• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.2
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• pp.98-108
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• 2016

In recent days, perhaps the biggest driver in new material development is the desire to improve restorations esthetics compared to the traditional metal substructure based ceramics or all-ceramic restorations. Each material type performs differently regarding strength, toughness, effectiveness of machining and the final preparation of the material prior to placement. For example, glass ceramics are typically weaker materials which limits its use to single-unit restorations. On the other hand, zirconia has a high fracture toughness which enables multi-unit restorations. This material requires a long time sintering procedure which excludes its use for fast chair side production. Hybrid ceramic material developed for CAD/CAM system is contained improved nano ceramic elements. This new material, called a Resin Nano Hybrid Ceramic is unique in durability of function and aesthetic base compositions. The new nano-hybrid ceramic material is not a composite resin. It is also not a pure ceramic. The material is a mixture of both and consists of nano-ceramic fillers. Like a composite, the material is not brittle and is fracture resistant. Like a glass ceramic, the material has excellent polish retention for lasting esthetics. The material is easily machined by chair side or in a dental lab side, could be an useful restorative option.

• The Journal of the Korean dental association
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• v.50 no.3
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• pp.140-147
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• 2012

Recently, the digital solution of fabricating removable prosthesis by applying haptic input device, electronic surveying, and rapid prototyping was introduced. This review article covers the concept of electronic surveying, computer-aided denture framework designing procedure, discussions after several digital denture cases, directions of future development, such as digital tooth arrangement and RP flasking.

• The Journal of the Korean dental association
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• v.52 no.1
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• pp.17-26
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• 2014

Computerized 3D virtual dental models are currently available, and their use has started to improve treatment outcomes. The accuracy of digital models has been demonstrated by many studies and various intra-oral scanners are innovated for short scanning time and high precision. Recently, a digital model was combined with a high technology computer-driven system, which was developed for the application of a digital set-up and indirect bonding of lingual attachments. In this section, virtual treatment planning using a virtual set-up program is be introduced, and the clinical applications and accuracy of computer-generated indirect bonding are discussed.

• Journal of the KSME
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• v.29 no.3
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• pp.279-293
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• 1989

CAD/CAM 시스템에서 유한요소해석에 필요한 과정들과 이와 관련된 기술 및 연구 동향을 살펴 보았다. 근래에 이르러 CAD/CAM 시스템의 개념이 초기의 자동제도 시스템에 그치지 않고, 이제는 제품의 설계 개발에서부터 제조에 이르는 일련의 엔지니어링 작업을 통합하는 CAE(Computer Aided Engineering) 시스템의 개념으로 발전되고 있으며, 우리나라에서도 이 분야에 많은 관심과 수요가 크게 늘고 있음은 당연한 추세라 할 수 있다. 그러나 아직까지 이에 필요한 소프트웨어들이 국내에서 개발되지 않아 전량 수입에 의존하고 있는 실정으로, 앞으로 이러한 수입추세는 점점 늘어날 것으로 전망된다. 더욱이 최근 들어 선진국들이 원천 프로그 램(source code)의 이전을 기피함에 따라 관련기술의 국산화가 어렵고, 이들의 응용에 제약이 많아 기술의 예속화가 우려된다 하겠다. 따라서 현재 국내의 산어 규모와 기술 수준으로 미루 어볼 때, 국내에서도 소프트웨어들을 개발해야 할 시점에 와 있다고 하겠다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.9
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• pp.2286-2293
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• 1993

The study presents the development of a cost-effective CAD/CAM system for metal moulds by use of personal computer. In the personal CAD/CAM system named DKSYS, metal moulds are defined by the operations of basic elements such as prism, pyramid and sphere, plane, rotational body, and surface elements including curved surface. The internal expression of shape elements in the computer is based on the wire model, which is a set of cross-sectional curves of the shape elements. With the addition of OMS system to CAD/CAM system the optimum cutting condition can be selected automatically. After programming NC information with the form definition and the optimum cutting condition, the metallic mould can be formed by transferring cutting information to CNC machine through DNC system. Using a computer for the above process, it is possible to increase the productivity and reduce the cost.

• The Journal of the Korean dental association
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• v.49 no.5
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• pp.279-285
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• 2011

Currently there is no dental ceramic material can be used in all dental situations need to be restored. However, in view of recent clinical reports, the most viable alternative is zirconia ceramic. Clinical success of dental zirconia restorations strongly depends on proper selection of materials, accurate laboratory procedure and final cementation, which can be achievable with the correct understanding of zirconia. As dental materials, zirconia ceramics have a very bright future, because they are being used increasingly in the anterior region as implant fixtures, as well as crown and bridge restorations and implant abutments. Many dental ceramics showing poor clinical performance have been gone from the dental market. However, in terms of outstanding mechanical properties and esthetic nature, new dental materials can replace zirconia ceramics will not be available in the foreseeable future.

• The Journal of the Korean dental association
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• v.49 no.5
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• pp.260-264
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• 2011

Zirconia ($ZrO_2$) is a crystalline dioxide of zirconium. Dental zirconia blocks for CAD/CAM are usually fabricated with powders of tetragonal zirconia polycrystals (TZP) stabilized with 3mol% yttria. Because of its mechanical properties similar to those of metals and color similar to tooth, it is evaluated to attain the two purposes at a time, strength and aesthetic in prosthetic dentistry. The ability of transformation of Y-TZP from tetragonal to monoclinic helps to prevent crack propagation and contributes the increase of strength and fracture toughness. Two different types of blocks, soft and hard, are used to prepare the zirconia frameworks. The fuzzy-sintered block is difficult in machining, so pre-sintered soft 3Y-TZP block is usually used to mill by computer aided machining.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.307-313
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• 2017

The object of this case report is to introduce milled zirconia bar and PEKK female part made by CAD/CAM technology for bar attachment implant supported overdenture in maxillary edentulous patients. For over 2 years, in terms of function and esthetics, satisfactory result was obtained. Esthetically and functionally satisfactory results were obtained in periodic follow up check.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2446-2456
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• 1993

By virtue of progress of computer science, CAD/CAM technology has been developed greatly in each area. But the problems in the integration of CAD/CAM are not yet solved completely. The reason is that the exchange of data between CAD and CAM is difficult because the domains of design and manufacturing are different in nature. To solve this problem, a feature based modeller is developed in this study, which makes it possible to communicate between design and manufacturing through features. The modeller has feature, the concept of semi-bounded plane is introduced, and implemented as a B-rep sheet model using half-edge data structure. The features are then created on a part by local modification of the boundary on a part based on feature template information. This approach generalizes the modelling of features in a geometry model.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.1
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• pp.96-105
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• 1992

A study on the construction of a CAD/CAM system operated by 16 Bit PC basic language, for machining sculptured surface of die, was carried out. The system consists of 2 steps i.e., process for geometric modelling by wire frame and process for machining data generation. Geometric modelling for sculptured surface is made by the point data fitting, parallel sweeping, normal sweeping and linear connection of cross section curve. Machining data are gained by cutter off-set of geometric model data and machining carried out by DNC. This system is to be proved enough for rough cutting by actual machining experiment. But, for becoming a high level system, another method of cutter off-set has to be regarded and system must be reconstructed by another program language.