• 대한소아치과학회지
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• 제10권1호
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• pp.131-138
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• 1983

381 students including elementary school boys 75, girls 76 & middle school boys 115, girls 115 were examined to study the factors of dental esthetic self-evaluation: as measured by questionnaire & dental examination. The following results were obtained: 1. In the case of the girls, the more severely rotated or displaced the upper anterior teeth were, the uglier they felt themselves. 2. The students showed the tendency to answer that they were satisfied or had no feeling one way or the other even though their teeth were less straight than others. 3. Most of the students could not relate their teeth to the over-all facial appearance. 4. In the case of the elementary-school-boys, they felt themselves ugly when the overjet & overbite were excessive: in the case of the middle-school-girls, they felt themselves ugly when the rotation & displacement of the upper & lower anterior teeth were severe. 5. Angle's classification showed no statistical significancy.

• 대한치과교정학회지
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• 제14권1호
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• pp.161-172
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• 1984

This study was undertaken to evaluate the cephalometric changes of the soft tissue and skeletal profile subsequent 10 the rapid palatal expansion in 25 Angle's Class III cases, ranging in age from six to fifteen years, with cross-bite of the anterior teeth, underdevelopment of maxilla and facial disharmony Following results were obtained: 1. ANS moved downward, Point A presented forward & downward movement increasing SNA and Point B presented backward & downward movement decreasing SNB. 2. Mandible was rotated to backward & forward and maxilla moved forward & downward with the bite opening and improvement of anterior teeth cross-bite. 3. Soft tissue on mandible was rotated to backward & forward following hard tissue changes causing the decrease of facial convexity angle and backward & downward rotation of Point B', Pog'. 4. Response of the upper lip was more significant in downward than forward direction, and correlated with the upper central incisor and mandible rotation. 5. Response of the lower lip was more significant in downward than backward direction, and correlated with the mandible rotation. 6. There was a rather high degree of correlation between skeletal profile and soft-tissue profile, 1 : LS, $\bar{1}$:Pog', Pog:LS, Pog:LI, Pog:Pog' in horizontal measurements and $\bar{1}$:Pog', Pog:LI, Pog:Pog' in vertical measurements.

• 대한치과의사협회지
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• 제55권3호
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• pp.249-256
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• 2017

Gingival recession is one of the common mucogingival problems during the orthodontic treatment. The causes of the gingival recession are similar to gingival recession in patients with periodontal diseases. Accumulation of bacterial deposits around the natural teeth induces the gingival inflammation and gingival recession occurs in the teeth with the lack of the supporting bone. However, malpositioned teeth which are labially positioned teeth or rotated teeth are more risky for gingival recession. Once root is exposed to oral cavity due to gingival recession, the orthodontic tooth movement is compromised and esthetic problems appeared. In addition, excessive gingival recession over the mucogingival junction jeopardizes the oral hygiene control, which has a risk of further gingival recession and bone loss around the tooth. To cover exposed root or to prevent further gingival recession, mucogingival surgery with gingival graft is recommended for the patients under orthodontic treatment. This case report aimed to present the mucogingival treatments of gingival recession observed during orthodontic treatment. Case I had had initial slight gingival recession before the orthodontic treatment. However, during the retraction phases, the gingival recession progressed and the periodontal treatment was referred. In case II, miller Class III gingival recession was occurred after correction of rotation. Both cases were treated by coronally advanced flap with free gingival grafts and recovered to the level of adjacent teeth despite of complete root coverage was not achieved in Case II. After periodontal treatment, orthodontic treatment was successfully completed. In conclusion, mucogingival surgery during the orthodontic treatment is recommended for the successful orthodontic treatment as well as periodontal health.

• 대한소아치과학회지
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• 제41권1호
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• pp.64-71
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• 2014

과잉치는 정상치아의 수보다 증가되어 나타나는 치아로서 상악 중절치 사이의 과잉치를 정중과잉치라 부른다. 정중과잉치는 상악 전치의 맹출 장애를 포함하는 여러가지 병발증을 야기하지만 그 제거시기에 대해서는 아직 논란이 있다. 정중과잉치에 의해 발생하는 병발증을 피하기 위해 가능한 조기에 발견하여 제거해야 한다는 주장과 외과적 발거에 따른 인접 치아의 손상을 최소화하기위해 상악 영구 전치의 치근발육이 완성된 후 제거해야한다는 주장이 있다. 이에 저자는 정중과잉치로 인해 회전된 상악 중절치를 가진 세 명의 환자들에서 중절치가 치근발육 초기단계에 있을 때 정중과잉치를 제거함으로써 회전된 상악 영구중절치의 자연적인 개선이 보이는 바 이를 보고하고자 한다.

• 대한소아치과학회지
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• 제31권4호
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• pp.630-635
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• 2004

정중과잉치의 원인은 잘 알려지지는 않았지만 dental lamina의 hyperactivity에 의해 발생한다는 가설이 가장 많이 받아들여지고 있다. 이러한 정중과잉치의 병발증으로는 주변 영구절치의 맹출 장애, 만곡 치근, 치근흡수, primordial 혹은 follicular cyst의 형성, 회전, 이환된 부위의 총생 및 비정상적인 정중이개를 일으킬 수 있다. 이러한 이유로 영구전치의 회전이 야기되면 보통 공간의 부족은 적거나 없으며 재발이 흔하므로 과개선이 요구된다. 재발의 방지를 위해서는 조기치료, 과개선, 긴 보정기간, 적절한 접촉면의 형성, 짝힘의 사용, 그리고 수술적인 방법 등이 제안되어왔다. 이에 저자는 정중과잉치로 인하여 심하게 회전된 상악중절치를 주소로 내원한 환아에서 교정적, 외과적 술식을 이용하여 양호한 결과를 얻은 두 증례를 보고하는 바이다.

• 인지과학
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• 제18권4호
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• pp.445-455
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• 2007

본 논문은 주성분분석기법을 이용한 치아의 다면특징을 기반으로 한 새로운 생체 식별시스템을 제안한다. 치아의 다면 특징들은 정면치아와 좌측, 우측 치아들로 이루어진다. 우리는 실생활 환경에서 보안 접속을 위하여 치아를 이용한 생체식별을 목표로 한다. 다면 치아 영상들은 특별히 고안된 실험환경에서 획득되었으며, 개인 식별을 위한 특징으로 42개의 주성분이 개발되었다. 개인 식별은 학습된 다면치아와 회전된 다면치아 사이의 최소근접기법에 의해 계산되었다. 2도 회전 후의 다면치아 인식성능은 평균값으로 좌측면 치아 95.2%, 우측면 치아 91.3%을 보였다.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.468-473
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• 2014

PURPOSE. This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS. To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by $10^{\circ}-20^{\circ}$ and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal-Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction (${\alpha}=.05$). RESULTS. Precision discrepancies for the canine, premolar, and molar were $3.7{\mu}m$, $3.2{\mu}m$, and $7.3{\mu}m$, respectively, indicating the poorest precision for the molar (P<.001). Trueness discrepancies for teeth types were $6.2{\mu}m$, $11.2{\mu}m$, and $21.8{\mu}m$, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION. In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall.

• 대한치과의사협회지
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• 제16권11호통권114호
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• pp.849-856
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• 1978

Relapse following rotational movement of the tooth is a common problem in orthodontic practice. To overcome such relapse, many procedures have been advocated: prolonged retention, permanent retention, over-rotation, rotation of teeth at an early age, surgical procedures such as gingivectomy, redressement force, septotomy, et cetra. A 23-year-old woman presented with Angle's Class I malocclusion and extreme rotation of maxillary central incisors. After 15 months' active therapy, septotomy was performed on maxillary central incisors and Howley retainer was applicated for the purpose of overcoming rotational relapse. During the 1 year post-operative observation, negligible, if any, rotational relapse occurred.

• 대한치과교정학회지
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• 제50권6호
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• pp.391-400
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• 2020

Objective: Increased gingival elasticity has been implicated as the cause of relapse following orthodontic rotational tooth movement and approaches to reduce relapse are limited. This study aimed to investigate the effects of sulforaphane (SFN), an inhibitor of osteoclastogenesis, on gene expression in gingival fibroblasts and relapse after rotational tooth movement in beagle dogs. Methods: The lower lateral incisors of five beagle dogs were rotated. SFN or dimethylsulfoxide (DMSO) were injected into the supra-alveolar gingiva of the experimental and control group, respectively, and the effect of SFN on relapse tendency was evaluated. Changes in mRNA expression of extracellular matrix components associated with gingival elasticity in beagles were investigated by real-time polymerase chain reaction. Morphology and arrangement of collagen fibers were observed on Masson's trichrome staining of buccal gingival tissues of experimental and control teeth. Results: SFN reduced the amount and percentage of relapse of orthodontic rotation. It also decreased the gene expression of lysyl oxidase and increased the gene expression of matrix metalloproteinase (MMP) 1 and MMP 12, compared with DMSO control subjects. Histologically, collagen fiber bundles were arranged irregularly and were not well connected in the SFN-treated group, whereas the fibers extended in parallel and perpendicular directions toward the gingiva and alveolar bone in a more regular and well-ordered arrangement in the DMSO-treated group. Conclusions: Our findings demonstrated that SFN treatment may be a promising pharmacologic approach to prevent orthodontic rotational relapse caused by increased gingival elasticity of rotated teeth in beagle dogs.

• The Journal of Advanced Prosthodontics
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• 제8권3호
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• pp.214-218
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• 2016

PURPOSE. We assessed the repeatability and reproducibility of abutment teeth dental impressions, digitized with a blue light scanner, by comparing the discrepancies in repeatability and reproducibility values for different types of abutment teeth. MATERIALS AND METHODS. To evaluate repeatability, impressions of the canine, first premolar, and first molar, prepared for ceramic crowns, were repeatedly scanned to acquire 5 sets of 3-dimensional data via stereolithography (STL) files. Point clouds were compared and the error sizes were measured (n=10, per type). To evaluate reproducibility, the impressions were rotated by $10-20^{\circ}$ on the table and scanned. These data were compared to the first STL data and the error sizes were measured (n=5, per type). One-way analysis of variance was used to assess the repeatability and reproducibility of the 3 types of teeth, and Tukey honest significant differences (HSD) multiple comparison test was used for post hoc comparisons (${\alpha}=.05$). RESULTS. The differences with regard to repeatability were 4.5, 2.7, and $3.1{\mu}m$ for the canine, premolar, and molar, indicating the poorest repeatability for the canine (P<.001). For reproducibility, the differences were 6.6, 5.8, and $11.0{\mu}m$ indicating the poorest reproducibility for the molar (P=.007). CONCLUSION. Our results indicated that impressions of individual abutment teeth, digitized with a blue light scanner, had good repeatability and reproducibility.