• 대한의생명과학회지
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• 제21권1호
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• pp.15-22
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• 2015

Dexamethasone, a synthetic glucocorticoid (GC), is clinically administered to woman at risk for premature labor to induce fetal lung maturation. However, exposure to repeated or excess GCs leads to intrauterine growth restriction (IUGR) and subsequently increases risk of psychiatric and cardio-metabolic diseases in later life through fetal programming mechanisms. GCs are key mediators of stress responses, therefore, maternal nutrient restriction or psychological stress during pregnancy also causes negative impacts on birth and neurodevelopment outcome of fetuses, and other congenital defects, such as craniofacial and skeletal abnormalities. In this study, to examine the effect of prenatal stress on fetal skeletal development, dexamethasone (1 mg/kg [DEX1] or 10 mg/kg [DEX10] maternal body weight per day) was administered intraperitoneally at gestational day 7.5~9.5 and the skeletons were prepared from embryos at day 18.5. Seven out of eighteen (39%) embryos treated with DEX10 showed axial skeletal abnormalities in either the T13 or L1 vertebrae. In addition, examination of the sternum revealed that xiphoid process, the protrusive triangular part of the lower end of the sternum, was bent more outward or inward in DEX group embryos. In conclusion, our findings suggest a possible link to the understanding of the effect of uterine environment to the fetal skeletal features.

• 대한치과교정학회지
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• 제12권2호
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• pp.177-191
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• 1982

The study was performed to establish the cephalometric standards of Hellman dental age III B, IV A, IV C groups of the age of puberty and to aid for the case analysis and diagnosis of malocclusion. A roentgenocephalometric study was made from 365 subjects, that consist of 162 males, 203 females with normal occlusion, acceptable profile and no history of orthodontic and prosthodontic treatment. The results of this study were obtained as follows: 1. The tables of standards from the measurements by age, sex group were made. 2. All linear measurements of skeletal pattern in male were greater than in females. 3. The Bjork's sum was reduced gradually by aging in group I $396^{\circ}$, group II $395^{\circ}$, and group III $393^{\circ}$. 4. Posterior facial height to anterior facial height was 63% in group I, 64% group II, and 67% in group III. 5. The angulation of SNA and SNB were $81^{\circ}$ & $78^{\circ}$ in group I, $81^{\circ}$ & $78^{\circ}$ in group II, and $82^{\circ}$ & $79^{\circ}$ in group III.

• 대한치과교정학회지
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• 제18권1호
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• pp.65-78
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• 1988

The development of good arch form, the orientation of the dentition with relation to the craniofacial skeleton and the establishment of correct relationship of axial inclination of upper and lower teeth are required in normal occlusion, but different teeth present different degrees of axial inclination. The purpose of this study was to investigate the axial inclination of upper and lower teeth by analyzing $45^{\circ}$ oblique and $90^{\circ}$ cephalometric roentgenograms of 35 Korean males and 34 females with normal occlusion. The obtained results were as follows: 1. Mean and standard deviation of mesiodistal axial inclination of upper and lower teeth related to palatal plane and occlusal plane were obtained. 2. Mesiodistal axial inclination of upper first premolar was nearly perpendicular to palatal plane, and the axis of lower first premolar was nearly perpendicular to occlusal plane. 3. There was no difference in the mesiodistal axial inclination of anteriorly positioned teeth between the three groups: third molar eruption into good alignment (Group 1), third molar impaction or partial eruption (Group 2), third molar agenesis (Group 3). 4. There were low correlationships only between the axial inclination of central incisor and the mesiodistal axial inclination of canine and first premolar, but no correlationships between central incisor and posterior teeth behind first premolar.

• 대한치과교정학회지
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• 제18권1호
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• pp.175-188
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• 1988

The purposes of the present study were to describe the vortical and anteroposterior facial dysplasia, and to identify morphologic differences associated with various facial patterns. Anteroposterior dysplasia was classified by traditional Angle's malocclusion classification and according to vertical relationships based on the SN-MP angle, facial pattern was subclassified to 3 vertical groups in each malocclusion group. Each vertical group composed of 20 samples and total 180 samples aged from 9 to 14 years. The results were as follows; 1. The skeletal differences that lead to disportionate lower facial height in vortical and anteroposterior facial dysplasia were closely related to mandibular morphology. 2. Hyperdivergent group, compared with hypodivergent group, demonstrated decrease of SNA and SNB and linguoversion of maxillary and mandibular central incisors in all malocclusion groups. 3. Irrespective of rotation of the jaws, Wits appraisal was a useful measurement in evaluation of relative anteroposterior relationship of maxilla and mandible. 4. As SN-MP angle increased, anterior facial height, especially lower anterior facial height, demonstrated significant increase and intermaxillary space also tended to increase. 5. The correlation coefficients of SN-MP angle and PTFH/ATFH demonstrated the highest value in all malocclusion groups.

• 한국발생생물학회지:발생과생식
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• 제27권3호
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• pp.137-147
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• 2023

Pharyngeal pouches are an important epithelial structure controlling facial skeletal development in vertebrates. A series of pouches arise sequentially in the pharyngeal endoderm through collective cell migration followed by rearrangement of pouch-forming cells. While crucial transcription factors and signaling molecules have been identified in pouch formation, a role for Neuropilins (Nrps) in pouch development has not yet been analyzed in any vertebrates. Nrps are cell surface receptors essential for angiogenesis and axon guidance. In all vertebrates, the two Nrp family members, Nrp1 and Nrp2, are conserved in the genome, with two paralogs for Nrp1 (Nrp1a and Nrp1b) and Nrp2 (Nrp2a and Nrp2b) being identified in zebrafish. Here, I report a potential requirement of Nrp signaling in pouch development in zebrafish. nrp1a and nrp2b were expressed in the developing pouches, with sema3d, a ligand for Nrps, being expressed in the pouches. Knocking down Nrps signaling in the pharyngeal endoderm led to severe defects in pouches and facial cartilages. In addition, blocking Mitogen-activated protein kinase (MAPK) activities, a downstream effector of Nrp signaling, in the pharyngeal endoderm caused similar defects in pouches and facial skeleton to those by knocking down Nrps signaling. My results suggest that Nrp signaling acts for pouch formation through MAPK.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권5호
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• pp.447-453
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• 2010

The hemifacial microsomia is characterized by variable underdevelopment of the craniofacial skeleton, external ear, and facial soft tissues. So, patients with hemifacial microsomia have an occlusal plane canting and malocclusion with facial asymmetry. Distraction osteogenesis (DO) with an intraoral or extraoral device is a technique using tension to generate new bone with gradual bone movement and remodeling. DO has especially been used to correct craniofacial deformities such as a hemifacial microsomia, facial asymmetry, and mandible defect that could not adequately be treated by conventional reconstruction with osteotomies. It has a significant advantage to lengthen soft and hard tissue of underdeveloped site without bone graft and a few complication such as nerve injury or muscle contracture. A 13-years old girl visited our clinic for the chief complaint of facial asymmetry. She had a left hypoplastic maxilla and mandible, occlusal plane canting and malocclusion. We diagnosed hemifacial microsomia and lanned DO to lengthen the affected side. Le Fort I osteotomy, left mandibular ramus and symphysis osteotomy were performed. The internal distraction devices fixed with screw on maxillary and mandibular ramus osteotomy sites. External devices were adapted to lower jaw for DO on symphysis osteotomy site and to upper jaw for rapid maxillary expansion (RME). At 7days after surgery, distraction was started at the rate of 1mm per day for 13days, and after 4months consolidation periods, distraction devices were removed. Simultaneous multiple maxillo-mandibular distraction osteogenesis with RME resulted in a satisfactory success in correcting facial asymmetry as well as occlusal plane canting for our hemifacial microsomia.

• 대한치과교정학회지
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• 제33권6호
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• pp.485-497
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• 2003

악안면 구조의 형태와 기능은 대개 유전자 정보에 의해 결정된다. 분자생물학의 발달로 인해 정상 성장과 형태 형성에 중요한 유전자에 대한 정보가 밝혀지고 있고 이는 현대 두개안면 생물학의 근간이 되고 있다. 밝혀진 사실들 중 주목할만한 것은 섬유아세포 성장인자2 (FGFR2)에 서 의 특이한 돌연변이 가 어 퍼트 증후군 (Apert syndrome) 의 발생과 관련이 있다는 것이다. 어퍼트 증후군은 두개 관상봉합의 조기 유합과 사지의 기형으로 특징지워진다. 그 중 특히 두개골 유합증의 병인과 형성기전을 연구하기 위해 본 연구에서 유전자 변환기법을 시도하여 어퍼트 증후군의 유발인자로 알려진 FGFR2에 서 의 단일 아미노산 치 환 돌연변이를 재연한 인위 유전자구조물을 제작하고 이를 미 세주입법으로 쥐의수정란에 삽입하여 형질변환 쥐를 제작하였다. 본 연구에서는 전체 조직이 아닌 골조직에서 특이하게 활성화되는 전사촉진자(promoter, 제 I형 교원질 유전자의 전사촉진자)를 이용하여 골조직에서만 돌연변이 유전자의 발현을 재현함으로써 이 시도가 쥐에서 두개골유합증을 유발하는지 검증하고자 하였다. 초기 표현형 분석을 통해 어퍼트 환자에서 기대되는 두개골 유합증을 확인하였다. 또한 본 연구에서 삽입된 변환유전자가 원활히 돌연변이 단백질을 생산하고 기능의 증가를 보임을 확인하였다. 이러한 동물 모델을 이용함으로써 이제 정상적 혹은 비정상적 두개골 및 봉합 발육에서의 FGFR2의 역할을 연구하는 것이 가능하리라 사료된다

• 대한소아치과학회지
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• 제26권1호
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• pp.172-184
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• 1999

The present study was performed to identify morphologic sub-groupings in Korean children with Class I malocclusions, and to find out anatomic differences between the sub-groups. Standardized lateral cephalometric radiographs of 152 Korean children, aged between 6 and 12 years, with Class I malocclusions were analyzed by the Counterpart Analysis. A statistical method, Ward's Minimum Variance Cluster Analysis, was employed to divide the sample into sub-groups those with similar morphologic characteristics. The results were as follows; 1. There appeared two facial types, Type I and Type II, in Korean children with Class I malocclusions, 48.7% and 51.3%, respectively. 2. In both sub-groups, there existed strong Class III skeletal patterns due to a counterclockwise rotation of the Middle Cranial Fossa alignment, and strong Class II skeletal patterns due to the long Posterior Maxillary vertical dimension and a clockwise rotation of the Ramus alignment. 3. There were no significant differences in Upper Anterior Facial Height between Type I and Type II, $52.6{\pm}2.92mm\;and\;52.8{\pm}3.23mm$, respectively. 4. The Lower Anterior Facial Height in Type II was longer ($66.0{\pm}4.03mm$) due to the long Posterior Maxillary vertical dimension, the clockwise rotation of the Ramus alignment, and a clockwise rotation of the Mandibular plane alignment than that of Type I ($64.2{\pm}4.15mm$).

• Journal of Periodontal and Implant Science
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• 제46권2호
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• pp.96-106
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• 2016

Purpose: Stress distribution and mandible distortion during lateral movements are known to be closely linked to bruxism, dental implant placement, and temporomandibular joint disorder. The present study was performed to determine stress distribution and distortion patterns of the mandible during lateral movements in Class I, II, and III relationships. Methods: Five Korean volunteers (one normal, two Class II, and two Class III occlusion cases) were selected. Finite element (FE) modeling was performed using information from cone-beam computed tomographic (CBCT) scans of the subjects' skulls, scanned images of dental casts, and incisor movement captured by an optical motion-capture system. Results: In the Class I and II cases, maximum stress load occurred at the condyle of the balancing side, but, in the Class III cases, the maximum stress was loaded on the condyle of the working side. Maximum distortion was observed on the menton at the midline in every case, regardless of loading force. The distortion was greatest in Class III cases and smallest in Class II cases. Conclusions: The stress distribution along and accompanying distortion of a mandible seems to be affected by the anteroposterior position of the mandible. Additionally, 3-D modeling of the craniofacial skeleton using CBCT and an optical laser scanner and reproduction of mandibular movement by way of the optical motion-capture technique used in this study are reliable techniques for investigating the masticatory system.

• 대한구순구개열학회지
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• 제10권2호
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• pp.75-80
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• 2007

For the treatment of cleft palate patients, orthognathic surgery has been used by standard protocol. Predictable results have been achieved with standard techniques in slight to moderate maxillary hypoplasia. However, limited advancement and high relapse rate was reported in severe cases. The purpose of the present study was to review the clinical results of distraction osteogenesis in the patients with cleft lip and palate. Distraction osteogenesis has improved results in these patients by allowing soft tissue relaxation and gradual bone generation. Therefore, greater movement of the craniofacial skeleton is possible in severe cases of maxillary retrusion with lower relapse rates. In conclusion, distraction osteogenesis for the advancement of hypoplastic maxilla of cleft patients has shown successful treatment method.