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This paper aims to present a new design for removable partial dentures (RPDs) for partially edentulous patients to improve the efficiency and quality of RPD manufacturing. Additive and subtractive manufacturing technologies and zirconium silicate micro-ceramic bonding in the aesthetic zone are used herein.

A case was presented. First, RPD digital definitive casts were acquired, and then digital frameworks with crown retainers and digital crowns were obtained by computer-aided design (CAD). The titanium alloy frameworks and resin crowns were fabricated by three-dimensional (3D) printing and computer-aided manufacturing (CAM) processes, respectively. The crowns adhered to the crown retainers. Ceramage bonding was used to reform the gingival anatomy in the aesthetic zone during the fabrication of the RPDs. The finished RPDs were assessed by a clinician and delivered to the patient.

The RPDs were conventionally assessed by a clinician, were deemed to be accurate and satisfied both the patient and clinician.

This novel method provides a way to fabricate RPDs with a combination of additive and subtractive manufacturing technologies. The design of the framework was different from that of a conventional framework because it contained the crown retainers, and the traditional base retainer no longer existed. Ceramage bonding was used to replicate the gingival anatomy in the aesthetic zone. The new RPDs provided accuracy and were less time-consuming to produce than those produced with the traditional method. The new method enables the digital manufacturing of nearly the entire RPDs.

This paper aims to improve the efficiency and the quality of metal dental prostheses, reporting on the first patient‐fitted titanium (Ti) complete denture base plate fabricated by integrating the technologies of computer‐aided design and computer‐aided manufacture (CAD/CAM) and laser rapid forming (LRF).

To make a complete Ti denture base plate, the traditional lost‐wax‐casting technique is commonly used in dentistry. In order to simplify this labor‐intensive process, a new method combined with LRF was invented. Initially, a maxillary edentulous plaster cast was converted to point cloud data by laser scanning system. Subsequently, point cloud data were reconstructed into a 3D solid digital cast, which is stored in standard triangulation language format. Thereafter the 3D denture base was sliced electronically into a sequence of layers defining the regions of the component and, based on it, the complete Ti denture base plate was built layer‐by‐layer using a laser additive manufacturing technology.

After CAD/CAM/LRF process, the Ti denture base plate was designed and successfully fabricated layer‐by‐layer. After the traditional dental finishing techniques, the complete Ti denture base plate was made and assessed by clinician and patient. The clinical evaluation on quality of fit was judged to be acceptable.

The CAD/CAM/LRF system is a potential candidate to replace the traditional lost‐wax‐casting technique and provides a new platform for the design and manufacturing of custom‐made Ti denture plates and other restorations especially for implant substructure and framework of partial removal of denture.

The purpose of this paper is to explore an application of computer‐aided design and manufacture (CAD/CAM) to a process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework.

With the introduction of laser scan technology and commercial reverse engineering software, a standard plaster maxillary dental cast with dentition defect was successfully scanned and created as a STL‐formatted digital cast. With the software, the unwanted undercuts were eliminated based on the desired path of insertion. Parts of the RPD framework were then successfully custom‐designed and combined as a whole.

A sacrificial pattern was produced by rapid prototyping (RP) method and finally casted with chromium cobalt alloy. With suitable finishing process, both the sacrificial pattern and the casted framework fitted the cast well.

The research indicated the feasibility of creating a library of RPD framework components. It is believed that, in the future, with the advance of the techniques, a totally new platform can be developed for the design and fabrication of custom‐fit RPD framework based on the CAD/CAM/RP system.

The aim of this study was to explore the application of rapid manufacturing (RM) to the production of patient specific, custom‐fitting removable partial denture (RPD) alloy frameworks. RPDs are metal frameworks designed to retain artificial replacement teeth in the oral cavity.

The study was undertaken by applied case study. An RPD was designed using computer‐aided design software according to well‐established dental technology design principles, based on a digitally scanned cast produced from an impression of the patient's mouth. The RPD design was then exported as an STL file in preparation for direct manufacture using selective laser melting. Dimensionally accurate frameworks were manufactured in 316L stainless steel and chromium‐cobalt alloy. These were assessed for accuracy of fit and function on the patient cast and on the patient in clinic.

This successful case study demonstrates that an RM approach can produce fully functional, precisely fitting RPD frameworks for specific individual patients.

The study was based on a single design produced using two materials. Further studies are in progress to show that the results can be achieved on a regular and predictable basis.

This study provides some practical guidance for the application described and suggests that similar success may be achieved in related custom‐fitting applications.

The paper demonstrates the successful application of a novel approach to the design and manufacture of custom‐fitting dental devices.

This in vitro study aims to explore the effects of selective laser melting (SLM) process parameters on the accuracy of the intaglio surface of cobalt–chromium alloy (Co–Cr), commercially pure titanium (CP Ti) and titanium alloy (Ti–6Al–4V) maxillary removable partial denture (RPD) frameworks and optimize these process parameters.

Maxillary RPD framework specimens designed on a benchmark model were built. The process parameters, including contour scan speed and laser power, infill scan speed and laser power, hatch space, build orientation and metallic powder type, were arranged through the Taguchi design. Three-dimensional deviations of the clasps area, connector area and overall area of maxillary RPD frameworks were analyzed by using root mean square (RMS) as a metric. One-way analyses of variance with the above RMSs as the dependent variable were carried out (α = 0.05).

Maxillary RPD frameworks built horizontally had a more accurate intaglio surface than those built at other orientation angles; CP Ti or Ti–6Al–4V maxillary RPD frameworks had a more accurate intaglio surface than Co–Cr ones; the Maxillary RPD framework built with a higher infill scan speed and lower infill laser power had the more accurate intaglio surface than the one built with other levels of these two process parameters.

A novel benchmark model for evaluating the accuracy of the intaglio surface of maxillary RPD frameworks manufactured by SLM is proposed. The accuracy of the intaglio surface of maxillary RPD frameworks can be improved by adjusting SLM process parameters. The optimal setting of process parameters concerning the accuracy of the intaglio surface of maxillary RPD frameworks was given.

Three-dimensional (3D) printing technologies have gained attention in dentistry because of their ability to print objects with complex geometries with high precision and accuracy, as well as the benefits of saving materials and treatment time. This study aims to explain the principles of the main 3D printing technologies used for manufacturing dental prostheses and devices, with details of their manufacturing processes and characteristics. This review presents an overview of available 3D printing technologies and materials for dental prostheses and devices.

This review was targeted to include publications pertaining to the fabrication of dental prostheses and devices by 3D printing technologies between 2012 and 2021. A literature search was carried out using the Web of Science, PubMed, Google Scholar search engines, as well as the use of a manual search.

3D printing technologies have been used for manufacturing dental prostheses and devices using a wide range of materials, including polymers, metals and ceramics. 3D printing technologies have demonstrated promising experimental outcomes for the fabrication of dental prostheses and devices. However, further developments in the materials for fixed dental prostheses are required.

3D printing technologies are effective and commercially available for the manufacturing of polymeric and metallic dental prostheses. Although the printing of dental ceramics and composites for dental prostheses is promising, further improvements are required.

Rapid manufacture‐produced cobalt chromium alloys are beginning to be used in dentistry but there are few published results relating to their properties. The purpose of this paper is to determine the corrosion resistance of a rapid manufacture‐produced dental alloy and compare it to a standard dental casting alloy.

In accordance with ISO 22674, ten samples of each alloy were fabricated in approximately 45 mm×10 mm×2 mm rectangular prisms, a sample number in excess of the standard requirements. The groups were further divided into those with highly polished surfaces and those with electrobrightened surfaces. Each sample was immersed in artificial saliva, suspended by a nylon thread for 42 days at 37°C. Readings for cobalt, chromium and molybdenum ions released into solutions were obtained using an atomic absorption spectrometer at 1, 4, 7, 14, 21, 28, 35, and 42 day intervals at a detection limit of one part per million.

Ion release of cobalt, chromium and molybdenum was well within the threshold prescribed by the standard. The alloys were safe for use as dental devices with respect to the above metals. The rapid manufacture alloy however performed better. In addition the data indicated that for both alloys, there was no discernable difference between a polished and an electrobrightened surface.

The rapid manufacture alloy studied shows a safe level of corrosion resistance with respect to cobalt, chromium and molybdenum according to ISO definitions. Further biocompatibility tests are recommended.

The purpose of this study is to investigate dimensional accuracy (Δd), surface roughness (Ra) and micro hardness (HV) of partial dentures (PD) prepared with synergic combination of fused deposition modelling (FDM) assisted chemical vapour smoothing (CVS) patterns and conventional dental casting (DC) from multi-factor optimization view point.

The master pattern for PD was prepared with acrylonitrile butadiene styrene (ABS) thermoplastic on FDM set-up (one of the low cost additive manufacturing process) followed by CVS process. The final PD as functional prototypes was casted with nickel–chromium-based (Ni-Cr) alloy by varying Ni% (Z). The other input parameters were powder to water ratio P/W (X) and pH value (Y) of water used.

The results of this study suggest that for controlling the Δd and R_a of the PD, most important factor is X, followed by Z. For hardness of PD, the most important factor is Z. But from overall optimization viewpoint, the best settings are X-100/12, Y-10 and Z-61% (in Ni-Cr alloy). Further, based upon X-bar chart (for HV), the FDM-assisted DC process used for preparation of PD is statistically controlled.

This study highlights that PD prepared with X-100/12, Y-10 and Z-61% gives overall better results from multi-factor optimization view point. Finally, X-bar chart has been plotted to understand the statistical nature of the synergic combination of FDM, CVS and DC.

The purpose of this research paper is to compare corrosion data obtained from additive-manufactured heat-treated (HRx) and non-heat-treated (NHRx) cobalt-chromium (Co–Cr) alloys. Heat treatments are indicated as necessary in complex intra-oral framework production by additive manufacturing to remove accumulated thermal stresses. However, heat treatments have been linked to corrosion in cast dental alloys. Currently, there are few publications on this subject for laser-sintered dental alloys required for academic review.

Five rectangular specimens (n = 5), each with a total surface area of 10.27 cm2, were fabricated for the two groups. Specimens were immersed in an artificial saliva solution suspended by a nylon thread for 42 days at 37°C. Readings for Co, Cr and molybdenum ions released into the solution were obtained using an atomic absorption spectrometer at 1-, 4-, 7-, 14-, 21-, 28-, 35- and 42-day intervals at a detection limit of one part per million. Test methods are in accordance with ISO 10271.

Results showed a higher ion release in the HRx sample, statistically significant at 99 per cent confidence level (p < 0.01). A two-way ANOVA test conducted showed that there was a main effect of day and a main effect of finish, and there was also a significant interaction between these factors.

The study concludes that, although ion release in both samples was within the safe level recommended by ISO for the three major alloying elements, heat treatment, indeed, contributed extensively to the reduced corrosion resistance in the laser-sintered Co–Cr alloy. Further biocompatibility tests are recommended.

The goal of rapid mechanical prototyping is to be able to quickly fabricate complex‐shaped, 3D parts directly from computer‐aided design models. The key idea of this novel technology is based upon decomposition of 3D computer models data into thin cross‐sectional layers, followed by physically forming the layers and stacking them up; “layer by layer technique.” This new method of modeling has raised many attentions in dentistry especially in the field of surgery and implantology. The purpose of this review study is to represent the historical development and various methods currently used for building dental appliances. It is also aimed to show the many benefits which can be achieved by using this new technology in various branches of dentistry.

The major existing resources, including unpublished data on the internet, were considered.

Although, creating 3D objects in a layered fashion is an idea almost as old as human civilization but, this technology has only recently been employed to build 3D complex models in dentistry. It seems that in near future many other methods will develop which could change traditional dental practices. It is advisable to include more unit hours in dental curriculums to acquaint dental students with the many benefits of this novel technology.

It is hard to believe that the routine dental techniques were affected by revolutionary concepts originally theorized by engineering methods. It is a reality that in future, most of the restorative disciplines will be fully revised and the computer methods be evolved to an extent where dentistry can be performed by computer‐assisted methods with optimum safety, simplicity, and reliability.