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rev port estomatol med dent cir maxilofac . 2024;65(2):85-93 87

In the early stages of CAD/CAM application in Prosthodon-
tics, laboratory scanners were used to digitize gypsum cast
before the milling and manufacturing of the denture. In the
last two decades, many commercially available intraoral scan-
ners have been developed, and both in-vivo and in-vitro stud-
ies have examined their accuracy and precision compared to
12
conventional impressions. The accuracy of intraoral scanners
in recording clear anatomic landmarks, like hard tissues with
attached mucosa, was considered comparable to convention-
al edentulous arch impressions. However, higher discrepancies
were noted when digitizing mobile tissues, like the peripheral
13
border and the soft palate. Despite this limitation, total dig-
ital workflow protocols for constructing dentures have been
described for several years. 14
This article describes a clinical and laboratory alternative
protocol used at the University of Lisbon for manufacturing
complete CAD/CAM removable dentures. The aim of this work Figure 1. Frontal view of the edentulous patient
is to understand whether CAD/CAM technology can be an add- showing visible perioral alterations.
ed value to denture fabrication, considering the times and
costs involved in the case.

Case Report

A fully edentulous 90-year-old male patient (Figures 1 and 2)
attended the Department of Removable Prosthodontics of the
Faculty of Dental Medicine of the University of Lisbon. His
teeth had been extracted 30 years earlier due to caries, and he
had been using a complete removable denture since then. Sys-
temic pathologies were not reported, and clinical examination
revealed a highly reabsorbed residual ridge without other
changes in the mucosa. All possible rehabilitation treatments
were explained, and due to financial constraints, the patient
agreed to new dentures. Five appointments were planned with
the following respective goals: preliminary impressions, defin-
itive impressions, jaw relation record, teeth try-in, and inser-
tion. Post-insertion denture adjustment appointments would
be scheduled as needed. Figure 2. Profile view of the patient.
Preliminary impressions were made with irreversible hy-
drocolloid (Hydrogum 5, Zhermack, Italy) and stock impression
trays (Doric Master Trays, Schottlander, UK). Then, gypsum type
III (Pro-Solid Super, Pro-Dental, Germany) was poured to obtain
the preliminary casts. The preliminary casts were scanned (S
600, Zirkonzahn, Italy), and the custom trays were designed
(Zirkonzahn.Tray, Zirkonzahn, Italy) and 3D printed (NextDent
5100, 3D SYSTEMS, The Netherlands) with light-polymerizing
PMMA resin (NextDent Tray, 3D SYSTEMS, The Netherlands)
(Figure 3). The clinician did the border molding with impression
compound (Kerr, SpofaDental, Czech Republic) and the final
impression with zinc-oxide eugenol paste (Cavex outline,
Cavex, The Netherlands). After boxing the impressions, the
master casts were obtained in gypsum type III (Pro-Solid Super,
Pro-Dental, Germany) and digitalized (S600, Zirkonzahn, Italy).
The palatal sealing was done in the cast before the definitive
cast scanning. Afterward, baseplates were designed (Zirkon-
zahn.Tray, Zirkonzahn, Italy) (Figure 4) and 3D printed (Next-
Dent 5100, 3D SYSTEMS, The Netherlands) with light-polymer-
izing PMMA resin (NextDent Tray, 3D SYSTEMS, The Netherlands), Figure 3. CAD of custom trays.
and the wax occlusion rims were made with pink wax.