• The korean journal of orthodontics
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• v.20 no.1
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• pp.87-100
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• 1990

This study was designed to compare the craniofacial structure of orthodontic patients with that of normal adult. For that purpose, 61 male and 64 female adults with normal occlusion were selected and utilizing the cephalogram that had taken under the natural head position and computerized graphic image, the special position of each anatomical structure against true horizontal and vertical reference plane was investigated. The following results were obtained. 1. The absolute special positions of each anatomic structure were calculated. 2. The inclination of Sella-Nasion plane to true horizontal plane was $8.3^{\circ}{\pm}3.9$ in male and $9.3^{\circ}{\pm}3.2^{\circ}$ in female. 3. The inclination of Frankfort horizontal plane to true horizontal plane was $1.3^{\circ}{\pm}3.0^{\circ}$ in male and $1.7^{\circ}{\pm}3.0^{\circ}$ in female. 4. The dimensions of Nasion-sella and Nasion-Anterior nasal spine to be used as the basic units of mesh diagram were $70.7mm{\pm}3.1mm$, $61.8mm{\pm}2.7mm$ in male and $67.8mm{\pm}3.3mm$, $57.0mm{\pm}2.6mm$ in female respectively. 5. The standard templates of craniofacial structure of male and female adult normal group were constructed. 6. The mesh diagrams of craniofacial structure of male and female adult normal group were constructed.

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.97-105
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• 2001

In many cases of orthodontic treatment the upper anterior teeth are retracted. Periodontal problems may arise during incisor retraction, if the amount of tooth movement and the amount of remodeling in the anterior cortical bone are not the same. Therefore in this study, to find out the relationship between the amount of tooth movement and the amount of bone remodeling during retraction of the upper anterior teeth, lateral cephalograms of 56 female patients over 18-year-old were taken before and after treatment. Among the 56 patients, two groups were divided according to the type of root movement during retraction. 26 patients mainly moved by tipping and 30 by bodily movement. The cephalograms taken before and after treatment were superimposed upon the true horizontal plane. In the Tip-Group, the horizontal bone remodeling/tooth movement ratio was 1:1.63, and in the Torque-Group it was 1:1.66. Because the amount of tooth movement and the amount of bone remodeling were not the same in both groups, in the Tip-Group the root apex moved away from the palatal cortical plate and closer to the labial cortical plate, whereas in the Torque-Group the root moved away from the labial cortical plate and closet to the palatal cortical plate. Therefore, there are limitations in the amount of incisor retraction in patients with a very thin anterior cortical plate in the maxilla, and in patients with severe skeletal discrepancies orthognathic surgery should be considered and when orthodontic camouflage treatment is the only possible method, the orthodontist must be aware of the limitations of treatment.

• Economic and Environmental Geology
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• v.32 no.4
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• pp.365-371
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• 1999

Ture diplacement of a fault monement is calculated from the displacement of the index plane such as bedding on an outcrop surface. The input parameters are the orientations of the index, fault, and outcrop planes. It is also necessary to input the orientation of fault striation and the offset distance of the index plane on the outcrop surface. The distances of the total, strike, horizontal and dip slip components of the fault movement are calculated from the input parameters. Hwang(1998) conducted a simlar calculation using trigonoment method. To apply the previous method, the offset distance of the index plane must be measured on a vertical outcrop surface. The calculation method of this study accepts the offset distence of index plane on an outcrop plane of any orientation. Calculation results from both method are indentical, regardless of the simplicity of the new method.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.4
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• pp.345-352
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• 1999

This study was conducted for the purpose of suggestion of the new technique of sagittal split ramus osteotomy pararell to the true sagittal plane. This pararellism is the important concept of the sagittal split ramus osteotomy to reduce the condylar sagging including mandibular hypomobility, temporomandibular disorder, occlusal relapse and other complications. We used 26 adult dry manibles(52 rami), and obtained the computed tomographs through the sagittal, horizontal and coronal sections. The results were obtained as follows. 1. On sagittal section, mean area of S1 was $8.63{\pm}2.10cm^2$, S2 was $8.93{\pm}1.94cm^2$, S3 was $9.49{\pm}2.15cm^2$, S6 was $10.72{\pm}2.22cm^2$. The wider area of sagittal section, the more lateral section, But, no significant differency between the areas of the sagittal sections(P>0.05). 2. On horizontal section, The distance between the inferior alveolar canal and the lateral cortical plate of the mandibular ramus were $6.73{\pm}1.24mm$ minum, $7.70{\pm}1.44mm$ maximum. 3. On coronal section, Outer mandibular angle were $4.84{\pm}2.37^{\circ}$ right side, $4.93{\pm}2.12^{\circ}$ left side. 4. The design of the ideal true sagittal split ramus osteotomy is that posterior border of osteotomy must be limited vertically, at the right posterior point of lingula mandibularis and anterior of osteotomy must be extended to mandibular body, anteroinferiorly.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.514-520
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• 2008

Purpose: Many attempts have been made to describe ideal facial proportions for over two thousands year and constantly lasted till now. Dr. Marquardt has derived supposedly ideal facial proportions from the facial golden mask using golden ratio of 1 : 1.618. On the other hand, facial reducing surgeries such as mandible angle reduction are popularized in Asia because the width of mid and lower face of Korean is recognized to be wider. The purpose is to analyze characters of Korean university students' faces in horizontal plane and establish the objective data for facial width distributions and clinical applications. Methods: We applied the facial golden mask to the photographs in 1000 cases, compared the width of mid and lower face between the facial golden mask and Korean university students' faces. And we first calculated the horizontal ratio(HR) of middle and lower face each for using comparative scale of width, facial golden mask. We divided 1,000 cases into 3 groups by degrees of HR and analyzed data of HR on each groups. Using calculated horizontal ratio, we newly invented the cumulative frequency of distribution graphs in Korean university students' faces. Results: Mean data of HR were over 1.0 in all groups, which means that Korean university students' faces are typically wider than facial golden mask in horizontal planes. And this study was statistically significant(p- value < 0.05). Clinically using the cumulative frequency distributions of Korean university students' face width, we can easily explain changes of facial width to patient after facial reducing surgery and describe the changes into objective data. Conclusion: This study concludes thatKorean university students' faces are wider than facial golden mask is significantly true and the cumulative frequency of distribution graphs are expected to be widely used for comparison of results in facial reducing surgery.

• The korean journal of orthodontics
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• v.50 no.1
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• pp.3-12
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• 2020

Objective: This study compared three prominent midsagittal planes (MSPs) to identify the MSP that best approximates the true symmetrical MSP. Methods: Forty-three patients (mean age, 23.0 ± 8.20 years) were grouped as follows: group 1 consisted of 10 patients with skeletal Class I and a menton (Me) deviation of < 2 mm; group 2, 11 patients with skeletal Class III and a Me deviation < 2 mm; group 3, nine patients with skeletal Class III and a Me deviation of 2 to less than 4 mm; and group 4, 13 patients with skeletal Class III and an Me deviation ≥ 4 mm. The candidate MSPs were established by three-dimensional (3D) cone beam computed tomography (CBCT) reorientation methods (RMs): (1) the MSP perpendicular to the Frankfort horizontal (FH) plane while passing through the crista galli and basion; (2) the MSP including the nasion, incisive foramen, and basion; (3) the MSP including the nasion, anterior nasal spine, and posterior nasal spine. The mean absolute distances (MADs) to the MSPs were calculated from the coordinates of 1,548 points on 129 CBCT images. The differences in the values of the 3D coordinates among RMs were compared. Results: The MADs of the three RMs showed significant differences (p < 0.05). Most of the differences in values of the coordinates were not significant among RMs. Conclusions: Although the differences in distance among the three MSPs were minor, the MSP perpendicular to the FH plane while passing through the crista galli and basion best approximated the true symmetrical MSP.

• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.125-130
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• 2016

PURPOSE. The purpose of this study was to determine the effect of changes in the horizontal plane angle on the mesiodistal width ratios of the maxillary anterior teeth during the acquisition of frontal view photographs, derive these ratios for Korean adults on the basis of the data obtained, and analyze them using the Golden Proportion as a reference. MATERIALS AND METHODS. In experiment I, 30 plaster casts were mounted on an articulator and positioned on the angle-measuring device with a center setting of $0^{\circ}$. The device was rotated to $10^{\circ}$ in $1^{\circ}$ increments in a counterclockwise direction. At each angle, photographs were obtained and analyzed. Experiment II was based on 60 patients who visited the Department of Prosthodontics at Kyungpook National University Dental Hospital from February 2012 to February 2015. The patients were divided into three groups [Male (M), Female (F), Total (M + F)]. Frontal views were obtained for all groups and analyzed. RESULTS. From $1^{\circ}$ to $10^{\circ}$, the relative mesiodistal width ratios for the maxillary anterior teeth showed no significant differences from those at $0^{\circ}$. In all three groups, the relative width ratio of the maxillary central incisor was smaller than that specified in the Golden Proportion; the opposite was true for the canine. CONCLUSION. Our results suggest that the mesiodistal width ratios of the maxillary anterior teeth do not follow the Golden Proportion in Korean adults, and that a change in the horizontal plane angle from $1^{\circ}$ to $10^{\circ}$ during frontal photography does not affect these ratios.

• The korean journal of orthodontics
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• v.40 no.6
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• pp.421-431
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• 2010

Objective: This study aimed to verify the intra-individual reproducibility of the natural head position (NHP) in adult Korean patients in the centric relation (CR) position and to prove the inter-individual variability of the Frankfurt horizontal (FH) plane and sella-nasion (SN) line compared to the true horizontal line (THL). In addition, the study aimed to investigate the correlations between linear measurements from A-point and B-point to the nasion true vertical line (NTVL) and angular measurements from A-point and B-point to the SN line. Methods: Two lateral cephalograms were taken of 116 subjects (23 males, 93 females) with CR wax bites in a NHP at a one-week interval. Results: Method errors of three variables and intraclass correlation coefficients of six parameters proved the intra-individual reproducibility of NHP (p < 0.001). The angle of the FH to the THL was not significantly different from $0^{\circ}$ (p > 0.05), but it was clinically variable (SD $3.89^{\circ}$) on the inter-individual level. Conversely, the angle of the SN line to the THL was significantly different from $7^{\circ}$ (p < 0.05). Very low correlation was found between the linear measurements and angular measurements of A-point and B-point (p < 0.01). Conclusions: The NTVL could be a useful reference line for assessing the antero-posterior position of the maxilla and mandible of Korean adult patients in NHP and CR.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.352-361
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• 2003

We have evaluated the extent of saltwater intrusion from electrical resistivity distribution in a coastal aquifer system in the southeastern part of Busan, Korea. This aquifer system is divided into four layers according to the hydrogeologic characteristics and the horizontal extent of intruded saltwater is determined at each layer through the geostatistical interpretation of electrical resistivity data. In order to define the statistical structure of electrical resistivity data, variogram analysis is carried out to obtain best generalized covariance models. IRF-k (intrinsic random function of order k) kriging is performed with covariance models to produce the plane of spatial mean resistivities. The kriged estimates are evaluated by cross validation to show a good agreement with the true values and the statistics of cross validation represented low errors for the estimates. In the resistivity contour maps more than 5 m below the surface, we can see a dominant direction of saltwater intrusion beginning from the east side. The area of saltwater intrusion increases with depth. The northeast side has low resistivities less than 5 ohm-m due to the presence of saline water in the depth range of 20 m through 70 m. These results show that the application of geostatistical technique to electrical resistivity data is useful for assessing saltwater intrusion in a coastal aquifer system.

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.253-262
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• 2017

In lateral projection imaging method of knee joint, a method that adjusts the incidence angle of central X-ray toward the head side to $5{\sim}7^{\circ}$ in true lateral position which is existing recommended is called imaging method A, Method of imaging the central X-ray perpendicular to the horizontal plane of the examination table toward the knee is called imaging method B, and a method in which the central X-ray is perpendicularly applied to the joints while the lateral side of the distal tibia is compensated by radiolucent materials is called as method C. After tests each imaging method to classified study subject respectively, the joint space distance and the distance between lateral and medial condyle of femur were measured and compared as the quantitative index from the three imaging methods. In addition, the convenience of each imaging method was confirmed through questionnaires to practician. According to the result of the quantitative index, there is no statistically significant difference in imaging method A and C(p>0.05). However, imaging method B showed a significant difference in both A and C(p<0.05). As a result of evaluating the convenience of the imaging method, imaging method A was relatively assessed lower in all items than imaging methods B and C, and as a small difference, imaging method B is assessed higher than C. In this study suggested new knee joint lateral projection imaging method, by using a simple support device, could describe joint space as not much different as existing recommended method without some complex process, and could increase convenience of the practician in the process of the imaging.