Preoperative CBCT, digital impression, and implant planning
STL, Callus
Resin models for hands-on training and education mimicking D3-type bone according to the Misch classification (U-009 A, BoneModels S.L.U., Castellon, Spain) were randomly assigned to three study groups.CBCT scans (Planmeca Promax 3D, Planmeca, Helsinki, Finland) were carried out with an 8 × 8 cm field of view at a voxel size of 200 μm, exposure time of 12.45 s, tube voltage of 62 kV, and tube current of 5 mA prior to the model surgeries. The models were digitized to Standard Tessellation Language (STL) files using a desktop scanner (Medit T710, Medit, Seoul, Republic of Korea).The remaining dentition on the models consisted of the upper incisors. Prosthetic planning was performed using DWOS 16.0.1 software (Dental Wings, Montreal, Canada, USA) to replace the missing teeth (World Dental Federation, FDI 13, 14, 15, 16, 23, 24, 25, and 26) with four-unit, screw-retained fixed partial dentures on both sides with dental implants at the sites of the canines, first premolar, and first molar. Virtual planning of the positions of the dental implants (4.2 mm diameter, 10 mm length, CP 1042 − 100, Callus Pro, Callus Implant Solutions GmbH, Nuremberg, Germany) and surgical templates was carried out using coDiagnostiX 10.6 software (Dental Wings, Montreal, Canada). STL files of the models were registered with the Digital Imaging and Communications in Medicine (DICOM) data of the CBCT reconstructions. Surgical templates for the pilot-guided interventions of Groups 1 and 2 were designed with sleeves of a 2.0 mm inner diameter, 4.0 mm outer diameter, and height of 4.0 mm (article number: GSLEEVE, Callus Implant Solutions GmbH, Nuremberg, Germany). Sleeves were positioned 19.2 mm from the planned position of the implant apex at each site, resulting in a free drilling distance of 15.2 mm to correspond with the free drilling distance of the surgical templates used in Group 3. Three sleeves for the guide fixation pins (article number: 3DM00671, 3DIEMME, RealGUIDE, Cantù, Como, Italy) were planned to stabilize the surgical guides.Surgical templates for the fully guided procedures of Group 3 were planned with sleeves (article number: 3DM00604CAD1.10, 3DIEMME, RealGUIDE, Cantù, Como, Italy) specific to the universal fully guided kit and three sleeves for the guide fixation pins similar to the ones used in Groups 1 and 2. The sleeves available for this fully guided system (article number: 3DM00604CAD1.10, 3DIEMME, RealGUIDE, Cantù, Como, Italy) have an inner diameter of 5.0 mm, an outer diameter of 6.0 mm and a height of 4.0 mm. The shank of the drills used in this system is modified to fit inside the metal sleeve in the surgical template. All six sleeves were planned to be placed 19.2 mm from the planned position of the implant apex, resulting in a free drilling distance of 15.2 mm.Rapid prototyping (3D printing) of the surgical templates was carried out using Form 2 hardware (Formlabs, Somerville, Massachusetts, USA) and Clear Resin material (Formlabs, Somerville, Massachusetts, USA) in all three study groups.