• The Journal of the Korean dental association
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• v.57 no.12
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• pp.747-756
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• 2019

This paper reviews the adaptation accuracy and mechanical properties of currently used denture processing systems with base resin materials and introduces the latest research on the development of antimicrobial denture base resins. Poly(methyl methacrylate) has been successfully used as a dental denture base resin material by the compress-molding method and heat polymerization for a long time, but recently, new processing techniques, injection molding-methods or fluid-resin technique are also used for fabricating denture base. However, studies indicated that there was no difference between the injectionmolding and the conventional compression-molding method in terms of adaption accuracy of denture base. The fluid-resin fabrication and one injection-molding systems exhibited better adaptation accuracy than the other processing methods. Resin denture bases in the oral cavity may undergo midline fractures due to flexural fatigue from repeated masticatory loading. For those patients, impact resistant denture base resins are recommended to prevent denture fracture during service. Thermoplastic denture base resins can be helpful for patients suffering from allergic reaction to resin monomers with a soft-fit, however, thermoplastic resins with low stiffness can irritate gum tissues and accelerate abnormal alveolar ridge resorption. Moreover, due to low chemical durability in oral cavity, those should be used for a limited period of time.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.347-353
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• 2018

PURPOSE. The purpose of this study was to evaluate the marginal discrepancy of heat-pressed ceramic veneers manufactured using a CAD/CAM system. MATERIALS AND METHODS. The ceramic veneers for the abutment of a maxillary left central incisor were designed using a CAD/CAM software program. Ten veneers using a microstereolithography apparatus (AM group), ten veneers using a five-axis milling machine (SM group), and ten veneers using a traditional free-hand wax technique (TW group) were prepared according to the respective manufacturing method. The ceramic veneers were also fabricated using a heat-press technique, and a silicone replica was used to measure their marginal discrepancy. The marginal discrepancies were measured using a digital microscope (${\times}160$ magnification). The data were analyzed using a nonparametric Kruskal-Wallis H test. Finally, post-hoc comparisons were conducted using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The $mean{\pm}SD$ of the total marginal discrepancy was $99.68{\pm}28.01{\mu}m$ for the AM group, $76.60{\pm}28.76{\mu}m$ for the SM group, and $83.08{\pm}39.74{\mu}m$ for the TW group. There were significant differences in the total marginal discrepancies of the ceramic veneers (P<.05). CONCLUSION. The SM group showed a better fit than the AM and TW groups. However, all values were within the clinical tolerance. Therefore, CAD/CAM manufacturing methods can replace the traditional free-hand wax technique.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.234-239
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• 2020

Purpose: We investigated the marginal fit between abutment and metal copings according to impression technique, wax block types, and metal types. Methods: We selected the traditional impression method of using rubber impression materials and the digital impression method of using oral scanners, three types of wax blocks, and two types of metal, both of which were domestically and commercially available, were selected to produce metal copings, and the marginal fit was determined through the use of silicon replication. Results: The measurements of axial wall fit revealed that the IYV specimens had the best fit, with a mean gap of 24.11±5.95 ㎛, followed by CEV, CHV, CSS, CSV, CES, CHS, and IYS specimens (mean: 33.44±8.41 ㎛). The differences were not statistically significant. The marginal gap measurements showed that the CEV specimen had the smallest gap, 17.25±4.13 ㎛, followed by the CSV, CHV, CSS, CES, CHS, IYV, and IYS specimen (mean: 43.47±15.63 ㎛). The differences were statistically significant. Conclusion: The axial wall fit of the metal coping (VeraBond2V; Aalba Dent, Inc., Fairfield, CA, USA) produced by the lost wax technique with the traditional impression method was excellent. The marginal fit of the metal coping (VeraBond 2V) produced by wax milling with the use of an oral scanner was also excellent. The marginal fit of the metal coping was within the clinically acceptable limits in all groups.

• The Journal of Advanced Prosthodontics
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• v.14 no.6
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• pp.379-387
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• 2022

PURPOSE. The aim of this study is to compare the casts obtained by using conventional techniques and liquid crystal display (LCD) three-dimensional (3D) print techniques in the All-on-4 treatment concept of the edentulous mandibular jaw. MATERIALS AND METHODS. In this study, a completely edentulous mandibular acrylic cast (typodont) with bone-level implants placed with the Allon-4 technique served as a reference cast. In this typodont, impressions were taken with the conventional technique and dental stone casts were obtained. In addition, after scanning the acrylic cast in a dental laboratory scanner and obtaining the Standard Tessellation Language (STL) data, 3D printed casts were manufactured with a 3D printing device based on the design. The stone and 3D printed casts were scanned in the laboratory scanner and STL data were obtained, and then the interimplant distances were measured using Geomagic Control X v2020 (3D Systems, Rock Hill, SC, USA) analysis software (n = 60). The obtained data were statistically evaluated with one-way analysis of variance (ANOVA) and Tukey's pairwise comparison tests. RESULTS. As a result of the one-way ANOVA test, it was determined that the stone casts, 3D printed casts, and reference cast values in all distance intervals conformed to the normal distribution and these values had a significant difference among them in all distance intervals. In Tukey pairwise comparison test, significant differences were found between casts at all distance intervals. In all analyses, the level of significance was determined as .05. CONCLUSION. 3D printed casts obtained with a 3D LCD printing device can be an alternative to stone casts when implants are placed in edentulous jaws. [J Adv Prosthodont 2022;14:379-87]

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.185-191
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• 2016

Purpose: The purpose of this study were to evaluate the quality of dental prostheses printed by 3-dimensional printing system. Methods: Mater model was prepared and ten study models were fabricated. Ten single crowns were printed by 3D-printing system(Resin group) and another ten single crowns using casting method were manufactured(Metal group). The marginal adaptation of single crowns were measured using by silicone replica technique. Silicone replicas were sectioned four times. The marginal adaptations were evaluated using by digital microscope. Statistical analyses were performed with Mann-Whitney test(${\alpha}=0.05$). Results: $Mean{\pm}standard$ deviations of all marginal adaptations were $92.1(20.0){\mu}m$ for Metal group and $69.7(12.3){\mu}m$ for Resin group. Two groups were no statistically significant differences(p>0.05). Conclusion: Marginal adaptation of single crowns printed by 3D-printing system were ranged within the clinical recommendation.

• Journal of Technologic Dentistry
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• v.41 no.1
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• pp.1-7
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• 2019

Purpose: The objectives of this study was to evaluate clinical adaptation of dental prostheses printed by 3 dimensional(3D) printing technology. Methods: Ten study models were prepared. Ten specimens of experimental group were printed by 3D printing(3DP group). As a control group, 10 specimens were fabricated by casting method on the same models. Marginal gaps of all specimens were measured to evaluate clinical adaptation. Marginal adaptations were measured using silicone replica technique and measured at 8 sites per specimen. Wilcoxon's signed-ranks test was used for statistical analysis(${\alpha}=0.05$). Results: Means of marginal adaptations were $95.1{\mu}m$ for 3DP group and $75.9{\mu}m$ for CAST group(p < 0.000). Conclusion : However, the mean of the 3DP group was within the clinical tolerance suggested by the previous researchers. Based on this, dental prosthesis fabricated by 3D printing technology is considered to be clinically acceptable.

• Journal of Technologic Dentistry
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• v.23 no.2
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• pp.75-93
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• 2002

This research was preformed for the purpose of preparing the items of standard model of the national dental technician test base on the duty analysis of the dental technician. The results of the duty analysis for the dental technician follows. 1. The dental technician is a profession to make the oral function smooth through the dental supplement and equipment in a scientific method and the skilled technique. 2. The duty of the dental technician are determined as A. preparation for manufacture B. manufacture C. management of the place of the dental technology D. self-development. A. The field of "the preparation for manufacture" are determined as 1. to confirm work authorization 2. To confirm the working model, B. The field of "In manufacture" are determined as 1. to manufacture the temporary crown 2. to manufacture the inlay and crown & bridge prosthesis 3. to manufacture the porcelain fused metal crown prosthesis 4. to manufacture the all ceramic crown prosthesis 5. to manufacture the temporary denture prosthesis 6. to manufacture the partial denture prosthesis 7. to manufacture the complete denture prosthesis 8. to manufacture the attachment prosthesis 9. to manufacture implant prosthesis 10. to manufacture the removable orthodontic device, 11. to manufacture the fixed orthodontic device, 12. to manufacture the orthodontic study cast C. The field of "in management of the dental lab." are determined as 1. management 2. to control the dental lab. D. The field of "In the self-development" are determined as 1. to improve the professionalism 2. self-control. 3. The developing items selected under the duty evaluation of the dental technician are l7s in the manufacture preparation, 1,011s in the manufacture, 7s in the management for the dental technology, 5s in self-development, and in all together 1,040s

• Journal of Technologic Dentistry
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• v.9 no.1
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• pp.5-19
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• 1987

The factors which impact on the productivity of medical organization are technique, manager, raw materials, management style, manpower structure, job construction, and so on. Human resources is the most important factor among them, but the productivity of serice organization can not be measured easily. The purpose of this study was to verify the effect of laboratory status, the degree of job cognition, and stress on the productivity of dantal prosthetic products, and to fine out the factors which impact on the productivity. The results were as follows: 1. The job characteristice of crown bridge laboratory part and porcelain laboratory part similar to each other. Also partial denture laboratory part and complete denture laboratory part were similar to each other. But that of orthodontic laboratory part was different from other. 2. the degree of job cognition made significant difference statisfically according to job characteristics of each dental laboratorise. 3. The correlation coefficient between job cognition of dental laboratory technician and workshop environment was.23, but the correlation between job cognition job stress appeared reversely, its coefficient was-.17. 4. The productivity of technician engaged in dental laboratory was much heigher than that of technician engaged in dental clinical laboratory room, and each were different in the degree of job cognition. 5. the most important factors which impact one the performance productivity of dental laboratory technician were the fact whether he married or not and his status.

• Journal of Information Technology Services
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• v.22 no.5
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• pp.87-98
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• 2023

Traditionally, tooth restoration has been carried out by replicating teeth using plaster-based materials. However, recent technological advances have simplified the production process through the introduction of computer-aided design(CAD) systems. Nevertheless, dental restoration varies among individuals, and the skill level of dental technicians significantly influences the accuracy of the manufacturing process. To address this challenge, this paper proposes an approach to designing personalized tooth restorations using Generative Adversarial Network(GAN), a widely adopted technique in computer vision. The primary objective of this model is to create customized dental prosthesis for each patient by utilizing 3D data of the specific teeth to be treated and their corresponding opposite tooth. To achieve this, the 3D dental data is converted into a depth map format and used as input data for the GAN model. The proposed model leverages the network architecture of Pixel2Style2Pixel, which has demonstrated superior performance compared to existing models for image conversion and dental prosthesis generation. Furthermore, this approach holds promising potential for future advancements in dental and implant production.

• Journal of Technologic Dentistry
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• v.3 no.1
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• pp.33-35
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• 1981