Immediate Full-Arch Maxillary Rehabilitation Following Reduction Alveoloplasty Using the All-on-4 Concept and a Digital Photogrammetry Workflow: A 12-Month Case Report
Mohamed Eltoukhy, BDS, MDS *
*Correspondence to: Mohamed Eltoukhy, BDS, MDS. Privete Clinic, Dammam, Eastern Province,
Saudi Arabia.
Copyright.
© 2026 Mohamed Eltoukhy, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 31 July 2026
Published: 10 August 2026
DOI: https://doi.org/10.5281/zenodo.22224286
Abstract
Background: Immediate loading of a four-implant-supported fixed prosthesis according to the All-on-4 concept is an established approach for rehabilitating the edentulous maxilla. In patients with excessive vertical maxillary bone height, a pronounced gummy smile, and a collapsed occlusal vertical dimension, combining reduction alveoloplasty with a fully digital, prosthetically driven workflow—comprising CBCT-based virtual planning, photogrammetric digital impression-making, and CAD/CAM prosthesis fabrication—may improve the predictability, efficiency, and esthetic outcome of full-arch rehabilitation.
Case Presentation: A 65-year-old woman with a failing maxillary dentition, generalized periodontal bone loss, excessive vertical maxillary bone height, and a pronounced gummy smile presented for fixed implant-supported rehabilitation of the maxilla. Following extraction of the remaining maxillary teeth, reduction alveoloplasty was performed to eliminate the vertical bone excess, reposition the smile line, and create adequate restorative space. Implant planning was performed virtually on preoperative CBCT data using prosthetically driven, software-based planning (BlueSky Plan; Blue Sky Bio, LLC, Grayslake, IL, USA). Four 4-mm-diameter Hiossen implants (Hiossen Inc., Fairfield, NJ, USA) were placed according to the All-on-4 concept—two axial anterior implants and two posterior implants restored on 30° multi-unit abutments to increase the anteroposterior spread and reduce cantilever length. All implants achieved a primary insertion torque greater than 40 N·cm and were loaded immediately with a screw-retained PMMA interim prosthesis. Following soft-tissue healing, a definitive digital impression was captured with a photogrammetry module (Shining 3D Elite; SHINING 3D Tech. Co., Ltd., Hangzhou, China), from which a CAD/CAM titanium bar and a screw-retained monolithic zirconia prosthesis were fabricated and delivered.
Results: At the 12-month follow-up, implant survival was 100%, with no biological complications (peri-implant infection or soft-tissue inflammation) and no prosthetic complications (screw loosening, framework fracture, or ceramic chipping). The definitive prosthesis demonstrated satisfactory passive fit, function, and esthetics, and the preoperative gummy smile was successfully corrected.
Conclusion: The combination of reduction alveoloplasty with a fully digital, prosthetically driven All-on-4 workflow—comprising CBCT-guided virtual planning, immediate loading, photogrammetric digital impression-making, and CAD/CAM fabrication of a titanium-bar-supported monolithic zirconia prosthesis—provided a favorable functional and esthetic outcome at 12 months in this patient. Larger comparative series with longer follow-up are required to confirm the reproducibility of this digital workflow.
Keywords: All-on-4 concept; immediate loading; reduction alveoloplasty; digital photogrammetry; CAD/CAM titanium bar; monolithic zirconia; edentulous maxilla; full-arch rehabilitation.
Introduction
Rehabilitation of the edentulous jaw remains a considerable clinical challenge, particularly in older patients with compromised bone quality, reduced healing capacity, and heightened functional and esthetic expectations [1]. Immediate-loading protocols supported by digital planning and fabrication technologies have progressively addressed this challenge, shortening treatment time while improving the predictability of full-arch outcomes.
The All-on-4 concept, originally described by Maló et al., uses two anterior axial implants and two posterior tilted implants to support an immediately loaded fixed full-arch prosthesis [2]. Initially developed for mandibular rehabilitation, the concept has since been successfully extended to the maxilla, where posterior implant tilting minimizes the need for sinus augmentation while reducing distal cantilever length, improving load distribution, and enabling immediate functional rehabilitation with high long-term implant and prosthesis survival rates [3–6].
In patients with excessive vertical maxillary bone height, a low or “gummy” smile line, and a collapsed occlusal scheme, implant placement alone is insufficient to achieve a satisfactory outcome. In these cases, reduction alveoloplasty is required to re-establish adequate crown height space, correct the position of the smile line, and create favorable conditions for prosthetically driven implant placement [7]. Prosthetically driven planning is best achieved through CBCT-based, software-assisted virtual treatment planning, which allows implant position to be dictated by the anticipated position of the definitive prosthesis rather than by residual bone volume alone, and which forms the digital foundation for the remainder of the treatment workflow.
Beyond its high reported trueness and precision, photogrammetry offers several practical advantages during immediate full-arch rehabilitation. Conventional implant impression workflows frequently require multiple components and verification steps, including impression copings, splinted verification jigs, sectioning and re-splinting techniques, and denture-conversion protocols. Each additional clinical step is a potential source of cumulative transfer error and increases chairside time. Moreover, repeated manipulation of newly placed implants during the early healing period—when primary mechanical stability is transitioning toward secondary biological stability—may impose unnecessary loading on the implant–abutment interface. By directly capturing the three-dimensional spatial position of implants with high accuracy, photogrammetry simplifies the restorative workflow, minimizes cumulative error, and reduces implant manipulation.
This streamlined approach may be particularly advantageous during immediate-loading protocols, as it reduces the number of restorative procedures performed during the critical transition from primary to secondary implant stability and facilitates fabrication of a passively fitting implant-supported prosthesis with minimal chairside adjustment.
Accurate implant position transfer is particularly critical in All-on-4 rehabilitations, because only four implants support a rigid full-arch prosthesis over a relatively long span. Even minor inaccuracies may compromise passive fit, increase mechanical stress on prosthetic components, and contribute to biological or technical complications. High-precision implant position capture therefore plays an essential role in achieving predictable full-arch restorations.
CAD/CAM manufacturing has similarly transformed fabrication of the definitive prosthesis. Milled titanium bars provide a rigid, dimensionally stable substructure, while monolithic zirconia has emerged as a durable, esthetic, and chip-resistant veneering or full-contour material for implant-supported complete-arch prostheses, with systematic reviews reporting favorable short- to medium-term survival and low mechanical complication rates [8–11].
Digital workflows incorporating photogrammetry also reduce reliance on conventional denture-conversion techniques, which are technique-sensitive and may introduce additional laboratory and clinical inaccuracies. The ability to fabricate a precisely fitting definitive prosthesis through a streamlined digital workflow enhances efficiency while reducing the number of clinical appointments and adjustments.
Although reduction alveoloplasty, the All-on-4 concept, and digital implant workflows have each been extensively investigated individually, reports describing their integration into a single, prosthetically driven treatment protocol remain limited. The present case demonstrates how reduction alveoloplasty, CBCT-based virtual planning, immediate loading, photogrammetric implant position capture, and CAD/CAM fabrication of a titanium-bar-supported monolithic zirconia prosthesis can be combined into a single streamlined digital workflow. This integrated approach was designed to improve impression accuracy, minimize cumulative procedural errors, and reduce implant manipulation during early healing, while simultaneously correcting excessive vertical maxillary bone height, restoring adequate prosthetic space, and improving smile esthetics.
Case Presentation
A 65-year-old, systemically healthy woman presented seeking fixed implant-supported rehabilitation of the maxillary arch because of progressive functional impairment and dissatisfaction with the esthetic appearance of her existing prosthetic restoration. Her medical history was non-contributory, with no systemic disease or medication contraindicating implant surgery.
Clinical examination revealed that only the anterior maxillary teeth remained, restored with a long-span fixed dental prosthesis. These teeth exhibited advanced periodontal breakdown with a hopeless long-term prognosis, rendering the existing restoration non-maintainable and indicating extraction of the remaining dentition.
Initial radiographic assessment included panoramic radiography followed by cone-beam computed tomography (CBCT), which demonstrated generalized alveolar bone loss while confirming sufficient residual bone volume for prosthetically driven implant placement following the planned reduction alveoloplasty (Figure 1).
Extraoral and intraoral examination revealed excessive vertical maxillary bone height associated with a pronounced gummy smile, inadequate restorative space, and a collapsed occlusal scheme. These findings represented significant esthetic, functional, and biomechanical challenges that could not be predictably managed by implant placement alone. Reduction alveoloplasty was therefore planned to establish adequate restorative space, reposition the smile line, and create favorable conditions for prosthetically driven implant placement.
Following comprehensive clinical and radiographic evaluation, treatment options were discussed with the patient, and a fully digital, immediate full-arch rehabilitation based on the All-on-4 concept combined with reduction alveoloplasty was selected. Virtual implant planning was performed using BlueSky Plan software to optimize implant positioning according to the planned definitive prosthesis, while facilitating immediate loading and the subsequent digital restorative workflow.
Preoperative Assessment, Diagnosis, and Digital Treatment Planning
Based on the clinical and radiographic findings, extraction of the remaining maxillary anterior teeth was planned, followed by reduction alveoloplasty to eliminate excessive vertical alveolar bone, reposition the smile line, and create adequate restorative space for fixed full-arch rehabilitation. This approach also facilitated prosthetically driven implant positioning while improving the overall esthetic and functional outcome.
A CBCT scan was acquired and imported into BlueSky Plan software (Blue Sky Bio, LLC, Grayslake, IL, USA) for prosthetically driven virtual implant planning. Four Hiossen implants (Hiossen Inc., Fairfield, NJ, USA) were planned according to the All-on-4 concept, with two anterior implants placed axially and two posterior implants tilted to receive 30° multi-unit abutments. The posterior implant angulation maximized the anteroposterior implant spread, reduced distal cantilever length, and avoided the need for maxillary sinus augmentation.
The digital treatment plan also incorporated immediate loading with a screw-retained provisional PMMA prosthesis. Establishing an appropriate vertical dimension of occlusion, restoring adequate prosthetic space following alveoloplasty, and optimizing the definitive prosthetic design were all considered at the virtual planning stage to achieve predictable functional and esthetic rehabilitation.
The digital workflow was designed to ensure continuity from virtual implant planning to definitive prosthetic rehabilitation, allowing subsequent photogrammetric implant-position capture and CAD/CAM fabrication of a passively fitting, titanium-bar-supported monolithic zirconia prosthesis.
Surgical and Prosthetic Protocol
All surgical procedures were performed under local anesthesia using 2% lidocaine with 1:80,000 epinephrine. Prophylactic amoxicillin–clavulanic acid (1 g) was administered one hour before surgery and continued twice daily for three days postoperatively. The patient was also prescribed a nonsteroidal anti-inflammatory medication and instructed to rinse twice daily with 0.12% chlorhexidine gluconate for two weeks.
Preoperative CBCT data were imported into BlueSky Plan software (Blue Sky Bio, LLC, Grayslake, IL, USA) for prosthetically driven virtual treatment planning. Implant positions, angulations, and prosthetic emergence profiles were planned according to the anticipated definitive prosthesis. The digital plan also guided the extent of reduction alveoloplasty required to establish adequate restorative space and optimize implant positioning.
Following extraction of the remaining maxillary anterior teeth, reduction alveoloplasty was performed using a piezoelectric surgical device (Woodpecker Medical Instrument Co., Ltd., Guilin, China) under copious sterile saline irrigation. Bone reduction was carried out according to the preoperative digital plan to eliminate excessive vertical alveolar bone, create adequate restorative space, reposition the smile line, and establish a broad, level alveolar platform for prosthetically driven implant placement. Piezoelectric surgery allowed precise, controlled bone reduction while minimizing trauma to the surrounding soft tissues.
Implant osteotomies were prepared sequentially according to the manufacturer's drilling protocol. Four Hiossen implants (Hiossen Inc., Fairfield, NJ, USA), all 4 mm in diameter, were placed according to the virtual treatment plan. Two anterior implants were inserted axially, while two posterior implants were tilted and restored with 30° multi-unit abutments to maximize the anteroposterior spread, reduce distal cantilever length, and avoid maxillary sinus augmentation. All implants achieved a primary insertion torque exceeding 40 N·cm, allowing immediate loading according to the planned protocol.
Flap closure was achieved using a continuous locking suture technique with 4-0 polypropylene suture.
A screw-retained provisional polymethyl methacrylate (PMMA) prosthesis was delivered within 3 days of surgery, following verification of implant stability. The provisional restoration re-established the planned vertical dimension of occlusion and provided immediate function while supporting peri-implant soft-tissue healing throughout the osseointegration period.
Digital Impression and Prosthesis Fabrication Workflow
Immediately following implant placement, scan bodies were connected to the multi-unit abutments, and a photogrammetric digital impression was obtained using the Shining 3D Elite system (SHINING 3D Tech. Co., Ltd., Hangzhou, China). The digital implant-position data were used to fabricate the screw-retained provisional PMMA prosthesis, allowing immediate loading without the need for conventional implant-level impressions or denture-conversion procedures.
Following the osseointegration period, implant positions were recorded using the photogrammetry module of the Shining 3D Elite system (SHINING 3D Tech. Co., Ltd., Hangzhou, China). Scan bodies were connected to the four multi-unit abutments, and the photogrammetry system captured the precise three-dimensional spatial relationship of the implants, generating a highly accurate digital implant-position file. This dataset was subsequently merged with the digital soft-tissue scan to create the definitive digital master model used for CAD/CAM prosthesis fabrication.
The photogrammetric workflow eliminated the need for conventional implant-level impressions, splinted verification jigs, and denture-conversion procedures, thereby simplifying the restorative workflow while minimizing cumulative transfer error and implant manipulation.
The digital implant-position file was imported into CAD software for fabrication of a screw-retained CAD/CAM titanium bar. The framework was clinically evaluated to verify passive fit before fabrication of the definitive prosthesis proceeded.
A screw-retained monolithic zirconia prosthesis was fabricated over the verified CAD/CAM titanium bar. The definitive restoration was delivered after clinical verification of passive fit, occlusion, esthetics, and complete seating. Prosthetic screws were tightened to the manufacturer's recommended torque values, and postoperative radiographs confirmed complete seating of the prosthesis.
Results
All four Hiossen implants were placed according to the preoperative digital treatment plan, comprising two anterior axial implants and two posterior tilted implants restored with 30° multi-unit abutments. All implants achieved a primary insertion torque exceeding 40 N·cm, allowing immediate loading with a screw-retained provisional PMMA prosthesis. The surgical procedure was completed without intraoperative complications.
Photogrammetric digital implant-position capture was successfully performed during both the immediate provisional and definitive restorative phases, without technical difficulty. The digital workflow enabled fabrication of a CAD/CAM titanium bar with satisfactory passive fit, followed by delivery of a screw-retained monolithic zirconia prosthesis demonstrating favorable esthetics, functional occlusion, and complete seating on all implant abutments. Post-delivery panoramic radiographic evaluation confirmed complete seating and accurate adaptation of the definitive prosthesis.
At the 12-month follow-up, all four implants remained clinically stable, resulting in a 100% implant survival rate. No biological complications — including peri-implant mucositis, peri-implantitis, suppuration, or soft-tissue inflammation — were observed. Likewise, no prosthetic complications — including screw loosening, framework fracture, prosthesis fracture, or ceramic chipping — were recorded.Esthetic outcomes were favorable, with restoration of an appropriate smile line, harmonious peri-implant soft-tissue contours, and a marked reduction in gingival display following reduction alveoloplasty (Figure 7). The patient reported a high level of satisfaction with both the functional and esthetic outcomes of treatment.
Discussion
The primary goals of full-arch implant rehabilitation are restoration of masticatory function, patient comfort, and facial esthetics, all of which contribute substantially to quality of life and social confidence [1]. In the present case, these objectives were achieved through an integrated surgical–prosthetic approach in which reduction alveoloplasty corrected the excessive vertical maxillary bone height, re-established an appropriate smile line, and created adequate restorative space. This was followed by immediate loading using the All-on-4 concept, enabling functional rehabilitation without the need for adjunctive bone grafting or sinus augmentation. The favorable clinical and esthetic outcomes remained stable throughout the 12-month follow-up period.
CBCT-based, prosthetically driven virtual planning enabled implant positioning to be determined according to the planned definitive prosthesis rather than residual bone anatomy alone, consistent with the fundamental principles of the All-on-4 concept. Systematic reviews have reported cumulative implant survival rates exceeding 98%, with low incidences of biological and prosthetic complications following immediate loading of All-on-4 restorations [4,5]. The present case demonstrated comparable clinical outcomes, with 100% implant survival and no biological or prosthetic complications after 12 months of follow-up. In addition to optimizing implant positioning, the digital workflow facilitated seamless integration of surgical planning, immediate provisionalization, and definitive prosthetic rehabilitation.
The original All-on-4 protocol described by Maló and colleagues uses two anterior axial implants and two posterior tilted implants to maximize the anteroposterior implant spread while avoiding anatomical structures such as the maxillary sinus [2,3]. In the present case, the posterior implants were restored using 30° multi-unit abutments, providing favorable prosthetic emergence and minimizing distal cantilever length. Furthermore, all implants achieved a primary insertion torque exceeding 40 N·cm, supporting immediate loading with a screw-retained provisional PMMA prosthesis, in accordance with established clinical recommendations for immediate full-arch rehabilitation [4,5].
Photogrammetry has emerged as a highly accurate method for recording implant positions in complete-arch implant rehabilitation, with several studies demonstrating trueness and precision comparable or superior to conventional digital impression techniques, particularly as implant number and arch span increase [12–15]. In the present case, photogrammetry was incorporated during both the immediate provisional and definitive restorative phases, allowing accurate digital implant-position capture throughout treatment. This eliminated the need for conventional implant-level impressions, splinted verification jigs, and denture-conversion procedures, while simplifying the restorative workflow. In addition, the digital workflow minimized cumulative transfer error, reduced repeated manipulation of the implants during the early healing period, and facilitated fabrication of a CAD/CAM titanium framework with satisfactory passive adaptation before delivery of the definitive prosthesis.
The combination of a CAD/CAM-milled titanium framework and a screw-retained monolithic zirconia prosthesis provided a rigid, accurately fitting, and esthetically pleasing definitive restoration. Monolithic zirconia has demonstrated excellent mechanical performance, favorable esthetics, and low rates of chipping or fracture in full-arch implant-supported rehabilitation, making it an increasingly preferred material for definitive prostheses [8–11]. Consistent with these findings, no prosthetic complications — including screw loosening, framework fracture, or ceramic chipping — were observed during the 12-month follow-up period.
Reduction alveoloplasty remains an essential component of prosthetically driven rehabilitation in patients presenting with excessive vertical alveolar bone, irregular ridge morphology, or inadequate restorative space [13]. Beyond facilitating ideal implant positioning, the procedure establishes sufficient prosthetic space, improves soft-tissue architecture, and allows development of an appropriate emergence profile. In the present case, reduction alveoloplasty also played a critical role in correcting excessive gingival display, resulting in a harmonious smile line and improved facial esthetics that remained stable throughout follow-up[14].
The present report is limited by its single-case design and the absence of quantitative outcome measures, such as marginal bone-level analysis, implant stability quotient measurements, or validated patient-reported outcome questionnaires[15]. Although clinical examination and panoramic radiographic evaluation confirmed stable peri-implant conditions and satisfactory prosthesis seating throughout the 12-month follow-up period, larger prospective studies with longer follow-up are required to validate the reproducibility, long-term survival, biological stability, and prosthetic performance of this fully digital, photogrammetry-based workflow for immediate full-arch rehabilitation.
Conclusion
This case demonstrates that integrating reduction alveoloplasty within a fully digital, prosthetically driven All-on-4 workflow—including CBCT-based virtual planning, immediate loading, photogrammetric implant-position capture, and CAD/CAM fabrication of a titanium-bar-supported monolithic zirconia prosthesis—provided predictable functional and esthetic rehabilitation of the edentulous maxilla. The digital workflow facilitated accurate implant-position transfer, minimized restorative complexity, and achieved favorable biological and prosthetic outcomes, with 100% implant survival and no biological or prosthetic complications after 12 months of follow-up. Further prospective studies with larger patient cohorts and longer follow-up are warranted to validate the reproducibility and long-term outcomes of this treatment approach.
Ethics Approval and Consent to Participate
The treatment described in this case report was performed in accordance with the ethical principles of the Declaration of Helsinki. Written informed consent was obtained from the patient for treatment and for publication of the clinical data and accompanying clinical photographs.
Consent for Publication
Written informed consent for publication of the clinical data and accompanying images was obtained from the patient.
Availability of Data and Materials
The data supporting the findings of this case report are available from the corresponding author upon reasonable request.
References