3D-printed screw-retained single crown

Dr Antonino Cacioppo

Tue. 8. July 2025

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The digital revolution in dentistry has introduced increasingly efficient and predictable workflows, enabling clinicians to drastically reduce treatment times while maintaining high standards of precision and functionality. In particular, the combination of guided surgery and chairside prosthetic manufacturing technologies is reshaping the approach to single-tooth implant restorations.

3D-printing technologies (additive methods) are now emerging as viable alternatives to subtractive methods (e.g. milling), particularly in scenarios where time efficiency and in-office production are critical. Resin-based additive manufacturing systems such as the Dfab tilting stereolithography (TSLA) laser printer with Photoshade technology enable clinicians to produce aesthetic and functional restorations directly in the dental office with unprecedented speed and accuracy.

Screw-retained implant restorations are a widely accepted option owing to their retrievability, lack of cement-related complications and simplified maintenance. Their use in single-tooth cases, when combined with a fully digital workflow, offers the potential for same-day prosthesis delivery, improving patient comfort and reducing the number of clinical appointments.

This report presents the case of a patient with a single edentulous site in the mandibular posterior region. A fully digital chairside workflow was employed, including prosthetically guided planning, guided implant placement and immediate fabrication of a screw-retained crown using a 3D-printing resin. The definitive prosthesis was delivered in a single visit.

Fig. 1: Radiograph of the single edentulous site in the region of tooth #36 requiring restoration.

Case report

Patient assessment and initial situation
A 62-year-old female patient presented with a single edentulous site in the mandibular left first molar region (tooth #36; Fig. 1). The missing tooth had been extracted six months previously owing to a vertical root fracture. The patient was in good general health and expressed a desire for rapid and minimally invasive implant-supported rehabilitation. Clinical and radiographic evaluation confirmed sufficient bone volume and soft tissue to allow placement of a standard diameter implant without requiring regenerative procedures.

Digital planning and preoperative prosthesis fabrication
A digital workflow was started with the acquisition of intra-oral scans of the maxillary and mandibular arches using the ViSIOScan WL wireless scanner (Cefla; Fig. 2). The STL files were aligned with the CBCT data in RealGUIDE software (3DIEMME), which allowed prosthetically guided planning of the implant position (Fig. 3).

Based on the virtual implant position, a screw-retained crown was fully designed and fabricated prior to surgery without the need for an intra-oral scan after implant placement. The aim was to transfer the prosthetic plan to the surgical phase by ensuring perfect congruence between the digitally planned and clinically executed implant positions.

Fig. 2: Intra-oral scan of the mandibular arch.

Fig. 3: RealGUIDE software showing the alignment of the STL files with the CBCT data for prosthetically guided planning of the implant position.

The crown was designed using digital prosthetic libraries (IPD Dental Group) to ensure compatibility with both the Oxy Implant PSK implant system (Biomec) and the selected titanium base (Ti-base). The emergence profile, occlusal morphology and screw access hole were designed to fit precisely on the Ti-base, assuming strict adherence to guided placement (Fig. 4).

The final design was then printed in-house using the Dfab TSLA printer with Photoshade technology (RD-Printing; Fig. 5), which allowed for high-resolution reproduction with aesthetic colour gradation. The printing time was 22 minutes, and post-processing included ultraviolet (UV) and heat photopolymerisation, finishing and cementation to the Ti-base.

Guided surgery and prosthesis delivery
A stereolithographic surgical guide generated from the RealGUIDE planning was used to perform fully guided implant placement under local anaesthesia. A PSK implant was inserted at the site of tooth #36 to a final torque of 50 N cm, confirming sufficient primary stability for immediate restoration.

A straight Ti-base was placed according to the angulation designed in the prosthetic plan. The prefabricated screw-retained crown was seated immediately after implant placement without the need for modification or intra-oral scanning. Clinical verification confirmed excellent marginal adaptation and passive fit, both visually and radiographically. Minimal occlusal adjustment was required, and the crown was permanently screwed in place. The screw access hole was sealed with PTFE and composite resin. The patient was discharged with full function and aesthetics restored in the same session.

Fig. 4: 3D CAD in STL format.

Fig. 5: Dfab desktop TSLA laser 3D printer.

Prosthetic workflow

A unique aspect of this clinical protocol is the absence of a postoperative intra-oral scan for prosthetic purposes. Instead, the prosthesis was designed and fabricated prior to implant placement based on the virtual implant position generated during the planning phase in the RealGUIDE software. This approach requires meticulous attention to detail in both the surgical and prosthetic phases to minimise potential deviations between the virtual and actual implant positions.

Virtual implant planning and preoperative design of the prosthesis
The virtual implant position, aligned according to the prosthetic requirements, served as the definitive reference for the design of the definitive screw-retained crown. This concept of preoperative transfer of the prosthetic plan relies on a high degree of accuracy in surgical execution, supported by a fully guided protocol.

CAD of the crown was performed using the IPD digital library, which offers extensive compatibility with various implant systems and Ti-base geometries. The crown was designed to sit on a Ti-base compatible with the Oxy Implant PSK system and with a screw access hole aligned and sized for retrievability. The emergence profile and occlusal morphology were designed with special attention to the spatial tolerance of the Ti-base interface and insertion axis to ensure passive fit of the prefabricated restoration.

Fig. 6: Irix Max Photoshade Dfab cartridge.

Printing and post-processing
Once the design was complete, the file was sent to the Dfab printer for fabrication of the high-strength hybrid polymer crown. The chosen hybrid composite, Irix Max (DWS Systems; Fig. 6), is a biocompatible material for definitive restorations and has been validated for intra-oral applications. Direct printing assured:

high accuracy without the need for retouching;
a smooth surface and defined details; and
a natural colour gradient owing to resin layering enabled by Photoshade technology.

The accuracy of 3D printing compared with conventional techniques is supported by clinical studies, which have demonstrated high reproducibility and prosthetic fit. Dfab employs TSLA technology, designed for chairside manufacture, and works with disposable cartridges, available in small, medium, and large according to the volume of material contained, allowing the workflow to be optimised according to the number and size of restorations to be printed. An evolution of stereolithography, TSLA uses an inclined build platform and a moving high-viscosity material to create a cascade effect that allows heavy fillers to be mixed evenly during printing. This technology increases printing speed and allows the size of the supporting structures to be reduced.

The process begins by loading the CAD restoration as an STL file into the Photoshade software, which automatically positions and correctly supports it for the best accuracy and fit with the occlusal surface facing the platform and the marginal and internal surfaces free of supports and facing the cartridge reservoir. The desired Photoshade colour gradient and positioning of the cervical and incisal colour boundaries are then selected, the width of the interspace resulting in a sharp (narrow) or gradual (wider) transition (Fig. 7).

Fig. 7a–c: Selecting the shade and the colour gradient in the Photoshade software.

Fig. 7b

Fig. 7c

Once the appearance of the restoration has been approved, the printing process can begin. A Dfab cartridge of the selected material and size, incorporating the resin tub, is loaded into the top of Dfab, along with the printing block and disposable platform. The top of the printer is closed, tilting the cartridge at a 45° angle. Printing is initiated by the Nauta Photoshade Pro software, and a continuous flow of material is begun and maintained by gravity and a quiet peristaltic pump (Fig. 8).

At this stage, the software precisely controls the extrusion of material in two different shades to produce the desired colour gradient of the restoration. The blue UV laser beam is directed at the surface of the composite, selectively polymerising it to create the restoration. The build platform is gradually lowered into the resin tub, and the process is repeated layer by layer until the object is complete. The printer is then opened and the top section tilted to return the build platform and used cartridge to their original horizontal position, and they are removed, starting with the platform, to prevent unpolymerised liquid material from dripping into the printer.

After printing, the crown underwent standardised post-processing procedures. It was cleaned with 95% ethanol to remove all liquid composite from the restoration surfaces and maintain the high trueness of the TSLA printing process. This is accomplished by immersing the printing base and platform in a shaker containing 95% ethanol for 1–2 minutes, followed by scrubbing of all surfaces with a flat brush (Fig. 9). The supports were then removed, a simple manual procedure achieved by grasping the platform with one hand and the restoration with the other and twisting to safely separate the prosthesis without damage thanks to the patented easy break support configuration. Any unpolymerised composite residue in areas such as the occlusal and internal surfaces can now be removed with a flat brush dipped in 95% ethanol. Once dry, the restoration should appear opaque. Any shiny areas would indicate the presence of liquid composite residue that must be removed. Final post-polymerisation was then performed in the proprietary dual-energy (UV light and heat) unit (Dcure, RD-Printing; Fig. 10) with an automated, material-specific cycle that takes approximately 9 minutes to complete. This step is essential to obtain the best conversion rate for the material used and the best mechanical properties. Manual finishing and polishing of the margins were performed using a simplified and effective two-step sequential procedure with diamond-impregnated polishers of decreasing grit (Diacomp, EVE) performed at low speed (3,000–8,000 rpm). The crown was then cemented to the Ti-base using a dual-polymerising resin cement according to the manufacturer’s protocol (Figs. 11 & 12).

Fig. 8: Video graphics still image of a phase of the Dfab printing process.

Fig. 9: Dfab-printed crown, still on the platform, after washing with 95% ethanol and drying.

Fig. 10: Dcure post-polymerisation unit.

Fig. 11 & 12: Finished crown cemented to the Ti-base with a dual-polymerising resin cement.

Fig. 12

Try-in and delivery of the definitive prosthesis

After implant placement and connection of the Ti-base, the prefabricated crown was directly seated without adjustment. The passive fit was verified clinically and radiographically. Occlusal contacts were evaluated and required minimal to no adjustment, confirming the accuracy of the virtual workflow.

The prosthesis was permanently screwed into place using a calibrated torque wrench, and the screw access hole was sealed with PTFE tape and composite resin (Figs. 13 & 14). After a radiographic check of the treated area (Fig. 15), the patient was discharged with full function restored in a single session and reported high satisfaction with comfort and aesthetics.

Fig. 13: Crown permanently screwed in place using a calibrated torque wrench.

Fig. 14: Screw access hole sealed with PTFE tape and composite resin.

Fig. 15: Radiographic evaluation of the restoration in place.

Discussion

The integration of guided implant surgery with chairside additive manufacturing represents a significant evolution in digital implantology, enabling clinicians to deliver definitive restorations in a single clinical session. This case illustrates the feasibility of using a prefabricated, screw-retained crown designed on a virtual implant site and printed directly in the dental office for immediate delivery after implant placement.

The decision to forgo a postoperative intra-oral scan introduces a conceptual shift towards prosthetically driven backward planning, in which the accuracy of surgical execution is the key to the clinical success of a prefabricated prosthesis. In this scenario, the use of a high-precision guided system (RealGUIDE) and validated implant components (Oxy Implant PSK implant system and IPD Ti-base libraries) was essential to reduce positional deviations that could have compromised the passive fit.

Several aspects deserve critical consideration:

Accuracy and fit: The congruence between the virtually planned implant position and the actual clinical outcome was sufficient to allow precise seating of the prefabricated crown without occlusal or marginal discrepancies. This confirms the potential of guided surgery to achieve submillimetre precision when properly executed.
Material and printing performance: The Photoshade technology used in the Dfab system enabled high-quality aesthetic reproduction with realistic colour transitions. The 22-minute total printing time is significantly faster than the fabrication time of milling or laboratory-based 3D-printing solutions, making it ideal for immediate chairside applications.
Workflow simplification: Eliminating the postoperative impression phase reduces the number of clinical steps, potential contamination and patient discomfort while reducing chair time. This aligns with the principles of modern digital dentistry, in which minimal invasiveness and workflow efficiency are increasingly prioritised.
Limitations and risks: Despite its success, this approach is sensitive to deviations between virtual and actual implant positions. Even small inaccuracies can lead to misfit, occlusal interference or screw access hole misalignment. Therefore, strict adherence to the guided protocol and the use of high-quality components are essential. In addition, long-term data on the mechanical behaviour and wear resistance of chairside-printed materials for definitive restorations remains limited, and these areas require further investigation.
Clinical relevance: This case illustrates how digital workflows can be integrated for same-day delivery, improving the patient experience while maintaining precision. The strategy is particularly valuable in restoring single edentulous sites in non-aesthetically critical areas where implant stability is high and occlusal loading is moderate.

Conclusion

This clinical report demonstrates that the integration of guided implant surgery with high-speed chairside 3D printing enables the delivery of a definitive screw-retained crown in a single visit with high precision and patient satisfaction. Strategic use of the virtual implant position, combined with accurate planning and surgical execution, allowed the prefabrication of a definitive restoration that required no postoperative adjustment.

A key element of this workflow was the use of the Dfab TSLA printer with Photoshade technology, which provided aesthetic, functional and structurally stable results in just 22 minutes of fabrication time. This rapid printing capability transforms the traditional implant placement to restoration timeline, allowing clinicians to meet increasing patient demands for immediate, high-quality treatment solutions without compromising control or accuracy.

The success of this case confirms that chairside additive manufacturing is not only feasible but also highly effective when integrated into a rigorously planned digital workflow. As 3D-printing technologies and materials continue to evolve, their application to single-visit implant restorations is expected to become more widespread, bringing new standards of speed, personalisation and efficiency to modern dental practices.

Editorial note:

This article was published in CAD/CAM—international magazine of dental laboratories Vol. 16, Issue 1/2025.