• 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 korean journal of orthodontics
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• v.27 no.2
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• pp.197-208
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• 1997

Class III malocclusion patients can be approached with many different types of treatment methods, and thus, each patient's problems must be accurately evaluated to allow selection of the best possible treatment method. Cephalometric analysis is an essential part of diagnosis and treatment planning of orthodontic patients, and it would certainly be helpful if reliable cephalometric guidelines could be set. The author divided 482 Class III malocclusion patients(253 males and 229 females) into fourgroups according to different types of treatment methods they have received to correct imbalance between upper and lower jaws: 1) orthopedic appliance (face mask & RPE), 2) camouflage treatment with fixed appliance, 3) surgical-orthodontic treatment, 4) cross-bite correction with removable plates/ functional appliance. Cephalometric values at the time of first clinical examination were compare among the four groups. Cephalometric analysis indicates the following results: 1)the amounts of antero-posterior and vertical skeletal discrepancies and dental compensation were greatest in surgery group 2) SNB, Wits, distance from Nasion Perpendicular Plane to point a facial angle, facial convexity, and APDI were greater in orthopedic appliance group than fixed appliance(camouflage) group, but there was no statistical difference 3) removable plates/ functional appliance group showed least amounts of skeletal discrepancies and dental compensation with statistical significance.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.222-232
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• 2014

Purpose: This study aims to investigate if 2D analysis method is applicable to analysis of CBCT by comparing measuring points of CBCT with those of Adjusted 2D Lateral Cephalogram (Adj-Ceph) with magnification adjusted to 100% and finding out at which landmarks the difference in position appear. Materials and methods: CBCT data and Adj-Ceph (100% magnification) data from 50 adult patients have been extracted as research objects, and the horizontal (Y axis) and vertical (Z axis) coordinates of landmarks were compared. Landmarks have been categorized into 4 groups by the position and whether they are bilaterally overlapped. Paired t-test was used to compare differences between Adj-Ceph and CBCT. Results: Significant difference was found at 11 landmarks including Group B (S, Ar, Ba, PNS), Group C (Po, Or, Hinge axis, Go) and Group D (U1RP, U6CP, L6CP) in the horizontal (Y) axis while all the landmarks in vertical (Z) axis showed significant difference (P<.05). As a result of landmark difference analysis, a meaningful difference with more than 1 mm at 13 landmarks were indentifed in the horizontal axis. In the vertical axis, significant difference over 1 mm was detected from every landmark except Sella. Conclusion: Using the conventional lateral cephalometric measurements on CBCT is insufficient. A new 3D analysis or a modified 2D analysis adjusted on 19 landmarks of the vertical axis and 13 of the horizontal axis are needed when implementing CBCT diagnosis.

• The korean journal of orthodontics
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• v.39 no.5
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• pp.330-336
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• 2009

Objective: To examine the differences in lateral cephalometric characteristics between patients with dental protrusion and crowding in order to determine what factors affect dental protrusion or crowding while both malocclusion types are caused by large tooth size. Methods: Twenty nine individuals with dental protrusion and 22 individuals with dental crowding were enrolled in this study. All subjects had larger teeth than average and Class I molar relationships. Craniofacial characteristics and hyoid bone positions were determined from lateral cephalograms and compared between the two groups. Results: In the comparisons of craniofacial characteristics, the measurements indicating maxillary length and facial convexity showed greater values in the protrusion group than in the crowding group. Comparisons of hyoid bone positions showed that the hyoid bone was positioned more anteriorly and superiorly in the protrusion group than in the crowding group. Conclusions: The results of the present study indicate that some craniofacial characteristics and tongue position may affect the development of dental protrusion or crowding; when an individual has large teeth, dental protrusion or crowding might be determined according to maxillary growth and tongue position.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.377-388
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• 2020

The aim of this study was to evaluate the association between various predicting tools and Apnea-Hypopnea Index (AHI) to identify children with sleep disordered breathing (SDB). From 5 to 10 years old who came for orthodontic counseling, 61 children, whom had lateral cephalograms, pediatric sleep questionnaire (PSQ) records, and portable sleep monitoring results, were included in this study. A total of 17 measurements (11 distances and 6 angles) were made on lateral cephalograms. The measurements of lateral cephalograms, PSQ scales and portable sleep monitoring results were statistically analyzed. 49 of 61 (80%) patients showed AHI > 1, which suspected to have SDB and their mean AHI was 2.75. In this study, adenoid size (A/N ratio), position of the hyoid bone from mandibular plane, gonial angle, and PSQ scale were related to a higher risk of pediatric SDB. Also, oxygen desaturation index (ODI) and snoring time from sleep monitoring results were statistically significant in children with SDB using Mann-Whitney test (p < 0.05). In conclusion, evaluation of hyoid bone position, adenoidal hypertrophy, gonial angle in lateral cephalogram, and PSQ scale was important to screen out potential SDB, especially in children with frequent snoring.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.214-220
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• 2001

The clinical application of the three-dimensional radiographic technique had been limited to standard Broadbent-Bolton cephalometer with biplanar stereoradiography. We developed a new method for compensating the error of head position in ordinary non-biplanar cephalostat. It became to possible to use the three dimensional cephalogram commonly in clinical bases. 1. The method of methemetical compensation of head positioning error in non-biplanar condition was evaluated with dry skull. The error of the method of first and the second trial was $0.46{\pm}1.21$, $0.33{\pm}0.90mm$, which means the error of the head positioning correction in conventional cephalogram was within clinical acceptance. 2. The reproducibility of this system for clinical application was 0.54 mm ($-2.99{\sim}2.26mm$) which defines the absolute mean difference of the first and second trial. Compare to the The landmark identification error $1.2{\pm}1.6mm$, the error of the measurement was within the range of landmark identification error. The result indicates the adequate clinical accuracy of the computation of three-dimensional coordinates by compensation of the error of the head position in ordinary non-biplanar cephalostat.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.307-313
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• 2018

The respiratory function is relevant to the craniofacial growth and orthodontic diagnosis. The size of the pharyngeal airway was measured in lateral cephalometric view in children visited Kyung Hee University Hospital from January 2015 to August 2017. A total of 74 healthy children (36 boys and 38 girls) aged 7 - 11 years (mean, 8.5 years) with a normodivergent facial pattern were divided into three groups according to anteroposterior jaw relation measuring A point-Nasion-B point (ANB) angle. Lateral cephalometric data were used to measure the airway dimensions. The dimensions of the middle airway were significantly lower, reducing the upper airway space, in large ANB angle group than in other children, suggesting that children with large ANB angle have narrower airway space than others.

• The korean journal of orthodontics
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• v.41 no.5
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• pp.312-323
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• 2011

Objective: This study compared the bone thickness of the palate between lateral cephalogram and 3D model measurements. Methods: The subjects consisted of 30 adults (15 men,15 women) with a normal skeletal pattern and occlusion. The CT images were transformed to a 3D model, and were compared with the cephalometric image. Descriptive statistics for each variable were calculated. Results: In the 3D CT model, the mid-palatal area was the thickest part. It became thinner as the palate tapered laterally. In the male group, the thinnest portion was positioned 6 mm away from the mid-palate, while in the female group the thinnest portion was 8mm away from the mid-palate. Correlation analysis between the lateral cephalometric and 3D CT model revealed a significant correlation except in the mid palatal area and the area 2 mm lateral to the mid-palate in men, whereas there was a significant relationship in every area in the women. In both men and women, the highest correlation appeared in the area 8 mm lateral to the mid palate. Conclusions: Using regression analysis, an actual prediction of the bone thickness between the measured bone thickness of the lateral cephalometric radiograph and 3D model was made. This will provide useful information for mini-implant length selection when inserting into the palate.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.414-420
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• 1996

Cephalometric measureements have disadvantage of representing cranio-facial structures in two dimension only and therefore they pose limitations in describing three-dimentional structures of cranio-facial region. More interests have been put on the correlation between the two planes. This study evaluated correlations between facial type score, which allows effects on malocclusion, growth change prediction and establishment of treatment method and prognosis, and measurements from submentovertex view. Cephalometric view and submentovertex view were taken of skeletal Class I adults with optimal profile and correlations between them have been observed. Following results were obtained: 1. To learn about factors that influence average condylar angulation, FACE, INT-CO-ANG, MN-CORPUS, CON-RATIO, GON-RATIO, MN-RATIO were used as variables and underwent multiple regression analysis. As a result, the following equation was obtained : CON-AVE=.l73(FACE)-.322(INT-CO-ANG)+36.34(GON-RATIO) +.420(MN-CORPUS) (($R^2=.85451$) 2. The following equation was obtained concerning facial type score. FACE= .050(CON-ANG)+.023(INT-CO-ANG)-.075(MN-CORPUS)($R^2=.31547$) 3. Among the submentovertex measurements, MN-CORPUS, CON-RATIO, GON-RATIO, MN-RATIO showed close correlations. (P<0.05) 4. Average condylar angualtions were $23.37^{\circ}$ on the right and $20.71^{\circ}$ on left. There was a difference between the two. FACE : facial type soore. CON-ANG: mean value of condylar angulation. CON-AVE: mean value of Rt. Lt condylar angulation. INT-CO-ANG : angle between Rt. Lt condylar axis. MN-CORPUS : angle formed between RT. Lt gonion & pogonion. CON-RATIO: lntercondylar distance/mandibular body length. GON-RATIO : intergonion distanoe/mandibular body length. MN-RATIO: lntermylohyoid distance/mandibular body length. MX-RATIO: intermaxillary tuberosity distance/ANS-PNS distance.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.161-169
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• 2011

Longitudinal serial cephalometric films in the every second year from fifty girls were used for the analysis of growth pattern of maxillary alveolar bone (MAE). Six parameters regarding MAB height were measured and were compared with stature and chronological age. Descriptive analysis. correlation coefficient test and linear regression analysis were done for the statistical analyses. 1. The height of MAE increased until 14 years although growth velocity was gradually decreased. which was different with stature growth pattern. 2. The correlation coefficients between chronological age and MAB height were high and had no statistical differences with those of stature and MAB height. In addition. the correlation coefficients between chronological age groups within each parameter of MAB were very high. 3. The growth amount of MAB could be predicted using linear regression analysis on the basis of chronological age data. The growth pattern between MAE and statue was quite different because of the growth pattern difference between skeletal and neuronal system. Therefore. growth pattern of Korean MAB must be considered in dental treatment of youth. Also. close relationship between chronological age and MAB height would be useful when clinicians want to predict growth amount of MAE for the dental implant treatment.