• Journal of dental hygiene science
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• v.18 no.1
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• pp.42-49
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• 2018

The computer-aided design/computer-aided manufacturing (CAD/CAM) system was introduced to shorten the production time of all-ceramic restorations and the number of patient visits. Among these types of ceramic for dental CAD/CAM, they have been processed into inlay, onlay, and crown shapes using leucite-reinforced glass-ceramics to improve strength. The purpose of this study was to observe the mechanical properties and microstructure of leucite-reinforced glass-ceramics for dental CAD/CAM. Two types of leucite-reinforced glass-ceramic blocks (IPS Empress CAD, Rosetta BM) were prepared with diameter of 13 mm and thickness of 1 mm. Biaxial flexural testing was conducted using a piston-on-three-ball method at a crosshead speed of 0.5 mm/min. Weibull statistics were used for the analysis of biaxial flexural strength. Fracture toughness was obtained using an indentation fracture method. Specimens were observed by field emission scanning electron microscopy to examine the microstructure of the leucite crystalline phase after acid etching with 0.5% hydrofluoric acid aqueous solution for 1 minute. The results of strength testing showed that IPS Empress CAD had a mean value of $158.1{\pm}8.6MPa$ and Rosetta BM of $172.3{\pm}8.3MPa$. The fracture toughness results showed that IPS Empress CAD had a mean value of $1.28{\pm}0.19MPa{\cdot}m^{1/2}$ and Rosetta BM of $1.38{\pm}0.12MPa{\cdot}m^{1/2}$. The Rosetta BM sample exhibited higher strength and fracture toughness. Moreover, the crystalline phase size and ratio were increased in the Rosetta BM sample. The above results are expected to elucidate the basic mechanical properties and crystal structure characteristics of IPS Empress CAD and Rosetta BM. Additionally, they will help develop leucite-reinforced glass-ceramic materials for CAD/CAM.

• Journal of KIISE:Software and Applications
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• v.27 no.1
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• pp.33-40
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• 2000

Computer Aided Process Planning (CAPP) plays a key role by linking CAD and CAM. Given CAD data of a part, CAPP has to recognize manufacturing features of the part. Despite the long history of research on feature recognition, its research results have rarely been transferred into industry. One of the reasons lies in the separation of feature recognition and process planning. This paper proposes to integrate the two activities through AI techniques, and presents efforts for manufacturable feature recognition, setup minimization, feature dependency construction, and generation of an optimal machining sequence.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.695-700
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• 2016

Objectives: The purpose of the study was to investigate the effect of CAD/CAM ceramic thickness on shade. Methods: 24 disk-shaped ceramic specimens (E.Max CAD & Empress CAD, $12mm{\times}12mm$) were prepared and divided into 4 groups (n=6). Ceramic specimens in 2 thicknesses (0.8 mm, 1.0 mm) were made low translucency(LT) shade A2. All specimens were measured as L*, a*, b* using spectrophotometer. The color differences(${\Delta}E$ values) between the specimen and a control target block ($12{\times}12{\times}1.2mm$) were calculated. Two-way ANOVA performed between 2 groups(material and thickness). Results: As the thickness increased, the $L^*$ (for all groups) and $b^*$ value (for all groups) increased and the $a^*$ value(for LR group) decreased. The mean color differences caused by thickness was acceptible (${\Delta}E$ > 2) for group LD1. But the mean color differences by thickness were not selected (${\Delta}E$ < 2) for group LD2, LR1, LR2. Conclusions: The different thickness can influence the final color of CAD/CAM ceramic.

• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.439-446
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• 2017

PURPOSE. To evaluate the effects of different surface treatments on the bond strength of novel CAD/CAM restorative materials to resin cement by four point bending test. MATERIALS AND METHODS. The CAD/CAM materials under investigation were e.max CAD, Mark II, Lava Ultimate, and Enamic. A total of 400 bar specimens ($4{\times}1.2{\times}12mm$) (n=10) milled from the CAD/CAM blocks underwent various pretreatments (no pretreatment (C), hydrofluoric acid (A), hydrofluoric acid + universal adhesive (Scotchbond) (AS), sandblasting (Sb), and sandblasting + universal adhesive (SbS)). The bars were luted end-to-end on the prepared surfaces with a dual curing adhesive resin cement (Variolink N, Ivoclar Vivadent) on the custom-made stainless steel mold. Ten test specimens for each treatment and material combination were performed with four point bending test method. Data were analyzed using ANOVA and Tukey's test. RESULTS. The surface treatment and type of CAD/CAM restorative material showed a significant effect on the four point bending strength (FPBS) (P<.001). For LDC, AS surface treatment showed the highest FPBS results ($100.31{\pm}10.7MPa$) and the lowest values were obtained in RNC ($23.63{\pm}9.0MPa$) for control group. SEM analyses showed that the surface topography of CAD/CAM restorative materials was modified after treatments. CONCLUSION. The surface treatment of sandblasting or HF acid etching in combination with a universal adhesive containing MDP can be suggested for the adhesive cementation of the novel CAD/CAM restorative materials.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.22 no.1
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• pp.22-29
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• 2013

In general, to conduct aesthetic restorations, various analyses are carried out using a camera from the initial examination with the final prosthesis in consideration. With the reality that many dentists are using digital cameras, it can be considered that the time of digital impression has already started. Just as the recent general trend is that more and more internationally renowned photographers are switching their film cameras to digital counterparts, it is likely that CAD/CAM will show another direction in the area of the aesthetic dentistry that we may want to pursue. With the word 'digital', the convenience and economics often come to mind in the first place. However, from the dental clinical viewpoint, it is important to improve and develop the CAD/CAM system based on understanding its specialty and superiority while respecting the conventional analog techniques. However, a regretful aspect is that it is often difficult to catch up with the latest advancements for proper referencing and follow-up of digital technologies since the CAD/CAM device and material are developing very rapidly. Accordingly, although it is ideal to have hands-on experiences in various digital material and devices, and adapt to their fast changes, it must be stressed that the clinical application is to be implemented on the basis of the proven traditional way of dental clinics in order to obtain better outcomes. This presentation will explore types of approaches that can be made by combining the traditional techniques and the CAD/CAM from the aesthetic viewpoint. In addition, it is hoped and eagerly awaited that the CAD/CAM restoration may play a significant role in the field of the 'digital art'.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.1
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• pp.12-21
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• 2008

Statement of problem: There have been many studies about marginal adaptation of Zirconia core fabricated with various CAD/CAM systems. But, the comparative study has not been conducted much. Purpose: This study was to compare marginal adaptations of zirconia cores fabricated with 3 different CAD/CAM systems. Material and methods: The in vitro marginal adaptations of zirconia cores fabricated with 3 different CAD/CAM systems($Adens^{(R)}$ system, $Lava^{(R)}$ system, and $Cerasys^{(R)}$ system) were evaluated and compared. In this study 30 zirconia cores were fabricated(10 zirconia cores per each system). The measurements of the marginal adaptatioin were carried out using microscope $L-150A^{(R)}$(Nikon, Japan). Measurements were recorded at 50 points. The measurements were analyzed using Kruskal-Wallis test and Wilcoxon rank sum test. Results: Within the limits of this study, the results were as follows. 1. Mean marginal gap values obtained were $284.5{\pm}152.9{\mu}m$ in Adens system, $99.0{\pm}73.0{\mu}m$ in Lava system, and $153.5{\pm}85.7{\mu}m$ in Cerasys system. 2. Zirconia core made by Lava system showed the smallest marginal gap(P<0.05). Conclusion: In the limitation of this study, we concluded that $Lava^{(R)}$ System was superior than other systems($Adens^{(R)}$ system and $Cerasys^{(R)}$ system) in the marginal adaptation.

• Journal of the Korean Society of Safety
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• v.10 no.3
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• pp.42-46
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• 1995

To purpose of this study is to model design and motion analysis of tangential cam mechanism using personal computer system. The CAD(Computer Aided Design) system used in this study was constructed with CPU(Central Processing Unit) 80486, RAM(Random Access Memory) 8M, CGA graphic card. By using developed program for tangential cam mechanism, we designed tangential cam models and analysed displacement, velocity, acceleration of follower.

• International Journal of CAD/CAM
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• v.9 no.1
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• pp.17-24
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• 2010

For several years, researchers have focused on improving the integration of the CAD, CAM and Analysis through a better communication between the various analysis tools. This tendency to integrate the CAD/Analysis and automation of the corresponding processes requires data sharing between the various tasks using an integrated product model. We are interested in this research orientation to CAD/CAM/Analysis integration by rebuilding the CAD model (BREP), starting from the Analysis results (deformed mesh). Because this problem is complex, it requires to be split into several complementary parts. This paper presents an original interoperability process between the CAD and CAE. This approach is based on a new technique of rebuilding the CAD surface model (Nurbs, Bezier, etc.) starting from triangulation (meshed surface) as a main step of the BREP solid model. In our work, the advantages of this approach are identified using a centrifugal pump example.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.443-447
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• 1986

오늘날 제조업에 있어서는 시장의 다양화, 원가절감 및 리드타임의 단축이라는 대내외적 요구에 부응할 수 있는 기술 생산체재의 확립이 요구되고 있다. 이에 따라 설계 및 기술변경(Engineering Change)에따른 원가상승을 막기 위해 CAE(Computer aided engineering), CAD(Computer aided design)의 도입을 서두르게 되었고 CAD데이타의 효율적 이용에 의한 가공 및 생산적 측면에서 CAM(Computer aided manufacturing)의 도입도 검토하게 되었다. 본 논문은 이러한 개념의 발상동기와 이를 뒷받침하기 위한 한국 아이 비 엠이서 제공하는 하드웨어 및 소프트웨어를 소개하고 공장자동화를 위한 기술 생산 통합시스템의 구축이라는 측면에서 아이 비 엠이 추구하는 방향을 검토하고 있다.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.276-283
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• 2013

Purpose: The purpose of this study was to investigate the fit and screw joint stability between Ready-made abutment and CAD-CAM custom-made abutment. Materials and methods: Osstem implant system was used. Ready-made abutment (Transfer abutment, Osstem Implant Co. Ltd, Busan, Korea), CAD-CAM custom-made abutment (CustomFit abutment, Osstem Implant Co. Ltd, Busan, Korea) and domestically manufactured CAD-CAM custom-made abutment (Myplant, Raphabio Co., Seoul, Korea) were fabricated five each and screws were provided by each company. Fixture and abutments were tightening with 30Ncm according to the manufacturer's instruction and then preloding reverse torque values were measured 3 times repeatedly. Kruskal-Wallis test was used for statistical analysis of the preloading reverse torque values (${\alpha}=.05$). After specimens were embedded into epoxy resin, wet cutting and polishing was performed and FE-SEM imaging was performed, on the contact interface. Results: The pre-loading reverse torque values were $26.0{\pm}0.30Ncm$ (ready-made abutment; Transfer abutment) and $26.3{\pm}0.32Ncm$ (CAD-CAM custom-made abutment; CustomFit abutment) and $24.7{\pm}0.67Ncm$ (CAD-CAM custom-made abutment; Myplant). The domestically manufactured CAD-CAM custom-made abutment (Myplant abutment) presented lower pre-loading reverse torque value with statistically significant difference than that of the ready-made abutment (Transfer abutment) and CAD-CAM custom-made abutment (CustomFit abutment) manufactured from the same company (P=.027) and showed marginal gap in the fixture-abutment interface. Conclusion: Within the limitation of the present in-vitro study, in domestically manufactured CAD-CAM custom-made abutment (Myplant abutment) showed lower screw joint stability and fitness between fixture and abutment.