Affiliation: Istanbul University, Department of Prosthodontics

This clinical case was performed by an interdisciplinary team of implantologists and prosthodontists. The goal was to rehabilitate an edentulous upper jaw using an implant-supported full-arch concept.

A 67-year-old female patient presented with multiple failing crown restorations and advanced periodontal disease. Clinical examination revealed tooth mobility and sensitivity in several teeth. Although the patient did not express significant concern regarding esthetics, the functional and biological prognosis of the remaining dentition was deemed unfavorable. Therefore, extraction of the remaining teeth was indicated to allow prosthetic rehabilitation. Prior to surgical intervention, a cone-beam computed tomography (CBCT) scan (Morita Veraview 3D; J. Morita Corp) was obtained to evaluate the existing bone anatomy and to facilitate implant planning. Based on the clinical and radiographic findings, a full-arch rehabilitation using the All-on-4 concept was planned. Intraoral scans were acquired both with and without the existing restorations to enable prosthetically driven digital planning. The digital impressions were obtained using an intraoral scanner (Alliedstar Sensa; Alliedstar Co) (Figs. 1–3).

Using DICOM data obtained from cone-beam computed tomography and standard tessellation language (STL) files from intraoral scans, virtual implant planning was performed according to the All-on-4 treatment concept. The datasets were imported into implant planning software (Exoplan 3.1; Exocad GmbH), and Straumann implants (Straumann AG) were selected. Implant positions and angulations were determined based on prosthetically driven principles and digitally verified to ensure optimal restorative space, biomechanical distribution, and emergence profile (Fig. 4). The locations of fixation pins were established during the virtual planning phase to enhance surgical guide stability. Based on the finalized plan, a surgical guide was designed using CAD software and fabricated with a 3D printing system (Asiga MAX UV; Asiga) using a biocompatible surgical guide resin (DentaGuide; Asiga). The guide was postprocessed and disinfected according to the manufacturer’s protocol before surgery (Figs. 5–6).

The surgical guide was positioned intraorally and stabilized using fixation pins. Sequential osteotomies were performed according to the manufacturer’s guided surgery protocol. All implants were placed through the surgical guide to ensure accurate transfer of the virtual treatment plan to the clinical setting (Fig. 7). Primary implant stability was evaluated using resonance frequency analysis (Osstell ISQ; Osstell AB). Implant stability quotient (ISQ) values were recorded to determine eligibility for immediate loading. The measured ISQ values were within the acceptable range for immediate prosthetic loading (Fig. 8). Following implant placement, a digital impression was obtained using a photogrammetry system (Oxo Core; OXO Technology) to capture the precise three-dimensional implant positions. In addition, a soft tissue scan was performed with an intraoral scanner (Alliedstar Sensa; Alliedstar Co) to record the peri-implant soft tissue contours (Fig. 9).

The photogrammetry data and the intraoral soft tissue scan were aligned and merged within the CAD software environment (DentalCAD 3.1 Rijeka; Exocad GmbH) to generate an accurate digital working model (Fig. 10). The pre-existing restoration scan was used as a reference for tooth arrangement, as the patient was esthetically satisfied with the original appearance (Fig. 11). Occlusal relationships were digitally evaluated and refined to achieve balanced articulation and appropriate prosthetic parameters. Soft tissue contours were adjusted to optimize the emergence profile and ensure adequate tissue support. After final verification of esthetics, occlusion, and prosthetic design parameters, the provisional full-arch restoration was exported as an STL file (Fig. 12).

The provisional imported into the printer software (Composer; Asiga), where the restoration was oriented on the build platform and support structures were generated on the occlusal surface to minimize distortion of the intaglio surface and critical prosthetic interfaces (Fig. 13). The appropriate material parameter set was selected from the manufacturer’s database. Fabrication was performed using a 3D printing system (Asiga MAX UV; Asiga) with a permanent crown resin (saremco print CROWNTEC; Saremco Dental AG) according to the manufacturer’s recommended printing parameters (Fig. 14). After printing, the restoration was detached from the build platform. Initial cleaning was performed using a cleaning concentrate solution (saremco print CLEANING CONCENTRATE; Saremco Dental AG) in an ultrasonic bath for 3 minutes (Fig. 15). The restoration was then rinsed thoroughly with warm water, and excess resin was removed using compressed air. Final polymerization was carried out in a UV curing unit (Otoflash G171; NK-Optik GmbH) for 2 × 2000 flashes, with the restoration rotated between exposure cycles to ensure uniform polymerization (Fig. 16).

After postpolymerization, the provisional restoration was finished and polished to achieve a high-gloss surface. Support remnants were carefully removed, and minor surface irregularities were refined. Polishing was performed using sequential polishing instruments, including rotary polishing brushes and silicone polishers, according to the manufacturer’s recommendations (Fig. 17). Care was taken to preserve occlusal morphology and maintain the integrity of the intaglio surface. A high-gloss finish was achieved to optimize esthetics, reduce plaque accumulation, and enhance patient comfort prior to delivery. The provisional full-arch prosthesis was then seated and secured using prosthetic screws according to the manufacturer’s recommended torque values. Screw access channels were sealed with polytetrafluoroethylene (PTFE) tape and composite resin (Fig. 18). A postoperative radiograph was obtained to verify the passive fit of the prosthesis and confirm proper seating of the abutments and prosthetic components (Fig. 19).