• 한국정밀공학회지
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• 제17권2호
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• pp.211-219
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• 2000

This paper simulated surface grinding process with statistically simulated grinding wheel topography, considering ridge formation phenomenon when grain scratch workpiece. Wheel grain is modeled as hybrid sphere and cone. Grinding wheel characteristic was evaluated with stylus by expanding the scanning region of the profilometer from a straight line to a plane. Each grain's diameter and semi-angle are assumed as normal distribution, each grain's protrusion height from wheel plane is assumed gamma distribution. So grinding wheel is simulated with grain's position randomly distributed without overlapping. Ground surface is 3-dimensionally simulated considering ridge formation of workpiece by each grain's cutting, and then surface profile and surface roughness parameters are compared with real ground workpiece.

• 대한치과교정학회지
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• 제24권1호
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• pp.149-159
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• 1994

The purposes of present study were to evaluate changes in models and lateral cephalometric head films during orthodontic treatment and to compare the amount of incisal retraction and anterior movement of molars with the two approaches of the retraction method of canine(sectional canine retractions vs sliding canine retractions) and the anchorage management(head gears vs no head gears, transpalatal arches vs no transpalatal arches and lingual arches vs no lingual arches) and to evaluate changes during orthodontic treatment in models with relation to lateral cephalometric head films. 67 Korean women with Angle's Class I bialveolar protrusion were selected, whose initial chronologic age was above 16 yrs. Models and lateral cephalometric head films were taken before and after orthodontic treatment with four bicuspid extraction. the results were obtained as follows. 1. Significant decreases were observed in intermolar width, arch length and arch perimeter of maxilla and mandible but significant difference was not observed in intercanine width of maxilla and mandible during treatment period. 2. The linear change of the upper incisor to upper lip was 2.84:1 and the linear change of the lower incisor to lower lip was 1.45:1 3. There were no significant differences between the two groups(sectional canine retractions vs sliding canine retractions), the !we groups(transpalatal arches vs no transpalatal arches) and the two groups(lingual arches vs no lingual arches) in the amount of incisal retraction and anterior movement of molars. There were a greater amount of maxillary incisal retraction and a lesser amount of anterior movement of maxillary molars with the use of head gears than no use of head gears. 4. Changes during orthodontic treatment in models with relation to lateral cephalometric head films were obtained as follows : 1) Maxilla Central incisors were moved 3.79mm backward, canines were moved 0.22mm laterally and 3.70mm backward, and molars were moved 0.535mm medially and 2.29mm forward. 2) Mandible Central incisors were moved 3.04mm backward, canines were moved 0.145mm laterally and 3.92mm backward, and molars were moved 0.755mm medially and 1.77mm forward.

• 대한치과교정학회지
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• 제40권6호
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• pp.383-397
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• 2010

본 연구는 상순돌출을 동반한 골격성 III급 부정교합에서 전방분절골절단술(anterior segmental osteotomy, ASO)을 병용한 상행지시상분할골절단술(bilateral sagittal split ramus osteotomy, BSSRO)과 Le Fort I 골절 단술을 병용한 상행지시상분할골절단술(BSSRO) 후 상악의 경 연조직 변화 및 경조직 변화에 대한 연조직 변화율을 비교하였다. A군은 ASO/BSSRO를 시행한 군 14명, B군은 Le Fort I/BSSRO를 시행한 환자 중 상악의 후방부가 상방으로 이동(posterior impaction)된 15명으로 구성되었다. 수술 전 2개월 이내와 수술 후 6개월 이후에 촬영한 측모두부방사선사진을 분석하여 다음과 같은 결과를 얻었다. 두 군 모두 수술 후 상악 전방부 경조직과 연조직이 후방이동되었고, A군에서 더 큰 변화량을 보였다. A point의 후방이동에 따른 superior labial sulcus의 변화율은 A군에서 79%, B군에서 15%를 보였고, supradentale에 대해 labrale superious는 A군에서 80%, B군에서 68%의 비율로 후방이동하였다. 교합평면각은 B군에서 증가한 반면, A군에서는 통계적으로 유의성 있는 변화가 없었다. 이상의 연구결과 골격성 III급 부정교합의 양악수술 시 상악 수술은 상악 전방부와 상순의 돌출이 심한 경우에는 ASO를 시행하고 교합평면각의 증가가 필요한 경우에는 posterior impaction을 동반한 Le Fort I 골절단술을 시행하는 것이 바람직하다.

• 대한치과교정학회지
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• 제25권2호
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• pp.175-185
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• 1995

이 연구는 정상 교합자와 개방교합자 사이에, 측모두부방사선계측사진 분석을 하고, 이설근과 구륜근의 활성도를 비교하여 근활성도와 골격의 형태간에 상호 상관 관계를 알고자 하였다. 연구 대상으로는 전신건강 상태가 양호하고, 교정치료 경험이 없으며, 악관절 장애가 없는 Angle I급 교합관계를 가진 20명의 정상교합자와 overbile가 -0.5에서 -6mm인 19명의 개방교합자를 선정하였으며 각 대상에서 측모두부방사선계측사진을 촬영하여, 20가지 항목을 계측하고, 안정위, 연하시, 개구시, 등장성 혀 내밀기, 최대 혀 내밀기때의 이설근과 구륜근의 근활성도를 관찰하고. 근활성도와 골격의 형태간에 상관관계를 알고자 하였다. 이 연구로부터 얻어진 결과는 다음과 같다. 1. 안정위를 제외하고, 이설근의 근활성도는 개방교합자에서 정상교합자보다 유의성있게 높았다. 2. 연하시를 제외하고, 구륜근의 근활성도는 개방교합자에서 정상교합자보다 유의성있게 높았다. 3. 최대 혀 내밀기에서 개방교합자의 이설근이 가장 높은 근활성도를 보였다. 4. 골격형태와 이설근과 구륜근의 상관관계가 정상교합군에서는 적고, 개방교합군에서는 더 많은 항목에서 유의성있는 상관관계가 있었다.

• 대한치과교정학회지
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• 제26권4호
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• pp.401-413
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• 1996

안모의 수직적 부조화는 안면의 전방 고경 요소와 후방 고경 요소 사이의 상관 관계에 따라 결정되는 것이므로, 전 하안면 고경에 대한 후하안면 고경의 비인 FHI에 따라 수직적 control이 치료 성공의 관건인 2급 1류 부정 교합을 분류하고 FHI에 영향을 미치는 요소를 파악하여 치료의 지침으로 삼고자 본 연구를 시행하였다. 단국대학교 치과대학 교정과에 내원한 혼합치열기의 2급 1류 부정 교합자를 대조군의 FHI(평균 0.6999)의 1 S.D (0.25)를 기준으로 수직적으로 분류하였다. 임상적으로 수직적 부조화에 영향을 미칠 것으로 사료되었던 상악 제 1 대 구치 치조 고경, 구치간 각도, 구개평면 기울기, 하악지 기울기 등의 영향을 검증하고, 만약 영향을 미치지 않는다면 어느 요소가 FHI에 영향을 미치는가 알아보고자 하였으며, 각 군간에 골격적 양상을 알아보고자 하여 다음의 결론을 얻었다. 2급 1류 부정 교합자의 FHI에 주로 기여하는 요소는 구개 평면과 하악 평면 사이의 경사도이고, RH, ID의 순으로 나타났으며, 구개 및 하악 평면의 독립적인 경사도 보다는 상호 경사도가 중요하게 나타났다. 2급 1류 부정 교합의 양상은 FHI에 따라보면, Low group은 상악이 전돌되고 하악지의 발육이 아주 강하며 하악체의 길이 및 전후방 위치는 정상이다. Normo group은 상악은 약간 전돌되고 하악지의 발육이 정상보다 약하고 하악이 다소 후방에 위치하고, High group은 상악은 정상위치이고 하악지 및 하악체의 발육이 제일 약하며 하악이 후방에 위치하는 것으로 나타났다. 2급 1류 부정 교합자의 각 군간 FHI를 결정짓는 요소를 보면 Low group은 MP-PP각이 아주 작고, ID는 정상군과 유사하나 RH가 아주 커서 FHI가 크게 된다. Normo-group은 PP-MP각이 정상이고, ID는 정상군보다 약간 작고 RH 가 정상군보다 작아 FHI가 정상비를 유지하였다. High group은 PP-MP각이 아주 크고 ID는 정상군과 유사하나 RH가 정상군보다 작아 FHI가 작았던 것으로 나타났다.

• 대한치과교정학회지
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• 제44권2호
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• pp.88-95
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• 2014

Objective: The purpose of this study was to compare the treatment duration and dentoskeletal changes between two different anchorage systems used to treat maxillary dentoalveolar protrusion and to examine the effectiveness of en-masse retraction using two miniscrews placed in the midpalatal suture. Methods: Fifty-seven patients (9 men, 48 women), who had undergone level anchorage system treatment at Aichi-Gakuin University Dental Hospital (Nagoya, Japan) were divided into two groups according to the method of maxillary posterior anchorage reinforcement: midpalatal miniscrews (25 patients, mean age 22 years) and conventional anchorage (32 patients, mean age 19 years). The en-masse retraction period, overall treatment duration, pre-treatment effective ANB angle, and change in the effective ANB angle were compared with an independent-samples t -test. Results: Compared to the headgear group, the duration of en-masse retraction was longer by approximately 4 months in the miniscrew group (p < 0.001). However, we found no significant difference in the total treatment duration between the groups. Moreover, a greater change in the effective ANB angle was observed in patients treated with miniscrews than in those treated with the conventional method (p < 0.05). Conclusions: The level anchorage system treatment using miniscrews placed in the midpalatal area will allow orthodontists more time to control the anterior teeth during en-masse retraction, without increasing the total treatment duration. Furthermore, it achieves better dentoskeletal control than does the conventional anchorage method, thereby improving the quality of the treatment results.

• 대한치과교정학회지
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• 제20권3호
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• pp.519-539
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• 1990

It is the aim of this study to observe the distribution of various facial types in class III malocclusion and to characterize the craniofacial features of the very facial types. Cephalometric headptates of a hundred and ten persons showing bilateral class III malocclusion whose mean age was 12.51 years and sixty nine persons of normal occlusion whose mean age was 12.23 years were measured and statistically analyzed. The following summary and conclusions were drawn. 1. Affording the bases for SNA and SNB, $35.45\%$ of sample showed normally positioned maxilla and protruded mandible, $30.00\%$ for retruded maxilla and normally positioned mandible, $15.45\%$ for retruded maxilla and protruded mandible, $10.90\%$ for both maxilla and mandible within normal range and $8.20\%$ for miscellaneous types were arranged in class III malocclusion. 2. $52.72\%$ of sample showed neutrodiveigent, $35.45\%$ for hyperdivergent and $11.81\%$ manifested hypodivergent mandible in class III malocclusion. 3. Providing the bases for facial and mandibular planes, $33.63\%$ of sample showed prognathic and neutrodivergent, $20.90\%$ for mesognathic and hyperdivergent, $17.27\%$ for prognathic and hyperdivergent and $15.45\%$ for mesognathic and neutrodivergent were arranged in class III malocclusion. 4. The class III malocclusion brought out shorter cranial base, smaller saddle angle, and larger articular and genial angle. It showed retropositioned maxilla and forward positioned mandible in spite of no significant differences in linear measurements of mandible. Anterior lower facial height was significantly larger in class III malocclusion, while posterior total facial and anterior total facial heights exhibited no significant differences. 5. It is suggested class III malocclusion was attributed to shorter cranial base, smaller saddle angle, maxillary deficiency and/or retrusion, mandibular excess and/or protrusion, excessive vertical growth of the anterior lower face, and their complex as well.

• Archives of Plastic Surgery
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• 제44권5호
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• pp.400-406
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• 2017

Background The purpose of this study was to evaluate changes in nasal growth after the implementation of a preoperative nasal retainer in patients with bilateral incomplete cleft lip. Methods Twenty-six infants with bilateral incomplete cleft lip and cleft palate were included in the study. A preoperative nasal retainer was applied in 5 patients from the time of birth to 2.6-3.5 months before primary cheiloplasty. Twenty-one patients who were treated without a preoperative nasal retainer were placed in the control group. Standard frontal, basal, and lateral view photographs were taken 3 weeks before cheiloplasty, immediately after cheiloplasty, and at the 1- and 3-year postoperative follow-up visits. The columella and nasal growth ratio and nasolabial angle were indirectly measured using photographic anthropometry. Results The ratio of columella length to nasal tip protrusion significantly increased after the implementation of a preoperative nasal retainer compared to the control group for up to 3 years postoperatively (P<0.01 for all time points). The ratios of nasal width to facial width, nasal width to intercanthal distance, columellar width to nasal width, and the nasolabial angle, for the two groups were not significantly different at any time point. Conclusions Implementation of a preoperative nasal retainer provided significant advantages for achieving columellar elongation for up to 3 years postoperatively. It is a simple, reasonable option for correcting nostril shape, preventing deformities, and guiding development of facial structures.

• Archives of Plastic Surgery
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• 제49권4호
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• pp.510-516
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• 2022

Background Surgical correction of bilateral cleft lip deformities remains one of the most challenging areas in facial plastic surgery. Many surgical techniques and conservative devices have been offered for the early management of bilateral cleft lip in infants. The purpose of this study was to evaluate the effect of lip adhesion on the lip and nose of patients with bilateral cleft lip. Methods A retrospective review of 13 patients with bilateral cleft lip was performed and compared with age-matched noncleft children. Patients underwent lip adhesion at a mean age of 2.8 months, and cheiloplasty at 6.6 months of age using a modification the Mulliken method. Secondary rhinoplasty was performed at the age of 6 in 13 patients. The surgical results were analyzed using photographic records obtained at the age of 1 and 7 years. Twelve length measurements and one angle measurement were obtained. Results All measurements were not statistically different from those of the noncleft age-matched control group at the age of 1. At 7 years of age, upper lip height and vermilion mucosal height were shorter (p < 0.05) than in the control group. Nasal tip protrusion and the nasolabial angle were greater (p < 0.05) than in the control group. Conclusion Lip adhesion followed by secondary rhinoplasty resulted in an acceptable lip and nasal appearance. Although nasoalveolar molding is now widely used, lip adhesion can be an appropriate alternative if an orthodontist is not available due to geographical or economic constraints.

• 대한치과교정학회지
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• 제50권2호
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• pp.120-128
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• 2020

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes. Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R^® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations. Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle. Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.