• Maxillofacial Plastic and Reconstructive Surgery
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• 제42권
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• pp.37.1-37.13
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• 2020

Background: The human mandible is variable in shape, size and position and any deviation from normal can affect the facial appearance and dental occlusion. Objectives: The objectives of this study were to determine whether the Sassouni cephalometric analysis could help predict two-dimensional mandibular shape in humans using cephalometric planes and landmarks. Materials and methods: A retrospective computerised analysis of 100 lateral cephalometric radiographs taken at Kingston Hospital Orthodontic Department was carried out. Results: Results showed that the Euclidean straight-line mean difference between the estimated position of gonion and traced position of gonion was 7.89 mm and the Euclidean straight-line mean difference between the estimated position of pogonion and the traced position of pogonion was 11.15 mm. The length of the anterior cranial base as measured by sella-nasion was positively correlated with the length of the mandibular body gonion-menton, r = 0.381 and regression analysis showed the length of the anterior cranial base sella-nasion could be predictive of the length of the mandibular body gonion-menton by the equation 22.65 + 0.5426x, where x = length of the anterior cranial base (SN). There was a significant association with convex shaped palates and oblique shaped mandibles, p = 0.0004. Conclusions: The method described in this study can be used to help estimate the position of cephalometric points gonion and pogonion and thereby sagittal mandibular length. This method is more accurate in skeletal class I cases and therefore has potential applications in craniofacial anthropology and the 'missing mandible' problem in forensic and archaeological reconstruction.

• Imaging Science in Dentistry
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• 제35권1호
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• pp.15-23
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• 2005

Purpose : To compare cephalometric measurement between measuring methods in digital and conventional lateral cephalometric radiograph. Materials and Methods : Twenty digital and conventional lateral cephalometric radiographs were selected. In digital group, cephalometric measurements were performed manually using hardcopies and automatically using $V-Ceph^{TM}$ program on the monitor. In conventional group, the same measurements were performed manually on conventional films, and for automatic measurement conventional films were digitized by scanner. All measurements were performed twice by 4 observers, and 24 cephalometric variables were calculated and the time spent for each measurement was recorded. The differences in measurements data and the time spent for each measurement were compared within each group. Intra-observer and inter-observer comparisons were performed. Results : In both groups, no statistically significant difference between manual and automatic measurements was observed and most of the variables didn't show statistically significant differences between methods. The observer with less experience tended to show statistically significant differences of measurements between methods, and differences from other observers. The differences of measurements between methods in digital group were lesser than those of conventional group with statistical significance in 8 variables out of 24. With automatic method and in digital group, the spent time was shorter. Conclusion : With direct digital radiograph, automatic method using manually idenitified landmarks can be preferable in cephalometric analysis. (Korean J Oral Maxillofac Radiol 2005; 35 : 15-23)

• 대한치과교정학회지
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• 제29권2호
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• pp.277-284
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• 1999

제 I급 부정교합 환자에서 PAR지수가 교정치료기간 및 측모두부방사선 계측 항목과 관계가 있는지를 규명하고자 100명의 교정 환자의 치료 전후 석고모형에서 PAR지수를 구하고, 측모두부방사선사진에서 12개의 계측치를 측정하여 분석한 후 다음과 같은 결과를 얻었다. 1. 치료 기간은 발치 여부 및 치료전 PAR지수와 상관관계를 보였다. 2. ANB, FMA, FMIA, IMPA는 치료전 PAR지수와 치료전 측모두부방사선 계측치에서 순상관관계를 보였다. 3. $\underline{1}$ to FP는 치료후 PAR지수와 치료후 측모두부방사선 계측치에서 순상관관계를 보였고 $\overline{1}$ to FP는 역상관관계를 보였다. 4. $\underline{1}$ to SN, IIA, $\bar{1}$ to FP는 ${\%}\;PAR$와 치료전후 측모두부방사선 계측치의 변화량과의 관계에서 순상관관계를 보였고 FMA, FMIA, WITS, UL은 역상관관계를 보였다. 이상의 결과는 석고모형상의 치아관계에서 측정한PAR지수가 측모두부방사선 계측치 중 상하 전치와 관련된 항목과 연관이 있으며, 제I급 구치 관계를 보이는 환자중 ANB 값이 크고 hyperdivergent한 안모를 갖는 경우 치료전 PAR 지수가 큰 경향을 나타냄을 시사하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권3호
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• pp.267-275
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• 2005

Obstructive sleep apnea syndrome (OSAS) is characterized by sleep-induced obstruction of the upper airway that results in cessation of airflow. Obstruction can occur at a number of points in the airway, but frequently in the oropharynx. A diagnostic evaluation includes cephalometry, computed tomography, magnetic resonance imaging, acoustic reflection technique, polysomnography and fibroptic endoscopy. Cephalometric measurements of the patients with obstructive sleep apnea have revealed that posterior airway anatomy has strong relations with the symptoms of them. A lateral cephalogram is routinely obtained in the radiologic evaluation of sleep apnea patients. The purpose of this study is to provide a the lateral cephalometric korean norms for the diagnosis and treatment of the patients with obstructive sleep apnea by analyzing the abnormal occlusion of Korean adults.

• 대한치과교정학회지
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• 제47권1호
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• pp.31-38
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• 2017

Objective: This study aimed to quantitatively assess the relationship of smile esthetic variables with various types of malocclusion, and identify the cephalometric factors affecting smile measurements. Methods: This retrospective study included 106 patients who were treated with retention at the orthodontic department of Taipei Medical University Hospital. Hard-tissue variables were measured using lateral cephalographic tracings, and nine smile esthetic variables were measured using facial photographs. The patients were divided into three groups according to their overjet (< 0, 0-4, and > 4 mm). An analysis of variance was conducted to compare the pretreatment cephalometric variables and smile esthetic variables among the three groups. Multiple linear regression analysis was performed to identify the cephalometric factors affecting the smile measurements in each group. Results: Except the upper midline and buccal corridor ratio, all of the smile measurements differed significantly among the three groups before orthodontic treatment. Some of the smile characteristics were correlated with the cephalometric measurements in different types of malocclusion. The overjet was the major factor influencing the smile pattern in all three types of malocclusion. Conclusions: Smile characteristics differ between different types of malocclusion; the smile may be influenced by skeletal pattern, dental procumbency, or facial type. These findings indicate that establishment of an optimal horizontal anterior teeth relationship is the key to improving the smile characteristics in different types of malocclusion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제25권4호
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• pp.330-336
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• 1999

Study of dentofacial structure relationships relative to TMJ internal derangement is required to increase the predictability of TMJ internal derangement. But few studies have been reported. The purpose of this study is to reveal any correlation of dentofacial characteristics with TMJ internal derangement by lateral cephalometric analysis. Patients were devided into two groups. (1) Symptomatic patients with TMJ internal derangement (2) Asymptomatic volunteers with no TMJ internal derangement. Twenty symptomatic patients with TMJ internal derangement(7male, 13female) were selected from our clinic and had undergone a standarized clinical examination, panorama, transcranical view, TMJ tomography. Twenty asymptomatic volunteers(9male, 11female) were selected from our clinic with no pain, no limitation of motion. All subjects had undergone lateral cephalometric analysis. The results were obtained as follows. 1. No significant difference between ID and normal group is detected in cranial base. 2. Maxilla position of ID group is located more posterioly than normal group. 3. Mandible position of ID group is located more posteriorly than normal group and facial profile is hyperdivergent. 4. Posterior facial height of ID group is less than normal group thus facial profile is hyperdivergent. The patients, as mentioned, have a high prevalance of ID thus it should be careful in TMJ ID diagnosis and treatment.

• 대한구순구개열학회지
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• 제6권2호
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• pp.59-67
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• 2003

A cephalometric study was performed to reveal differences between skeletal Class III malocclusion patients and cleft lip and palate patients, The material for this study consisted of 16 males (mean age 19.8, range 17-29) and 9 females(mean age 19.4, range 16-27) with cleft lip and palate, and 222 Skeletal Class III malocclusion patients(males 106, females 116), Cephalometric tracing and measurements were done by one investigator. Results were followed: 1. Cleft lip and palate group had more retrusive maxilla than the skeletal Class III malocclusion group. 2, Cleft lip and palate group had smaller effective maxillary and mandibular length than skeletal Class III malocclusion group, and the difference was more prominent in the mandible than in the maxilla. 3. Dental compensation was not observed in the upper incisors of cleft lip and palate group and in the lower incisors it was smaller than skeletal Class III group. 4, In the Gonial angle and lower anterior facial height values, there was no significant difference between cleft lip and palate and skeletal Class III malocclusion group. These results can be used in orthodontic treatment planning and orthognathic surgery for the cleft lip and palate patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권2호
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• pp.131-135
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• 2004

The purpose of this study was to evaluate the resistant force of medial pterygoid muscles against the mandibular advancement and distraction to anterior, and inquire into the relationship between medial pterygoid muscles and cephalometric variables. Sixty six patients with class III malocclusion underwent bilateral sagittal splitting of ramus with intraoralvertico-sagittal ramus osteotomy for mandibular set-back. The spring scale was used to measure the resistance of medial pterygoid muscles after splitting of ramus. Skeletaldental cephalometric analysis was made and statistic package was used for correlation between resistance and cephalometric variables. The resistant force of the right medial pterygoid muscle was greater than the left one in Koreans with class III malocclusion, and the force had a linear regression relationship with facial depth. The results suggested that facial depth has significant correlation with the resistance of medial pterygoid muscle, which can be acquired from patient's cephalometric analysis.

• 치과방사선
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• 제24권2호
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• pp.427-437
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• 1994

Clinical examination, photometric evaluation, & radiographic analysis have been used to evaluate the asymmetry of the face. Commonly used skull radiographs to assess skeletal asymmetry include poatero-anterior cephalometries, submentovertex view, & panoramic view. The purpose of this study is the comparison of the reliance of the postero-anterior cephalometric view, submentovertex view, & panoramic view in the asymmetry evaluation. All measurements were performed on the each radiographs of 31 control group & 30 asymmetric group. The measurements are MSL(midsagittal plane)-Co, MSL-Go, MSL-Me, MSL-Al, MSL-Bl, Mn. Ramus Height(Co-Go), Mn. Body Length(Go-Me), and Total Mn. Length(Co-Me). The results were as follows: 1. The lack of either a right-sided or left-sided asymmetric dominant was found. 2. The postero-anterior cephalometric view & submentovertex view relatively agreed with each other in the result. The postero-anterior cephalometric view & submentovertex view had the clinical reliability & effectiveness in the diagnosis of the skeletal asymmetry(p<0.05). 3. The panoramic view showed more magnification compared to the other radiographs. In the vertical measurements the panoramic view had clinical reliability relatively(p<0.05). But we cannot rely on the horizontal measurements in the panoramic view(p>0.05).

• 대한치과의사협회지
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• 제53권8호
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• pp.558-568
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• 2015

Objective: The objectives of this study were to measure pediatric organ and effective doses of cone-beam computed tomography (CBCT) for orthodontic analysis and to compare them to those of panoramic and lateral cephalometric radiography, the conventional radiography for orthodontic analysis. Materials and Methods: Alphard VEGA for CBCT, Planmeca Proline XC for panoramic radiography and Orthophos CD for cephalometric radiography were used for this study. Thermoluminescent dosimeter (TLD) chips were located at 24 anatomic sites of 10-year-old anthropomorphic phantom and exposed during CBCT (C-mode; $200{\times}179mm$ FOV), panoramic and lateral cephalometric radiographic procedures at the clinical exposure settings for 10-year-old patient. Pediatric organ and effective doses were measured and calculated using ICRP 2007 tissue weighting factors. Results: Effective doses of CBCT, panoramic radiography and lateral cephlometric radiography in pediatric clinical exposure settings were $292.5{\mu}Sv$, $19.3{\mu}Sv$, and $4.4{\mu}Sv$ respectively. The thyroid gland contributed most significantly to the effective dose in all the radiographic procedures. Conclusion: Effective dose of CBCT was about 12 times to conventional radiographic procedures for orthodontic analysis in pediatric patient. The use of CBCT for orthodontic analysis should be fully justified over conventional radiography and dose optimization to decrease thyroid dose is needed in pediatric patients.