• The korean journal of orthodontics
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• v.30 no.3 s.80
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• pp.343-355
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• 2000

The purpose of this study was to evaluate the amount and interrelationship of hard and soft tissue changes after mandibular setback osteotomy and reduction genioplasty in mandibular prognathism with long anterior facial height. The control group (Group A) consisted of 20 patients who had severe horizontal discrepancy. They experienced Presurgical orthodontic treatment and orthognathic surgery via mandibular setback. The experimental group (Group B) consisted of 20 patients who had severe horizontal and vertical discrepancy. They experienced presurgical orthodontic treatment and orthognathic surgery via mandibular setback and reduction genioplasty. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was tarried on with EXCEL 97 program. The results were as follows : 1. The correlation of hard and soft tissue horizontal changes in lower 2/3 of lower anterior facial height were high for both groups. The correlation coefficients of hard tissue changes and Ls, Stm, Li changes in Group B were moderately higher than Group A. 2. The correlation of hard and soft tissue vortical changes in Group B were lower than Group A. (except for pointB-Ils, Me-Me') 3. The ratio for soft tissue to Pog in Group B was lower than Group A. The ratios of hard and soft tissue vertical changes were 32% at Ils, 54% at Pog', and 60% at Me'. 4. The ratio of lower anterior facial height to total anterior facial height was reduced for both groups. But ratio of upper 1/3 of lower anterior facial height to total anterior facial height did not changed significantly in Group B. 5. Reduction genioplasty combined with mandibular setback procedure showed no change in upper one third(Sn-Stm) and significant decrease(Stm-Me') in the lower two thirds of the soft-tissue anterior lower facial height

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.74-83
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• 2006

Analysis of lateral cephalometric radiograph (cephalogram) has been used routinely to evaluate skeletal and dental relationships, but analysis of the lateral facial photograph has not been used frequently for evaluation of skeletal relationships. As concerns about harm of X-ray irradiation increases, this study was planned to evaluate the possibility of substituting analysis of the lateral cephalogram with analysis of the lateral facial photograph by comparing these two analyses. According to the ANB values from cephalometric analysis, subjects were divided into three groups: Class I malocclusion group (n=32). Class II malocclusion group (n=32), and Class III malocclusion group (n=31). After measurements of angles indicating horizontal and vertical relationships of the maxilla and mandible on the lateral cephalograms and photographs, differences between Class I, II and III groups were evaluated. To evaluate the similarity between two similar values in the cephalograms and photographs, t-test using standardized variable Z and correlation analysis were performed in the Class I malocclusion group. The results showed that 1) SnN'Pg' on the photograph can be used to evaluate the antero-posterior relationship of the maxilla and mandible (ANB), 2) N'-Sn/Sn-Pg' on the photograph can be used to evaluate facial convexity (NA/APg), 3) Sn-Tra-Me' on the photograph can be used as a measurement similar to FMA. In conclusion, partly substituting lateral cephalogram analysis with lateral facial photograph analysis was possible in the evaluation of the maxilla and mandible.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.297-313
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• 1997

The purposes of this study were to compare the soft tissue changes following hard tissue change after surgery between the one jaw and two-jaw surgery in skeletal class III patients and to get the reference of the incisal inclination at presurgical orthodontics. For this study 24 patients for the two-jaw surgery group and 18 patients for one jaw surgery group were selected. Lateral cephalograms were taken at pretreatment, after presurgical orthodontic treatment, immediately after surgical treatment and at least 6 months after surgery. They were traced and analyzed on skeletodental structure and soft tissue. The results were as follows: 1. After surgery, maxilla, maxillary incisors and upper lip were moved anteriorly and superiorly in two-jaw surgery group. Mandible and mandibular incisors were moved posteriorly and superiorly, and thickness of lower lip was increased in both group but there were no statistically significant difference. Anterior facial height was more decreased in two-jaw surgery group (p<0.05). At least 6 months after surgery, by the postorthodontic treatment, maxillary incisors were moved labially 1.44mm, mandible and mandiibular incisors were moved lingually 1.43mrn, 1.26mm respectively in one jaw surgery group. But there was no statistically significant changes of hard tissue in two :jaw surgery group. 2. The correlation coefficients of maxillary hard and soft tissue horizontal changes were high in two jaw surgery group and the ratios for soft tissue to A point were 19% at Sri, 80% at SLS, 82% at LS. The ratios for soft tissue to B point were 92% at LI, 104% at ILS in one jaw surgery group, 89% at LI, 101% at ILS in two-jaw surgery group. 3. The correlation coefficients and change ratios of mandibular incisors and LL HS on lower lip horizontal changes were 0 0.89 and 75%, 85% in one jaw surgery group, 0.93, 0.90 and 76%, 87% in two-jaw surgery group. The correlation coefficients of maxillary incisors and Sn, SLS and LS on upper lip horizontal changes were 072, 0.76 and 0.75 in two jaw surgery group and ratios of changes were 57%, 58% and 59%. 4. The regression equations between skeletal horizontal discrepancy and incisal inclinaton were taken in one jaw surgery group. Those were FMIA=57.48-2.17ANB, U1-SN=-75.02+2.17SNB and $R^2$ were 0.63, 063 respectively. So if there is skeletal horizontal discrepancy by mandibular prognathism in one jaw surgery case, we consider attaining more labial inclination of maxillary incisors than normal and more lingual inclination of mandibular incisors than normal. But correlation coefficient of the regression equations in two jaw surgery group was low, so, that equation was not reliable.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.481-492
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• 1997

In order to investigate the possibility of using a cervical vertebral maturation indicator as a mandibular growth indicator, the relationship of cervical vertebral maturation and mandibular & body height growth changes was assessed in biennial serial lateral cephalometric radiographs of eighteen korean male and fourteen korean female while they were 8.5 to 18.5 years old. The following results were obtained. 1. It was a reliable method to evaluate skeletal maturation by using cervical vertebrae. 2. In general, cervical vertebral maturation stages of females were higher than those of males at the same age and there were significant differences in statistics at the age of 10.5, 14.5. 3. The age of a female at the same cervical vertebral maturation stage were earlier than that of a male. 4. In the case of males, significant Ar-Gn increases were found between stage 3 and 4,5; Ar-Go increases between stage 4 and 5. 5. In the case of females, significant S-Gn and Ar-Gn increases were (end between stage 3 and 4. 6. Significant body height increases were found between stage 3 and 4 in both sexes. 7. The peak velocity of body height and mandibular length was observed between cervical vertebral maturation stage 3 and 4 in both sexes. 8. The relationship between mandibular & body height changes and specific maturation stage of cervical vertebra was found, therfore using a cervical vertebral maturation indicator as mandibular growth indicator is quite within realms of possibility.

• The korean journal of orthodontics
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• v.39 no.2
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• pp.120-129
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• 2009

Objective: To estimate dental maturity using the Demirjian Index for the mandibular third molar and investigate the relationships between dental maturity and skeletal maturity among growing children. Methods: The samples were derived from panoramic, lateral cephalometric and hand-wrist radiographs of 270 female subjects registered as patients at the orthodontic department, dental hospital, Yonsei University. Dental maturity [Demirjian Index (DI)] and skeletal maturity [skeletal maturation indicators (SMIs)] and cervical vertebrae maturation indicators (CVMIs)] were estimated from these radiographs. Results: There was a significant correlation (r = 0.64) between SMIs and DI, and a similar correlation (r = 0.59) was observed between CVMIs and DI (p < 0.001). If DI was above Stage E, then the SMI was above Stage 10 and the CVMI was above Stage 5. There was a weak correlation (r = 0.26) between age at menarche and DI (p < 0.001). There was no significant difference in DI among Class I, II or III malocclusions. Conclusions: Dental maturity evaluation using the mandibular third molar will be an adjunctive tool in combination with cervical vertebrae and hand-wrist maturity evaluations.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.33-41
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• 2000

Although it is well known that the chincup, used to correct a skeletal class III malocclusion in growing children, reduce the mandibular prognathism by arresting the growth of the mandibular length and rotating the mandible posteroinferiorly, the majority of the studies about chincup is focused on condylar head that plays an Important role in mandibular growth. The aim of this study was to evaluate the morphologic change of the mandibular symphysis where extraoral force is applied directly during chincup treatment. The data lot this study were obtained from lateral cephalometric radiographs of 62 growing children(chincup group:32, control group:30) with mixed dentition who had been accepted lot the orthodontic treatment at Chonbuk National University Dental Hospital. The results were as follows : 1. Symphysis height was increased both in chincup therapy group and control group during treatment. Symphysis depth was decreased or maintained the initial values in chin cup therapy group, whereas increased in control group. Posterior symphysis depth was decreased both in chin cup therapy group and control group, but anterior svmphysis detph was increased in control group, whereas decreased in chincup therapy group. 2. Chin depth and chin curvature were increased in control group, whereas maintained or decreased in chincup therapy group during treatment. Chin angle, menton ang1e and symphysis angle were decreased in control group, whereas increased in chincup therapy group. It suggested that bone deposition in pogonion area that occur normally with mandibular growth was supressed by direct contact of chincup. 3. When growing children wear chincup, symphysis morphology was maintained due to inhibition of forward growth at mandibular symphysis. It may be due to the suppression of bone deposition in anterior part of symphysis.

• The korean journal of orthodontics
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• v.36 no.2 s.115
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• pp.161-169
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• 2006

The purpose of this study was to investigate cephalometrically the short term static velopharyngeal changes in 25 patients (10 boys and 15 girls, aged from 5 years 9 months to 12 years 10 months in the beginning of treatment) with skeletal Class III malocclusions who underwent nonsurgical maxillary protraction therapy with a facemask. The linear, angular and ratio measurements were made on lateral cephalograms. Only the change in hard palatal plane angle was negatively correlated with the change in maxillary depth or N-perp to A (p<0.01). The change in velar angle showed a statistically significant increase (p<0.001). This change was influenced more by the soft palatal plane angle than by the hard palatal plane angle (p<0.001). The changes in soft tissue nasopharyngeal depth and hard tissue nasopharyngeal depth showed statistically significant increases (p<0.001). Correlations between the changes in soft tissue (or hard tissue) nasopharyngeal depth and the change in soft palatal plane angle were significant (p<0.05). The increase in hard palate length was statistically significant (p<0.001). The change in hard palate length was negatively correlated with the change in soft tissue nasopharyngeal depth (p<0.05). The change in need ratio S (C) showed a statistically significant increase (p<0.001). But this difference was within the normal range reported by previous studies. These findings indicate that the velopharyngeal competence was maintained even if the anatomical condition of the static velopharyngeal area were changed after maxillary protraction.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.461-477
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• 1998

To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male,16 female) operated by IVRO. Each subject took four lateral cephalograms : just before surgery(T1), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested. The obtained results are as follows ; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular horizontal late relapse and surgical change of articular angle in SSRO group. 4. There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.305-322
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• 2005

Watermarking is a widely employed method tn protecting copyright of a digital image, the owner's unique image is embedded into the original image. Strengthened level of watermark insertion would help enhance its resilience in the process of extraction even from various distortions of transformation on the image size or resolution. However, its level, at the same time, should be moderated enough not to reach human visibility. Finding a balance between these two is crucial in watermarking. For the algorithm for watermarking, the predefined strength of a watermark, computed from the physical difference between the original and embedded images, is applied to all images uniformal. The mean brightness or contrast of the surrounding images, other than the absolute brightness of an object, could affect human sensitivity for object detection. In the present study, we examined whether the detectability for watermark noise might be attired by image statistics: mean brightness and contrast of the image. As the first step to examine their effect, we made rune fundamental images with varied brightness and control of the original image. For each fundamental image, detectability for watermark noise was measured. The results showed that the strength ot watermark node for detection increased as tile brightness and contrast of the fundamental image were increased. We have fitted the data to a regression line which can be used to estimate the strength of watermark of a given image with a certain brightness and contrast. Although we need to take other required factors into consideration in directly applying this formula to actual watermarking algorithm, an adaptive watermarking algorithm could be built on this formula with image statistics, such as brightness and contrast.

• Sijohaknonchong
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• v.23
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• pp.107-131
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• 2005

The purpose of this is to make sure what the scholar of the Choseon thought the object of aesthetics, and which psychological element did they use to clear the center of the aesthetics. In addition, I consider their way to recognize the human's aesthetic point of view. A literary man in Choseon regarded the five senses as an obstacle which interrupted to see the nature of all things. So they set up the spiritual condition as their aesthetic subject, with suppressing the pleasure through five senses. The goal to make one's mind calm was to cause someone's spirit to activate freely. The condition of the calmness was considered as a process of recovering the human's natural spirit, which was connected to the poetic spirit and became the aesthetic subject. Simultaneously, a literary man at that time set up the condition of the calmness as a subject of objective consciousness, and estimated the common things as a objective existence, which led to the result that all the materials of the poem and the poet could be unified. This aesthetic centra put a premium on the senses caused by contacting with all natural things, and adopted the 'Xing' as a method of expression. This 'Xing' is not a sense based upon one's experience, but a sense which is created of itself. The expression method of 'Xing' caused the reader to feel and express, encourage, and sublimate what they feel through the poem, as well as purified reader's mind.