The rehabilitation of partially edentulous arches, particularly in distal extension scenarios classified under Kennedy Class I and II, presents considerable clinical complexity. The absence of distal abutments limits the feasibility of conventional fixed partial dentures due to biomechanical inadequacies. Furthermore, implant-supported prostheses may not be viable alternatives for many patients owing to insufficient alveolar bone, systemic health limitations, or economic constraints. In such cases, cast partial dentures (CPDs) incorporating precision attachments have emerged as a dependable and conservative treatment option that combines mechanical stability, esthetic appeal, and cost-effectiveness.^[1]

Traditionally, CPDs have been fabricated using the lost-wax technique, a method that, despite its long-standing clinical success, is technique-sensitive and prone to dimensional inaccuracies. The sequential manual steps involved in wax-up, investing, burnout, and casting increase the potential for human error and distortions that may compromise the final fit and function of the prosthesis. The integration of advanced digital technologies, specifically computer-aided design (CAD), computer-aided manufacturing (CAM), and direct metal laser sintering (DMLS), has transformed this landscape by offering a more streamlined, precise, and reproducible workflow. These innovations allow for high-resolution virtual design and the additive manufacturing of intricate metal frameworks with micron-level accuracy and superior surface characteristics.^[2]

A critical enhancement in this modern approach is the use of extracoronal precision attachments, which significantly improve both the functional and esthetic performance of CPDs. Located externally to the abutment tooth, these attachments preserve pulp vitality and reduce the need for extensive tooth preparation. Their stress-breaking, non-rigid connection mechanism plays a pivotal role in the biomechanical success of the prosthesis by effectively distributing masticatory forces across the supporting structures. When fabricated using CAD/CAM and DMLS workflows, these components exhibit exceptional adaptation and mechanical integrity, contributing to increased patient comfort, prosthesis longevity, and reduced maintenance requirements.^[3] Functionally, such designs alleviate undue pressure on the edentulous ridge, restore masticatory efficiency and speech clarity, and provide esthetic results comparable to fixed prostheses. Long-term retrospective data support their efficacy, reporting survival rates of 83.3% at five years, 67.3% at fifteen years, and nearly 50% when extrapolated over two decades.^[4,5]

This case report presents the prosthetic rehabilitation of a patient with a Kennedy Class II modification 2 partially edentulous maxillary arch using a digitally designed and DMLS-fabricated CPD retained with extracoronal castable precision attachments. The case exemplifies how the integration of advanced digital technologies with proven prosthodontic principles can result in a highly functional, esthetically pleasing, and biologically respectful prosthesis, setting a new standard for the management of complex removable partial denture cases.

A 48-year-old female was referred to the Department of Prosthodontics for evaluation and management of multiple missing teeth, specifically teeth 16, 14, 13, 12, 21, 22, 26, and 27(Fig. 1A, B). She reported difficulties with chewing and dissatisfaction with her appearance due to the gaps left by the missing teeth. Her medical history was non-contributory. Intraoral examination showed wear on the anterior mandibular teeth, which were otherwise healthy(Fig. 1C). The periodontal condition was stable, with the alveolar ridges adequately preserved but with slight resorption in the areas of the missing teeth. After completing a thorough clinical and radiographic examination, a prosthetic treatment plan was established for the partially edentulous patient. The plan utilized a hybrid approach that incorporated both removable and fixed dental prostheses. Specifically, a combined prosthesis with extracoronal precision attachments was chosen. All treatment steps were carried out with informed consent obtained from the patient.

Tooth preparation was carried out on teeth 15 and 25(Fig. 1D) , followed by creating an impression using additional silicone putty and light body (LB) elastomeric impression material (Avue Gum Putty and LB: Hydrophilic Vinyl Polysiloxane Impression Material)(Fig. 1E, F) .

The impression was subsequently scanned using the 3Shape D850 desktop scanner (3Shape Dental System, Copenhagen, Denmark). The scanned data generated a Standard Tessellation Language (STL) file. Digital designing of the metal coping with the male component was done using specialized software (ExoCad), and the STL file facilitated the design and fabrication of these components(Fig. 2) .

A unique custom tray was created using auto-polymerizing resin (DPI Self-Cure, India) to ensure precise adaptation(Fig. 3A). The metal coping with the male component was fabricated using the Direct Metal Laser Sintering (DMLS) technique with cobalt–chromium alloy (Mediloy® RPD, BEGO GmbH, Bremen, Germany), ensuring high strength, corrosion resistance, biocompatibility, and suitability for removable partial denture frameworks and precision attachment fabrication(Fig. 3B). The fit of the metal coping with the male component was assessed on the respective abutment teeth(Fig. 3C). The final impression was taken using the addition of silicone putty and light body (LB) elastomeric impression material, capturing the details of the metal coping with the male component for the final prosthetic construction(Fig. 3D). Additionally, the jaw relation was recorded continuously to ensure accurate occlusal alignment and fit of the final prosthesis(Fig. 3E) .

After scanning the final impression, the digital design of the cast partial denture with the female component was done using specialized software (ExoCad). An STL file was generated from this design to facilitate the manufacturing of the final prosthetic components(Fig. 4) .

The cast partial denture was fabricated using the Direct Metal Laser Sintering (DMLS) technique with cobalt–chromium alloy (Mediloy® RPD, BEGO GmbH, Bremen, Germany). After finishing the cast partial denture with the female component, the jaw relation was integrated into the denture. It was then mounted onto Bio-Art semi-adjustable articulators, where the teeth arrangement was meticulously refined to ensure optimal fit and function(Fig. 5A). A ceramic layer was added over the metal coping to improve esthetics and finalize the prosthesis. After arranging the teeth, waxing up, festooning, and conducting a trial, adjustments were made to their positioning in the patient’s mouth. During this trial, the prosthesis with the male component was first cemented using temporary cement(Fig. 5B). The cast partial denture with the female component was then tried to ensure a proper fit with the male component(Fig. 5C). Occlusal discrepancies were assessed and adjusted(Fig. 5D). Once everything was confirmed to be satisfactory, the denture was sent for acrylization(Fig. 5E). The combined prosthesis was positioned in the patient’s mouth, and a trial seating of the finished prosthesis was conducted. Cementation of the crowns was performed using glass ionomer cement (GC Fuji). To aid in the removal of the cast partial denture after seating, a thin layer of petroleum jelly (Vaseline) was applied to the attachments for protection. The final seating of the maxillary combined prosthesis, incorporating extra coronal castable precision attachments, was thoroughly evaluated clinically to ensure proper fit and function(Fig. 5D) .

After the denture was successfully inserted, comprehensive post-insertion care instructions were provided to the patient. The patient was pleased with the denture’s esthetics, functionality, and overall stability. To ensure the best long-term results and to address any potential adjustments, the patient was encouraged to attend scheduled follow-up visits regularly(Fig. 6) .

A cast partial denture (CPD) continues to serve as a reliable and conservative prosthetic option for the rehabilitation of partially edentulous arches. It is especially valuable in patients for whom fixed prostheses or implant-supported restorations are contraindicated due to anatomical, financial, or medical limitations. CPDs offer the advantage of reversibility and tissue preservation, and they can be fabricated to restore esthetics, function, and phonetics with minimal alteration of the remaining natural teeth. A well-designed metal framework ensures the strategic distribution of occlusal forces, enhancing the mechanical stability of the prosthesis while maintaining the periodontal health of the abutments. Moreover, compared to fixed dental prostheses, CPDs require less invasive preparation of adjacent teeth and offer long-term maintainability, making them a suitable choice in many clinical scenarios.^[6,7]

The mechanical and esthetic performance of CPDs can be significantly improved with the incorporation of precision attachments. These attachments serve as mechanical connectors between the prosthesis and the supporting tooth, root, or implant, providing retention and resilience while allowing some degree of movement under functional load. Attachments are generally classified into four types: intracoronal, extracoronal, stud, and bar. Intracoronal attachments are housed within the contours of a full-coverage restoration, primarily used for fixed prostheses. In contrast, extracoronal attachments are placed external to the crown’s contour and are especially useful in distal-extension removable prostheses, where they act as stress breakers and enhance support without requiring extensive tooth reduction. Stud attachments, such as Zest anchors or Swiss Logic systems, are commonly used in overdenture designs to improve stability, while bar attachments splint multiple abutments to enhance retention and distribute forces more evenly. Precision attachments offer advantages including better esthetics, biomechanical efficiency, protection of underlying tissues, and the ability to accommodate future prosthetic modifications. However, they are contraindicated in situations with limited clinical crown height, as insufficient vertical space can compromise the seating and function of the components.^[8,9]

The integration of digital dentistry has significantly advanced the fabrication process of CPDs, particularly when precision attachments are involved. The combined use of computer-aided design/computer-aided manufacturing (CAD/CAM) and direct metal laser sintering (DMLS) has enabled clinicians and dental technicians to design and manufacture highly accurate, patient-specific prosthetic components. Using dedicated software such as Exocad, the framework and attachments can be virtually planned with optimal orientation, angulation, and path of insertion. The generated STL files allow for precise layering and sintering of metal alloys during the DMLS process. In the present case, a ball attachment system was used in which the male component was integrated into a metal coping and the female component was incorporated into the CPD framework. This digitally guided approach facilitated a high degree of accuracy, eliminating the discrepancies typically encountered in conventional wax-up and casting techniques and ensuring passive fit, optimal retention, and improved patient comfort.^[10,11]

DMLS-manufactured frameworks exhibit superior mechanical properties, including enhanced tensile strength, fatigue resistance, and corrosion resistance due to their homogenous microstructure. The digital workflow also enables faster fabrication, reduced material waste, and easy reproduction of lost or damaged components. However, certain limitations persist, such as the high cost of equipment, the requirement for trained personnel, and a steeper learning curve associated with software manipulation and machine calibration. Despite these challenges, the use of CAD/CAM and DMLS in fabricating CPDs with extracoronal precision attachments has shown promising results. In clinical practice, such approaches offer excellent functional outcomes, increased patient satisfaction, and improved long-term prognosis, particularly in distal extension cases where conventional clasp-retained dentures may not be appropriate.^[12]

The rehabilitation of partially edentulous arches is greatly improved by the use of CAD/CAM and DMLS technology for the fabrication of extracoronal, precise attachments. Compared to conventional approaches, our methodology guarantees exact fit and functionality, enhances durability, and shortens the fabrication time. Ball attachment design and placement are efficiently supported by the digital process, improving prosthesis stability and patient comfort. Improved results for complex partial denture situations are provided by digital fabrication, which is a valuable tool in modern prosthodontics despite its higher initial costs and requirement for specialized expertise.