• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.79-88
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• 1988

The purpose of this study was to investigate the factors which might be related to mandibular third molar eruption and to predict the possibility of whether or not it will be erupted. The material of this study was lateral cephalometric radiograms, pantomograms and dental casts obtained from 70 patients (19 males, 51 females) ranging in age from 18.0 to 32.1 years. They were devided into erupted group and impacted group of mandibular third molars. For the comparison of each group, a total of 20 measurement items were employed and the data were analyzed by means of computer statistical method. As a result of this study, the following conclusion can be made; 1. The longer mandibular body length and narrower mandibular ramus width, the higher eruption tendency of the lower third molar, but the degree of genial angle was not related to mandibular third molar eruption. 2. The lower percentage of posterior mandibular body height to anterior mandibular body height, the higher eruption tendency of the lower third molar. 3. The total tooth size, including the lower second molar, appeared to be larger in the impacted group than in the erupted group of the lower third molar. 4. The arch length discrepancy of the impacted group was more severe in contrast with the erupted group of the lower third molar.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.175-188
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• 1988

The purposes of the present study were to describe the vortical and anteroposterior facial dysplasia, and to identify morphologic differences associated with various facial patterns. Anteroposterior dysplasia was classified by traditional Angle's malocclusion classification and according to vertical relationships based on the SN-MP angle, facial pattern was subclassified to 3 vertical groups in each malocclusion group. Each vertical group composed of 20 samples and total 180 samples aged from 9 to 14 years. The results were as follows; 1. The skeletal differences that lead to disportionate lower facial height in vortical and anteroposterior facial dysplasia were closely related to mandibular morphology. 2. Hyperdivergent group, compared with hypodivergent group, demonstrated decrease of SNA and SNB and linguoversion of maxillary and mandibular central incisors in all malocclusion groups. 3. Irrespective of rotation of the jaws, Wits appraisal was a useful measurement in evaluation of relative anteroposterior relationship of maxilla and mandible. 4. As SN-MP angle increased, anterior facial height, especially lower anterior facial height, demonstrated significant increase and intermaxillary space also tended to increase. 5. The correlation coefficients of SN-MP angle and PTFH/ATFH demonstrated the highest value in all malocclusion groups.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.12 no.1
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• pp.49-56
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• 1982

The purpose of this study was to observe the anatomic variation of condylar head and the positional relationship between condylar head and other anatomic structures of head by means of cephalometry using the submentovertex cephalogram from each person in centric occlusion for producing a good quality of temporomandibular joint radiograph. The 100 submentovertex cephalograms of 100 Korean adults consisted of 50 females ranged from 20 to 24 years age and 50 males ranged from 22 to 30 years age, were studied and analyzed statistically. The results were as follows; 1. The mean of the horizontal angulation of condylar head to the transmeatal line (EE-LA) was 18.5° (S.D. 7.9°), and all measurements that indicate the horizontal angulation of condylar head showed considerable differences among individuals. 2. In the comparison of male vs. female in the measurements, statistically significant differences were found in the majority of measurement items, and with exception of R-LA and LA-LA, the rest of these measurements were larger in male than in female. 3. In the comparison of left vs. right in the measurements, statistically significant differences were found in the majority of measurement items, and with exception of PC-CC, the rest of these measurements were larger in right than in left. As above, because the majority of measurements that involve the horizontal angulation of condylar head varied among individuals, between male and female, and between left and right, the condition of various temporomandibular joint radiography should be determined by means of cephalometry using the submentovertex cephalogram for producing the accurate radiographic image of temporomandibular joint.

• Journal of Korean Dental Science
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• v.15 no.1
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• pp.19-30
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• 2022

Purpose: The purpose of the study was to assess the validity of three-dimensional (3D) facial scan taken with facial scanner and digital photo wrapping on the cone-beam computed tomography (CBCT). Materials and Methods: Twenty-five patients had their CBCT scan, two-dimensional (2D) standardized frontal photographs and 3D facial scan obtained on the same day. The facial scans were taken with a facial scanner in an upright position. The 2D standardized frontal photographs were taken at a fixed distance from patients using a camera fixed to a cephalometric apparatus. The 2D integrated facial models were created using digital photo wrapping of frontal photographs on the corresponding CBCT images. The 3D integrated facial models were created using the integration process of 3D facial scans on the CBCT images. On the integrated facial models, sixteen soft tissue landmarks were identified, and the vertical, horizontal, oblique and angular distances between soft tissue landmarks were compared among the 2D facial models and 3D facial models, and CBCT images. Result: The results showed no significant differences of linear and angular measurements among CBCT images, 2D and 3D facial models except for Se-Sn vertical linear measurement which showed significant difference for the 3D facial models. The Bland-Altman plots showed that all measurements were within the limit of agreement. For 3D facial model, all Bland-Altman plots showed that systematic bias was less than 2.0 mm and 2.0° except for Se-Sn linear vertical measurement. For 2D facial model, the Bland-Altman plots of 6 out of 11 of the angular measurements showed systematic bias of more than 2.0°. Conclusion: The facial scan taken with facial scanner showed a clinically acceptable performance. The digital 2D photo wrapping has limitations in clinical use compared to 3D facial scans.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.735-753
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• 1992

The purpose of this study was to analyze the positions of upper and lower incisors according to facioskeletal patterns. The lateral cephalometric radiographs of sixty persons with normal occlusion, forty persons with Class II Division 1 malocclusion, and forty persons with Class III malocclusion all above the age of 18, were analyzed. The following results were obtained. 1. C I angle, the measurement related to masticatory system, were $89.20{\pm}4.34^{\circ}$ in normal occlusion group, $81.68{\pm}士5.95^{\circ}$ in Class II Division 1 malocclusion group and $101.96{\pm}6.31^{\circ}$ in Class III malocclusion group. 2. In comparison with the positions of upper and lower incisors according to facioskeletal patterns, Class II Division 1 malocclusion group showed that upper incisors were different significantly in all measurements and inclined labially (P < 0.05). Lower incisors were different significantly in all measurements except LI-APog, LI-APog (mm), LI-AB, LI-AB (mm) and inclined labially (P < 0.05), Class III malocclusion group showed that upper incisors were different significantly in all measurements except UI-SN, UI-OP, and inclined labially (P < 0.05). Lower incisors were different significantly in all measurements and inclined lingually (P < 0.05). 3. In all facioakeletal patterns, LI-SN and LI-PH ware correlated moderately to facioskeletal measurements, and FMA was correlated moderately to measurements of lower incisor position. 4. Regardless of the facioskeletal patterns, the reference planes equally applicable were AB line in the measurements of upper incisor and APog line in the measurements of lower incisor.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.543-552
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• 2000

The purposes of this study were to evaluate the reproducibility of posteroanterior(PA) cephalograms obtained by two methods, the Head Posture Aligner(HPA) method in natural head posture and the conventional method(operator-guided method), and to compare the vertical rotational differences of the head Posture between lateral and PA cephalograms according to the method. The sample was consisted of 30 adults. At first day, a PA cephalogram and a lateral cephalogram were obtained from each subject by two methods to investigate the difference of vertical rotational posture between lateral and PA cephalograms. Two weeks later, another PA cephalogram was obtained using each method to evaluate the reproducibility of head posture. Five height measurements and nine width measurements were used in the paired t-test to compare the reproducibility of the PA cephalometric measurements between two methods. The differences of vertical rotational posture between lateral and PA cephalograms were calculated from a computer program and compared according to the method used, and following results were obtained. 1. Height measurements obtained by operator-guided method showed significant differences according to the time interval and revealed low reproducibility. 2. Height measurements obtained by HPA method did not show significant differences according to the time interval and presented high reproducibility. 3. In the comparison of width measurement, two methods did not show distinct differences in reproducibility. 4. The difference of vertical rotational posture between lateral and PA cephalograms showed $0.8^{\circ}$ in the HPA method, more less than $2.5^{\circ}$ in the operator-guided method. The results of the present study suggest that the HPA may be helpful in the PA cephalometric radiography in terms of reproducibility.

• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.575-587
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• 1999

This study was designed to evaluate the correlations between tongue with skeletal pattern and intermaxillary space in Class II malocclusion adult patients. Craniofacial skeletal pattern was analyzed on the lateral cephalometric radiograph and the subjects were devided two groups by facial ratio, the 30 subjects of hyperdivergent group and the 30 subjects of hypodivergent group. The size and posture of tongue and intermaxillary space were measured on the lateral cephalometric radiograph. These data were statistically analyzed to examine significant differences between both groups and compared the correlation between tongue with skeletal measurements and intermaxillary space in each group. The results of this study were as follows. 1. In comparison of the tongue and intermaxillary space, the measurement of TS/IS showed significantly larger in hyperdivergent group and PIH and IS showed significantly larger in hypodivergent group. There were no statistically significant differences in the measurements of the height and posture of tongue. 2. In correlation between tongue with craniofacial skeletal measurements, the length and height of tongue showed the highest correlation with AFH(anterior facial height) in both groups(p<0.01). And that measurements showed high correlation with PFH(posterior facial height) in hypodivergent group. 3. In both groups, most measurements of tongue showed high correlation with intermaxillary space and the height and space of tongue showed high correlation with AIH and PIH(p<0.01).

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.649-656
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• 2005

The present study was designed to formulate cephalometric norms of normal occlusion for usage in orthodontic diagnosis of malocclusion in Korean children. Thirty two children, aged 4 to 6, with normal occlusion were chosen for this study, Sagittal and vertical relations were analyzed using lateral cephalogram and clinical photos and the measurements were compared with those of adults. On skeletal sagittal analysis, the mean values of the SNA and SNB angles were $83^{\circ}\;and\;78.72^{\circ}$. It showed that the mandible was retrognathic and retropositioned in comparison to those of adults. On skeletal vertical analysis, the mean values of the genial angle was $127^{\circ}$. This showed high angle pattern in children and reduction of genial angle due to counterclockwise rotation of the mandible is expected with growth. On soft tissue analysis, children showed convex pronto, obtuse nasolabial angle. On dental analysis, the mean values of the U1 to SN and IMPA were $91.04^{\circ}\;and\;86.57^{\circ}$. This showed retroclined upper and lower deciduous teeth in comparison to adults. For skeletal values, the liner values were generally greater in males than females.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.4 no.1
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• pp.23-36
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• 1995

The purpose of this artic1e is to compare soft tissue profiles between Korean adults with normal occ1usion and malocclusin and to identify the differences between them. The subjects of this cephalometric study were 40 males with normal occlusion(Group 1), 27 females with normal occlusion(Group 2), 28 adults with Angle's Class II malocclusion(Group 3) and 41 adults with Angle's Class III malocclusion(Group 4). The results of this study were as follows ; 1) People with Angle's Class II malocclusion had tendency to have more labial tipping of lower teeth than people with normal occ1usion. Through NOA angle measurement, it was determined that people with Angle's Class II malocclusion had more protruding midface than people with normal occlusion and people with Angle's Class III malocclusion had retruding midface. 2) Through Powell's esthetic triangle analysis, it was determined that people with Angle's Class II malocclusion had retruding chin and protruding nose. 3) No significant differences between people with normal occlusion and maloclusion could be identified by measuring soft tissue profile angle basis of S-NS plane. 4) There were significant differences between groups with normal occlusion and malocclusion by measuring Facial convexity angle(Significance level 99%). 5) By measuring the distance between each landmark basis of N-Pog plane, People with Angle's Class II malocclusion were identified as having more protruding midface, but there were no significant differences between people with normal occlusion and Angle's Class III malocclusion. 6) By measuring the vertical dimension of the face, it was determined that the lower facial height was higher than the upper facial height in all groups, particularly in group with Angle's Class III malocclusion. 7) By measuring the lips basis of E-line and S-line, it was determined that people with Angle's Class III malocclusion had more, protruding lower lips than people with normal occlusion, while people with normal occlusion, while people with Angle's Class II malocclusion had more protruding upper lips. By measuring the distance between the superior sulcus and inferior sulcus basis of H-line, people with Angle's Class II malocclusion had thicker upper lips than the other's.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.459-474
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• 1988

A study was made of a method of rational assessment on the roentgeno-cephalogram in orthodontic practice. Fifty eight measurements were analyzed on the roentgeno-cephalograms of 50 male and 50 female Korean adults with the acceptable profile and the normal occlusion. The means and standard deviations of measurements were studied in male and female groups by various analytic methods, and the sex difference was examined statistically. The obtained data were compared with those of the Japanese and American standards by useing a Japanese adults standard polygon chart reported by lizuka and Ishikawa. Amongs of 58 measurements, 14 have been selected as statistically significant and clinically useful, and used to make a Korean adult standard polygon chart. The results obtained were as follows: 1. Standards for cphalometric analysis in Korean adults were obtained, and the polygon chart and cephalometric profilogram were also made by using the standards in order to apply to a clinical diagnosis. 2. The sex difference was recognized in linear measurements, but not in angular measurments. 3. In comparison with the American standards from Downs and Graber, the Korean showed significant differences in angle of convexity, mandibular plane angle, Y-axis angle, interincisal angle and lower incisor to mandibular plane angle. Thus, the Korean showed a more retruded chin position, convex facial type, than white people. 4. In comparison with the Japanese standards from Iizuka and Ishikawa, the Korean showed a significant similarity with the Japanese, especially in females. 5. Upper incisor to Huxely line angle, established as a new measurement, proved to be paralell to X-Y axis angle.