Digital Workflow Strategies for All-on-X Immediate Loading: Wash-Impression vs. Fiducial-Marker
by AO Fellow Tirakhsh Emadi, DDS, MS, DABOI/ID, Editorial News Consultant
The All-on-X concept has become one of the most widely adopted surgical and prosthetic approaches for the treatment of terminal dentition and complete edentulism.
Introduction
In the United States alone, recent estimates suggest that more than 36 million people are completely edentulous, and more than 120 million are missing at least one arch of teeth.¹ Worldwide, edentulism remains a major oral health burden, with prevalence rates reported between 7% and 69%, depending on age group and geography.² With an aging population and improved implant survival, demand for full-arch, fixed implant restorations continues to rise.
One of the strongest drivers of patient acceptance is the possibility of same-day teeth. Patients increasingly expect to leave surgery with a functional, esthetic provisional prosthesis, minimizing the psychosocial and functional impact of tooth loss. Immediate loading protocols, enabled by advances in implant surface technology, digital planning and CAD/CAM, have made this a reliable option with high survival rates.³
Within this context, digital workflows have transformed immediate loading. They not only increase efficiency and predictability but also allow integration of intraoral scanning, photogrammetry and virtual design for streamlined prosthesis delivery. Among digital methods, two workflows dominate current practice: (1) the wash-impression digital workflow, which blends analog esthetic registration with digital design, and (2) the fiducial-marker workflow, which captures digital records intraoperatively. Understanding their differences helps clinicians choose the most appropriate pathway for predictable patient outcomes.
The Wash-Impression Digital Workflow
In this workflow, the foundation is prepared before surgery with the fabrication of maxillary and mandibular record dentures. These dentures are designed by the laboratory based on preoperative records, including diagnostic casts, intraoral scans or radiographic information (Fig. 1). Having these record bases available at the time of surgery provides a reliable guide for esthetics and occlusion.
Following implant placement and the connection of multiunit abutments, the maxillary record denture is placed intraorally to establish esthetic references for the upper teeth and to index the position of the multiunit abutments and surrounding soft tissue. A fast-setting polyvinyl siloxane impression material is then used to stabilize and register the correct position (Fig. 2 and 3). This step allows the clinician to directly confirm and adjust the midline, smile line, occlusal plane and other esthetic determinants in the patient’s mouth. Once the upper is verified, the mandibular record denture is positioned to register the vertical dimension of occlusion (VDO) and centric relation. Together, the upper and lower records provide a functional bite registration that reflects both esthetic and occlusal goals.
Next, these relationships are transferred to the digital domain. Using an intraoral scanner, the bite is captured intraorally. Additionally, the intaglio surfaces of both record dentures are scanned extraorally to create a complete digital representation. These files are then uploaded to the design team, who will digitally align and process the data for the prosthesis conversion.
Finally, photogrammetry is performed to capture the three-dimensional implant positions with submicron accuracy. Depending on the clinician’s preference and soft-tissue management, this step can be completed either before suturing — immediately after implant placement and multiunit abutment connection — or after soft-tissue closure. By integrating impression-based esthetic control, intraoral digital scans and photogrammetry, this workflow provides a balance between hands-on verification and precise digital processing.
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The Fiducial-Marker Workflow
Unlike the wash-impression digital method, the fiducial-marker workflow eliminates intraoral impressions altogether and relies exclusively on digital records. The process begins before surgery, when fiducial markers are placed in the patient’s mouth (Fig. 4). These markers serve as reference points for the intraoral scanner and must remain stable throughout the procedure. An initial intraoral scan is performed with the markers in place to establish a baseline dataset (Fig. 5).
Once surgery is initiated, workflow interruptions are required at key steps. After the maxillary arch surgery is completed, photogrammetry is performed. Then the fiducial markers and the implant positions — along with the connected multiunit abutments — are scanned intraorally (Fig. 6). The same process is repeated after the mandibular arch surgery. These scans, combined with photogrammetry of implant positions, are transferred directly to the design team.
Because no wash impression is captured intraorally, this workflow relies heavily on preoperative planning. Esthetic and occlusal information is derived from diagnostic records rather than chairside adjustments. In particular, establishing a highly accurate vertical dimension of occlusion (VDO) during the preoperative phase is critical. Unlike in the wash-impression workflow, adjustments to VDO cannot easily be made once digital records are captured, as even minor digital modifications can potentially disrupt centric relation.
While this approach offers the advantage of efficiency and fully digital processing, it also carries potential challenges. If the fiducial markers become loose, the accuracy of the entire workflow may be compromised. In some cases — especially in the mandible — fiducial markers may physically interfere with implant placement. Furthermore, in edentulous patients or those with highly mobile teeth, the stability of markers can be unreliable, jeopardizing the accuracy of the scans.
In summary, the fiducial-marker workflow is a powerful digital solution for immediate loading, but its success is highly dependent on marker stability, precise preoperative planning and seamless coordination with the digital design team.
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Clinical Pearls
Wash-Impression Workflow
- Provides direct, chairside control over esthetic and occlusal outcomes. Clinicians can verify the midline, smile line, occlusal plane and vertical dimension of occlusion (VDO) in real time, reducing the risk of postoperative adjustments.
- Particularly valuable in cases with complex esthetic demands, uneven ridges or when the patient’s soft-tissue anatomy requires careful intraoperative verification.
- May be preferable when patient-specific nuances, such as lip support or facial profile, need to be confirmed immediately, allowing adjustments before finalizing the digital design.
Fiducial-Marker Workflow
- Optimized for efficiency and streamlined digital prosthesis delivery. Eliminates the need for chairside impressions, making it well-suited for high-volume practices focused mainly on same-day prosthesis workflow.
- Relies heavily on precise preoperative planning and accurate marker placement. Success depends on stable markers, reliable intraoperative scans and smooth coordination with the digital design team.
- Useful for nonsedated patients who cannot tolerate impressions or have gag reflex issues.
Hybrid Strategy
- In complex or high-stakes esthetic cases, consider combining both approaches: using the wash-impression technique on the maxillary arch and the fiducial-marker method on the mandibular arch.
- This approach balances efficiency with esthetic security, providing a “best of both worlds” workflow for immediate-loading full-arch cases.
