• The Journal of Advanced Prosthodontics
• /
• 제9권3호
• /
• pp.159-169
• /
• 2017

PURPOSE. The purposes of this study were to evaluate the marginal and internal gaps, and the potential clinical applications of three different methods of dental prostheses fabrication, and to compare the prostheses prepared using the silicone replica technique (SRT) and those prepared using the three-dimensional superimposition analysis (3DSA). MATERIALS AND METHODS. Five Pekkton, lithium disilicate, and zirconia crowns were each manufactured and tested using both the SRT and the two-dimensional section of the 3DSA. The data were analyzed with the nonparametric version of a two-way analysis of variance using rank-transformed values and the Tukey's post-hoc test (${\alpha}=.05$). RESULTS. Significant differences were observed between the fabrication methods in the marginal gap (P < .010), deep chamfer (P < .001), axial wall (P < .001), and occlusal area (P < .001). A significant difference in the occlusal area was found between the two measurement methods (P < .030), whereas no significant differences were found in the marginal gap (P > .350), deep chamfer (P > .719), and axial wall (P > .150). As the 3DSA method is three-dimensional, it allows for the measurement of arbitrary points. CONCLUSION. All of the three fabrication methods are valid for measuring clinical objectives because they produced prostheses within the clinically acceptable range. Furthermore, a three-dimensional superimposition analysis verification method such as the silicone replica technique is also applicable in clinical settings.

• 한국기계연구소 소보
• /
• 통권19호
• /
• pp.163-169
• /
• 1989

Many computer programs are being developed to aid the design of physical models. These efforts highlight the importance of computer model of three dimensional object. In this paper a CAD application program is introduced which can be implemented to modeling some part that composed with 3 types of surface form ; free form surface, fillt surface, surface of revolution, and a geometry description language which can represent a shape efficiently is preseneted.

• 한국CDE학회논문집
• /
• 제14권3호
• /
• pp.137-149
• /
• 2009

For recent years, there has been significant research achievement on the feature-based multiresolution modeling technique along with widely application of three-dimensional feature-based CAD system in the areas of design, analysis, and manufacturing. The research has focused on several topics: topological frameworks for representing multiresolution solid model, criteria for the LOD, generation of valid models after rearrangement of features, and applications. This paper surveys the relevant research on these topics and suggests the future work for dissemination of this technology.

• 대한치과의사협회지
• /
• 제56권11호
• /
• pp.616-621
• /
• 2018

This clinical case highlights the failure of long length implants, and the prosthodontic procedures necessary to rehabilitate the maxillary dentition of a patient with microstomia. The integrated digital technology of intra-oral scanning, computer-aided design, and three-dimensional printing can provide an alternative method to make conventional impressions for patients with microstomia who cannot insert the appropriate tray in their mouths.

• 대한치과교정학회지
• /
• 제51권6호
• /
• pp.375-386
• /
• 2021

Objective: To evaluate the accuracy of a one-piece bracket jig system fabricated using computer-aided design and manufacturing (CAD/CAM) by employing three-dimensional (3D) digital superimposition. Methods: This in vitro study included 226 anterior teeth selected from 20 patients undergoing orthodontic treatment. Bracket position errors from each of the 40 arches were analyzed quantitatively via 3D digital superimposition (best-fit algorithm) of the virtual bracket and actual bracket after indirect bonding, after accounting for possible variables that may affect accuracy, such as crowding and presence of the resin base. Results: The device could transfer the bracket accurately to the desired position of the patient's dentition within a clinically acceptable range of ± 0.05 mm and 2.0° for linear and angular measurements, respectively. The average linear measurements ranged from 0.029 to 0.101 mm. Among the angular measurements, rotation values showed the least deviation and ranged from 0.396° to 0.623°. Directional bias was pronounced in the vertical direction, and many brackets were bonded toward the occlusal surface. However, no statistical difference was found for the three angular measurement values (torque, angulation, and rotation) in any of the groups classified according to crowding. When the teeth were moderately crowded, the mesio-distal, bucco-lingual, and rotation measurement values were affected by the presence of the resin base. Conclusions: The characteristics of the CAD/CAM one-piece jig system were demonstrated according to the influencing factors, and the transfer accuracy was verified to be within a clinically acceptable level for the indirect bracket bonding of anterior teeth.

• 한국염색가공학회지
• /
• 제18권1호
• /
• pp.33-43
• /
• 2006

The purpose of this study was to eximine the effect of different yam twisting methods on mechanical properties and 3D CAD images of plain knitted fabrics made of composite yarns. Six yams were used in this study: four different composite yams of the six consist of acetate and functional polyester (Poly-m) with the ratio of 70:30, and the rest two are the original acetate $100\%$ yam and the poly-m $100\%$ yarn. The four kinds of composite yarns were processed in combinations of twisting processes such as interlacing, false twisting, two for one twisting, combined twisting and single covering, and the two original yams were knitted without any twisting process. Sixteen mechanical properties of all the six knitted fabrics, knitted under the same knitting conditions, were measured by KES-FB system with the outer knit condition. The results were as follows; 1) When the sample applied with the false twisting process at the temperature as high as $220^{\circ}C$, ENT, B, HB, G and RC values of samples increased which leads to increasing dimensional stability. 2) To gain the high bending and shear properties in the single covering process, selecting the core yarn with such properties is the most important factor. 3) Interlacing process effected to increase RC value. 4) False twisting process after interlacing process gave bulkiness and un-interlaced part in yam was increased SMD value. The SMD value of the kilted fabric of the composite yarn, which was put through the combined twist process, was higher than those of which simple process such as the two for one twist or the single covering process applied. In order to achieve the silk-like surface feel of knitted fabric, the sin91e covering process is recommended. 5) Examining the simulation images of the knifed fabrics of composite yarn, which were generated by the 3D CAD system based on the mechanical properties of the fabric, led that appearance could be changed as different twisting methods were applied.

• 대한치과기공학회지
• /
• 제40권1호
• /
• pp.1-8
• /
• 2018

Purpose: The purpose of this study is to evaluate the trueness and fitness of machined prostheses according to drill radius setting in CAD software. Methods: For this study, standard abutment were replicated in Type IV stone. The stone abutment were scanned using a dental scanner. The CAD design software was designed using scanned abutment data. When designing, the drill radius was set to 0.3 mm and 0 mm, respectively, and saved. The saved design data was milled using a milling machine (n=13). The inner surface of the milled crown was scanned. The trueness and fitness were measured using the inner scan data of prostheses. Independent t-tests were performed to identify significant differences in each data. Results: Trueness values of the data saved with 0.3 mm and 0 mm drill radius were $18.9{\pm}2.3{\mu}m$ and $19.1{\pm}0.9{\mu}m$, respectively. There was no statistically significant difference between the groups. Fitness values of the data saved with 0.3 mm and 0 mm drill radius were $65.5{\pm}0.8{\mu}m$ and $33.8{\pm}1.0{\mu}m$, respectively. There was a statistically significant difference between the groups (p<.05). Conclusion : Setting the drill radius is important to produce clinically good fit prostheses.

• 보존과학회지
• /
• 제27권2호
• /
• pp.181-190
• /
• 2011

2006년 전남 고흥군 안동고분에서 발굴된 5세기의 백제 금동관모의 3D 스캐닝작업을 통하여 정밀실측 및 디지털 영상복원을 실시하였다. 3D 스캐닝은 대상물의 정밀한 형상을 3차원 공간상에 구현하여 디지털데이터로 보존하는데 목적이 있다. 데이터 구축은 3차원 형상과 색상정보를 획득하는 과정인 3D 스캐닝(부위별 원시 데이터 촬영) - 3D 모델링(원시 데이터 정합 및 비촬영부 재생과 손실부 복원) - CG영상 제작 순으로 이루어 졌다. 복원 CG영상은 원시데이터의 정합된 형상을 기초근거로 하였고 도면상(CAD)의 각 부재 실측 수치를 참고하여 제작하였다. 이때 비촬영 부분과 소실된 부분은 각 부재의 실측자료와 더불어 옛 백제지역에서 출토된 5~8세기의 관모들을 조사하여 복원하였다. 이러한 3D영상 복원은 손상된 유물의 복원방법 중 하나로써 고증과 검증을 통해 유물의 직접적인 손상 없이 유물을 재구성하여 복원함으로써 역사적 및 학술적 가치향상과 유물 복원에 의미가 있다고 하겠다.

• 한국공작기계학회논문집
• /
• 제13권1호
• /
• pp.48-54
• /
• 2004

This paper describes the development of automatic shape design program for spur gear. It produces automatically third-dimensional surface and solid model used in CAD/CAM system with inputting simple measurements. This program can maximize user's convenience and get surface and solid model quickly as accepting GUI(graphic user interface). Automatic shape design program for spur gear was developed by Visual LISP, a developer program. Besides, a geometrical method and a mathematical algerian are used in this program. Use frequency of a fine spur gear is on the increase recently and manufacture process of this gear is heat treatment after press processing with molding. In this press processing, the upper punch portion of a fine spur gear shape is drafted by CAM. Therefore, estimated that surface and solid model of spur gear used to CAM are needed in this research. In this research, after 2 ㎜ gear was modeled by auto shape design program, the upper punch portion of a fine spur gear was manufactured as giving third-dimensional model to CAM software and then, displayed the result as applying to press process.

• 복식문화연구
• /
• 제10권4호
• /
• pp.377-391
• /
• 2002

The purpose of this study was to research grading work according to the targets of women's wear manufacturers in Korea. For the questionnaire, 91 women's wear brands, which were in higher ranking of sales, were selected, and the age groups were separated into 3: 20's, 30's, and 40's & 50's, according to their customers. The graders of each brand were questioned about 20 items for this research. The results of the questionnaire were as follows: 1 The brands for older women manufactured more sizes and cared more about somatotypes fur grading than other brands did. 2. For upper garments on the basis of bust girth, the numbers of dimensional increments were different depending on the age groups: 9 for 20's, 7 for 30's, and 7 for 40's & 50's. 3. For lower garments on the basis of hip girth, the numbers of dimensional increments were different depending on the age groups: 9 for 20's, 6 for 30's, and 5 for 40's & 50's. 4. As a model size of grading, many brands used the smallest size, but the brands for 40's & 50's also used the second size. 5. The parts needed to be corrected after grading were sleeve ease, armhole, shoulder line, neckline, crotch curve, etc. The grading with CAD system had more correction after grading than hand grading.