Edentulism is a significant global health issue affecting over 350 million people. Tooth replacement with complete dentures can help mitigate the negative health and social impacts of edentulism. To meet this ongoing demand, efficient complete denture workflows are needed in dental education and practice. Advances in materials and technologies can improve predictability and reduce treatment time. Today, clinicians have the opportunity to combine digital and conventional workflows to find the best solutions for patients seeking removable complete and implant overdentures.
Key points
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Edentulism is a significant global health burden, making removable complete dentures a key treatment option for clinicians.
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The evolution of digitally fabricated complete dentures streamlines workflows, enhancing accessibility for patients and practicality for clinicians.
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Contemporary materials for removable complete and implant overdentures offer improved physical properties, enhancing treatment outcomes.
Introduction
Globally, oral diseases rank as some of the most prevalent conditions—regardless of national income. The World Health Organization includes edentulism in its list of 5 oral diseases with the greatest disease burden. Severe tooth loss is defined as having fewer than 10 natural teeth, including complete edentulism, and is correlated with several negative health effects. , As one loses teeth, the ability to masticate decreases, often impacting dietary choices. Unfortunately, this often means fewer vitamin-rich foods. , As a result, patients with edentulism often suffer from malnutrition or obesity. , There are also numerous chronic conditions associated with edentulism, including diabetes, arthritis, cardiovascular diseases (including myocardial infarction), respiratory diseases (including chronic obstructive pulmonary disease and pneumonia), cognitive disorders, and cancer. , Additionally, severe tooth loss is also implicated in an increase of all-cause mortality. ,
When persons with edentulism utilize complete dentures to function, a varied diet is more likely. Interestingly, Dai and colleagues reported a lower risk of mortality associated with cardiovascular diseases, respiratory diseases, and mortality related to other causes for those utilizing complete dentures when compared to those with no protheses. This is similar to conclusions reported in a 2016 review, which concluded that complete denture wearers are less likely to suffer from malnutrition than those without prostheses, and well-fitting dentures may decrease the risk of some comorbidities.
Prevalence of Edentulism
There are currently over 350 million patients with edentulism worldwide, affecting slightly less than 7% of the global population. Interestingly, the most recent report of the World Health Organization for Healthy People 2023 reported the lowest prevalence of edentulism for low-income countries (3%), with the highest prevalence rates of edentulism for high-income countries (10.3%). Despite evidence of the decreasing prevalence of edentulism over the last several decades, , , the United States ranks third globally with a prevalence rate of 7.1%. Additionally, the decrease in edentulism rates was not equal among all groups. According to Centers for Disease Control data, the number of teeth retained by American adults increased, except for the consideration of several socioeconomic factors (including age, race, poverty level, education level, and smoking status). Although the prevalence of complete edentulism may be declining, it continues to be a significant concern, underscoring the ongoing need for complete denture treatment.
Treatment Options for the Patient with Edentulism
With increased access to information, it is not uncommon for patients who are edentulous or with a terminal dentition to request implant-supported, fixed, complete arch prostheses rather than removable complete dentures. These prostheses can serve as an excellent option for many patients; they have a sound evidence base with several decades of literature support, starting with the research of PI Branemark’s group in the 1960s and 1970s. While this treatment option may be life changing, it is not ideal for every patient. Though the literature has sought to compare patient outcomes between implant-supported fixed and implant-assisted removable restorations, inconsistent methods of measurement make it a challenge to directly compare. Much of the literature shows a slight patient preference for fixed solutions when compared to removable implant overdentures, though not necessarily enough to be conclusive. , A recent literature review on this subject found that while patients tend to favor fixed restorations, removable implant overdentures are no less efficient in their function.
Discussion
For some, a removable prosthesis, with or without implant support, maybe a better treatment option for many reasons; these include the patient’s capacity for oral hygiene, tissue health, systemic health, anatomy, finances, and personal preference. , , Furthermore, patients with excessive resorption in the premaxillary region often rely on soft tissue support from the buccal flange of a removable prosthesis for esthetics and function. There is not currently an implant-supported fixed prosthetic solution that can restore tissue support for this group of patients while still allowing adequate access for cleaning at the implant interface. Despite the advances in osseointegration and the growth of implant dentistry, however, complete dentures are still the treatment of choice for many patients with edentulism.
Removable complete dentures
Complete dentures have been a restorative solution for many centuries, and historically, they have been fabricated from any number of materials, including bone, ivory, and vulcanized rubber. In 1937, compression molded, heat-polymerized polymethyl methacrylate (PMMA) was first used as a denture base resin, attributed to Dr Walter Wright. , Within a few years, this technique and material was widely adopted, accounting for most of the denture base fabrication for the next several decades. The dimensional changes of compression molded, heat-polymerized PMMA have been documented, as well as the impact this can have on denture base adaptation. To overcome some of these effects, injection molding for denture base fabrication was developed in the 1940s and commercially introduced in the 1970s (Ivobase, Ivoclar – Amhurst, NY). , Denture bases fabricated using this method have been shown to have improved properties (particularly occlusion and dimensional stability) when compared to conventional compression molded dentures. , , The investment in the equipment necessary for injection molding often precludes its use, likely contributing to the staying power of compression molding techniques. Many other forms of conventional denture bases are available, including autopolymerizing (cold-cure), microwave-polymerized, and light-polymerized.
The conventional complete denture workflow has been outlined in many textbooks over the last several decades and has remained relatively unchanged ( Fig. 1 ). Though some variation exists within the impression materials used or the philosophies of tray design, the 5 appointment workflow remains consistent throughout dental school curricula in the United States and abroad. Considering students are novice learners, complete denture appointments within dental schools are typically longer in duration than private practice, and it is not uncommon to extend treatment even beyond the outlined 5 appointments.
In the mid to late 2000s, there seemed to be a call to action for complete denture education and practice. The need for complete denture services had not decreased, but they were receiving less “journal space” and decreased curriculum time. To overcome this, several authors have cited a need for efficient, lower cost solutions that could be incorporated into the predoctoral curriculum. , Perhaps digitally fabricated complete dentures (DFCDs) can be the response to that call.
Digitally fabricated complete dentures
Digitally fabricated complete dentures (DFCD) were first introduced in dental literature in the 1990s and became commercially available to clinicians in 2012. At that time, there were only 2 workflows available (namely the original Dentca workflow and the Avadent anatomic measurement device (AMD) workflow; Fig. 2 A–D), and they were extremely specific about the clinical techniques used for impressions and interocclusal records. Additionally, clinicians were limited to a single dental laboratory for each workflow; these considerations made it a challenge to incorporate them into daily practice. These workflows both, however, afforded 2 appointment workflows for complete dentures—a notable decrease from the standard 5 appointment workflow. Over the last decade, digital workflows have evolved from these 2 original treatment options. Due to advances in hardware and software, there are now many options for clinicians to consider when fabricating digital dentures. , Though there is no classification system at this time, DFCDs can be organized by the workflow utilized or the material(s) with which the prosthesis is fabricated.
Digitally fabricated complete denture workflows
Aside from the standard conventional workflow, complete denture workflows can be either completely digital or a hybrid of digital and conventional steps ( Table 1 ). All of the workflows include 3 clinical steps ( Fig. 3 ).
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Impressions (digital or conventional)
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Interocclusal record/clinical try-in
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Insertion of digitally fabricated prosthesis
| Number of Appointments | Commercial System/Workflow | Appointment Summary |
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| Five appointments |
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| Four appointments | Record Base Protocol using monolithic try-ins by nonproprietary systems, Ceramill FDS or Bouma try-in (BTI) by Avadent Digital Denture, Global Dental Science LLC (Scottsdale, AZ) |
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| Three appointments | Ivoclar Digital Denture, Ivoclar Vivadent AG (Amherst, NY) a |
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| Wagner Try-in (WTI) Protocol by Avadent Digital Denture, Global Dental Science LLC |
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| Reference Denture Protocols by Nonproprietary systems and Avadent Digital Denture, Global Dental Science LLC |
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| Two appointments | Baltic Denture System, Merz Dental GmbH (Lütjenburg, Germany) a |
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| Dentca CAD/CAM Denture, Dentca Inc (Torrance, CA) a |
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a An optional monolithic try-in will add an additional appointment to the workflow.
Impressions
Even today, most DFCD workflows start with a conventional impression. The impressions are digitized with an intraoral or extraoral scanner to enter the computer-aided design (CAD) phase. This was confirmed by a recent systematic review, finding that very few published workflows start with an intraoral scan. As hardware and software for intraoral scanners has improved, however, clinicians are beginning to adopt intraoral scanning as a starting point for complete dentures. Even the workflows that start with a scan of the ridge are typically followed up by an impression, often using a printed custom tray, record base, or monolithic try-in. The literature is unclear at this time as to whether an intraoral scan of the edentulous arch is equivalent to a conventional impression. One study indicates that a border molded definitive impression may result in improved denture retention when compared to an intraoral scan of the edentulous arch. One must consider that an intraoral scan will result in a mucostatic impression, while a conventional impression will compress the tissue (mucocompressive). The difference in tissue displacement makes it challenging to compare the techniques directly, but the technology seems to provide a clinically acceptable solution that is becoming more predictable to attain. , ,
Interocclusal Record/Clinical Try-in
Whether digital or conventional, an interocclusal record must be made to interrelate the maxillary and mandibular casts. This establishes the horizontal and vertical maxillomandibular relationship. This step is often combined with the impression or clinical try-in ( Table 2 ) or may be completed with a conventional wax occlusion rim ( Fig. 4 ). The interocclusal record is typically recorded conventionally with wax or other registration material, but digital techniques are beginning to emerge. These include incorporating a facial scan of the soft tissue to establish vertical dimension and soft tissue support. ,
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Based on fabrication technique, there are 3 types of clinical trial dentures that are commonly utilized ( Table 3 ).
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Conventional wax tooth arrangement : This classic technique includes carded, manufactured denture teeth arranged in wax, allowing the clinician to do a complete tooth try-in with the ability to move each tooth ( Fig. 5 A).
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Wagner try-in : This hybrid trial denture incorporates a milled or printed replica of the definitive denture base, with computer-aided manufacturing (CAM) fabricated anterior teeth arranged in wax and posterior wax rims. This allows the clinician to control anterior tooth position and establish interocclusal records conventionally utilizing the posterior wax occlusion rim. This can also condense the workflow by combining the interocclusal records and clinical tooth try-in ( Fig. 5 B).
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Monolithic trial denture : This digital trial denture is designed in any denture design software, and subsequently printed or milled. As it is all 1 unit, the clinician cannot individually move the teeth chairside; they may be otherwise modified with a handpiece, composite, or wax to communicate desired changes ( Fig. 5 C).
| Trial Denture | Considerations |
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| Conventional wax |
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| WTI |
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| Monolithic |
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