• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.235-242
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• 2008

The purpose of this study was to investigate the relationship of the skeletal maturity of hand-wrist and the development of mandibular third molar in subjects with class I and class III malocclusion. The subjects used in this study were 304 children(149 boys, 155 girls) with class I malocclusions and 308 children( 153 boys, 155 girls) with class III malocclusions, ranged from 8 to 15 years of age. Hand-wrist radiographs and panoramic radiographs were used to evaluate the stage of skeletal maturity and teeth development. Fishman's method for the skeletal maturity stages of the hand-wrist and new six-developmental-stage method for the calcification stages of mandibular third molars were analyzed. The results were as follows : 1. In subjects with class I and class III malocclusion, skeletal maturity of the hand-wrist occured earlier in females than in males(p<0.05), while the calcification stages of mandibular third molars were no significant gender differences. 2. There were no significant differences between the groups, when comparing the skeletal maturity stages of the hand-wrist and the calcification stages of mandibular third molars between subjects with the class I and the class III malocclusion. 3. The correlation coefficients between the calcification stages of mandibular third molars and the skeletal maturity stages of the hand-wrist in subjects with class I and class III malocclusion showed a high interrelationship(p<0.01). 4. The correlation coefficients between the calcification stages of mandibular third molars and chronological age in subjects with class I and class III malocclusion showed a high interrelationship (p<0.01). As a result, there were no significant differences between class I and class III malocclusion group for skeletal maturity of the hand-wrist and third molar development.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.95-105
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• 2001

The present study was designed to compare morphological and structural relationships between basicranial measurements such as MCF angulation (Ar-SE-ptm), saddle angle (N-S-Ba, N-S-Ar) and facial structures including types of malocclusion. Twenty six children with Class III whose longitudinal headfilms were available from 7 to 12-year-old, and also 26 cross-sectional headfilms at each ages of 8, 9, 10 and 11 with Class I were selected for the investigation. Cephalometric measurements such as Ar-SE-ptm, N-S-Ba, N-S-Ar, N-SE-Ar, SNA, SNB, N-S/PM vert, CP/PM vert, $\underline{1}/FH$ plane, and $N-perp/\underline{1}$ were measured. Morphologic relationships and pattern of changes in facial structures in relation to the changes of MCF and saddle angle in both malocclusion types were analysed statistically employing ANOVA, t-test and Pearson correlation. Results suggest that the MCF rather than the saddle angle in children with Class I and III is more closely related with various facial structures and with their changes. It may be, therefore, suggested that the MCF be one of the biologically meaningful measurements in determining structural relationships between cranial base and facial complex including types of malocclusion. In addition, the MCF and its correlated facial structures in children with Class III, interestingly, showed somewhat marked changes between the ages of 9 and 11.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.267-276
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• 1999

Distributions trends were examined in 9159 malocclusion patients who had been examined and diagnosed at Department of Orthodontics, College of Dentistry Yonsei University over a 6 year-period from 1992 to 1997. The results were as follows ; 1. The total number of orthodontic patients in 1997 increased in comparing with that of 1992(86%) and after 1995, the number of annual patients showed an increase. 2. Age distribution had shown over-19 year-old group being the largest(39.9%) but percentages of pre-adolescent patients had been decreasing while that of adult patient had gradually increased. 3. Distributions in the types of malocclusion, the Angle's Classification had shown : 33.3% for Class I, 28.6% for Class II and the largest 38.1% for Class III. 4. Among Class I patients, crowding showed the largest(32.6%) and protrusion group had gradually increased to 33.9% in 1996. Otherwise openbite and crossbite groups tend to decrease, annually. 5. Geographic distribution showed a majority of patients from Seoul(above 70%). Among the patients from Seoul, group within the distance 3-6Km from Yonsei dental hospital was the largest(32.3%) and group within 9Km showed 69% of total patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.599-612
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• 2007

The present study was designed to compare the morphological and structural differences of craniofacial structures among 146 children with Class I and Class III malocclusions. The results below were obtained from the study. 1. Sphenoethmoidal synchondrosis continues to grow later in Class III. 2. Anteroposterior length of the nasomaxillary complex was significantly shorter in Class III, but the height of the nasomaxillary complex was similar. 3. Mandibular length and mandibular body length were longer in Class III, but had no statistical significance. Lower anterior facial height was shorter in Class III, but had no statistical significance. 4. Dentoalveolar height was similar between Class I and Class III. 5. In Class I, anterior cranial base took part in the anteroposterior length of the nasomaxillary complex and the mandible. 6. In Class III, anterior cranial base and middle cranial base had higher correlation with the mandible with aging. These results suggest that there exist a little differences between Class I and Class III malocclusions at age $7{\sim}11$, but growth patterns are mostly similar. Therefore it is necessary to correct Class III malocclusions at an early age before skeletal differences appear.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.564-571
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• 1999

The importance of the hyoid bone lies in its unique anatomic relationships. It has no bony articulations but provides attachment for muscles, ligaments, and fascia of the pharynx, mandible, and cranium. Various studies have documented a variability of hyoid bone position in relation to changed mandibular position or head posture. The aim of this study is to investigate the hyoid bone position and inclination on cephalometric radiographs of three groups of patients exhibiting Class I, II, and III malocclusions. The conclusions obtained from this study can be summarized as follows ; 1. Class III malocclusion patients show a more anterior position of the hyoid bone and also less steep inclination of the hyoid bone. 2. The anteroposterior position of the hyoid bone relative to the cervical vertebra and mandible was very constant. 3. The hyoid bone represented the anterior bony boundary of the pharynx at a lower level than PNS.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.521-533
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• 2000

This study was investigated to evaluate the morphologic characteristics of openbite and deep bite in Class I malocclusion patients and to find skeletodental factors which contributed to vertical discrepancy in Class I malocclusion. The subjects were consisted of 40 control subjects (male 20, female 20) and 40 Class I openbite patients and 40 Class I deep bite patients. Lateral cephalograms in centric occlusion were taken, traced and digitized lot each subjects. The computerized statistical analysis were carried out with SPSS program. The results were as follows. 1. The pattern of vortical discrepancy in Class I malocclusion is mainly influenced by the skeletodental factors under palatal plane. 2. In openbite group, vortical discrepancy is prominent on anterior lower face and is closely related with skeletal factors such as mandibular form and inclination. 3. In deep bite group, dental factors such as ewe of Spee, vertical height of maxillary molar and skeletal factor such as articular angle were contributed to the vertical discrepancy. 4. The multiple regression analysis showed that overbite in Class I molar relationship was determined mainly by dental factors such as lower incisor to occlusal plane angle, curve of Spee, interincisal angle, and ODI.

• The Journal of the Korean dental association
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• v.31 no.2 s.285
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• pp.118-124
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• 1993

• The korean journal of orthodontics
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• v.3 no.1
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• pp.35-40
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• 1972

• 대한치과교정학회:학술대회논문집
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• 1999.11a
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• pp.60.1-60.1
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• 1999

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.329-339
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• 2022

The purpose of this study was to compare the palatal dimensions (volume, width, length, and height) in different malocclusions (Class I, II, and III) in mixed dentition using a three-dimensional digital scanner. The study was performed on 30 selected casts from 1400 casts that were taken at the Department of Pediatric Dentistry at Dankook University. Casts consisted of Class I, II, and III malocclusion groups in Hellman's dental age IIIA. The mean age was 8 years and 6 months ± 11 months. Each cast was scanned by three-dimensional digital scanner, Medit T710 (Medit, Seoul, Korea), and shaped into the three-dimensional image and calculated palatal dimensions using the Plan T program (SMD solution, Seoul, Korea). The values were statistically compared and evaluated by Kruskal-Wallis followed by the Mann-Whitney test. According to our results, subjects with Class II malocclusion showed lower palatal width and longer palatal length compared to those with Class I and Class III. For palatal height, Class III malocclusion subjects in mixed dentition exhibited a larger number than Class II and Class I. Lastly, for palatal volume, compared to other malocclusions, Class III showed higher results; however, there were no significant differences. The form of the palate differs in types of malocclusions and understanding of these differences is important in clinical significance. Based on this study, the understanding of the relationship between the shape of the palate and the skeletal pattern provides useful information about orthodontic treatment plans, early diagnosis of malocclusion, and morphological integration mechanisms. Orthopedic treatment in the maxilla should be performed during early and intermediate mixed dentition to enhance treatment efficiency.