• 대한치과보철학회지
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• 제41권1호
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• pp.20-34
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• 2003

Novel methods producing supplementary and prosthetic material by cutting or discharge processing via computer design have been proposed as alternatives for traditional casting methods and are being utilized for commercial purposes. The CAD/CAM system used in dentistry can be classified into three-dimensional input of target values, restoration design, and material processing. The marginal fidelity in production of In-Ceram core has important clinical implications and is a key consideration issue in CAD/CAM production as well. Through this research, the author arrived at the following conclusion aaer conducting comparison analysis of marginal fidelities between the In-Ceram core produced via CAD/CAM and that produced through the traditional method ; 1. In the cases of mesial, distal, and lingual margins, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 2. In the case of labial flange, the core margins via CAD/CAM produced lower values than those via the traditional method and the differences were found to be statistically significant. (p<0.05) 3. In comparision with overall marginal fidelity, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 4. Among the core margins produced via the traditional method did not have statistically significant differences but fir those produced via CAD/CAM had statistically significant differences between labial and lingual sides and between labial and mesial sides. (p <0.05).

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.250-260
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• 1995

Bases have been used in order to prevent the leakage of bleachingagents through dentinal tubules in bleached teeth. But the proximal surfaces where the actual resorption takes place havenot been protected. The purpose of this study was to compare the conventional basing method with the basing of the labial and two proximal surfaces to the cementoenamel junction. The bases were placed after conventional root canal treatment. Group I: 2mm thickness bases were placed to the level of labial cementoenamel junction line. Group II : 2mm thickness bases were placed to the level of all c-e J lines including cervical area. Control : No bases were placed. After placement of sodium perborate and 30% hydrogen peroxide mixtureinto the teeth, the changes of pH were measured. The results were as follows. 1. Group II showed smaller leakage of bleaching agents and was statistically significant difference compared to Group I.(p<0.05) 2. Group I showed no statistically significant difference compared to the control group. (p>0.05) 3. There were no significant among the upper and lower teeth groups in each group and between the groups.(p>0.05). According to the above results, it was considered that basing of the labial and proximal surfaces to the cementoenamel junction can reduce the leakage of bleaching agents during bleaching procedure of pulplessteeth.

• The Journal of Advanced Prosthodontics
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• 제4권3호
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• pp.146-152
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• 2012

PURPOSE. The cortical bone thickness on the anterior region is important for achieving implant stability. The purpose of this study was to examine the thickness of the cortical and cancellous bones on the anterior region of the maxilla and mandible. MATERIALS AND METHODS. Twenty-five cadaver heads were used (16 male and 9 female; mean death age, 56.7 years). After the long axis of alveolar process was set up, it was measured in 5 levels starting from 2 mm below the cementoenamel junction (L1) at intervals of 3 mm. All data was analysed statistically by one-way ANOVA at the .05 significance level. RESULTS. The cortical bone thickness according to measurement levels in both the labial and lingual sides increased from L1 to L5, and the lingual side below L3 was significantly thicker than the labial side on the maxilla and mandible. In particular, the labial cortical bone thickness in the maxilla was the thinnest compared to the other regions. The cancellous bone thickness according to measurement levels increased from L1 to L5 on the maxilla, and on the mandible it was the thinnest at the middle level of the root. CONCLUSION. For implant placement on the anterior region, a careful evaluation and full knowledge on the thickness of the cortical and cancellous bone are necessary, therefore, these results may provide an anatomic guideline to clinicians.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.133-150
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• 1991

To study the mechanical behavior depended on the restoration method and alveolar bone height at endodontically treated teeth. a finite element model was made which was applied by four types of restoration methods and alveolar bone height on upper central incisor and then 1 Kg force was applied on each model as follows; 1) $45^{\circ}$ diagonal load on incisal edge. 2) $26^{\circ}$ diagonal load on lingual surface. and 3) horizontal load on labial surface. The author analyzed the displacement and stress of teeth and their supporting tissue by finite element method according to three type of loading conditions. The results were as follows : 1. The displacement by restoration method and the stress in dentin was found greater in restoration without a post than in that with a post. 2. The displacement and stress was found about the same when compared : A) in Resin model and PFM model applied by restoration method without a post and B) in PRC model and CPC model applied by restoration method with a post. 3. The lower alveolar bone height was. the greater was the displacement and stress. 4. The lower alveolar bone height was. the greater slightly was the stress of restoration without a post than in that with a post. 5. The stress in loading condition was the greatest in P1 in dentin and post. and was greatest in P3 in alveolar hone. 6. In the restoration method without a post. stress concentration in labial dentin was distributed to a figure of long belt in adjacent part to periodontal ligament. while in restoration method with a post. it was distributed in adjacent part to post side. And in all types of restoration method stress concentration in alveolar bone was distributed along the compact bone of labial and lingual surface.

• 대한치과교정학회지
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• 제46권5호
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• pp.310-322
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• 2016

Objective: The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods: A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results: The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions: Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.

• 대한소아치과학회지
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• 제50권2호
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• pp.142-154
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• 2023

상악 견치는 기능과 외모에 있어서 중요한 역할을 하지만, 맹출 장애로 인해 문제를 일으키는 경우가 많다. 상악 견치의 매복은 비교적 흔하며 구조적 장애, 발달 이상, 공간 부족, 유전과 같은 다양한 요인에 의해 발생할 수 있다. 상악 견치의 구개측 매복은 서양인에게서 흔한 것으로 보고되지만 한국인에게는 순측 매복이 더 흔한 것으로 관찰된다. 순측으로 변위된 상악 견치의 경우, 치아 총생 및 골격성 부정교합이 보일 수 있으며, 측절치의 선천적 상실이나 과잉 측절치는 상악 견치의 구개측 매복 가능성을 높일 수 있다. 상악 견치 매복의 조기 발견 및 적절한 처치는 조화로운 치열 발달과 정상적인 치아 기능을 위해 중요하다. 본 종설을 통해 매복 상악 견치의 다양한 처치법을 제안하고 그 원리를 설명하고자 한다.

• Imaging Science in Dentistry
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• 제54권1호
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• pp.63-69
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• 2024

Purpose: The objective of this study was to determine the minimum number of teeth in the anterior dental arch that would yield accurate results for individual identification in forensic contexts. Materials and Methods: The study involved the analysis of 28 sets of 3-dimensional (3D) point cloud data, focused on the labial surface of the anterior teeth. These datasets were superimposed within each group in both genuine and imposter pairs. Group A incorporated data from the right to the left central incisor, group B from the right to the left lateral incisor, and group C from the right to the left canine. A comprehensive analysis was conducted, including the evaluation of root mean square error (RMSE) values and the distances resulting from the superimposition of dental arch segments. All analyses were conducted using CloudCompare version 2.12.4 (Telecom ParisTech and R&D, Kyiv, Ukraine). Results: The distances between genuine pairs in groups A, B, and C displayed an average range of 0.153 to 0.184mm. In contrast, distances for imposter pairs ranged from 0.338 to 0.522 mm. RMSE values for genuine pairs showed an average range of 0.166 to 0.177, whereas those for imposter pairs ranged from 0.424 to 0.638. A statistically significant difference was observed between the distances of genuine and imposter pairs(P<0.05). Conclusion: The exceptional performance observed for the labial surfaces of anterior teeth underscores their potential as a dependable criterion for accurate 3D dental identification. This was achieved by assessing a minimum of 4 teeth.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권4호
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• pp.239-252
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• 1993

This study was done to analyze phonetic dysfunction and the effect of orthognathic surgery to phonation in the patients of mandibular prognathism. 20 persons were chosen as normal group and 20 patients of mandibular prognathism as abnormal for this study. 5 vowel sounds-'ㅏ(a)', 'ㅔ(e)', 'ㅣ(i)', 'ㅗ(o)', 'ㅜ(u)' and 14 consonant sounds-'ㄱ(g)', "ㄴ(n), 'ㄷ(d)', 'ㄹ(l)', 'ㅁ(m)', 'ㅂ(b)', 'ㅅ(s)', 'ㅇ(ng)', 'ㅈ(j)', 'ㅊ(ch)', 'ㅋ(k)', 'ㅌ(t)', 'ㅍ(p)', 'ㅎ(h)', were checked. We recorded these sounds in the period of preopration, postop. 12 months, postop. 24 months. A Formant ratio and a length of consonant time were studied with discriminant analysis. As a result of the study, the following conclusion were gained. 1. As a result of the analysis on vowel dysfunction patiensts of mandibular prognathism, more than 80% of men patients showed the dysfunction in prelingual sound 'ㅔ(e)' and 'ㅣ(i)'. More than 70% of women patients showed the dysfunction in all vowel. 2. One year later from the orthognathic surgery, men patients showed a marked improvement in 'ㅏ(a)'. The next were 'ㅗ(o)', 'ㅜ(u)' and 'ㅣ(i)'. Women patients showed a marked improvement in 'ㅜ(u)'. 3. Two year later from the orthognathic surgery, men patients showed a marked improvement in prelingual sound 'ㅔ(e)' and postlingual sound 'ㅗ(o)'. Women patients showed a marked improvement in 'ㅏ(a)'. More than 20% of patients showed the phonetic improvement compared with the condition of the postop. 12 months. 4. As a result of the analysis on consonant dysfunction patient of mandibular prognathism. more than 80% of men patients showed the dysfunction in lingual sound 'ㅅ(s)'. Most women patients showed the dysfunction in labial sound 'ㅁ(m)' and lingual sound 'ㄴ(n)'. More than 50% of patients showed the dysfunction in labial sound and lingual sound. 5. One year later from the orthognathic surgery. men patients showed a complete improvement in hard palatal sound 'ㅈ(j)'. The next were labial sound 'ㅂ(b)', lingual sound 'ㅅ(s)', soft palatal sound 'ㄱ(g)' and 'ㅋ(k)'. Women patients showed a marked improvement in soft palatal sound 'ㅇ(ng)' and 'ㄱ(g)'. 6. Two year later from the orthognathic surgery, all patients showed remarkable improvement in consonant sounds. except for labial sound 'ㅁ(m)', 'ㅍ(p)' and lingual sound 'ㄴ(n)'. The improvement ratio was increased as the time was going on compared with the condition of postop 12 months.

• 구강회복응용과학지
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• 제29권1호
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• pp.101-110
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• 2013

T4K는 혼합치열기의 2급 부정교합 환자에게 사용되는 기능성, 가철성 교정장치이다. 기능성 교정장치의 경우 치열과 악골의 성장에 영향을 주는 구강안면부의 근육의 부조화를 개선시키는 역할을 한다. T4K에 포함된 lip bumper는 과도한 하순의 힘을 차단하여 주고, 하순 내측 전정을 자극하는 요소가 포함되어 있다. 부적절한 혀의 위치를 교정할 수 있는 요소는 환자들이 장치를 장착하는 동안 부가적인 혀 운동을 할 필요성을 감소시킨다. 2급 부정교합 환자의 경우 하악 열성장을 동반하는 경우가 대부분을 차지한다. 이 장치는 상악 치아를 고정원으로 하여, 하악을 전방으로 성장할 수 있도록 자극하여 부족한 하악 성장을 촉진하는 역할을 하고 있다. 이와 함께 부가적으로 Labial bow와 같은 역할을 하는 요소는 상악 치열의 개선에 도움을 준다. T4K는 기성품으로 작은 부피와 부드러운 질감으로 어린 환자들의 장착 동의율을 높이는 데 장점을 가진다. 원광대학교 치과대학 산본치과병원 소아치과에 내원한 혼합치열기의 2급 부정교합 환자에서 만족스러운 결과를 얻었기에 이를 보고하는 바이다. 요약 1. T4K를 혼합치열기의 2급 부정교합 환자에게 사용하여 안모의 개선을 얻었다. 2. 과도한 수직, 수평 피개교합이 개선되었다. 3. 하악 열성장 환자에서 T4K를 장착하여 하악 성장을 촉진하는 결과를 얻었다. 4. 구호흡 등과 같은 구강악습관의 개선을 얻었다.

• Archives of Plastic Surgery
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• 제35권1호
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• pp.48-55
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• 2008

Purpose: We measured linear distances, angles and inclinations on the cast models of the noses, and compared these indirect measurements with the direct measurements obtained from the nose in order to validate the accuracy of the indirect anthropometry using the cast model. Methods: Subjects were 50 males and 50 females, medical students in twenties(mean 27.1 years). Cast models were made from the alginate impression material and the plaster. In direct anthropometry, 16 linear, 7 angular, and 2 inclination measurements between 11 landmarks on the nose were obtained using sliding caliper, spreading caliper, and fabric tape measure. At the same time, the same measurements were obtained from the cast models of the same people. Total 25 measurements were compared, and tested by the independent t-test of SPSS. Results: The standard values of Korean nose in twenties were obtained. 24 measurements except the columellar labial angle were not statistically different between the indirect anthropometry and the direct anthropometry. Conclusion: Indirect anthropometry on the cast model of the nose revealed no significant difference from the anthropometric measurement statistically, accounting for 24 in 25 measurements(96%). There are two possible reasons that caused the difference of columellar labial angle between direct and indirect anthropometry. First, the columellar labial angle could be decreased by protrusion of the lips which resulted from contracting mouth in which an drinking straw had been applied on the mouth corner for patients' respiration during making cast model. Second, it is generally known that the columellar labial angle could be measured larger when soft tissues were pressed by protractor in direct anthropometry. Using a drinking straw with greater diameter, and scheming respiration through the nostrils that patients don't feel discomfort, the more accurate data would be obtained from the indirect anthropometry using the cast models of the noses.