• Imaging Science in Dentistry
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• 제46권2호
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• pp.117-125
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• 2016

Purpose: This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Materials and Methods: Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Results: Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. Conclusion: In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns.

• 대한치과교정학회지
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• 제19권3호
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• pp.67-78
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• 1989

This study was designed to investigate the difference of teeth and craniofacial complex between normal occlusion and Angle's Class II, div. 1 malocclusion in Korean children. The sample was divided into 2 groups, the 66 subjects with normal occlusion and 96 subjects with Angle's Class II, div. 1 malocclusion in both sexes. The results obtained were as follows: 1. No significant differences were observed in ant. cranial base length & cranial flexure (saddle) angle) between normal occlusion & Angle's Class II, div. 1 malocclusion group, but posterior cranial base length of Class II, div. 1 malocclusion group was larger than that of normal occlusion group. 2. No significant difference was observed in the anteroposterior position of Maxilla to cranial base between two groups, but mandibular position in Class II, Div. 1 malocclusion was posterior and interior to that of normal occlusion. 3. The length of maxilla (ANS-PSN) was larger in Class II, div. 1 malocclusion than normal occlusion. The length of mandibular body (Go-Me) was nor different between Class II, div. 1 malocclusion and normal occlusion. 4. Maxillary incisor position of Class II, div. 1 malocclusion to cranial base was more protrusive than that of normal occlusion, but there was no difference in mandibular incisor position between two groups.

• 대한치과교정학회지
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• 제20권1호
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• pp.123-133
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• 1990

The work was undertaken to evaluate the calcification of the second and the third molars in skeletal Class II and III malocclusions. The differences in the calcification stages between skeletal Class II and III malocclusion were evaluated and statistically analysed from panoramic radiographs of 202 males and females ranging in age from 11 to 15 years old. The results were as follows, 1. The calcification stages of the second and the third molars were not different between the skeletal Class II and III malocclusions in each age groups of both sexes. 2. The calcification stages of lower second and third molars of the skeletal Class III malocclusion are more advanced than those of the skeletal Class II malocclusion in male. 3. The clacification stages of upper second and third molars are more advanced than those of lower second and third molars in skeletal Class II malocclusion. 4. The calcification stages of lower second and third molars are more advanced than those of upper second and third molars in skeletal Class III malocclusion.

• 대한치과교정학회지
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• 제16권1호
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• pp.107-118
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• 1986

This study was designed to investigate the variation of mandibular pattern and cranial base and their association in the craniofacial malocclusion. The material was the 165 cephalometric radiographs taken from craniofacial malocclusion. The sample was devided into two groups by age child group aged from 10 to 13 years and adult group aged over 18 years, and each group was devided into 3 types of malocclusion; class I, Class II div. 1 and Class III malocclusion. Child group consist of 35 samples and adult group consist of 20 samples in each malocclusion type. Various angular and linear measurements on the cephalometric radiographs were recorded and statistically analyzed. The results of the study were as follows; 1. The cranial base angle was largest in Class II div. 1 malocclusion and smallest in Class III malocclusion 2. The anterior cranial base length was largest in Class II div. 1 malocclusion but posterior cranial base length did not show statistical difference. 3. The mandibular body length of Class III malocclusion was larger than those of Class I and Class II div. 1 malocclusion in the adult group but did not shown difference in the child group. The ramus height of Class III malocclusion was larger than those of Class I and Class II div. 1 malocclusion in the child and adult group, but there were no difference between Class I and Class II div. 1 malocclusion. 4. The mandibular position was showed low correlation with the cranial base angele.

• 대한치과교정학회지
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• 제10권1호
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• pp.45-53
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• 1980

This study was based on the study models of 32 subjects with normal occlusion, 40 with Class I malocclusion, 32 with Class II, Division 1 malocclusion and 38 with Class III malocclusion, aged 12 to 20 years (mean age 16.4 years). The purpose of present study was to define the difference between normal and malocclusion groups in maxillary dental arch and palate. On the basis of findings of this study, the following results were obtained. 1. The intermolar widths and the intercanine widths in Class II, Div. 1 malocclusion group were smaller than in normal occlusion group significantly. 2. The arch lengths measured in both Class I and Class II, Div.1 malocclusion groups were larger than in normal occlusion group. 3. The palates in Class I and Class II, Div. 1 malocclusion groups were longer and narrower than in normal occlusion, but the palates in Class III malocclusion group were shorter than in normal occlusion group significantly. 4. The palatal depths measured at level 1 in Class III malocclusion group were significantly higher than in normal occlusion and in Class II, Div. 1 group they were significantly higher than in normal occlusion at level 2 and 3. 5. The measurements of palatal areas at various levels showed no significant difference between malocclusion and normal occlusion groups. 6. The palatal indies 1 (palatal length / palatal width) measured in both Class I and Class II, Div. 1 malocclusion groups were significantly greater than in normal occlusion and the palatal indice 2 (palatal depth at level 1/palatal width) measured in all malocclusion groups are greater than in normal occlusion. 7. It was determined from findings of this study that the measurements of maxillary dental arch and palate were influenced to a considerable extent by the molar relationship.

• 대한치과교정학회지
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• 제47권5호
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• pp.277-288
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• 2017

Objective: Treating Class II subdivision malocclusion with asymmetry has been a challenge for orthodontists because of the complicated characteristics of asymmetry. This study aimed to explore the characteristics of dental and skeletal asymmetry in Class II subdivision malocclusion, and to assess the relationship between the condyle-glenoid fossa and first molar. Methods: Cone-beam computed tomographic images of 32 patients with Class II subdivision malocclusion were three-dimensionally reconstructed using the Mimics software. Forty-five anatomic landmarks on the reconstructed structures were selected and 27 linear and angular measurements were performed. Paired-samples t-tests were used to compare the average differences between the Class I and Class II sides; Pearson correlation coefficient (r) was used for analyzing the linear association. Results: The faciolingual crown angulation of the mandibular first molar (p < 0.05), sagittal position of the maxillary and mandibular first molars (p < 0.01), condylar head height (p < 0.01), condylar process height (p < 0.05), and angle of the posterior wall of the articular tubercle and coronal position of the glenoid fossa (p < 0.01) were significantly different between the two sides. The morphology and position of the condyle-glenoid fossa significantly correlated with the three-dimensional changes in the first molar. Conclusions: Asymmetry in the sagittal position of the maxillary and mandibular first molars between the two sides and significant lingual inclination of the mandibular first molar on the Class II side were the dental characteristics of Class II subdivision malocclusion. Condylar morphology and glenoid fossa position asymmetries were the major components of skeletal asymmetry and were well correlated with the three-dimensional position of the first molar.

• 대한치과교정학회지
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• 제25권4호
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• pp.453-463
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• 1995

측모두부 방사선 계측사진에서 일반적으로 사용하는 상악 중절치의 장축은 치근첨(Root Apex)과 절치단(Incisor Edge)를 연결한 선을 사용하지만 일부 부정교합 환자에서는 치관장축과 치근장축이 일치하지 않는 경우가 있으며 이 경우 두장축이 이루는 각을 치관-치근각도(Collum Angle)라 하며, 이 각도는 교정치료의 진단 및 치료과정에 고려되어져야 한다. 본 연구에서는 제 I 급 부정교합 환자 31명, 제 II급 1류 부정교합 환자 30명, 제 II 급 2류 부정교합 환자 31명, 제 III급 부정교합 환자 31명에서 치관-치근 각도를 계측하여 부정교합과의 상관관계를 알아보았으며, 측모두부 방사선 계측사진에서 사용되는 항목들과의 상관분석을 통하여 다음과 같은 결론을 얻었다. 1. 부정교합 분류에 따른 치관-치근 각도의 평균값은 제 I 급 부정교합에서는 $3.11^{\circ}{\pm}3.54^{\circ}$, 제 II급 1류 부정교합에서는 $1.23^{\circ}{\pm}2.41^{\circ}$, 제 II급 2류 부정교합에서는 $3.77^{\circ}{\pm}4.39^{\circ}$, 제 III급 부정교합에서는 $3.90^{\circ}{\pm}4.08^{\circ}$ 이었다. 2. 제 II급 1류 부정교합군의 치관-치근 각도와 제 II급 2류, 제 III급 부정교합군의 치관-치근 각도에 유의성 있는 차이가 나타났다. 3. 치관-치근 각도와 측모두부 방사선 계측사진에서 사용되는 다른 항목들과의 상관관계에서 제 I급 부정교합에서는 IMPA, 제 II급 1류 부정교합에서는 Wits, 제 II급 2류 부정교합과 제 III급 부정교합에서는 Overbite이 가장 큰 상관성을 보였다.

• 대한치과교정학회지
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• 제42권4호
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• pp.182-189
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• 2012

Objective: The aims of this study were to use a 3-dimensional (3D) system to compare molar relationship assessments performed from the buccal and lingual aspects, and to measure differences in occlusal contact areas between Class II and Class I molar relationships. Methods: Study casts (232 pairs from 232 subjects, yielding a total of 380 sides) were evaluated from both the buccal and lingual aspects, so that molar relationships could be classified according to the scheme devised by Liu and Melsen. Occlusal contact areas were quantified using 3D digital models, which were generated through surface scanning of the study casts. Results: A cusp-to-central fossa relationship was observed from the lingual aspect in the majority of cases classified from the buccal aspect as Class I (89.6%) or mild Class II (86.7%). However, severe Class II cases had lingual cusp-to-mesial triangular fossa or marginal ridge relationships. Mean occlusal contact areas were similar in the Class I and mild Class II groups, while the severe Class II group had significantly lower values than either of the other 2 groups (p < 0.05). Conclusions: Buccal and lingual assessments of molar relationships were not always consistent. Occlusal contact areas were lowest for the Class II-severe group, which seems to have the worst molar relationships - especially as seen from the lingual aspect.

• 대한치과교정학회지
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• 제45권3호
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• pp.121-129
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• 2015

Objective: This study aimed to assess three-dimensional changes in the temporomandibular joint positions and mandibular dimensions after correction of dental factors restricting mandibular growth in patients with Class II division 1 or division 2 malocclusion in the pubertal growth period. Methods: This prospective clinical study included 14 patients each with Class II division 1 (group I) and Class II division 2 (group II) malocclusions. The quad-helix was used for maxillary expansion, while utility arches were used for intrusion (group I) or protrusion and intrusion (group II) of the maxillary incisors. After approximately 2 months of treatment, an adequate maxillary arch width and acceptable maxillary incisor inclination were obtained. The patients were followed for an average of 6 months. Intraoral and extraoral photographs, plaster models, and cone-beam computed tomography (CBCT) images were obtained before and after treatment. Lateral cephalometric and temporomandibular joint measurements were made from the CBCT images. Results: The mandibular dimensions increased in both groups, although mandibular positional changes were also found in group II. There were no differences in the condylar position within the mandibular fossa or the condylar dimensions. The mandibular fossa depth and condylar positions were symmetrical at treatment initiation and completion. Conclusions: Class II malocclusion can be partially corrected by achieving an ideal maxillary arch form, particularly in patients with Class II division 2 malocclusion. Restrictions of the mandible in the transverse or sagittal plane do not affect the temporomandibular joint positions in these patients because of the high adaptability of this joint.

• 대한치과교정학회지
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• 제20권1호
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• pp.111-122
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• 1990

To investigate the relationship of skeletal maturity among the normal occlusion group and each malocclusion groups, the author used hand and wrist X-ray of 133 Korean 13 year old boys (normal occlusion 30, Class I malocclusion 35, Class II malocclusion 35 and Class III malocclusion 33) and assessed their skeletal maturity. In this study, fourteen skeletal maturity stages were selected from; Radius, Hamate, Pisiform, Ulnar sesamoid of the metacarpophalangeal joint of the first thumb, proximal phalanges of the first, second and third finger, middle and distal phalanx of the third finger. The difference of skeletal maturity of each malocclusion groups in relative to normal occlusion group and that of each malocclusion groups were analyzed. The findings of this study can be summerized as follows: 1. Average skeletal maturity stage of each groups were MP3cap stage in normal occlusion group, H-2 stage in Class I malocclusion group, midstage between S and H-2 stage in Class II malocclusion group, MP3cap stage in Class III malocclusion group. 2. There was no significant difference in skeletal maturity of Class I malocclusion and Class III malocclusion groups in relative to normal occlusion group. 3. There was significant retardation of skeletal maturity in Class II malocclusion group in relative to normal occlusion group. 4. There was no significant difference in skeletal maturity between Class I and Class II malocclusion groups. 5. There was no significant difference in skeletal maturity between Class I and Class III malocclusion groups. 6. There was significant retardation of skeletal maturity in Class II malocclusion group in relative to Class III malocclusion group.