• Imaging Science in Dentistry
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• 제51권2호
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• pp.155-165
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• 2021

Purpose: This study aimed to evaluate changes of the alveolar bone and interdental bone septum of the mandibular incisors through cone-beam computed tomography (CBCT) after orthodontic treatment of mandibular dental crowding without dental extraction. Materials and Methods: The sample consisted of 64 CBCT images(32 pre-treatment and 32 post-treatment) from 32 adult patients with class I malocclusion and an average age of 23.0±3.9 years. The width and height of the alveolar bone and interdental septum, the distance between the cementoenamel junction (CEJ) and the facial and lingual bone crests, and the inclination of the mandibular incisors were measured. Results: The distance between the CEJ and the marginal bone crest on the facial side increased significantly (P<0.05). An increased distance between the CEJ and the bone crest on the facial and lingual sides showed a correlation with the irregularity index (P<0.05); however, no significant association was observed with increasing mandibular incisor inclination (P>0.05). The change in the distance between the CEJ and the marginal bone crest on the facial side was correlated significantly with bone septum height(P<0.05). Conclusion: Bone dehiscence developed during the treatment of crowding without extraction only on the incisors' facial side. Increasing proclination of the mandibular incisor was not correlated with bone dehiscence. The degree of dental crowding assessed through the irregularity index was associated with the risk of developing bone dehiscence. The interdental septum reflected facial marginal bone loss in the mandibular incisors.

• 대한치과교정학회지
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• 제27권2호
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• pp.297-313
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• 1997

본 연구는 부산대학교병원 치과교정과에 내원하여 교정 및 악교정수술 복합치료를 시행 받은 환자 총 42명 중 하악에만 수술을 받은 환자 18명과 상하악에 동시에 수술을 받은 환자 24명을 대상으로 하였으며 초진, 수술전, 수술직후, 수술 6개월 경과후의 측모두부방사선규격사진을 채득하고 투사도를 작성하여 계측하였다. 골격, 치아 및 연조직에 대한 분석을 통하여, 수술후 경조직 변화에 따른 연조직 변화를 편악수술군과 양악수술군에서 비교하고 술전교정치료시에 지침이 될 수 있는 상하악절치의 경사도에 대해 연구하여 다음의 결과를 얻었다. 1. 수술직후 양악수술군에서는 상악골 및 상악전치, 상순의 전방과 상방으로의 이동이 두드러졌다. 양군 모두에서 하악골 및 하악절치는 후방이동하였고 하순의 두께가 증가되었으나 두군 사이에 통계학적으로 유의성있는 차이는 없었고 전안모고경은 양악수술군에서 더 많이 감소되었다(p<0.05). 수술 6개월 경과후 편악수술군에서는 상악절치가 1.44mm 전방이동하였고, 하악절치와 하악골도 각각 1.26mm, 1.43mm 전방이동하였으나 양악수술군에서는 유의한경조직의 변화가 없었다. 2. 수술직전과 수술 6개월 경과후 양악수술군에서 상악골의 수평적 변화와 상순의 Sn, SLS, LS의 수평적 변화사이의 상관계수가 0.70, 0.73, 0.70이었고 변화율은 79%, 80%, 82%였다. 하악골의 수평적 변화와 하순의 LI, ILS의 수평적 변화사이의 상관계수는 각각 0.93, 0.94였고 변화율은 89%, 101%였다. 편악수술군에서는 하악골의 수평적 변화와 하순의 LI, ILS의 수평적 변화사이의 상관계수는 각각 0.73, 0.83이었고 변화율은 각각 92%, 104%였다. Pog과 Pog', Me와 Me' 사이의 수평적 변화율은 양군 모두 1:1 이었다. 3. 수술직전과 수술 6개월 경과후 양악수술군에서 상악절치의 수평적 변화와 상순의 Sn, SLS, LS의 수평적 변화사이의 상관계수는 0.72, 0.76, 0.75, 변화율은 각각 57%, 58%, 59%였다. 하악절치의 수평적 변화와 하순의 LI, ILS의 수평적 변화사이의 상관계수는 양악수술군에서 0.93, 0.90, 편악수술군에서 0.71, 0.89였고 변화율은 양악수술군에서 76%, 87%, 편악수술군에서 75%, 85%였다. 4. 편악수술군에서 악골의 전후방 부조화와 상하악절치 경사도사이 에 FMIA = 57.48-2.17 ANB, Ul-SN = -75.02+2.17 SNB의 회귀방정식을 구할 수 있었으며 결정계수는 각각 0.63, 0.63이었다. 양악수술군에서는 SNB와 FMIA, SNB 및 ANB와 U1-SN사이에 회귀방정식을 구할 수 있었으나 결정계수가 0.13에서 0.19사이로 낮아 유의성은 없었다.

• 구강회복응용과학지
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• 제20권2호
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• pp.135-141
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• 2004

Statement of problem: Arrangement and angulation of clinical crown is very important for esthetic restoration in the upper anterior dentition. However, there was no clinical criteria to mesial angulation of the crown for Korean. Purpose: This study was undertaken to estimate the mesial angulation of the crown of the anterior teeth and the Oh's E-triangle made of the inter-pupillary line and the mesial inclination lines of the canines. Material and Method: 270 portraits of Korean were used for this study. The mesial angulation of the upper anterior teeth and the relationship of the inter-pupillary line and the mesial inclination lines of the canines were measured with the tools of PhotoShop software on the scanned images. Results: The angulation between the clinical crowns having a same name in the upper anterior dentition were $3.6^{\circ}$ between the central incisors, $8.6^{\circ}$ between the lateral incisors, and $13.6^{\circ}$ between the canines. There was no significance according to occupation and gender( P > 0.05). The ratio of height to base line of Oh's E-triangle was 4.47. 81.6% of the subjects showed the mesial inclination line of the canine passed by mesial border area of pupil. Conclusion: These data for Korean would be useful clinically to give the esthetic arrangement and to make the contour of upper anterior teeth.

• 대한치과교정학회지
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• 제15권1호
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• pp.149-153
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• 1985

The purpose of this study was to pursue the morphology and position of mandibular symphysis and the positioning of lower incisors in 36 male and female adults with severe skeletal Class III malocclusion indicated for surgical orthodontic treatment. The following results were obtained. 1. Skeletal Class III malocclusion samples had thinner labio-lingual depth and more lingual inclination of mandibular symphysis than that of normal occlusion in both sexes. 2. Male and female with the skeletal Class III malocclusion showed marked lingual tipping of lower incisors. 3. In skeletal Class III malocclusion samples, lingual basal bone was thinner than that of normal occlusion in both sexes.

• 대한치과교정학회지
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• 제22권3호
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• pp.715-733
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• 1992

The objective of this study was to evaluate some clinical aspect of the crown inclination in Korean's naturally occuring optimal occlusion, and to statistically compare the crown inclination at Andrews' FA points group and another bracket slot level group based on marginal ridges. The materials consisted of study models of 30 patients (14; Korean's males, 16; Korean's females) who have nonorthodontic normal occlusion. The results were as follows; 1. Mean, standard deviation, range of clinical inclination in the Andrews' FA points and another bracket slot level were obtained. 2. Statistically difference between Andrews' FA points group and bracket slot level group based on marginal ridge was non significant (p > 0.05). But standard deviation and range in FA points group was more stability than marginal ridge group. 3. A lingual crown inclination at FA points in the upper posterior teeth existed (canines through molars). 4. The lingual crown inclination at FA points in the lower dentition progressively increased from the incisors through the second molars.

• Imaging Science in Dentistry
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• 제47권3호
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• pp.181-187
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• 2017

Purpose: The purpose of this study was to measure the buccal bone thickness and angulation of the maxillary incisors and to analyze the correlation between these parameters and the root position in the alveolar bone using cone-beam computed tomography (CBCT). Materials and Methods: CBCT images of 398 maxillary central and lateral incisors from 199 patients were retrospectively reviewed. The root position in the alveolar bone was classified as buccal, middle, or palatal, and the buccal type was further classified into subtypes I, II, and III. In addition, the buccolingual inclination of the tooth and buccal bone thickness were evaluated. Results: A majority of the maxillary incisors were positioned more buccally within the alveolar bone, and only 2 lateral incisors(0.5%) were positioned more palatally. The angulation of buccal subtype III was the greatest and that of the middle type was the lowest. Most of the maxillary incisors exhibited a thin facial bone wall, and the lateral incisors had a significantly thinner buccal bone than the central incisors. The buccal bone of buccal subtypes II and III was significantly thinner than that of buccal subtype I. Conclusion: A majority of the maxillary incisor roots were positioned close to the buccal cortical plate and had a thin buccal bone wall. Significant relationships were observed between the root position in the alveolar bone, the angulation of the tooth in the alveolar bone, and buccal bone thickness. CBCT analyses of the buccal bone and sagittal root position are recommended for the selection of the appropriate treatment approach.

• 대한치과교정학회지
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• 제6권1호
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• pp.55-63
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• 1976

This study was undertaken to establish the roentgenocephalometric standards of the Korean children in Hellman dental age III C. The subjects consisted of 33 males and 33 females with the normal occlusion and acceptable profile. The lateral cephalometric films were taken with the teeth in centric occlusion, the soft tissue outline of the nose, lips, and chin was made visible by the low-speed films, 70Kvp, 100Mas. Their linear and angular measurements were performed by Jarabak's methods. The following results were obtained; 1) The author made the tables of standard deviation from the measured values. 2) Each linear measurement of the skull was greater in males than in females. 3) The maxillary basal bones were more protrusive in Korean children than in Caucasian. 4) The degree of the facial convexity was larger in Korean children than in Caucasian. 5) The labial inclination of the upper & lower incisors was greater in Korean children than in Caucasian. The labial inclination of the upper incisor was greater in females, but the labial inclination of the lower incisor was greater in males.

• 대한치과교정학회지
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• 제17권1호
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• pp.63-72
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• 1987

This is to investigate the difference between craniofacial correlation of Angle's class III malocclusion and that of normal occlusion. For this investigation, 28 adult males and famales, who have class III malocclusion, and 35 adult males and 46 adult famals., who have normal occlusion were selected to measure actual dimension of cranial base and to investigate ratio of various parts of maxillofacial skeleton against cranial base. Class III malocclusion were, also , classified based on SNA and SNB angle in normal range. Results were as follows. 1. In class III malocclusion, actual dimension of cranial base were appeared to be less than normal occlusion in both sex. 2. In class III malocclusion, values were less than normal occlusion in BN/ptm-A in both sex, but had no significance between two. 3. In class III malocclusion, ramal inclination, mandible inclination, BN/Go-Pog, lower genial angle were appeared to be greater. Thus, characteristic mandibular protrusive appearance of class III malocclusion was due to relative ratio and morphologic characteristic of mandibular body dimension against cranial base. 4. In class III malocclusion, upper incisors were labially tilted and lower incisors were lingually tilted compared to normal occlusion. 5. In typing of class III malocclusion, the most common type was found to be one which maxillas were in normal range, while mandibles were in protrusive tendency.

• 대한치과의사협회지
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• 제15권3호
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• pp.199-204
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• 1977

The patient, 19 years old female, complained of protrusion of upper and lower anterior teeth. Teeth lining was good except slight crowding in lower anterior teeth. Teeth lining was good except slight crowding in lower incisors, but distocclusion in the region of right buccal segment was present. Cephalometric analysis revealed normal relation between maxilla and cranial base. The labial inclination of upper and lower anterior teeth was severe, so diagnosed as bialveolar protrusion case. She was treated by means of multibanded system under the extraction of four first bicuspids. After 1 year and 4 months. She gained good interdigitation of buccal segments and attractive facial profile because the labioversion of incisors was reduced properly.

• 대한치과교정학회지
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• 제24권2호
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• pp.275-294
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• 1994

The occlusal interference during adolescent period makes some effects on growth and development and morphological changes. And so, if we could predict the the timing and results of orthodontic treatment who have occlusal interference during adolescent period, it may be helpful for diagnosis and treatment planning of orthodontic treatment. For about those, the purpose of this study was to evaluate the effects of the posterolateral displacement by the metal casting crown with inclined pathway on the mandibular condyle and morphologic changes of mandible in the rat. The experimental animals were thirty six Sprague-Dawley male rats of 8 weeks old. Eight of them was used as control group, and experimental group 1 ( continuous appliance wearing group ) was composed of sixteen and experimental group 2 ( appliance removal group after worn the appliances during 3 months ) was composed of remaining twelve. The animals of experimental grouop 1 were sacrificed after 1, 2, 3, 6 months from beginning of the experiment and experimental group 2 were sacrificed 1, 2, 3 months after removal of the appliance from worn the appliance during 3 months. Both of mandible and temporomandibular joint were observed histologically and radiologically. The results were as follows : 1. In experimental group 1, the mandibular length and lower posterior height were decreased with experimental period, while the lower anterior height was increased, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were profound as compared with control group. 2. In experimental group 1, both of the thickness of the condylar cartilage were thinned in the posterosuperior region, and this phenomenon was more prominent on right than left in 3-Mo experimental period and both sides were marked thinned in 6-Mo experimental period. 3. In experimental group 2, the lower anterior height was low and lower posterior height was high as compared with experimental group 1, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were recovered to control group. 4. In experimental group 2, both of the thickness of the condylar cartilage were thickened in the posterosuperior region, and this phenomenon was more prominent with experimental period. 5. In experimental group 2, the mandibular length was short, lower anterior height was hight, the curvature of lower incisors were profound, and in histologically, both of the thickness of the condylar cartilage were thickened in the posterosuperior region as compared with control group. As shown above, the occlusal interfemce affected the condylar cartilage, curvature of lower incisor, inclination of anterior alveolar bone, mandibular length, and anterior and posterior height. When the interference was removed, significant recover was found in condylar cartilage, mandibular length, and posterior height. Although no significance was found, other items of measurement showed trends for recovery.