since all measurements were performed on the same patient and model. When descriptively comparing the accuracy of the two methods of treatment evaluation in the in vitro scenario, comparable results were obtained between IOS and CBCT, except for the angle. Conclusions: As the intraoral scanning procedure in fully edentulous patients is not yet clinically validated, utilizing CBCT can still be recommended for the accurate evaluation of computer-assisted implant placement.