Aspecte practice în confecționarea protezelor totale (Partea a II-a)

Introduction

As mentioned in the first part of this article, in recent years the field of dental prosthetics has undergone a significant transformation through the integration of modern technologies into the design and manufacturing processes. Traditionally, complete dentures were fabricated through time-consuming procedures, largely dependent on the manual intervention of the dental technician. Today, due to the rapid evolution of digital technologies, methods such as computer-aided design and computer-aided manufacturing (CAD/CAM), including both additive and subtractive techniques, are increasingly used. These methods contribute to the fabrication of more precise prostheses with superior esthetics; however, they are often less comfortable for patients compared to dentures manufactured using conventional technologies^(1-4).

Dental prosthetic rehabilitation represents one of the most important directions of modern dentistry, aiming at the functional and esthetic restoration of the dento-maxillary system (DMS). In this context, complete dentures constitute an essential therapeutic solution for patients suffering from total edentulism, a condition characterized by the complete loss of teeth from one or both dental arches^(1-4).

At present, because of the continuous increase in the number of totally edentulous patients, especially among the elderly population, there is an urgent need for efficient, accessible and durable prosthetic solutions. Thus, in this two-part article, we aimed to perform a comparative analysis between conventional and modern methods of complete denture fabrication, highlighting the advantages of each therapeutic approach. Specifically, the objective of this study is to improve the understanding of how technology contributes to enhancing patient quality of life, while also increasing the efficiency of both the dentist’s and the dental technician’s work.

Technological aspects in the manufacturing of complete dentures

Case 2: Manufacturing a complete denture using the digital method (printed base with bonded prefabricated artificial teeth)

A 65-year-old female patient presented to the dental clinic for prosthetic rehabilitation of complete maxillary edentulism. Following clinical examination and anamnesis, the diagnosis of complete bimaxillary edentulism was established. As the patient was already a wearer of complete dentures, she requested only maxillary complete denture for aesthetic reasons. In agreement with the patient, the dentist decided that this denture would be fabricated using a modern digital workflow, involving digital design and 3D printing, to achieve superior esthetic results. Together with the patient, the shape and shade of the artificial teeth were discussed, and a printed complete denture made from photopolymerizable polymers, with integrated artificial teeth in shade A3, was selected.

It should also be noted that, in this case, a combination of conventional impression techniques and digital scanning of the preliminary model made of dental stone was used. Specifically, the dentist obtained a preliminary impression using a standard impression tray and an irreversible hydrocolloid material. Subsequently, in the dental laboratory, the preliminary model was poured with type III dental stone and scanned using a laboratory dental scanner. Based on this scan, the custom impression tray was digitally designed and physically obtained by 3D printing (Figure 1).

Using the printed custom tray, the dentist has taken the functional impression to capture all relevant details of the prosthetic field. The functional impression was poured in the dental laboratory by the dental technician, resulting in working model made of type IV dental stone, which was subsequently scanned using the same laboratory scanner. The mandibular antagonist arch model was fabricated from type III dental stone, and it was also scanned (Figure 2).

Next, the maxillary occlusion rim was digitally designed on the virtual working model and subsequently 3D printed. Determination and registration of the intermaxillary occlusal relationships were performed conventionally by the dentist in the dental office. Afterwards, the assembly consisting of the models and occlusion rims was scanned using the same laboratory scanner. The scanned assembly was then mounted in a virtual articulator.

On the working model the virtual framework was designed, taking into account the tooth library available in the design software, with the dentist being able to verify and correct the design of the virtual denture (Figure 3).

In this case, the preliminary virtual framework was printed as a single piece to obtain a “try-in” denture, with the purpose of verifying both the intermaxillary occlusal relationships and the adaptation of the denture base to the prosthetic field.

Following intraoral examination of the printed try-in denture, minor design corrections were made. The margins of the denture were adjusted and the virtual image was prepared to print (Figure 4).

Case 3: Manufacturing of complete dentures by mold polymerization (compression molding and heat polymerization)

A 72-year-old female patient presented to the dental clinic for comprehensive prosthetic treatment. Clinical examination revealed complete bimaxillary edentulism (maxillary and mandibular). By mutual agreement, the dentist and the patient opted for the fabrication of two complete dentures made of acrylic resin, with acrylic artificial teeth in shade A2, morphologically and functionally adapted to the prosthetic fields. The two acrylic complete dentures were fabricated using the conventional method, which is currently the most commonly employed technique in dental laboratories in Romania.

The main clinical and technical stages of manufacturing using the conventional method are briefly presented below:

• Obtaining preliminary maxillary and mandibular impressions using standard trays and condensation silicone impression materials (putty and light-body) – clinical stage.
• Manufacturing preliminary models from type II dental stone and custom impression trays made of light-curing composite resin (technical laboratory stage) – Figure 5.

• Obtaining functional impressions of the maxillary and mandibular arches using custom trays and light-body condensation silicone materials.
• Manufacturing of functional models from type III hard dental stone and occlusal rims on the working models (Figure 6).
• Determination of intermaxillary occlusal relationships in the dental office by the dentist (clinical stage).
• Mounting of working models in an articulator based on the occlusal record (technical laboratory stage).
• Obtaining preliminary wax dentures with teeth on the working models (Figure 7).
• Engraving of the maxillary functional model at the junction between the hard and soft palate (Ah line) using a laboratory micromotor and specific burs.
• Final touches of the wax dentures with teeth (technical laboratory stage) – Figure 8 (a, b).
• Investing the final wax dentures in the first half of the flask and obtaining the mold (technical laboratory stage) – Figure 9.
• Mixing and filling of the acrylic paste into the mold, followed by its polymerization (technical laboratory stage).
• Deflasking, processing, finishing and polishing of the acrylic complete dentures (technical laboratory stage).
• Insertion of the acrylic complete dentures into the patient’s oral cavity (Figure 10).

Discussion

Complete dentures, as a treatment modality, have remained and will remain for a long time to come the main choice for completely edentulous patients^(5,6). Advances in implantology or those related to biomaterials cannot tip the current balance due to the increasing number of edentulous patients with medium and low economic possibilities⁽⁷⁾.

Innovations in the field of dental dentures are limited to improving materials or obtaining processes⁽⁸⁾.

The materials used, with strict reference to those for the denture base, have evolved towards increasing biocompatibility with soft tissues by reducing allergic reactions^(9,10). The way to obtain them has aimed at reducing or even eliminating the residual monomer responsible for most contact reactions with soft tissues. Another way has been the bacteriostatic effect of the incorporated components to maintain a clean surface of the denture and reduce adverse effects due to bacteria⁽¹¹⁾.

The improvement of the manufacturing processes was mainly due to the introduction of digital technologies, the CAD-CAM systems⁽¹²⁾. Although it was among the last branches of dentistry to be introduced, it put the entire manufacturing process in a new light, the most important aspect being the possibility of duplicating an accidentally damaged prosthesis without restarting the entire technological process^(8,13).

Conclusions

The manufacturing of complete dentures is not merely a sequence of technical procedures, but rather a complex clinical process in which science, technology and a profound understanding of patient needs converge to ensure functional and esthetic success. In cases of total edentulism, restoration of oral balance requires a comprehensive reconstruction of the relationships between anatomical structures, prosthetic components and the patient’s psychological dimension.

From the stage of functional impression taking, a rigorous evaluation of the prosthetic field is required, with emphasis on support, retention and stability areas. At this stage, the dental technician must accurately capture tissue behavior under both static and dynamic conditions, enabling precise modeling of the denture base. The process continues with registration of the occlusal relationship, establishment of the vertical dimension and determination of the occlusal plane, essential steps for proper distribution of masticatory forces.

In recent years, the integration of digital technologies and state-of-the-art equipment has significantly transformed the way complete dentures are designed and fabricated. Among the most widely used modern technologies, there are:

• CAD/CAM technology, which allows digital design of the denture based on intraoral scans or physical models, followed by milling or 3D printing of the prosthetic base with remarkable precision.
• Pressure injection systems, which ensure uniform polymerization, reducing the risk of porosity and internal stresses within the material, resulting in superior mechanical strength and enhanced patient comfort.
• 3D printing with biocompatible materials, increasingly used for occlusal rims, provisional bases, or even definitive prosthetic restorations, offering rapid adaptation and significant reduction in working time.
• Digital simulations of oral functions, which allow prediction of denture behavior during mastication and speech, reducing the need for subsequent adjustments and increasing outcome predictability.

Nevertheless, modern technology does not replace professional expertise. The experience of the dental technician, the ability to accurately interpret clinical data, and practical skills remain decisive factors in the success of prosthetic treatment. Technology provides refinement tools but does not substitute clinical judgment.

Successful complete denture fabrication requires meticulous adaptation to individual patient characteristics, including alveolar ridge morphology, mucosal mobility, neuromuscular coordination and subjective expectations. The primary objective remains complete functional rehabilitation: efficient mastication, correct phonation, harmonious facial appearance and, importantly, psychological comfort.

By combining time-tested traditional methods with modern digital dental technologies, the foundation is created for high-quality prosthetic restorations that are well-adapted, esthetic, durable and easy to maintain. This synergy between innovation and experience defines contemporary prosthetic practice, centered on the real needs of the totally edentulous patient.

Conflict of interests: none declared.

Financial support: none declared.

This work is permanently accessible online free of charge and published under the CC-BY.