• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.341-349
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• 2021

The evaluation of occlusion using digital methods is easier and simpler in terms of recording, comparison, analysis, and objectivity compared to existing methods such as articulating paper and occlusion foil. The purpose of this case report was utilizing the digital method for evaluating occlusion. The occlusion of patient requiring full veneer crown restoration was evaluated using an intraoral scanner (i500, Medit, Seoul, Korea) at every visit. The occlusion was also assessed using conventional articulating paper and a digital occlusal analysis system (Dental prescale II, GC corp., Tokyo, Japan) for comparison. Throughout the treatment process, the intraoral scanner and the conventional articulating paper method showed similar outcomes. The results suggest that the use of digital evaluation system is highly probable in the near future.

• Progress in Medical Physics
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• v.31 no.4
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• pp.163-171
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• 2020

Purpose: In this study, the accuracies of electron Monte Carlo (eMC) calculation algorithms were evaluated to determine whether electron beams were modeled by optional air profiles (APs) designed for each applicator size. Methods: Electron beams with the energies of 6, 9, 12, and 16 MeV for VitalBeam (Varian Medical System, Palo Alto, CA, USA) and 6, 9, 12, 16, and 20 MeV for Clinac iX (Varian Medical System) were used. Optional APs were measured at the source-to-detector distance of 95 cm with jaw openings appropriate for each machine, electron beam energy, and applicator size. The measured optional APs were postprocessed and converted into the w2CAD format. Then, the electron beams were modeled and calculated with and without optional APs. Measured profiles, percentage depth doses, penumbras with respect to each machine, and energy were compared to calculated dose distributions. Results: For VitalBeam, the profile differences between the measurement and calculation were reduced by 0.35%, 0.15%, 0.14%, and 0.38% at 6, 9, 12, and 16 MeV, respectively, when the beams were modeled with APs. For Clinac iX, the differences were decreased by 0.16%, -0.31%, 0.94%, 0.42%, and 0.74%, at 6, 9, 12, 16, and 20 MeV, respectively, with the insertion of APs. Of note, no significant improvements in penumbra and percentage depth dose were observed, although the beam models were configured with APs. Conclusions: The accuracy of the eMC calculation can be improved in profiles when electron beams are modeled with optional APs.

• The Journal of Advanced Prosthodontics
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• v.14 no.5
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• pp.294-304
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• 2022

PURPOSE. The purpose of this study was to evaluate the influence of different palatal vault configurations on the accuracy and scan speed of intraoral scans (IO) of completely edentulous arches. MATERIALS AND METHODS. Three different virtual models of a completely edentulous maxillary arch with different palatal vault heights- Cl I moderate (U-shaped), Cl II deep (steep) and Cl III shallow (flat)-were digitally designed using CAD software (Meshmixer; Autodesk, USA) and 3D-printed using SLA-based 3D-printer (XFAB; DWS, Italy) (n = 30; 10 specimens per group). Each model was scanned using intraoral scanner (Trios 3; 3Shape^TM, Denmark). Scanning time was recorded for all samples. Scanning accuracy (trueness and precision) were evaluated using digital subtraction technique using Geomagic Control X v2020 (Geomagic; 3DSystems, USA). One-way analysis of variance (ANOVA) test was used to detect differences in scanning time, trueness and precision among the test groups. Statistical significance was set at α = .05. RESULTS. The scan process could not be completed for Class II group and manufacturer's recommended technique had to be modified. ANOVA revealed no statistically significant difference in trueness and precision values among the test groups (P=.959 and P=.658, respectively). Deep palatal vault (Cl II) showed significantly longer scan time compared to Cl I and III. CONCLUSION. The selection of scan protocol in complex cases such as deep palatal vault is of utmost importance. The modified, adopted longer path scan protocol of deep vault cases resulted in increased scan time when compared to the other two groups.

• The Journal of Advanced Prosthodontics
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• v.16 no.1
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• pp.57-65
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• 2024

PURPOSE. The aim of this stuldy was to compare the clinical marginal fit of CAD-CAM inlays obtained from intraoral digital impression or addition silicone impression techniques. MATERIALS AND METHODS. The study included 31 inlays for prosthodontics purposes of 31 patients: 15 based on intraoral digital impressions (DI group); and 16 based on a conventional impression technique (CI group). Inlays included occlusal and a non-occlusal surface. Inlays were milled in ceramic. The inlay-teeth interface was replicated by placing each inlay in its corresponding uncemented clinical preparation and taking interface impressions with silicone material from occlusal and free surfaces. Interface analysis was made using white light confocal microscopy (WLCM) (scanning area: 694 × 510 ㎛²) from the impression samples. The gap size and the inlay overextension were measured from the microscopy topographies. For analytical purposes (i.e., 95-%-confidence intervals calculations and P-value calculations), the procedure REGRESS in SUDAAN was used to account for clustering (i.e., multiple measurements). For p-value calculation, the log transformation of the dependent variables was used to normalize the distributions. RESULTS. Marginal fit values for occlusal and free surfaces were affected by the type of impression. There were no differences between surfaces (occlusal vs. free). Gap obtained for DI group was 164 ± 84 ㎛ and that for CI group was 209 ± 104 ㎛, and there were statistical differences between them (p = .041). Mean overextension values were 60 ± 59 ㎛ for DI group and 67 ± 73 ㎛ for CI group, and there were no differences between then (p = .553). CONCLUSION. Digital impression achieved inlays with higher clinical marginal fit and performed better than the conventional silicone materials.

• The Journal of Advanced Prosthodontics
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• v.16 no.4
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• pp.201-211
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• 2024

PURPOSE. The aim of this prospective clinical study was to compare the influence of palatal vault forms on accuracy and speed of intraoral (IO) scans in completely edentulous cases. MATERIALS AND METHODS. Based on the palatal vault form, participants were divided into three equal groups (n = 10 each); Class I: moderate; Class II: deep; Class III: flat palatal vault. A reference model was created for each patient using polyvinylsiloxane impression material. The poured models were digitized using an extraoral scanner. The resultant data were imported as a solid CAD file into 3D analysis software (GOM Inspect 2018; Gom GmbH, Braunschweig, Germany) and aligned using the software's coordinate system to determine its X, Y, and Z axes. Five digital impressions (DIs) of maxilla were captured for each patient using an intraoral scanner (TRIOS; 3Shape A/S, Copenhagen, Denmark) and the resultant Standard Tessellation Language (STL) scan files served as test models. Trueness was evaluated by calculating arithmetic mean deviation (AMD) of the vault area between reference and test files while precision was evaluated by calculating AMD between captured scans to measure repeatability of scan acquisition. The scan time taken for each participant was also recorded. RESULTS. There was no significant difference in trueness and precision among the groups (P = .806 and .950, respectively). Average scan time for Class I and III palatal vaults was 1 min 13 seconds and 1 min 37 seconds, respectively, while class II deep palatal vaults showed the highest scan time of 5 mins. CONCLUSION. Palatal vault form in edentulous cases has an influence on scan time. However, it does not have a substantial impact on the accuracy of the acquired scans.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.289-296
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• 2014

The rebar detailing is an important work influencing the final performance and quality of RC structures. But it is one of the most irrational and illogical activity in construction site. Many groups of workers, including main contractors, structural engineers, shop drawers, rebar fabricators, and etc., participate in this activity. A loosely-organized process for this activity is apt to produce a big amount of rebar loss or even degraded structures. A 3-dimensional rebar auto-placing system, called as Rebar Hub, has been designed and implemented in this research. Rebar Hub provides a totally integrated service from 3D structural modeling of buildings to rebar auto-placing considering anchorage, splice, and the length of ordered rebar. In addition, Rebar Hub can recognize the 2D drawing CAD files and then build 3D structural models which are used for the start point of 3D rebar auto-placing. After rebar auto-placing, each members of the 3D structural model have rebar information belonging to them. It means that the rebar information can be used for the afterward works such as quantity-survey, manufacturing and fabrication of rebars. Rebar Hub is showing outstanding performance while applying to practical projects. It has almost five times productivity and reduces the rebar loss up to 3~8% of the initially-surveyed amount of rebar.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.4
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• pp.233-241
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• 2022

Purpose: The purpose of this study was to assess the dimensional change of 3D-printed dentures after post-curing. Materials and Methods: The upper and lower dentures were designed in Exocad DentalCAD software and exported as STL files. The upper and lower dentures were printed from 10 STL files using a DLP-type dental 3D printer. The printed upper and lower dentures were cleaned, and a scan file was created using a model scanner before and after post-curing. The dimensional change was evaluated by superimposing the scanned denture files before and after post-curing and measuring the distance between measurement points on the denture. SPSS was used for statistics, and the level of significance was 5%. Results: The maxillary denture reduced in size during post-curing, with the most notable color change occurring in the posterior palatal region. The reduction in anteroposterior maxillary denture length (A-D, A-E, A-F), as well as the distance between the first molars on both sides (B-C), was statistically significant. After post-curing, the mandibular denture showed more noticeable color change in the posteriorly buccal and lingual region. The decrease of length on the posterior (A-M, A-D, A-E, A-L, A-H, A-I, H-I) and lingual (J-K, L-M) sides of the denture were statistically significant. Conclusion: There was significant dimensional change in both the length and width of the 3D-printed maxillary and mandibular dentures after post-curing in this experiment. Consequently, it is seemed necessary to develop post-curing techniques and materials that reduce such denture deformation.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.5
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• pp.83-97
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• 1998

This paper developes an integrated environment CAD system that can design and implement an accurate and cost-effective FLC automatically. For doing this, an integrated development environment (IDE) (called FADIS; FLC Automatic Design and Implementation Station) is built by the seemless coupling of many existing. CAD tools in an attempt to the FADIS performs various functions such that (1) i~utomatically generate the VHDL components appropriate for the proposed FLC architecture from the various design parameters (2) simulate the generated VHDL code on the Synopsys's VHDL Simulator, (3) automatically compiler, (4) generate the optimized, placed, and routed rawbit files from the synthesized modules by Xilinx's XactStep 6.0, (5) translate the rawbit files into the downloadable ex- [:cution reconfigurable FPGA board (VCC's EVCI), and (7) continuously monitor the control status graphically by communicating the FLC with the controlled target via S-bus. The developed FADIS is tested for its validity by carrying out the overall procedures of designing and implementing the FLC required for the truck-backer upper control, the reduction of control execution time due to the controller's FPGA implementation is verified by comparing with other implementations.

• The Korean Journal of Emergency Medical Services
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• v.8 no.1
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• pp.149-160
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• 2004

Background : To save out-of-hospital cardiac arrest cases is a major concern for Korea. Cardiac arrest is a very common problem, with > 18,000 cases dying each year in Korea. Overall, survival to hospital discharge remains poor. Resuscitation has become an important multidisciplinary branch of medicine, demanding a spectrum of skills and attracting a plethora of specialities and organizations. Since the "Utstein Style" was advocated in 1991, many reports about out-of-hospital cardiac arrest have been published based on this guideline. These differences prevent valid inter-hospital and international comparisons. However, we do not know the true effectiveness of resuscitation. There are no guideline for reviewing, reporting, conducting research on resuscitation in Korea. This study evaluated the out-of-hospital factor associated with survival discharge of out-of-hospital cardiac arrest, was especially to provide basic data for the unified reporting guideline of resuscitation in Korea. Methods : From January 1990 to July 2004, we collected data about out-of-hospital cardiac arrest at Wonju Christian Hospital(WCH-CAD), Ewha Women University Mokdong Hospital(Ewha-CAD), I used same record form based on the "Utstein Style". The "Utstein Style" is internationally recommended guidelines for reporting outcome data from resuscitation events. Results : Resuscitation was performed in 1443 out-of-hospital cardiac arrest patients at 2 hospitals. Five hundred eighty(40.25%) patients recovered the spontaneous circulation at least once and One hundred sixty eight(11.66%) patients discharged alive. Initial EKG showed Ventricular Tachycardia/Ventricular Fibrillation in One hundred thirty five(9.33%) patients, asystole in one thousand nine(69.73%) patients and other rhythms in one hundred thirty nine(20.94%) patients. Among one hundred two cardiogenic cardiac arrest patients, two(2.0%) patients was discharged alive. Conclusion : Overall survival rate of out-of-hospital cardiac arrest patients was 11.66% which was poorer than that of the western country. The proportion of the cardiogenic cause was 33.38% which was only half of the western country. VT/VF is relatively not common ac a initial EKG rhythm. These differences might be to due difference in the prevalence pattern of out-of-hospital cardiac arrest as well as prematurity of the EMSS. It is needed that the best survival can be achieved if all following links have been optimized : rapid access, early CPR, early defibrillation, early ACLS.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.35-45
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• 2013

Facility Management is the longest in the building of life cycle. Because it occupies more than 80% of cost, the phase of Facility Management has to be managed and has to be perceived as important as design and construction phase. The method to manage building more efficiently is the introduction of Facility Management System used by CAD and database. But information Requirement is now input by hand in the most Facility Management System. This study aims to analyze the example of applying BIM in the Korea or abroad and the errors of this were deducted by many phase. Lastly, the possible solution is suggested in order to be used in the Facility Management System. This study's benchmarking is COBIE which is developed by the COE(Corps of Engineers) and now popular in the world. The suggestion in this study is the method that I have already mentioned is helpful for a designer to do modeling when a designer uses BIM S/W(software). To be more specific, the method plays a side role in helping data input considering the phase of Facility Management.