volume 37  |  No. 2  |  2026

Considerations for the Prosthetic Restoration of Fully Edentulous Patients With Severe Atrophy: Prosthesis Type, Material Selection and Digital Workflows

These decisions become more complex in the presence of increased atrophy, where vertical and horizontal deficiencies amplify biomechanical demands, prosthetic space, and leverage forces. Proper sequencing of prosthetic planning, material selection, and digital workflow verification is therefore essential.

Fixed vs. Removable Prostheses in Severe Atrophy
Severe atrophy is often assumed to necessitate a removable prosthesis to provide lip support through a flange, particularly in the maxilla.¹ If this were universally true, fixed restorations would be contraindicated in advanced atrophy. However, clinical comparisons of flange versus flangeless prostheses demonstrate that differences in lip support may be clinically insignificant when prosthetic teeth are properly positioned.²³⁴⁵  Adequate lip support may be achieved with fixed restorations provided tooth position, occlusal plane, and prosthetic contours, among other parameters, are appropriately designed. Therefore, ridge morphology alone should not dictate prosthesis type. Proper prosthetic planning following a detailed individual examination must guide treatment decisions.

Maintenance considerations, however, remain critical. Posterior atrophy combined with anterior resorption may limit implant distribution and increase prosthetic volume, potentially complicating access for hygiene. Fixed prostheses in severely atrophic patients may present unique hygiene challenges, particularly when substantial vertical and horizontal restorative space is required. Appropriate patient education in prosthesis maintenance, combined with enrollment in a structured professional hygiene recall protocol, is essential for long-term success.⁶

Material Selection and Biomechanical Implications of Severe Atrophy
Severe atrophy increases vertical prosthetic height, which enlarges the occlusal-to-implant platform distance and significantly elevates bending moments and tipping forces. Long spans and cantilevers, often unavoidable due to reduced bone volume and limited implant distribution, further increase tensile stresses across the prosthesis. Larger prostheses also increase overall weight and mechanical demand. In this environment of amplified leverage, material behavior under tensile stress and bending becomes critically important.

Monolithic Zirconia
Monolithic zirconia is widely used because of its high flexural strength and favorable esthetics. However, higher MPa values do not necessarily equate to safer frameworks in full-arch biomechanics. Zirconia performs well under compression but is less forgiving under tensile stress and bending.

Clinical evaluations of more than 100 full-arch zirconia prostheses followed for approximately six years reported only two catastrophic fractures.7 Importantly, those failures occurred despite connector dimensions exceeding the recommended minimums for monolithic zirconia. This suggests that zirconia, while strong, may demonstrate some unpredictability in catastrophic failure.

In severely atrophic cases, the increased leverage from vertical restorative space, long spans, and cantilevers amplifies tensile stress within the framework. When catastrophic fracture occurs, repair is not feasible, and complete prosthesis replacement is required. Therefore, zirconia’s brittle failure mode remains a concern in high-leverage situations.

Titanium–Zirconia Prosthetic Systems
Titanium–zirconia systems combine a milled titanium framework with a zirconia overlay cemented with resin cement, integrating titanium’s ductility and fatigue resistance with zirconia’s esthetics.8

Compared with monolithic zirconia, titanium–zirconia systems offer several biomechanical and clinical advantages. These systems are repairable, as fractured zirconia overlays can be remilled and recemented without replacing the entire prosthesis while titanium’s capacity for elastic deformation may reduce, to a degree, the risk of catastrophic failure under functional load. They are also approximately 15% lighter than comparable monolithic zirconia prostheses, as titanium is less dense than zirconia.9 Cantilever tolerance is enhanced because connectors are engineered in titanium, and titanium cylinders are eliminated altogether.

When severe atrophy necessitates substantial vertical restorative space, tipping forces increase significantly. A titanium framework that splints implants may distribute stress more effectively, acting as a stress-absorbing substructure and reducing tensile concentration within the ceramic component. This may be particularly advantageous in cases with long spans or limited implant distribution.

Workflow Accuracy and Verification
Passive fit remains critical in full-arch implant restorations. Although fully digital workflows are increasingly promoted, evidence regarding the accuracy of complete-arch intraoral scanning without verification remains mixed.10 Verification jigs or milled try-ins are used because unverified full-arch scans may not consistently produce passive frameworks.11 In most conventional protocols, the basic sequence therefore remains: scan, verify (through a physical jig), deliver.

In this author’s view, any workflow that incorporates a physical verification jig or analog confirmation step should be classified as “hybrid” rather than fully digital. The elimination of the verification jig must occur in conjunction with explicit laboratory agreement, whereby the laboratory assumes responsibility for achieving passive fit.

Alternative methods have been proposed to improve full-arch scanning accuracy, including reverse, splinted scan bodies and photogrammetry. For the first two, rigid verification remains necessary.12,13 The literature regarding photogrammetry is more conflicting: a recent meta-analysis by Pozzi et al.14 recommends rigid verification when photogrammetry is used, whereas other publications suggest that this step may be unnecessary.11 This inconsistency complicates clinical decision-making. Horizontal scan bodies have been proposed as an additional approach to improve full-arch scanning accuracy,11 and at least one commercially available system claims to obviate the need for a physical verification jig.15,16

If an alternative workflow increases accuracy but not to a level that allows elimination of verification jigs, its clinical advantage becomes questionable. In the absence of laboratory-guaranteed passive fit without verification, investing additional time and/or expense in more complex workflows may not be justified. Under such circumstances, the traditional “scan, verify, deliver” protocol remains a logical and economically efficient solution.

Conclusion
Prosthesis selection in fully edentulous implant rehabilitation must be individualized. Fixed restorations are feasible in severely atrophic cases when prosthetic factors such as lip support and tooth position, as well as maintenance considerations, are carefully addressed. However, severe atrophy increases leverage, tipping forces, and structural demands, making material selection critical.

Although monolithic zirconia is a reliable and esthetic option, its brittle behavior and limited repairability require careful case selection in high-demand situations. Titanium– zirconia prosthetic systems provide improved stress distribution, reduced catastrophic risk, lighter weight, and repairability, offering biomechanical advantages in cases involving large vertical and horizontal restorative space with long spans or cantilevers.

Workflow selection should follow the same biomechanical logic. A protocol can only be considered fully digital if physical verification is eliminated. If verification remains necessary, more complex or expensive workflows may offer limited practical advantage. In such cases, the “scan, verify, deliver” protocol with traditional jigs likely represents the most rational and cost-effective strategy.

References for this article are available here.