• 대한치과교정학회지
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• 제19권1호
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• pp.169-185
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• 1989

정상교합 및 안모가 단정한 성인(남자 60명, 여자 62명)을 대상으로 악교정수술을 위한 한국인 기준치를 얻고자 측모 두부방사선 규격사진을 이용하여 계측 분석과 결과 다음과 같은 결론을 얻었다. 카 계측항목의 평균치, 표준편차를 구하였다. 골격계측 항목중 각도계측치에서는 FH-SN과 SN-MP가 여자에서 더 크며, 거리계측치에서는 전 항목에서 남자가 더 큰 것으로 나타났다. 치아계측 항목에서는 수직적 관계를 나타내는 항목에서만 남녀간에 유의한 차를(P<0.05) 보였는데 ADH, PDH, overbite에서는 여자가 더 크고 Incisor exposure에서는 여자가 더 크게 나타났다. 연조직계측 항목에서는 NLA를 제외한 전 항목 즉 FCA, UFH, ULL, LLL에서 남자가 여자보다 더 크게 나타났다.

• Imaging Science in Dentistry
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• 제45권2호
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• pp.73-80
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• 2015

Purpose: This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Materials and Methods: Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. Results: Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. Conclusion: Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension.

• Imaging Science in Dentistry
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• 제47권1호
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• pp.11-15
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• 2017

Purpose: This study was performed to investigate the intra- and inter-observer variability in linear measurements with axial images obtained by PreXion (PreXion Inc., San Mateo, USA) and i-CAT(Imaging Sciences International, Xoran Technologies Inc., Hatfield, USA) CBCT scanners, with different voxel sizes. Materials and Methods: A cylindrical object made from nylon with radiopaque markers (phantom) was scanned by i-CAT and PreXion 3D devices. For each axial image, measurements were taken twice in the horizontal(distance A-B) and vertical (distance C-D) directions, randomly, with a one-week interval between measurements, by four oral radiologists with five years or more experience in the use of these measuring tools. Results: All of the obtained linear measurements had lower values than those of the phantom. The statistical analysis showed high intra- and inter-observer reliability (p=0.297). Compared to the real measurements, the measurements obtained using the i-CAT device and PreXion tomography, on average, revealed absolute errors ranging from 0.22 to 0.59 mm and from 0.23 to 0.63 mm, respectively. Conclusion: It can be concluded that both scanners are accurate, although the linear measurements are underestimations, with no significant differences between the evaluators.

• 지질공학
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• 제18권1호
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• pp.93-102
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• 2008

최근 국내 터널현장에서는 기존 H형 강지보의 단점을 보완한 격자지보의 사용이 증가하고 있다. 격자지보는 숏크리트와 일체구조를 형성하며 지반을 지지한다. 따라서 지반하중을 산정하기 위해서는 격자지보 계측이 필요하다. 그러나 국내 터널 현장에서 격자지보 계측은 거의 수행되지 않고 있으며 적절한 계측 방법에 대한 이론도 확립되지 못한 상태이다. 숏크리트 계측에서는 무응력 상태에서 지반하중과 관계없이 숏크리트에서 발생하는 변형률에 대한 고려가 필요하지만 이에 대한 보정은 거의 이루어지지 알고 있다. 본 연구에서는 터널 현장에서의 격자지보와 무응력 숏크리트 계측 결과를 분석하여 주지보 계측의 신뢰성을 향상시킬 수 있는 방안을 제시하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.9.1-9.14
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• 2019

Background: There is no normative craniofacial anthropometric data for the Kenyan-African population. The purpose of this investigation was to determine normative anthropometric craniofacial measurements and proportional relationships for Kenyans of African descent and to compare the data with African Americans (AA), North American Whites (NAW), and neoclassical canons. Methods: Twenty-five direct facial anthropometric measurements, and 4 angular measurements, were taken on 72 Kenyan-African participants (age range 18-30 years) recruited at the University of Nairobi in Kenya. The data were compared with AA and NAW populations, and neoclassical canons. Descriptive statistics of the variables were computed for the study population. Results: Significant differences between both Kenyan males and females were detected in forehead height (~ 5 mm greater for males, ~ 4.5 mm for females), nasal height (reduced by ~ 4 mm in males, ~ 3 mm in females), nasal width (8-9 mm greater), upper lip height (> 3 mm), and eye width (greater by ~ 3 mm) compared to NAW subjects. All vertical measurements obtained were significantly different compared with NAW. Differences were observed in comparison with AA subjects, but less marked. Mouth width was similar in all groups. Angular measurements were variable. Neoclassical canons did not apply to the Kenyan population. Conclusions: Anthropometric measurements of NAW showed clear differences when compared with the Kenyan population, and variations exist with comparative AA data. The anthropometric data in terms of linear measurements, angular measurements, and proportional values described may serve as a database for facial analysis in the KenyanAfrican population.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권1호
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• pp.37-45
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• 2001

The errors in orthognathic surgery can occur during the preoperative preparations including the model surgery, but till now there's been some lack of reserches about them. So we wanted to verify the accuracies in measurements used in model surgery. We compared the accuracy of measurements by vernier calipers, which has been the main measurement tool for conventional model surgery, and that by height gauge, which is recently claimed to be more accurate, with 3 dimensional coordinate analyzer. We could have following results and have a plan to use them for the invention of new model surgery techniques. 1. The measurement errors in Group 1, which mean the difference between "the measurements by 3-D analyzer"and "the measurements by height gauge", were small enough with the range of $0.1{\sim}0.2mm$ in all planes. 2. The mean error in Group 2, which is the differences between the measurements of 3-D analyzer and those of vernier calipers, was 1.1mm. 3. The measurement errors in Group 2 were variable according to the factors including the differences of individuality and expertness of each measurers. But in case of Group 1, they were small and not variable by the expertness. 4. The measurements were more accurate at the points in anterior teeth than in molar teeth in Group 1 and 2. 5. The errors after model surgery increased remarkably, compared with those before surgery in Group 2. And the situation was different in Group 1 in that errors decreased after surgery. According to these results, it assumed that the measurements with height gauge during the model surgery for orthognathic surgery are accurate enough and can be maintained, regardless of complexity of models, individuality, or expertness of measurers.

• Imaging Science in Dentistry
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• 제45권1호
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• pp.23-29
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• 2015

Purpose: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning. Materials and Methods: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) $60{\times}60mm$ FOV, $0.125mm^3$ ($FOV_{60}$); 2) $80{\times}80mm$ FOV, $0.160mm^3$ ($FOV_{80}$); and 3) $100{\times}100mm$ FOV, $0.250mm^3$ ($FOV_{100}$). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05. Results: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements. Conclusion: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

• 복식
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• 제56권3호
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• pp.107-115
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• 2006

This study is aimed to personally measure the body of physically handicapped women and compare the measurements to the results of the fifth project to investigate the measurements of the body of Koreans, identity the differences in the measurements in accordance with the subjects' handicap types and age, and find the characteristics of their physical figures, with a view to propose basic data for developing clothes suitable to the body of physically handicapped people. The findings of this study are summarized in the following: 1. There were significant differences in the measurements of the subjects' shoulder width, breast circumference, waist circumference, hip circumference, armpit circumference, left and right upper arms' circumference, length between front walls of the armpit, and length between back walls of the armpit after the subjects' handicap types were classified into paralysis of the lower half of the body, cerebral apoplexy, cerebral palsy, and amputation and the differences in the subjects' bodily measurements were compared and analyzed. 2. The shoulder width gradually increased for those in their 50s or younger while that of those in 60s or older is almost the same as that of those in their 30s. The waist circumference gradually increased in all the subjects. As a result, the present author concludes that the body of physically handicapped women increases the same way as the body of ordinary adult women does in its circumferential measurements as the subjects grow older.

• Clinics in Shoulder and Elbow
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• 제23권3호
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• pp.119-124
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• 2020

Background: This study was performed to compare glenoid version and inclination measured using two-dimensional (2D) images from computed tomography (CT) scans or three-dimensional (3D) reconstructed bone models. Methods: Thirty patients who had undergone conventional CT scans were included. Two orthopedic surgeons measured glenoid version and inclination three times on 2D images from CT scans (2D measurement), and two other orthopedic surgeons performed the same measurements using 3D reconstructed bone models (3D measurement). The 3D-reconstructed bone models were acquired and measured with Mimics and 3-Matics (Materialise). Results: Mean glenoid version and inclination in 2D measurements were -1.705° and 9.08°, respectively, while those in 3D measurements were 2.635° and 7.23°. The intra-observer reliability in 2D measurements was 0.605 and 0.698, respectively, while that in 3D measurements was 0.883 and 0.892. The inter-observer reliability in 2D measurements was 0.456 and 0.374, respectively, while that in 3D measurements was 0.853 and 0.845. Conclusions: The difference between 2D and 3D measurements is not due to differences in image data but to the use of different tools. However, more consistent results were obtained in 3D measurement. Therefore, 3D measurement can be a good alternative for measuring glenoid version and inclination.

• 대한치과교정학회지
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• 제45권6호
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• pp.282-288
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• 2015

Objective: This study investigated whether it is possible to use a two-dimensional (2D) standard in three-dimensional (3D) analysis, by comparing the angles and lengths measured from a midsagittal projection in 3D cone-beam computed tomography (CBCT) with those measured by 2D lateral cephalometric radiography (LCR). Methods: Fifty patients who underwent both LCR and CBCT were selected as subjects. CBCT was reoriented in 3 different methods and the measuring-points were projected onto the midsagittal plane. Twelve angle values and 8 length values were measured on both LCR and CBCT and compared. Results: Repeated measures analysis of the variance revealed statistically significant differences in 7 angular and 5 linear measurements among LCR and 3 types of CBCT (p < 0.05). Of these 12 measurements, multiple comparisons showed that 6 measurements (ANB, AB to FH, IMPA, FMA, Co-Gn, Go-Me) were not significantly different in pairwise comparisons. LCR was significantly different from 3 types of CBCT in 3 angular (SN to FH, interincisal angle, FMIA) and 2 linear (S-Go, Co-ANS) measurements. The CBCT method was similar for all measurements, except for 1 linear measurement, i.e., S-N. However, the disparity between the mean values for all parameters was within the range of clinical measurement error. Conclusions: 3D-CBCT analysis, using midsagittal projection, is a useful method in which the 2D-LCR normative values can be used. Although the measurements changed with reorientation, these changes were not clinically significant.