• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.347-359
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• 1994

The reproducibility of cephalography in repeated exposures were studied by tracing and photographic subtraction. The materials consisted of 50 pairs of 'same day' radiograph taken under identical conditions. The evaluation included skull, cervical column, hyoid bone, pharynx, tongue, soft tissue profile resulting 43 items in tracing, and 19 items in photographic subtraction. The results obtained from the differences between each pair were as follows: 1. The means and standard deviations by tracing of skull, cervical column, hyoid bone, pharynx, tongue, soft tissue profile were 0.34±0.62㎜, 1.02±1.59㎜, 1.37±1.78㎜, 0.55±1.16㎜, 0.51±1.51㎜, 0.15±0.3㎜ each. 2. The means and standard deviations by photographic subtraction of skull, cervical column, hyoid bone, pharynx, tongue were 0.09±0.35㎜, 0.70±0.95㎜, 1.22±1.33㎜, 0.53±0.86㎜, 0.27±0.41㎜ each.

• The korean journal of orthodontics
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• v.25 no.4
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• pp.453-463
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• 1995

Most commonly used axis for central incisors in lateral cephalometric radiographs is the line connecting root apex and incisor edge. However, crown axis and root axis do not always coincide in cases of malocclusion patients. The angle created by these axis are called the collum angle, which should be considered in orthodontic diagnosis and treatment. In this study, 31 Class I malocclusion, 30 Class II division 1 malocclusion, 31 Class II division 2 malocclusion, and 31 Class m malocclusion patients were selected and their collum angles were measured. Correlation between these angles and malocclusions was investigated, and the correlation analysis with other parameters in cephalometrics was done. The results were as follows ; 1. The mean collum angles according to the types of malocclusions are ; $3.11^{\circ}{\pm}3.54^{\circ}$ for Class I, $1.23^{\circ}{\pm}2.41^{\circ}$ for Class II division 1, $3.77^{\circ}{\pm}4.39^{\circ}$ for Class II division 2, and $3.90^{\circ}{\pm}4.08^{\circ}$ for Class III malocclusion. 2. Statistically significant differences in collum angles were noted between Class II division 1 group and Class II division 2 and Class III group. 3. Significant correlations were found between collum angles and other parameters used in cephalometrics, namely IMPA for Class I, Wits for Class II division 1, Overbite for Class II division 2 and for ClassIII.

• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.459-474
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• 2005

Making a precise and ideal set-up model is an essential part in the indirect bonding procedure for lingual orthodontic treatment. To evaluate the accuracy of the making a set-up model, 22 adult patients who received lingual orthodontic treatment with 4 bicuspid extractions were selected, and 3 sets of dental models (before, set-up, and after treatment) were measured using the set-up model gauge, an instrument for measuring the inclination and angulation of the clinical crowns on the dental model. Two sets of lateral cephalograms (before and after) from each patient were also evaluated. The mean difference between the before treatment model and the set-up model was $-3.93{\pm}6.98^{\circ}$ for the inclination and $1.87{\pm}5.79^{\circ}$ for the angulation. And the mean difference between the set-up model and the after treatment model was $-4.31{\pm}5.91^{\circ}$ labiolingually and $-2.16{\pm}3.27^{\circ}$ mesiodistally, The after treatment model differed from the before treatment model about $-8.24{\pm}5.39^{\circ}$ in inclination. There were no significant difference between the measured gauge that measured from the dental model using the set-up model gauge and the calculated gauge angle measured from the lateral cephalogram using constructed points and lines. Using the set-up model gauge, it is possible to evaluate the study model 3-dimensionally in relation with the patient's lateral cephalogram and establish whether the doctor's prescription or overcorrection is built in the set-up model precisely.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.240-251
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• 2008

Objective: The purpose of this study was to evaluate the effect of head position changes on the root parallelism between adjacent teeth on panoramic radiographs. Methods: A model with normal occlusion was constructed in the SolidWorks program, then RP (rapid protyping) model was fabricated. The model was repeatedly imaged and repositioned five times at each of the following nine positions: ideal head position, $5^{\circ}$ up, $10^{\circ}$ up, $5^{\circ}$ down, $10^{\circ}$ down, $5^{\circ}$, right, $10^{\circ}$, up, and $5^{\circ}$ right rotation, $10^{\circ}$ right rotation. Panoramic radiographs were taken by Planmeca ProMax and the angle between the long axes of adjacent teeth was directly measured in the monitor. Results: Axes of adjacent teeth tended to converge toward the occlusal plane when the head tilted up and converged in the opposite direction to the occlusal plane when the head tilted down. Anterior teeth showed the most notable differences. When one side of the head tilted up $5^{\circ}$ and $10^{\circ}$ along the anteroposterior axis (Y axis), tooth axes of the same side tended to converge toward the occlusal plane and tooth axes of the opposite side tended to converge in the opposite direction to the occlusal plane. When the head rotated to one side along the vertical axis (Z axis), the canine and lateral incisor of the same side converged in the opposite direction to the occlusal plane and the canine and lateral incisor of the other side converged toward the occlusal plane. Conclusions: When assessing the root parallelism on panoramic radiographs, the occlusal plane cant (anteroposterior or lateral) or asymmetry of the dental arch should be considered because these can cause distortion of tooth axes on panoramic radiographs.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.73-81
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• 1991

The purpose of this study was to analyze the position of mandibular condyle on the submentovertex radiograph, thereafter to evaluate the usefulness of submentovertex radiograph in diagnosis of temporomandibular joint dysfunction, and to check the best method of tomographic techniques. Submentovertex radiographs which were taken in 75 temporomandibular joint dysfunction patients and 75 normal persons were used as the sample for this study. The obtained results were as follows: The submentovertex radiograph was a improper method in diagnosis of temporomandibular joint dysfunction and discrimination of affected side. The selective tomography was a better method than any other tomographic techniques in diagnosis of temporomandibular joint dysfunction.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.277-284
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• 1999

The purpose of this study was to evaluate the relation between the treatment duration and cephalometric measurements and the PAR index in Class I malocclusion patients. In 100 Class I malocclusion patients, PAR score and cephalometric measurements were taken from study model and cephalometric radiographs and analyzed statistically. The results of this study were obtained as follows: 1. treatment duration was correlated with extraction and pre PAR index. 2. ANB, FMA, FMIA and IMPA exhibited positive correlation between pre PAR index and pretreatment cephalometric measurements. 3. $\underline{1}$ to FP exhibited positive correlation between post PAR index and posttreatment cephalometric measurements, and $\overline{1}$ to FP exhibited negative correlation. 4. $\underline{1}$ to SN, IIA and $\overline{1}$ to FP exhibited positive correlation between ${\%}\;PAR$ reduction and the change of cephalometric measurements and FMA FMIA, WITS and UL exhibited negative correlation. The results of this study indicate that PAR index taken from study model relate with items concerned with upper and lower incisors, and there are the tendency that pretreatment PAR index are larger in the patients with large Am value and hyperdivergent face.

• The Journal of Korean Academy of Prosthodontics
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• v.8 no.1
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• pp.65-71
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• 1968

저자(著者)는 성장(成長) 발육기(發育期)에 있는 한국인(韓國人)의 His' line과 전두기저선(前頭基底線) 안이평면(眼耳平面) 하악평면(下顎平面) 구개평면(口蓋平面)이 이루는 각도적(角度的) 변화(變化)를 관찰(觀察)하기 위하여 정당교합인(正當咬合人) 남(男) 여(女) 195명(名)의 두부방사선규격사진(頭部放射線規格寫眞)을 Hellma의 치령 분류법(齒齡 分類法)에 의(依)하여 분류(分類)하고 계측(計測) 관찰(觀察)하였든바 다음과 같은 결과(結果)를 얻었다. 1. 성장(成長) 발육기(發育期)에 있어서 전두기저선(前頭基底線)과 His' line이 일정(一定)한 각도(角度) 관계(關係)를 유지한다. 2. His' line은 수평성장축(水平成長軸)으로 생각(生覺)할 수 있다. 3. His' line은 구개평면(口蓋平面)과 대부분(大部分) 일치(一致)하며 남녀(男女)에는 별 차이(差異) 없다. 4. 하악평면(下顎平面)과 His' line이 이루는 각(角)이 심한 것으로 보아 강(强)한 경사도(傾斜度)를 나타내고 있다. 5. 서양인(西洋人)에 비해 하악골(下顎骨)의 후퇴(後退)를 볼 수있다.

• The korean journal of orthodontics
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• v.38 no.1
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• pp.41-51
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• 2008

Objective: The aim of this study was to compare the initial lateral cephalometric characteristics in two groups of patients: those that had mandibular setback surgery only and those that had mandibular setback surgery with advancement genioplasty. Methods: The lateral cephalograms of thirty-one patients were studied. Twenty-one Class III patients (group A) had only madibular setback surgery Twelve Class III patients (group B) had mandibular setback surgery with advancement genioplasty. Results: Differences between two groups were found in N-Me, ANS-Me, Occlusal Plane angle, Palatal Plane to U1, Mandibular Plane to L1, Mandibular Plane to L6, SN to U1, Sn-Stms, and Pog' projection. Compared to group A, group B showed more linguoversion and extrusion of upper incisors, more extrusion of lower incisors and lower first molar, and more steepness of the occlusal plane. N-Me, ANS-Me, and Sn-Stms were also longer in group B. But Pog' projection was shorter than group A. Conclusion: We conclude that certain initial lateral cephalometric characteristics may help indicate the inclusion of advancement genioplasty when mandibular setback surgery is planned in skeletal Class III patients.

• The korean journal of orthodontics
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• v.4 no.1
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• pp.49-55
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• 1974

The author studied the open-bite of 16 males and 25 females aged 20-23 using profile cephalometric roentgenogram and compared with normal occlusion to determine the morphological pattern of open-bite. The following results are obtained. 1) Open-bite patients showed remarkable vertical development of jaws than normal occlusion. 2) Females indicated conspicuous characteristics than males in open-bite. 3) Anterior teeth disclosed low positions in open-bite patients. 4) Mandible revealed obvious morphological features than maxilla in open-bite patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.416-426
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• 2020

The purpose of this study was to calculate uncertainty of orthodontic measurement in skeletal class III malocclusion children using lateral cephalometry analysis software which obtained traceability in previous study. Using this data, standard reference of measurement value for skeletal class III malocclusion was obtained. Lateral cephalometric data was collected from 144 children who visited Pediatric Dentistry from 2017 to 2020 for orthodontic treatment. Orthodontic measurement was analyzed with software which obtained traceability. Type A evaluation of uncertainty and type B evaluation of uncertainty was calculated to obtain combined standard uncertainty and expanded uncertainty. Standard reference of skeletal class III children was compared to standard reference of skeletal class I children. Distribution range for skeletal class III malocclusion children aged 6 to 10 with 95% confidence interval was provided using calculated uncertainty of orthodontic measurement value.