• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.192-203
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• 2007

Objective: The aim of this study was assessment of the relationship between airway space and facial morphology in Class III children with nasal obstruction. Methods: For this study, 100 Class III children (50 boys and 50 girls) were chosen. All subjects were refered to ENT, due to nasal obstruction. Airway space measurements and facial morphology measurements were measured on lateral cephalometric radiograph. Pearson correlation analysis was used to assess the relationship between airway space and facial morphology Results: Ramal height, SNA, SNB, PFH, FHR and facial plane angle were positively related to upper PAS, and sum of saddle angle, articular angle, and genial angle, SN-GoGn, Y-axis to SN and FMA negatively related to upper PAS. Genial angle, FMA were positively related to lower PAS, and articular angle, facial depth, PFH and FHR negatively related to lower PAS. PCBL, ramal height, Mn. body length, Mn. body length to ACBL, facial depth, facial length, PFH and AFH were positively related to tonsil size. Sum of saddle angle, articular angle, genial angle, facial length, AFH, FMA and LFH were positively related to tongue gap, and IMPA and overbite was negatively related to tongue gap. Upper PAS, related to size of adenoid tissue, was mainly related to posterior facial dimension following a vertical growth pattern of face and mandibular rotation. Lower PAS and tonsil size, related to anterior-posterior tongue base position, were significantly related to each other. Lower PAS was related to growth pattern of mandible, and tonsil size was related to size of mandible and horizontal growth pattern of face. Tongue gap was related to anterior facial dimension following a vertical growth pattern of face. Conclusion: Significant relationship exists between airway space and facial morphology.

• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.220-230
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• 2007

Objective: The purpose of this study was to determine the changes of mandibular anterior alveolar bone thickness with age. Methods: Cephalometric radiographs of 160 skeletal class I patients (male 80, female 80) with normal vertical growth pattern was investigated by measuring the buccolingual thickness of mandibular alveolar bone on the basis of root axis. Results: As the age increases, both male and female showed a significant decrease in buccolingual width of the mandibular anterior alveolar bone and in the width of mandibular anterior lingual alveolar bone except the CEJ area of females. However, there was no significant difference in the thickness of mandibular anterior buccal alveolar bone and in the width of maximum prominence of mandibular symphysis with age. Conclusion: From the above results, it is concluded that Korean children whose growth pattern is sagittally skeletal class l with a vertical normal growth pattern have a greater mandibular anterior lingual alveolar bone width than Korean adults; therefore, lingual movement of mandibular incisors, which is usually accompanied in extraction treatment, is considered to be more preferable in younger patients.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.393-401
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• 2001

The purposes of this study were to assess the treatment results in orthodontic department, Kyung Hee University, to evaluate the occlusion at 2 year follow-up control, in relation to the original malocclusion, and changes occurring in the follow-up period, and to determine whether treatment and posttreatment changes of the PAR index were related to the original Angle classification Dental study casts of 25 patients in permanent dentition were evaluated using Peer Assessment Rating (PAR) index. The PAR index was measured at the pretreatment stage, immediately after treatment, and at 2 yews posttreatment. The following results were obtained : 1. The treatment reduced the PAR index by 85.05% and it indicates that KHDC clinic has a high standard of treatment 2. The follow-up result of 75.40% PAR score reduction implies a gain of 9.55% of posttreatment PAR score during follow-up period. 3. There is no relationship between the treatment changes of the PAR index and the orignal Angle classification.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.487-498
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• 1998

This study was conducted to investigate changes of airway size, tongue and hyoid position following orthognathic surgery in mandibular prognathism, and how they are adapted to new environment in time dependent manner. 37 patients, who had recieved orthognathic surgery, were selected for this study. lateral cephalogram of each patient was taken at preoperation, immediate postoperation, and over 6 month after operation, and were traced and analyzed The findings of this study were as follows : 1. The size of airway was not changed at PNS and Epiglottis level after operation, but it was changed slightly at 2nd cervical vertebra level. 2. The hyoid was moved inferoposteriorly at immediate postoperation, and then it shifted toward preoperative position, but it remained slightly inferoposterior position. The distance from hyoid to genial tubercle decreased continuously. 3. The position of tongue was moved inferoposteriorly at immediate postoperatioa and then it shifted toward preoperation position, but the root of the tongue remained inferoposteriorly. 4. The distance between tongue and hyoid was increased at immediate postoperation and slightly decreased during follow-up period. 5. The change of the mandibular position was not significantly correlated with changes of airway size, hyoid position, tongue morphology and tongue position.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.557-566
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• 1995

Postpubertal craniofacial growth changes were assessed from serial lateral cephalograms taken at which subjects were 16 and 18 years of age. The sample consisted of 19 male and 14 female subjects with no previous orthodontic treatment who had normal occlusion. The craniofacial growth changes of these samples during this study period might be summarized as follows 1. Significant increase in mean maxillary and mandibular length, cranial base length, posterior md anterior facial height were observed at the age period studied in male(P<0.05), however, in female significant increase was observed only mandibular length(Ar-Gn, Ar-Go) and anterior and posterior facial height(P<0.05). 2. Total growth increment of all measumenats were below 1mm in female, but in male, total mandibular(Ar-Gn) growth increment was 2.0mm and those of mandibular tody length, ram length, posterior facial height, and anteior facial height were 1 to 1.54mm and the others were below 1mm 3. A closing, forward rotation of the mandible occured with a significant decrease in mandibular plane angle of $0.61^{\circ}$ in male(P<0.01). 4. Summarized the findings, even though statistically significant growth changes in some dimensions of female were observed, the amount of growth change were very small, however, in male the growth changes of some dimensions associated with mandible were significant and considerable amount.

• The korean journal of orthodontics
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• v.31 no.3 s.86
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• pp.301-309
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• 2001

Because many of patients seeking orthodontic treatment worry about the facial appearance and their chief motivation for orthodontic treatment is facial esthetics, it is critical to understand the influence of gender or culture on the evaluation of profile esthetics. The purpose of this study was to find out any influence of gender or culture on judging good facial profile. 4 different groups were asked to evaluate 133 facial profiles to test the influence of gender or culture on judging good facial profiles. Those 4 groups consisted of 10 Korean males, 10 Korean females, 10 Korean American males, and 10 Korean American females. 2 evaluation systems were introduced, absolute and relative. Soft tissues of selected good profile group were analyzed and statistic analysis was performed. Conclusions were as follows 1. Inter-evaluator difference for judging good facial profile was statistically significant, even if there was general agreement for the best profile among 40 raters. 2. Gender difference under the same cultural environment was not significant statistically. 3. The same ethnic groups with different cultural background showed statistically different preference on judging good Profile. 4. Good facial profile group had their own characteristics compared to remaining group in several soft tissue measurements which were vertical facial ratio, soft tissue facial convexity, and antero-posterior relative lip position.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.343-351
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• 1998

The purpose of this study was to investigate the pretreatment and posttreatment dentofacial characteristics of non-extraction patients with Class I malocclusion. And to compare this result with matched non-orthodontic normal occlusion and Class I premolar extraction patients. Such comparison might help identify morphologic characteristics of the non-extraction patients. Initial and final cephalometric evaluation were compared in a sample of 22 patients with Class I malocclusions treated in non-extraction manner with edgewise appliance and MEAW The mean age of the total population was 14 years 9 months and the average treatment time was 2 years 8 months. 32 landmarks were located and digitized on each cephalogram. From these landmarks, 24 linear and angular dimension were obtained. Student's t-test were used to compare the pretreatment - posttreatment results, Nonextraction - Normal groups, and nonextraction Extraction groups. Significance was predetermined at $p{\leq}0.05$. The results were as follows. 1. Before treatment, the mean value of the $ODI\;was\;69.9^{\circ},\;APDI\;was\;82.1^{\circ},\;CF\;was\;152^{\circ},\;EI\;was\;152^{\circ}$ in the non-extraction groups. 2. The skeletal pattern of the non-extraction groups were similar with non-orthodontic normal groupsr, but the non-extraction groups had larger interincisal angle. 3. Comparison between groups treated with and without extraction indicated at pretreatment, the extraction groups had more protrusive lips, smaller interincisal angle, and EI. 4. After treatment, there was no significant changes in the skeletal pattern of the non-extraction groups, but uprighting of the maxillary and mandibular first molar and decrease of the interincisal angle were seen.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.255-267
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• 2011

Objective: The purpose of this study was to confirm the reliability of a cone beam computed tomography (CBCT)-generated panoramic view based on a CBCT 3D image and to find the most helpful 2D panoramic image compared with CBCT 3D image when examining the mesiodistal tooth axis. Methods: A test model was constructed according to cephalometric norms. The test model was repeatedly repositioned for CBCT and panoramic radiographic imaging. Panoramic radiographs were acquired at each of the following 3 occlusal plane positions: $-5^{\circ}$, $0^{\circ}$, and $+5^{\circ}$. Measurements of mesiodistal tooth axis in CBCT 3D image, CBCT-generated panoramic view, and panoramic radiographs were compared. Results: Compared with the CBCT-generated panoramic view, CBCT 3D image showed significant difference in the mesiodistal tooth axis in the premolars and no significant difference in the mesiodistal tooth axis in the incisors and canines. Mesiodistal tooth axis on the CBCT-generated panoramic view was significantly different from that on panoramic radiographs. Conclusions: CBCT-generated panoramic view can be a useful tool for evaluating mesiodistal tooth axis.

• The korean journal of orthodontics
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• v.38 no.2
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• pp.83-94
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• 2008

Purpose: The first objective of this study was to compare the upper midface morpholgy, focusing on the soft tissues, between skeletal Class III maloccusion patients with midfacial depression and the norm. The second objective was to estimate and analyze the change in the upper midface soft tissues following surgical correction with maxillary advancement by Lefort I osteotomy and mandibular setback by bilateral sagittal split osteotomy (BSSRO). Methods: The samples consisted of 34 adult patients (15 males and 12 females) with an average age of 21 years, who had severe anteroposterior discrepancy with midfacial depression. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of simultaneous Lefort I osteotomy and BSSRO. Results: The correlation coefficient between changes in maxillary advancement and changes in Or' (soft tissue orbitale) was 0.599 (p < 0.05). Change in maxillary plane angle and vertical change of the maxilla were not correlated with the change in Or' (p < 0.05). The ratio of soft tissue change in Or' to maxillary advancement was 43.57 %, and 81.54 % in Sn. Regression equations between maxillary movement and Or' were devised. The $r^2$ value was 0.476. Conclusions: The majority of measurements in the upper midface in skeletal Class III maloccusions when compared to the norm, showed significant differences. In Class III malocclusion with midfacial depression, maxillary advancement produces soft tissue change in the upper midface.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.187-196
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• 2005

Since the allowable bearing capacities of piles in weathered/fractured rock are mainly governed by settlement, the load-displacement behavior of pile should be known accurately. To predict pile head settlement at the design stage, the exact understanding of the load-transfer mechanisms is essential. Therefore, in this research, the load-transfer mechanism of drilled shaft socketed into weathered rock was investigated. For the investigation, five cast-in-place concrete piles with diameters of 1,000 mm were socketed into weathered gneiss. The static axial load tests and the load-transfer measurements were performed to examine the axial resistant behavior of the piles. A comprehensive field/laboratory testing program on weathered rock at the Held test sites was also performed to describe the in situ rock mass conditions quantitatively. And then, the effect of rock mass condition on the load transfer mechanism was investigated. The f-w (side shear resistance-displacement) curve of the pile in moderately weathered rock reached to yielding point at a for millimeter displacements, and after yielding point, the rate of resistance increment dramatically decreased. However, the f-w curve in the highly/completely weathered rock did not show the obvious yielding point, and the resistance gradually increased showing the hyperbolic pattern until relatively high displacement (>15 mm). The q-w (end bearing resistance-displacement) curves showed linear response at least until the base displacement of approximately 10 mm, regardless of rock mass conditions.