• 대한치과교정학회지
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• 제43권5호
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• pp.225-234
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• 2013

Objective: The purpose of this study was to classify Korean young adults into 3 groups on the basis of upper incisor exposure rates (UIERs) and to compare the skeletal, dental, and soft tissue variables. Methods: Samples were obtained from 127 students at the College of Dentistry, Wonkwang University in South Korea. Facial photographs of frontal posed smiles and lateral cephalograms of the subjects were taken. The subjects were divided into 3 groups on the basis of UIERs and 20 measurements were compared among the 3 groups. The correlations between the variables were determined. Results: Male and female subjects showed significant differences in the group distribution. Male subjects showed higher frequencies of low smiles, and female subjects showed higher frequencies of high smiles. The vertical height of the anterior alveolar process of the maxilla directly correlated with the UIER. However, the UIER showed no significant correlation with the vertical height of the anterior basal bone or the inclination of the upper incisor axis. In female subjects, the upper central incisor clinical crown length showed an inverse correlation with the UIER. However, this variable showed no significant correlation with the UIER in male subjects. Conclusions: The UIER was directly correlated with the levator muscle activity of the upper lip and inversely correlated with the upper lip thickness, yet there was no correlation between the UIER and upper lip length at rest.

• 치과방사선
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• 제21권1호
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• pp.99-107
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• 1991

저자는 두부규격방사선사진 촬영기에서 건조 두개골 10개의 basal view와 lateral view상에서 측두골의 추체와 접형골의 후상상돌기가 악관절부위에 중첩되지 않는 수평면과 수직면에서의 입사각을 구하였고 Denar사의 Accurad-100의 형태대로 제작하고 고정장치와 cephalostat를 사용하여 촬영된 방사선사진의 재현성을 검토하여 다음과 같은 결과를 얻었다. 중심방사선의 입사각은 수직면에서는 24.5±4.1°, 수평면에서는 3.0±5.7°였으며 재현성을 검정하기 위해 건조두개골의 악관절부위에 임의의 3점을 계측하였든 바 Accurad-100의 형태대로 제작한 고정장치를 이용한 경우에는 AB간의 거리 24.60±0.25㎜, AC간의 거리 16.76±0.27㎜, BC간의 거리 8.79±0.18㎜이었고 cephalostat를 이용한 경우에는 AB간의 거리 29.03±0.14㎜, AC간의 거리 19.95±0.24㎜, BC간의 거리 10.08±0.07㎜로 나타났다. 따라서 이들은 상당히 양호한 재현성을 나타냈으며 특히 cephalostat를 이용한 경우 더욱 재현성이 좋았다.

• Archives of Plastic Surgery
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• 제44권1호
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• pp.19-25
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• 2017

Background Numerous condylar repositioning methods have been reported. However, most of them are 2-dimensional or are complex procedures that require a longer operation time and a highly trained surgeon. This study aims to introduce a new technique using a condylar repositioning plate and a centric relation splint to achieve a centric relationship. Methods We evaluated 387 patients who had undergone surgery for skeletal jaw deformities. During the operation, a centric relation splint, intermediate splint, final centric occlusion splint, and condylar repositioning plate along with an L-type mini-plate for LeFort I osteotomy or a bicortical screw for bilateral sagittal split ramus osteotomy were utilized for rigid fixation. The evaluation included: a physical examination to detect preoperative and postoperative temporomandibular joint dysfunction, 3-dimensional computed tomography and oblique transcranial temporomandibular joint radiography to measure 3-dimensional condylar head movement, and posteroanterior and lateral cephalometric radiography to measure the preoperative and postoperative movement of the bony segment and relapse rate. Results A 0.3% relapse rate was observed in the coronal plane, and a 2.8% relapse rate in the sagittal plane, which is indistinguishable from the dental relapse rate in orthodontic treatment. The condylar repositioning plate could not fully prevent movement of the condylar head, but the relapse rate was minimal, implying that the movement of the condylar head was within tolerable limits. Conclusions Our condylar repositioning method using a centric relation splint and miniplate in orthognathic surgery was found to be simple and effective for patients suffering from skeletal jaw deformities.

• 대한치과교정학회지
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• 제46권5호
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• pp.301-309
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• 2016

Objective: The aim of this study was to evaluate the skeletal and dental changes after intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontics by using cone-beam computed tomography (CBCT). Methods: This retrospective cohort study included 24 patients (mean age, 22.1 years) with skeletal Class III malocclusion who underwent bimaxillary surgery with IVRO. The patients were divided into the preorthodontic orthognathic surgery (POGS) group (n = 12) and conventional surgery (CS) group (n = 12). CBCT images acquired preoperatively, 1 month after surgery, and 1 year after surgery were analyzed to compare the intergroup differences in postoperative three-dimensional movements of the maxillary and mandibular landmarks and the changes in lateral cephalometric variables. Results: Baseline demographics (sex and age) were similar between the two groups (6 men and 6 women in each group). During the postsurgical period, the POGS group showed more significant upward movement of the mandible (p < 0.05) than did the CS group. Neither group showed significant transverse movement of any of the skeletal landmarks. Moreover, none of the dental and skeletal variables showed significant intergroup differences 1 year after surgery. Conclusions: Compared with CS, POGS with IVRO resulted in significantly different postsurgical skeletal movement in the mandible. Although both groups showed similar skeletal and dental outcomes at 1 year after surgery, upward movement of the mandible during the postsurgical period should be considered to ensure a more reliable outcome after POGS.

• 대한치과교정학회지
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• 제30권4호
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• pp.387-398
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• 2000

이 연구는 악외견인장치의 하나인 Anterior J hook headgear의 상악골 성장 억제효과를 관찰하기 위하여 혼합 치열기의 골격성 II급 부정교합 아동 20명을 대상으로 얻어진 측모두부 방사선규격사진이 분석되었다. 구강내 교정장치로서는 horseshoe appliance가 사용되었으며, J hook의 견인은 상악견치 중앙부에서 후상방으로 이루워졌다. Anterior J hook headgear의 적용기간은 평균 14개월이었으며 계수형 분석법에 의해 적용전후 측모두부 방사선규격사진이 분석된 바, 다음과 같은 결과를 얻었다. 1. 상악골의 전하방성장이 억제되었다. 2. 상악골의 회전효과는 일어나지 않았다. 3. 상악치열은 전체적으로 후방이동하였다. 4. 상악의 치아치조부 성장억제변화는 구치부보다는 전치부에서 더 뚜렷하였다. 5. 하악평면각(SN-MP)은 치료후 변화가 없었으며 하악골은 정상적인 성장을 나타냈다. 6. 전안면고경과 후안면고경 사이의 비율은 유의한 변화가 없었다.

• 대한치과의사협회지
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• 제45권8호통권459호
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• pp.483-490
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• 2007

The aim of this study was to investigate the relationship between the mandibular antegonial notch and the mandibular morphology, and the curve of Spee in anteroposterior skeletal relationship. Pre-treatment lateral cephalograms were obtained from 80(male 34, female 46) adult orthodontic patients and the samples were classified into 3 categories by ANB angle($0^{\circ}$$\leq$ANB< $4^{\circ}$ Class I, $4^{\circ}$$\leq$ANB Class II, ANB< $0^{\circ}$ Class III). The curve of Spee was measured directly from the pre-treatment mandibular study cast of each patient included in this study. Pearson correlation coefficient test and multiple regression analysis in each group revealed the following results; 1. Antegonial notch depth was positively correlated with hoth lower anterior facial height(ANS-Me) in skeletal Class I, II and III groups and Id-Me height in skeletal Class I and II groups. 2. A statistically significant negative correlation was found between the depth of the antegonial notch and the curve of Spee in the Class III group. 3. Significant relationship was not found between the antegonial notch depth and any of the other cephalometric variables such as mandibular body length(Go-Gn) and ramus height(Co-Go). As antegonial notch depth increased, more vertical growth of the mandible was observed. Antegonial notch can be used as a predictor of vertical mandibular growth in the diagnosis and treatment planning of malocclusion.

• 대한소아치과학회지
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• 제46권3호
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• pp.247-254
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• 2019

이 연구는 성장기 아동의 방사선 사진을 이용하여 상악 견치의 치아 성숙도와 골격적 성숙도를 평가하고, 상악 견치의 치아 성숙도와 골격적 성숙도 사이의 연관성을 알아보고자 하였다. 치아 성숙도는 Demirjian index (DI)를 이용하였고, 골격적 성숙도는 cervical vertebral maturation stages (CVMS)와 skeletal maturity indicators (SMI)를 이용하여 각각 경추골 성숙도와 수완부골 성숙도를 평가하였다. 그 결과, 남녀 모두 상악 견치의 DI와 CVMS 및 SMI 사이에서 유의하게 높은 상관관계를 나타냈다(p = 0.000). 이 연구를 통하여 상악 견치를 이용한 치아 성숙도 평가는 성장기 아동의 골격적 성숙도를 평가하는 보조적 수단으로 사용될 수 있음을 확인하였다.

• 대한치과교정학회지
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• 제51권3호
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• pp.179-188
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• 2021

Objective: To evaluate the overall treatment effects in terms of the amount of uprighting with changes in the sagittal and vertical positions of mandibular molars after applying an orthodontic miniplate with a nickel-titanium (NiTi) reverse curve arch wire (biocreative reverse curve [BRC] system). Methods: A total of 30 female patients (mean age, 25.99 ± 8.96 years) were treated with the BRC system (mean BRC time, 10.3 ± 4.07 months). An I-shaped C-tube miniplate (Jin Biomed) was placed at the labial aspect for the alveolar bone of the mandibular incisors. A 0.017 × 0.025-inch NiTi reverse curve arch wire was engaged at the C-tube mini-plate anteriorly and the first and second premolars and molars posteriorly in the mandibular arch. Pre- and post-BRC lateral cephalograms were analyzed. A paired t-test was used to analyze the treatment effects of BRC. Results: The mandibular second molars were intrusively uprighted successfully by the BRC system. Distal uprighting with a controlled vertical dimension was noted on the first molars when they remained engaged in the BRC and the distal ends of the arch wire were laid on the second molars. The mandibular first and second premolars showed a slight extrusion. The changes in the mandibular incisors were unremarkable, while the mandibular molar angulation improved significantly. The lower occlusal plane rotated counterclockwise (MP-LOP: 1.13° ± 2.60°). Conclusions: The BRC system can provide very effective molar uprighting without compromising the position of the mandibular anterior teeth.

• 대한치과교정학회지
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• 제52권2호
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• pp.112-122
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• 2022

Objective: This study aimed to present and evaluate a new deep learning model for determining cervical vertebral maturation (CVM) degree and growth spurts by analyzing lateral cephalometric radiographs. Methods: The study sample included 890 cephalograms. The images were classified into six cervical stages independently by two orthodontists. The images were also categorized into three degrees on the basis of the growth spurt: pre-pubertal, growth spurt, and post-pubertal. Subsequently, the samples were fed to a transfer learning model implemented using the Python programming language and PyTorch library. In the last step, the test set of cephalograms was randomly coded and provided to two new orthodontists in order to compare their diagnosis to the artificial intelligence (AI) model's performance using weighted kappa and Cohen's kappa statistical analyses. Results: The model's validation and test accuracy for the six-class CVM diagnosis were 62.63% and 61.62%, respectively. Moreover, the model's validation and test accuracy for the three-class classification were 75.76% and 82.83%, respectively. Furthermore, substantial agreements were observed between the two orthodontists as well as one of them and the AI model. Conclusions: The newly developed AI model had reasonable accuracy in detecting the CVM stage and high reliability in detecting the pubertal stage. However, its accuracy was still less than that of human observers. With further improvements in data quality, this model should be able to provide practical assistance to practicing dentists in the future.

• 대한치과교정학회지
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• 제53권4호
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• pp.276-285
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• 2023

Objective: The aim of this retrospective study was to compare changes in hard tissue and soft tissue after the four first premolars were extracted with anterior teeth retraction according to the presence or absence of lip incompetence. Methods: Patients who underwent the four first premolars were extracted with anterior teeth retraction were divided into competent (n = 20) and incompetent lip (n = 20) groups. Cephalometric measurements for hard tissue and soft tissue changes were performed pre-treatment and post-treatment. Results: In the competent group, the upper and lower lips retreated by 2.88 mm and 4.28 mm, respectively, and in the incompetent group by 4.13 mm and 5.57 mm, respectively; the differences between the two groups were significant (p < 0.05). A strong positive correlation between retraction of the upper lip and upper incisors was observed in both groups (p < 0.05), whereas a correlation between retraction of the lower lip and lower incisors was only found in the incompetent group. A simple linear regression analysis showed that the pattern of lip retraction following the retraction of the anterior teeth was more predictable in the incompetent group than in the competent group. Conclusions: These findings suggest that the initial evaluation of lip incompetence in patients with skeletal Class II is essential for the accurate prediction of the soft tissue changes following retraction of the anterior teeth in premolar extraction treatment. Therefore, sufficient explanation should be provided during patient consultations.