• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.1
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• pp.69-76
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• 1995

This study is the 3-D precision deformation measurement of a bridge, obtain results of precision control points by GPS and 3-D measurement system and develope efficientlty technices which can solve precision 3-D analysis by CRP In the result, we could overcome the problems of former control point measurement in the way of the combination system of GPS and 3-D measurement system to positioning decision of reference points and control points. Then we could symplify old measurement process on the 3-D deformation analysis of a linear structure and complement parted analysis fault of measurement instrument.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.159-172
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• 2001

Three dimensional analysis of malocclusion and craniofacial deformation is essential for the successful orthodontic treatment. But the orthodontists are not familiar with diagnosis and treatment plane based on lateral cephalometric analysis. Since orthodontists do not posses a sufficient knowledge in standard value of posteroanterior cephalometric anaysis and of clinical importance for transverse jaw growth. In this study male(n=130) and female(n=171) aged from 6 to 16 and diagnosed as Class I malocclusion were selected to analysis width of cranium, maxilla and mandible on the posteroanterior cephalogram. The changes as a function of chronologic age and cervical vertebrae maturity index(CVXI) were examined. The Proper regression model was selected by sex with polynominal regression models and method of variable selection. Mean of each measurements and 70% confidence interval of individual measurement according to age was assesed and a graphs were made. Results are as follows :1. All the measurements for the width are gradually incresed as increase in chronologic age and CVMI. From the total amount of change between age 6 and 16, there is a tendency that mandibular width is broader than maxillary width and the width of male is broader than female. 2. There is no statistically significant sexual difference in Mx-Mn difference, Mx-Mn width differential, Mx/Mn ratio according to age and CVMI. 3. Mean of each measurement and 70% confidence interval of individual measurement according to age and sex were assessed and graphs were made for maxillary width, mandibular width, Mx-Mn difference, Mx/Mn ratio. 4. The width of maxilla and mandible in Korean children are broader than Western children during growth period.

• The korean journal of orthodontics
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• v.36 no.2 s.115
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• pp.136-144
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• 2006

The purpose of this study was to determine whether association exists between temporomandibular joint (TMJ) characteristics in transcranial radiographs and TMJ internal derangement and to evaluate the validity of transcranial radiographs in diagnosis of internal derangement. Transcranial radiographs and magnetic resonance imaging (MRI) of 113 TMJs from 76 subjects were used for this study and all TMJs were classified into 3 groups according to the results of MRI: normal disk position, disk displacement with reduction, and disk displacement without reduction. Transcranial analysis included linear measurement of joint spaces and condylar head angle measurement. To determine any relationship between transcranial measurements according to disk displacement, one-way ANOVA was used. The results showed that condyle-fossa relationship in standard transcranial radiographs had no relationships with disk displacement. And, as disk displacement progressed, condylar angle between head and neck increased significantly. This result can be interpreted that condylar head angle reflects structural hard tissue change according to internal derangement progress. But this is insufficient in the determination of internal derangement. Therefore, although still clinically helpful, the validity of standard transcranial radiographs to diagnose TMJ internal derangement was questioned.

• The korean journal of orthodontics
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• v.25 no.4
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• pp.453-463
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• 1995

Most commonly used axis for central incisors in lateral cephalometric radiographs is the line connecting root apex and incisor edge. However, crown axis and root axis do not always coincide in cases of malocclusion patients. The angle created by these axis are called the collum angle, which should be considered in orthodontic diagnosis and treatment. In this study, 31 Class I malocclusion, 30 Class II division 1 malocclusion, 31 Class II division 2 malocclusion, and 31 Class m malocclusion patients were selected and their collum angles were measured. Correlation between these angles and malocclusions was investigated, and the correlation analysis with other parameters in cephalometrics was done. The results were as follows ; 1. The mean collum angles according to the types of malocclusions are ; $3.11^{\circ}{\pm}3.54^{\circ}$ for Class I, $1.23^{\circ}{\pm}2.41^{\circ}$ for Class II division 1, $3.77^{\circ}{\pm}4.39^{\circ}$ for Class II division 2, and $3.90^{\circ}{\pm}4.08^{\circ}$ for Class III malocclusion. 2. Statistically significant differences in collum angles were noted between Class II division 1 group and Class II division 2 and Class III group. 3. Significant correlations were found between collum angles and other parameters used in cephalometrics, namely IMPA for Class I, Wits for Class II division 1, Overbite for Class II division 2 and for ClassIII.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.119-127
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• 1997

The configuration of mandibular symphysis is likely to be dependent upon the genetic predeterminants and/or compensatory adjustments onto functional demands. The interrelation of morphological distinctives of symphysis in conjunction to the craniofacial skeleton had been scarcely anecdotal, therefore, the objective was to determine the correlation of morphological modifications between the mandibular symphysis and craniofacial complex. Lateral cephalometric headfilms of 212 subjects were employed for the conventional measurements. The proportion of chin height against chin depth length was referred as chin ratio, then, Low Symphysis (IS) and High Symphysis (HS) groups were turned out by means of the chin ratio. These samples yielded 35 in LS and 35 in HS groups. The data per capita were statistically analyzed and the following results were drawn ; 1. Overall characteristics of the craniofacial skeleton in HS group manifested hyperdivergence and LS group showed hypodivergence. 2. Gonial angle increased as chin ratio increased and was highly correlated to the chin ratio. 3. The chin ratio presented high correlation to the vertical face height, especially in terms of the chin height to anterior face height and the chin depth to posterior face height. 4. The morphological configuration of chin was hardly correlated with hyoid bone position.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.283-298
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• 2008

Objective: The purpose of this study was to investigate changes in the mandibular dental arch from presurgical orthodontic treatment and orthognathic surgery, and to evaluate the relationships between the pretreatment records and changes of mandibular dental arch in skeletal Class III malocclusion individuals. Methods: Lateral cephalometric radiographs and mandibular study models of 31 adults with skeletal class III malocclusion were taken and measured. All measurements were evaluated statistically by ANOVA, Scheffe's Post Hoc, and paired t-test, and correlation coefficients were evaluated. Results: No significant difference in Mn-LMMC, Mn-LIE, Mn-MnOcc was detected between pretreatment and presurgical groups. Statistically significant but low correlations were demonstrated between the initial arch length discrepancy (ALD) and change in ICW, IPW1 (r = 0.492, 0.615) and change in arch length (r = 0.641). No association was seen between the initial depth of curve of Spee and change in mandibular incisor angle and arch width or arch length. Regression analysis showed that the amount of change for arch length and IPW1 could be explained by 64.0% and 75.8% of the pretreatment variables respectively. Conclusions: This study suggests that orthognathic surgery results can be predictable by measuring the pretreatment records.

• The korean journal of orthodontics
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• v.36 no.3 s.116
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• pp.218-227
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• 2006

Although the submentovertex radiograph and surface EMG are not often used due to the difficulty of interpretation, they are accepted as useful diagnostic and analytic aids for skeletal asymmetry. There have been reports which state that they were also useful for the evaluation of vertical skeletal relations. The purpose of this study was to evaluate the correlations between EMG data, measurements from submentovertex radiographs, facial types and facial asymmetry following examination of 60 asymmetric patients. The radiographic corpus length were greater in the nonaffected sides (p<0.001), gonion to interspinosum axis were greater in the affected sides and the mandibular condyle and gonion were located more anteriorly in the non-affected sides than in the affected sides but not significant (p=0.07). The activity of the anterior temporal muscle in rest position was higher in the affected sides than in the non-affected sides (p<0.01). The activity of the masseter muscle at maximum clenching was found to be nonsignificant but it was higher in the affected sides than in the non-affected sides (p=0.09). There was positive correlation between facial index and the intercondylar axes angle (p<0.01). There was positive correlation between masseter muscle activity in maximum occlusion and facial index in the affected and non-affected sides (p<0.05). The results demonstrate that the submentovertex radiograph and EMG can provide useful information for the evaluation of horizontal and vertical skeletal relations.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2006.03a
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• pp.217-236
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• 2006

In this study, the LCM was applied as the preliminary study for the cutterhead design of TBM and the drilling performance evaluation. The optimum cutting condition is obtained from the LCM tests and the effects of the design factors of IBM cutterhead, such as penetration depth and cutter spacing, on drilling performance are estimated. In this study, hence, to predict the accurate performance of TBM, instead of one-dimensional penetration depth applied in existing studies, three-dimensional cutting volume was quantified and measured. For this, the digital photogrammetry technique was applied to the LCM tests. Also, AUTODYN 2D was applied to investigate the applicability of the numerical analysis technique to simulate the cutting process of rock by the TBM disc cutter.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.169-185
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• 1989

The purpose of this study was to establish Korean norms that will be valuable aids for diagnosis in orthognathic surgery patients. Lateral cephalometric measurements were established for adult Koreans (60 males, 62 females) with normal occlusion and acceptable profiles. The results were as follows: 1. Means, standard deviation and sexual differentiation were included within each measurement. 2. In skeletal measurements, FH to SN and SN to mandibular plane measurements in females were larger than those in males while all linear measurements in males were larger than those in males were larger than those in females. 3. Significant differences were observed between male and female groups on all of the items that showed vertical relationship in dental measurements. And the measurements of ADH, PDH and overbite in males were larger than those in females while the measurements of incisor exposure in females were larger than those in males. 4. In all measurements of soft tissue except NLA, that is, of FCA, UFH, ULL and LLL, males were larger than those in females.

• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.285-301
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• 1999

There is a need for more accurate prediction in surgical orthodontic treatment. Video imaging is an important technology in planning orthognathic surgery and educating patients about the esthetic results after treatment. Preoperative and postoperative lateral cephalogram of 30 patients who had one piece Le Fort I osteotomy advancement and mandibular set back by bilateral intraoral vertical ramal osteotomy with or without genioplasty were used in this study. The computer generated soft tissue line drawing prediction were compared with the actual postoperative cephalograms .The results are as follows. 1. 14 variables showed Statistically significant differences from 24 variables between computer predicted profile and post operative profile 2. Most of the differences were found in the maxilla-related soft tissue landmarks. 3. The predicted results were more accurate in the groups who had small amount of mandibular set back. 4. The predicted results were more accurate in the groups who had no genioplasty. Most of these differences were within 2mm ranges. Therefore profile change prediction by video imaging could be considered clinically acceptable.