Earticle

Digital innovations have transformed removable partial denture (RPD) fabrication by improving precision, consistency, and efficiency. This report describes a mandibular Kennedy Class I RPD framework fabricated by computer-aided design (CAD) and masked stereolithography (MSLA) 3D printing. The mandibular cast was scanned, and the framework was digitally designed with a defined path of insertion, blockout, relief, and clasp and connector configurations. The resin framework was printed, post-cured, invested, and cast in cobalt– chromium alloy. The definitive prosthesis showed clinically acceptable adaptation, retention, and functional stability without patient discomfort. This MSLA-based workflow reduced human error, shortened fabrication time, and reproduced anatomical details accurately. The case demonstrates the clinical feasibility and advantages of integrating CAD and 3D printing into RPD fabrication as a predictable alternative to conventional lost-wax techniques.

Purpose: This review aimed to classify and narratively synthesize the literature on digital complete dentures based on the manufacturing methods, structural types, tooth-base bonding strategies, and intended clinical applications. Methods: A semi-systematic literature review was conducted using the PubMed and RISS databases to identify relevant publications from January 2010 to March 2026. The records were screened using the predefined inclusion and exclusion criteria, organized with Zotero, and classified by study design, fabrication method, structural type, bonding strategy, application scope, and major research topic. Results: The included publications were classified into milling, 3D printing, and hybrid digital workflows and further into monolithic and separate base-and-teeth structures. Hybrid digital workflows were common and referred to as workflows combining different fabrication routes or component sources. Milling was mainly associated with definitive complete dentures, whereas 3D printing was reported across definitive, interim, and trial applications. Conclusion: Digital complete denture workflows should be interpreted not only by manufacturing principle but also by structural designs, bonding strategies, material characteristics, intended use, and maintenance requirements. Furthermore, these factors should be considered together in the clinical and laboratory decision-making process.

Purpose: To assess the effects of different sterilization methods on the trueness and precision of 3D-printed surgical guides. Methods: In this study, surgical guides were 3D-printed using resin to facilitate the planned placement of a missing mandibular right second premolar in a training model. Sterilization was performed using hydrogen peroxide plasma (55℃ for 25 minutes) and autoclaving (132℃ for 20 minutes, followed by a 30-minute drying cycle). Each surgical guide was scanned, and the data were exported in standard tessellation language format. The root mean square (RMS) values were calculated using 3D superimposition software, with the original design file as the reference data and the scan file of the 3D-printed guide as the measurement data. Thirty surgical guides were divided into three groups (n=10): non-sterile, plasma sterilization, and autoclave sterilization. Statistical analyses of the extracted RMS values were conducted using ANOVA for trueness assessment and the Kruskal–Wallis test for precision evaluation. Results: In the trueness evaluation, no statistically significant differences in RMS values were observed among the non-sterile, plasma sterilization, and autoclave sterilization groups (p>0.05). In contrast, the precision evaluation revealed significant differences among the groups, with the plasma sterilization group showing the lowest RMS value. Color map analysis showed relatively greater localized internal surface deviations in the autoclave sterilization group, whereas the plasma sterilization group exhibited comparatively uniform internal surface stability. Conclusion: The internal trueness of the 3D-printed surgical guides did not differ significantly depending on the sterilization method; however, a significant difference in precision was observed.

Purpose: This study aimed to compare the accuracy of intra-oral and model scanners using structured light scanning technology in the external, internal, and marginal surfaces of a single zirconia crown. Methods: The maxillary right first molar was selected as the abutment tooth, and an impression was taken to create a master model. Each specimen was scanned 10 times using an intra-oral scanner (IOS group; i600, MegaGen Implant) and a model scanner (MS group) (n=20). All scan data were exported and saved in standard tessellation language format. A three-dimensional analysis program was employed to evaluate the root mean square (RMS) deviations across the external, internal, and marginal surfaces. Statistical analysis was performed using IBM SPSS Statistics 26.0 (IBM), with the Shapiro–Wilk test applied for normality and the Mann–Whitney U test (α=0.05). Results: In the trueness analysis, no statistically significant differences were found between the 2 groups for the external and marginal surfaces (p>0.05). However, the MS group demonstrated significantly higher trueness in the internal surface (p=0.008). In the precision analysis, the IOS group showed higher precision on the external surface, whereas the MS group had higher precision on both the internal and marginal surfaces, with significant differences observed across all surfaces (p<0.05). Conclusion: This study revealed that the MS group demonstrated higher trueness and precision in certain areas. Both scanners achieved accuracy within 120 μm, confirming their potential for clinical application.

Purpose: This in vitro study aimed to compare the trueness of 3-unit fixed dental provisional prostheses (FDPs) fabricated by three different additive manufacturing and subtractive manufacturing procedures. Methods: A reference model with a maxillary left second premolar and the second molar prepped and the first molar missing was scanned for the fabrication of 3-unit FDPs. An anatomically shaped 3-unit FDP was designed on computer-aided design software. 10 FDPs were fabricated by subtractive (MI group) and additive manufacturing (stereolithography: SL group, digital light processing: DL group, liquid crystal displays: LC group) methods, respectively (N=40). All FDPs were scanned and exported to the standard triangulated language file. A three-dimensional analysis program measured the discrepancy of the internal, margin, and pontic base area. As for the comparison among manufacturing procedures, the Kruskal–Wallis test and the Mann–Whitney test with Bonferroni correction were evaluated statistically. Results: Regarding the internal area, the root mean square (RMS) value of the 3-unit FDPs was the lowest in the MI group (31.79±6.39 μm) and the highest in the SL group (69.34±29.88 μm; p=0.001). In the marginal area, those of the 3-unit FDPs were the lowest in the LC group (25.39±4.36 μm) and the highest in the SL group (48.94±18.98 μm; p=0.001). In the pontic base area, those of the 3-unit FDPs were the lowest in the LC group (8.72±2.74 μm) and the highest in the DL group (20.75±2.03 μm; p=0.001). Conclusion: A statistically significant difference was observed in the RMS mean values of all the groups. However, in comparison to the subtractive manufacturing method, all measurement areas of 3-unit FDPs fabricated by three different additive manufacturing methods are within a clinically acceptable range.

Purpose: The purpose of this study is to analyze the depth according to curing using photocurable resin for dental three-dimensional printing. Methods: A stainless mold with a height of 4 mm was prepared. Ultraviolet (UV) polymerization resin was injected into the mold. Photocuring was then performed for 5 minutes using a photopolymerizer, and the height was measured using a digital measuring instrument (first group). Second, light polymerization was also performed outside the mold for 5 minutes, and the height was measured using a digital measuring instrument. Third, light polymerization was further performed for 5 minutes, and the height was measured using a digital measuring instrument. Statistical analysis was performed with the Kruskal-Wallis test, which is a nonparametric test (α=0.05). Results: The third group had the largest measurement length, whereas the first group had the smallest. However, the difference between groups was not statistically significant (p>0.05). The color of the first group was different from that of the second and third groups. Conclusion: All of the 4-mm-thick photocured specimens had a curing reaction, but the part that was not directly irradiated with UV did not show its original color.

Purpose: The aim of this study was to evaluate the accuracy of provisional crowns manufactured using a milling machine and a digital light processing (DLP) printer. Methods: A full-contour crown was designed using computer-aided design software. Provisional crowns of this design were manufactured using a milling machine and using a DLP three-dimensional (3D) printer (N=20). The provisional crowns were digitized with an extraoral scanner, and 3D deviation analysis was applied to the scanned data to confirm their accuracy. An independent t-test was performed to detect the significant differences, and the Kolmogorov-Smirnov test was used for analysis (α=0.05). Results: No significant differences were found among the precision of marginal surface between the printed and milled crowns (p=0.181). The trueness of marginal and internal surfaces of the milled crowns were statistically higher than those of the printed crowns (p=0.024, p=0.001; respectively). Conclusion: The accuracy of provisional crowns manufactured using a milling machine and a 3D printer differed significantly except with regards to the precision of the internal surface. However, all the crowns were clinically acceptable, regardless of the manufacturing method used.

By classifying temporary denture production for surgical guides, digital guide-based surgery, and final prosthesis production, the problems of each process were assessed in advance and the factors that could be improved were confirmed in this study. The manufacturing process of fusion dental prosthesis uses virtual programs and computed tomography images to manufacture devices using the latest technologies of computer-aided design/computer- aided manufacturing and three-dimensional printing, which enables implants to be placed in the desired location in advance. Moreover, implant placement is not dependent on the skill and condition of the dentist, and because it uses a computer system, it can always be performed at a constant and optimal position. This can reduce the remanufacturing rate compared with the general method, shorten the treatment period, and eliminate patient discomfort. Unlike the traditional method of using impression materials and plaster models, digital fusion dental prostheses would be evaluated as a technology for producing prosthesis through professional design technology and communication.

Purpose: The purpose of this study is to compare and analyze the accuracy of single crowns based on the type of occlusal surface. Methods: A single crown wax pattern was fabricated in three types of occlusal surface. The prepared wax pattern was replicated with silicone, and stone was injected to create a stone model. The prepared specimens were scanned using a model scanner. Scans were classified into three groups, and each scan was performed six times to analyze the trueness and precision of a single crown. In addition, only the occlusal surface area was analyzed for trueness and precision. Data were analyzed using the Kruskal–Wallis H test, a nonparametric test (α=0.05). Results: With regard to the trueness value of the occlusal scan area, the no occlusal tooth attrition (NA) group showed the largest error of 3.5 μm, and the complete occlusal tooth attrition (CA) group showed the lowest value of 3.1 μm. The NA group had the greatest precision, and the medium occlusal tooth attrition (MA) group and CA group showed a low precision value of 3.2 μm; the difference between the groups was statistically significant (α=0.05). In the color difference map, the CA group showed a lower error than the NA group. Conclusion: The occlusal surface with severe attrition had excellent accuracy, but the accuracy of the group without attrition was low. There were significant differences between groups, but clinically acceptable values were shown.

Background: In this study, zirconia copings were fabricated by setting clinically acceptable inner values for prostheses using computer-aided design/computer-aided manufacturing (CAD/CAM). The processed copings were evaluated for the marginal and internal fit of each abutment shape with a CAD program using the silicone replica technique. Methods A total of 20 copings was produced by selecting models commonly used in clinical practice. After injecting the sample, the minimum thickness, internal adhesion interval, and distance to the margin line were set to 0.5, 0.05, and 1.00 mm using a dental CAD program, respectively. It was measured using a 2D section function in a threeway program of the silicon replication technology. Although the positions and number of measurements of the anterior and posterior regions differed, nine parts of each pre-tube were designated and measured by referring to a previous study to compare the two samples. Results As a result, the average margin of the mesial, distal, and buccal (labial) surfaces was 59.90 μm in the anterior region and 60.40 μm in the posterior region. The mean axial wall margin was 67.25 μm in the anterior region and 69.25 μm in the posterior region. In occlusion, the anterior teeth (77.70 μm), posterior teeth (77.60 μm), and both anterior and posterior regions were within the clinically acceptable range. Conclusion The edge and inner fit of zirconia coping manufactured using the CAD/CAM system showed clinically applicable results. To reduce errors and increase accuracy, materials and machine errors that affect the manufacture of prosthetics should be investigated. Based on our results, the completeness of prosthetics could increase if the inner value and characteristics of the material are adjusted when applied in clinical practice.

Combining digital automation solutions throughout recent manufacturing process is essential. Advanced robot and mechanical techniques are required for design, manufacture, and distribution process. Manual design of repetitive similar mechanical components during the development phase of these advanced machines and robots can occur wasting time and money. Developed gear design module, which is the power transfer system mechanical component, was programmed in the Visual Basic language in CATIA V5 environment. Automation Process is Based on Parametric Modeling Method. and it was found to be effective in reducing design time compared to designers manual modeling.

The vehicle weight and alternative light materials development like aluminum alloys are hot issues around the world. In order to obtain the goal of the weight reduction of automobiles, the researches about lighter and stronger suspension links have been studies without sacrificing the safety of automotive components. Therefore, in present study, the structure analysis of the torque strut links made by aluminum alloys (A356) was performed by using CAE (computer aided engineering) to investigate the light weight design process from the reference of the rear suspension torque strut link which was made by STKM11A steel and was already proven in the commercial market. Especially, the simulated maximum von Mises stresses after strength analysis were normalized as fatigue limit and these were converted to the WF (weight factor) of the same type as the fatigue safety factor suggested and named like that in present study. From these, it was suggested that the fatigue properties of the torque strut could be simply predicted only from this static CAE simulation.

In order to obtain the goal of the weight reduction of automobile components, the researches about lighter and stronger wheel carriers have been studied without sacrificing the safety of them. In this study, the weight reduction design process of wheel carrier could be proposed based on the variation of von-Mises stress contour by substituting an AA6061 (aluminum 6061 alloy) having tensile strength of 310 MPa grade instead of FCD600 Irons. From the stress analysis results before and after design modification, the stress relaxation was done at every given loading conditions. Therefore, it could be reached that this approach method could be well established and be contributed for light-weight design guide and the optimum design conditions of the automotive wheel carrier development.

With the development trend of current economy and the rapid development of computer technology, intelligence is more and more widely applied in the construction industry. According to the actual situation of current society, this paper makes a brief introduction of building information model. Taking its application status at home and abroad and existing problems into consideration, as far as the development of the current field. The paper frames structure and simulates the interface with the help of computer-aided analyzing tools. Itapplies the computer intelligence factor analyzing method and gets the factors that influence the building information model are: the expected results, human intervention, promoting conditions, adoption intention, the ability to use technology and educational background variables. Then, through model testing, we got the direct link with strong degree between the expected results and adoption intention, human intervention and adoption intention, the expected results and the ability to use technology, promoting conditions and educational background variables. This paper analyzes the factors and the relations of building information model. Is has a certain economic value and practical significance. It can solve the existing problems in practical construction industry and lays a foundation for other related building software.

Use of computer aided process planning in CNC machining of spiral bevel gear, not only can improve overall parts manufacturing level, but also can greatly improve the quality of the products, by the driving bevel gear, planning process of driven bevel gear and the assembly process, understanding calculation computer aided process design can improve the work efficiency, accelerate the market response speed, shorten technical preparation cycle. At the same time, promote the standardization of the construction process, improve the process design. Optimizing design process, promote technological progress. Will bring greater social and economic benefits.