• The korean journal of orthodontics
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• v.50 no.1
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• pp.3-12
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• 2020

Objective: This study compared three prominent midsagittal planes (MSPs) to identify the MSP that best approximates the true symmetrical MSP. Methods: Forty-three patients (mean age, 23.0 ± 8.20 years) were grouped as follows: group 1 consisted of 10 patients with skeletal Class I and a menton (Me) deviation of < 2 mm; group 2, 11 patients with skeletal Class III and a Me deviation < 2 mm; group 3, nine patients with skeletal Class III and a Me deviation of 2 to less than 4 mm; and group 4, 13 patients with skeletal Class III and an Me deviation ≥ 4 mm. The candidate MSPs were established by three-dimensional (3D) cone beam computed tomography (CBCT) reorientation methods (RMs): (1) the MSP perpendicular to the Frankfort horizontal (FH) plane while passing through the crista galli and basion; (2) the MSP including the nasion, incisive foramen, and basion; (3) the MSP including the nasion, anterior nasal spine, and posterior nasal spine. The mean absolute distances (MADs) to the MSPs were calculated from the coordinates of 1,548 points on 129 CBCT images. The differences in the values of the 3D coordinates among RMs were compared. Results: The MADs of the three RMs showed significant differences (p < 0.05). Most of the differences in values of the coordinates were not significant among RMs. Conclusions: Although the differences in distance among the three MSPs were minor, the MSP perpendicular to the FH plane while passing through the crista galli and basion best approximated the true symmetrical MSP.

• The korean journal of orthodontics
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• v.46 no.5
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• pp.269-279
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• 2016

Objective: Rapid maxillary expansion (RME) is used to expand the maxilla and increase arch perimeter; yet, there are few reports on its effects on the sphenoid bone. With cone-beam computed topography (CBCT), it is possible to visualize sphenoid bone changes. The purpose of this study was to investigate sphenoid bone changes observed in conjunction with RME treatments, using CBCT. Methods: Sixty patients (34 women and 26 men, aged 11-17 years) underwent RME as part of their orthodontic treatment. Patients were randomly assigned to one of three groups: a tooth-anchored group, a bone-anchored group, or a control group. Initial CBCT scans were performed preceding the RME treatment ($T_1$) and again directly after the completion of expansion ($T_2$). Statistical analysis included ANOVA, descriptive statistics, and the intraclass correlation coefficient (ICC). Results: The reliability of the landmark location was at least 0.783, and the largest ICC mean measurement error was 2.32 mm. With regard to distances, the largest change was 0.78 mm, which was not statistically significant (p > 0.05). Statistical significance was established in patient groups of the same sex and treatment type for the following distance measurements: right anterior lateral pterygoid plate to the right edge of the hypophyseal fossa ($d_2$), anterior distance between the medial pterygoid plates ($d_4$), and anterior distance between the left medial and lateral plates ($d_8$). Conclusions: In this study, there were no clinically significant changes in the sphenoid bone due to RME treatments regardless of sex or treatment type.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.339-347
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• 2012

There still remains a controversial debate whether facial skeletal morphological differences exist between patients with nasal and mouth breathing habits. The aim of this study is to assess a relationship between over a period of time mouth breathing and facial skeletal morphology by analyzing lateral cephalometric radiographs of patients with nasal or mouth breathing habits. A total of 120 patients with skeletal class I, II, and III, who had undergone orthodontic diagnosis in department of pediatric dentistry - chonbuk national university, were chosen and their lateral cephalometric radiographs were analyzed. These patients were divided into six groups of 20, each with or without mouth breathing habits. The result of this study has not showed noticeable differences in cephalometric measurements between nasal and mouth breathing children of skeletal class I, II, and III (p > 0.05). However, when the groups were divided by age factor, mouth breathers of age 12 and older showed significant differences in cephalometrics such as decreased ramus height, maxillary retrusion, and clockwise pattern of mandible than children under age 12 (p < 0.05). In conclusion, a longer period of mouth-breathing habits in children displayed a greater chance of impaired facial growth.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.3
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• pp.278-290
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• 1991

Prediction of the sop tissue changes following hard tissue movements is very important in the preoperative analysis of surgical changes of the patient who have orthognathic surgery. This study examined post operative changes of the mid-facial sop tissues in Koreans depending upon two major positional changes of the maxilla following Le Fort - I type osteotomy for orthognathic purposes. Sixty patients(41 males and 19 females) of Koreans were selected and divided into two groups according to directional change of movement of anterior bony structures of the Maxilla as follows : Group I (44 patients) was mooed anteriorly and/or inferiorly, and Group II (16 patients) was mooed posteriorly and/or superioly. Postoperative changes of the sop tissue measurements following hard tissue changes were examined on pre - and post - operative cephalometrics by means of computerized digitation methods and the ratios of changes were analysed. The results were obtained as follows : 1. In Group I, all of the sop tissue measures except the Pn was closely followed by the changes of the hard tissue measures in the horizontal plane, but the Sn and the Cm were only correlated to the vertical changes(p<0.001). In group II, all of the sop tissue measures excluding of the N' and the Pn were significantly correlated to the hard tissue measures in horizontal plane(p<0.001), but the Ls and Stm were only correlated relatively to the vertical changes of the ANS(p<0.01). 2. Predictable ratio of the Sn was 66% of the ANS or 56% of the A in the horizontal plane and 89% of the A in the vertical plane in Group I. In Group II, the Sn was predictable as 85% of the ANS or 70% of the A in the horizontal plane but was not predictable in vertical plane. 3. Predictable ratio of the Cm was 28% of the ANS or 50% of the A in the horizontal plane and 56% of the ANS or 36% of the A in the vertical plane in Group I. In Group II, the Cm was predictable horizontally as 74% of the A. Predictable ratio of the Pn was 30% of the ANS or 38% of the A in horizontal plane in Group I, but it was not predictable both horizontally and vertically in Group II. 4. Predictable ratio of the Ls was 52% of the Pr in Group I and 77% in Group II in the horizontal plane. The Stm was predictable as 34% of the pr or 22% of the I in the horizontal plane in Group I, and was also predictable as 55% of the pr or 68% of the I horizontally and 21% of the pr or 65% of the I vertically in Group II. 5. All ratios of change in the thickness. length and area of the upper lip following maxillary movement were statiscally correlated, however, mangitudes of them were meaningful clinically.

• The korean journal of orthodontics
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• v.17 no.1
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• pp.135-148
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• 1987

To investigate the relationship between craniofacial growth and bone maturity of the hand wrist in normal occlusion, the author took cephalogram and handwrist radiogram of 391 students (male 192, female 199) and assessed the measurements of cephalogram according to skeletal maturity stages of the hand and wrist. In this study, four skeketal stages and 36 linear, angular measurements of the cephalometrics were selected. In hand-wrist X-ray the bones used to determine skeletal maturity were the middle phalanges of the third finger, and distal epiphysis of the radius. In cephalogram, the landmark used to measure the angle and length were N, S, Po., Ar., Go., Me., Gn., Pog., Point B, Point A, ANS, PNS, Or., U1, L1, U6, L6 etc.. The results were as follows, 1. The table of mean, standard deviation, p-value from measurements were made in each group and both sex. 2. The increased measurements according to skeletal maturity were anterior cranial bese length, posterior cranial base length, ramus height, anterior facial height, posterior facial height, L1 to mandibular plane (mm), facial plane angle. In contrast to, decreased measurements were genial angle, facial cnvexity and facial plane angle. 3. Denture pattern measurements (IMPA, FMIA, occlusal plane to Go-Gn, interincisal angle, U1 to SN plane, U1 to SN plane, U1 to facial plane, L1 to facial plane etc.) .had nothing to do with skeletal maturity. 4. Skeletal maturity had close relationship with craniofacial growth, but had little to do with tooth development.

• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.881-889
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• 1997

The purpose of this study was to compare four groups of Oriental young adults (169 males and 174 females) with normal occlusion and well balanced faced. Lateral cephalograms of 100 Koreans, 100 Chinese, 72 Vietnamese and 71 Japanese were digitized and six profile measures were computed. Analyses of variance showed that total facial profile(Gl'-Pr'-Pg') of Chinese was significantly less convex than the profile of Koreans or Vietnamese. Facial profile(Gl'-Pr'-Pg') of Chinese was also significantly less convex than that of Vietnamese. Holdaway's soft tissue angle(Pg'-LS:N-B) was significantly greater in Vietnamese than Chinese and Koreans, who were in turn greater than Japanese. The upper lip of Vietnamese is significantly closer to Ricketts' esthetic plane, than Chinese; Koreans and Japanese are significantly further behind the plane than Chinese. The lower lip of Koreans and Japanese was close to the esthetic plane, while Chinese and Vietnamese were approximately 2mm ahead. The nasolabial angle was significantly smaller for Chinese and Japanese than Koreans and Vietnamese. Sex differences were primarily dependent on the nose; total facial convexity and the nasolabial angle wert significantly larger in females than males. The results of this study demonstrate that a single standard of facial Profile is not sufficient or appropriate for Oriental patients.

• The korean journal of orthodontics
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• v.29 no.3 s.74
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• pp.317-325
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• 1999

In proper diagnosis of skeletal Class III malocclusion, it was important to know the pattern of three dimensional skeletal & facial disharmony. The purpose of this study was to obtain P-A cephalometric characteristics in skeletal Class III malocclusion comparing with normal occlusion. The samples were consisted of 120 subjects, divided into four groups : Male normal occlusion, Female normal occlusion, Male skeletal Class III malocclusion, Female skeletal Class III malocclusion. Posteroanterior and lateral cephalogram were taken from the subjects with a x-ray apparatus (ASHAI CX90SP, Japan) and traced on acetate paper with routine manner. The transverse and vertical values from posteroanterior cephalometry, the sagittal values from lateral cephalometry and their ratio were obtained. The results were as follows: 1. The anteroposterior discrepancy in skeletal Class III group was not due to short maxillary length(Cd-A), but to longer mandibular length(Cd-Gn) than normal occlusion group. 2. The faces of skeletal Class III group were longer than normal occlusion group. It was not due to increase of upper face height(Cg-ANS) but to increase of the lower face height(ANS-Me) especially mandibular height(Cd-Me). 3. There was no difference in the facial width values between normal occlusion group and skeletal Class III group, except upper molar width(U6-U6), lower molar width(L6-L6) and mandibular width(Ag-Ag) of female skeletal Class III group which were larger than normal occlusion group. 4. The increase of mandibular length of skeletal Class III group was reflected in the increase of lower facial height but did not have an effect on the mandibular width.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.1-7
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• 2000

It is important that the orthodontist accurately assess the degree to which facial asymmetry contributes to a given malocclusion before treatment planning. P-A, submentovertex and verticosubmental view have been used in the assessment of facial asymmetry. Among them, submentovertex view is rarely used because it has low reproducibility and is short of normal data and proper analysis method. The purpose of this study was to develop a submentovertex cephalomentrics and obtain normal data in Korean adults. The subjects consisted of 40 normal adults (male : 22, female 18) without the experience of orthodontic treatment. We find the 2 angular and 9 linear measurements. Though submentovertex cephalomentrics has the limitation in comparing the absolute length between right and left, it is useful to examine the relationship of skeletal and dental midline, the shape and location of condyle head and the shape of mandibular body in submentovertex view Therefore, if we understand the limitation of submentovertex cephalomentrics and use lateral , P-A and submentovertex cephalomentrics together, we will measure the location and amount of skeletal disharmony more exactly.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.33.1-33.9
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• 2015

Background: The porion (Po) is used to construct the Frankfort horizontal (FH) plane for cephalometrics, and the external auditory meatus (EAM) is to transfer and mount the dental model with facebow. The classical assumption is that EAM represents Po by the parallel positioning. However, we are sometimes questioning about the possible positional disparity between Po and EAM, when the occlusal cant or facial midline is different from our clinical understandings. The purpose of this study was to evaluate the positional parallelism of Po and EAM in facial asymmetries, and also to investigate their relationship with the maxillary occlusal cant. Methods: The 67 subjects were classified into three groups. Group I had normal subjects with facial symmetry ($1.05{\pm}0.52mm$ of average chin deviation) with minimal occlusal cant (<1.5 mm). Asymmetry group II-A had no maxillary occlusal cant (average $0.60{\pm}0.36$), while asymmetry group II-B had occlusal cant (average $3.72{\pm}1.47$). The distances of bilateral Po, EAM, and mesiobuccal cusp tips of the maxillary first molars (Mx) from the horizontal orbital plane (Orb) and the coronal plane were measured on the three-dimensional computed tomographic images. Their right and left side distance discrepancies were calculated and statistically compared. Results: EAM was located 10.3 mm below and 2.3 mm anterior to Po in group I. The vertical distances from Po to EAM of both sides were significantly different in group II-B (p=0.001), while other groups were not. Interside discrepancy of the vertical distances from EAM to Mx in group II-B also showed the significant differences, as compared with those from Po to Mx and from Orb to Mx. Conclusions: The subjects with facial asymmetry and prominent maxillary occlusal cant tend to have the symmetric position of Po but asymmetric EAM. Some caution or other measures will be helpful for them to be used during the clinical procedures.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.65-78
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• 1997

This study was carried out in order to determine soft tissue response to incisor movement and mandibular repositioning and to determine feasibility of predicting vertical and horizontal changes in soft tissue with hard tissue movement. For this study, cephalometric records of 41 orthodontically treated adult females who had Angle's Class II division 1 malocclusion were selected and stepwise multiple regression analysis was employed. Following conclusions were obtained by analysing the changes of soft tissue and hard tissue before and after treatment. 1. Hard tissue measurements that showed significant changes before and after treatment were horizontal and angular changes of maxillary incisor, horizontal,vertical and angular changes of mandibular incisor, overjet, overbite, interincisal angle, mandibular repositioning, A,B, skeletal convexity and soft tissue measurements that showed significant changes were horizontal, thickness and angular changes of upper lip, horizontal and angular changes of lower lip, interlabial angle, nasolabial angle labiomental angle, Sri, Ss, Si and soft tissue convexity(P<0.05). 2. All Soft tissue measurements changed significantly before and after treatment had between one and four hard tissue independent variables at statistically significant level, indicating that all soft tissue changes were direct relationship with hard tissue changes 3. Ova jet, horizontal change of maxillary incisor, horizontal change of maxillary root apex and horizontal change of pogonion entered into prediction equations most frequentely indicating that they were more significant variables in prediction of vertical and horizontal changes in the soft tissue with treatment, but vertical changes of mandibular incisor not entered any prediction equations, indicating that it was not considered a good predictor for soft tissue changes with maxillary incisor retraction. 4. Horizontal and vertical changes in subnasale were found to have most independent variables, significant at the 0.05 level in prediction-equations(${\Delta}$Sn(H):Ur, Is(H), Pg(H), UIA,${\Delta}$Sn(V): Is(H), Pg(H), overjet, A), indicating that subnasale changes are influenced by complex hard tissue interaction. 5. Multiple correlation coefficient($R^2$) of the soft tissue prediction equations ranges from 0.2-0.6.