• 대한치과기공학회지
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• 제11권1호
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• pp.89-93
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• 1989

The purpose of this study was to evaluate the effect of sprue length and casting pressure on the relative castability of the base metal alloys, commonly used to make porcelain metal restoration. Samples of total 30 were constucted and devided into 6 groups according to three variables (low, medium, high). The total number of complety cast squares were counted, verified and recorded. The results of this 1. main effect of casting pressure was statistically significant.(P<0.05). 2. main effect of sprue length was not statistically significant.

• 대한치과의사협회지
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• 제36권11호통권354호
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• pp.794-799
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• 1998

Many references report that abnormal diastema except temporary diastema existing in mixed dentition period is caused by maxilary heavy labial frenum, malocclusion, progressive periodontal disease, and loss of posterior teeth. We can diagnose patient as diastema caused by periodontal disease, especially, in case of accompanying progressively destructed anterior maxillary alveolar bone defect, and interseptal bone defect. We report Multiple disciplinary approach for diastema associated with periodontal disease. Periodontal treatment(Guided Tissue -Regeneration, alveoloplasty, bone graft), or thodontic treatment (space closure, redistribution), and the final proshodontic restoration for retention were used.

• 대한치과의사협회지
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• 제56권11호
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• pp.616-621
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• 2018

This clinical case highlights the failure of long length implants, and the prosthodontic procedures necessary to rehabilitate the maxillary dentition of a patient with microstomia. The integrated digital technology of intra-oral scanning, computer-aided design, and three-dimensional printing can provide an alternative method to make conventional impressions for patients with microstomia who cannot insert the appropriate tray in their mouths.

• 대한심미치과학회지
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• 제25권1호
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• pp.35-49
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• 2016

최근 심미성에 대한 요구가 점점 증가함에 따라, 이제는 임플란트 수복에 있어서도 기능적인 면 뿐만 아니라 심미적인 면이 더욱 강조되고 있다. 상악 전치부 임플란트 수복은 임상가들에게 항상 도전적인 과제로 다가오는데 그 이유는 다음의 세 가지 요소를 모두 필요로 하기 때문이다. 첫째, 충분한 경조직이 필요하고 둘째, 충분한 연조직이 필요하며 그리고 셋째, 심미적인 수복물이 필요하다. 연조직의 심미성은 그 하부에 있는 경조직에 의존하게 되는데 그 이유는 하부의 경조직의 골격적인 지지가 있어야만 그것을 바탕으로 그 위에 건강하고 심미적인 연조직이 안정적으로 유지될 수 있기 때문이다. 그러므로, 경조직 재건은 심미적인 임플란트 수복에 있어서 첫번째 단계이며, 특히 3차원적으로 적절한 임플란트의 식립 위치 설정은 심미성 있는 최종 수복물을 얻기 위해서 가장 중요한 단계라고 할 수 있다. 그 다음으로 두번째 단계가 순측으로 충분한 두께의 연조직을 얻기 위한 수술 기법이며, 마지막 세번쨰 단계가 적절한 출현외곽을 갖는 임시 수복물을 통해서 얻어진 심미적인 최종 수복물이다. 본 임상 증례 보고는 순측의 골 열개 결손에서의 골 증대술 과정과 전치부 영역에 주로 사용되는 VIP-CT 라고 일컫는 유경 판막술을 이용한 연조직 증대술, 그리고 임시 수복물을 통한 연조직 형태 만들기와 맞춤형 인상 코핑을 이용한 인상채득법 등을 소개함으로써 경조직, 연조직, 수복물의 세 가지 요소가 심미적인 최종 수복물을 위해 서로 어떻게 조화를 이루어내는지 알아보고자 한다.

• 대한치과마취과학회지
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• 제11권2호
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• pp.153-158
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• 2011

Midazolam is known to produce sedation as well as amnesia. Many articles reported about anterograde amnesia, but it is rare that articles about retrograde amnesia. The 61-year-old female patient (64 kg, 154 cm, ASA physical status I) was administered 3.02 mg (0.047 mg/kg) of midazolam during 2 hours. The patient's Modified Observer's Assesment of Alertness/Sedation Scale was 4. The patient who had been consciously sedated with midazolam, exhibited profound amnesia, both anterograde and retrograde after implantation. The patient's memory restoration was begun after 6 hours.

• 대한치과기공학회지
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• 제41권2호
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• pp.93-100
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• 2019

Purpose: This study is making a dog dental prosthesis using digital dental technology. The mechanical strength of the prosthetic material was observed in terms of compressive strength and fracture pattern. Methods: The experiment was performed using dog mandibular molars. The teeth were scanned and modeled. The specimens were made of zirconia, PMMA and Ni-Cr. The specimens were subjected to a vertical compression test with an artificial cancellous bone in UTM tester. Vertical compressive strength and fracture behavior of specimen were observed. Results: The result of observing the compressive load between specimen and artificial bone were $184.8{\pm}5.7N$ in the zirconia specimen, $185.6{\pm}8.9N$ in the PMMA specimen, and $184.4{\pm}4.0N$ in the Ni-Cr alloy specimen. Compression marks of artificial bones were observed. The fracture strength of specimen was observed. The fracture strength of the zirconia specimen was an average of 1,381.4N. The fracture strength of the PMMA specimen was an average of 572.2N. Conclusion: The crown made of three kinds(zirconia, PMMA, Ni-Cr alloy) of materials has the strength to chew about the artificial bone. zirconia and PMMA have vertical compressive strength applicable to medium dog dental prosthetic materials.

• Current Optics and Photonics
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• 제7권3호
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• pp.283-296
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• 2023

An intraoral spectral domain optical coherence tomography (SD-OCT) system has been developed, using a custom-built hand-held scanner and spectrometer. The hand-held OCT probe, based on a microelectromechanical systems scanner and a self-built miniaturized drive circuit, had a field of view sufficient for dental diagnosis. The spectrometer using a fabricated f-theta lens provided the image depth required for dental diagnosis. The axial and transverse resolutions of the OCT system in air were 7.5 ㎛ and 12 ㎛ respectively. The hand-held probe could scan an area of 10 × 10 mm², and the spectrometer could image along a depth of 2.5 mm. To verify the utility of the developed OCT system, OCT images of tooth hard and soft tissues were acquired, and a user-interface program for diagnosis was developed. Early caries and microcracks that were difficult to diagnose with existing methods could be found, and the state of restoration could be observed. Measuring the depth of the gingival sulcus, distinguishing subgingival calculus, and detecting an implant under the gingiva suggested the possibility of the SD-OCT system as a diagnostic for dental soft tissues. Through the presented OCT images, the capability of the developed SD-OCT system for dental diagnosis was demonstrated.

• Journal of Korean Dental Science
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• 제12권1호
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• pp.13-19
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• 2019

Purpose: The aim of this study was to compare the flexural strength of provisional fixed dental prostheses which was three-dimensional (3D) printed by several build directions. Materials and Methods: A metal jig with two abutment teeth and pontic space in the middle was fabricated. This jig was scanned with a desktop scanner and provisional restoration was designed on dental computer-aided design program. On the preprocessing software, the build angles of the restorations were arranged at $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ and support was added and resultant structure was sliced to a thickness of $100{\mu}m$. Processed restorations were printed with digital light processing type 3D printer using poly methyl meta acrylate-based resin. After washing and post-curing, compressive loading was applied at a speed of 1 mm/min on a metal jig fixed to a universal testing machine. The maximum pressure at which fracture occurred was measured. For the statistical analysis, build direction was set as the independent variable and fracture strength as the dependent variable. One-way analysis of variance and Tukey's post hoc analysis was conducted to compare fracture strength among groups (${\alpha}=0.05$). Result: The mean flexural strength of provisional restoration 3D printed with the build direction of $0^{\circ}$ was $1,053{\pm}168N$; it was $1,183{\pm}188N$ at $30^{\circ}$, $1,178{\pm}81N$ at $45^{\circ}$, $1,166{\pm}133N$ at $60^{\circ}$, and $949{\pm}170N$ at $90^{\circ}$. The group with a build direction of $90^{\circ}$ showed significantly lower flexural strength than other groups (P<0.05). The flexural strength was significantly higher when the build direction was $30^{\circ}$ than when it was $90^{\circ}$ (P<0.01). Conclusion: Among the build directions $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ set for 3D printing of fixed dental prosthesis, an orientation of $30^{\circ}$ is recommended as an effective build direction for 3D printing.

• 치위생과학회지
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• 제12권2호
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• pp.123-129
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• 2012

이 연구에서는 지르코니아 코어의 두께를 달리 제작하여 동일한 색조의 상부도재를 축성함에 있어 제작방법을 다르게 하여 두 상반된 시편을 각각 분광측색장치를 이용하여 CIE $L^*,a^*,b^*$ 색체계로 산출하여 객관적으로 색차를 비교, 분석하여 다음과 같은 결론을 얻었다. 1. 지르코니아 코어의 두께가 두꺼워 지고 상부도재의 두께가 얇아지면서 $L^*$ 값의 수치는 높아지며 $a^*,b^*$ 값은 낮아지는 경향을 띠었다. 상부도재 축성방법을 다르게 제작한 시편에서도 같은 결과를 보였다. 동일한 색조 시편에서 HP군은 PST군에 비해 $L^*$ 값의 수치는 낮게 측색되어 어두운 경향을 보였으며 $a^*,b^*$ 값도 낮은 수치를 보여 황색의 경향을 띠었다. 2. HP군, PST군 모두 동일한 색조에서 지르코니아 코어 두께와 상부도재 제작방법 간에 교호작용은 없었다(P=.083). 지르코니아 코어의 두께에 따라서는 통계적으로 유의한 차이는 존재하였으며(P=.001), 두께가 0.3 mm의 시편 A1, A2 색조에서 색차 값($E^*$)은 3.7 이상으로 나타났고, 그 이외 시편에서는 3.7 이하로 분석되어 임상가능 허용치로 나타났다. 이상의 결과로 볼 때 지르코니아를 이용한 전부 도재관 제작 시 같은 색조의 재료 일지라도 제작방식과 상부도재의 재료에 따라 색차 값이 존재하므로 이를 감안하여 보철물 제작에 사용해야 할 것으로 사료되며, 특히 코어의 두께가 얇은 보철물에서는 임상 허용치 이상의 색차 값을 보이므로 코어의 두께를 좀 더 추가하여 설계한 보철물이 바람직하다고 생각된다.

• Journal of Oral Medicine and Pain
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• 제16권1호
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• pp.95-102
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• 1991

The purpose of this study carried into the Electric pulp test for having knowledge of the difference of each one's stimulant threshold in normal teeth, the stimulant threshold at 10:00 A.M. and 3:00 P.M. in the same teeth, the differendce of the stimulant threshold between dental caries and normal contralateral teeth. In this study, 27 students aged between 22 and 24 years were selected from a pool of students who are sttending school of dentistry, chosun university who did not possessed dental disease like the dental caries, periodontal disease and restoration etc., and 30 outpatients who possessed dental caries(++). The obtained results were as follows : 1. The stimulant thresholds of the premolars and canine were higher than that of the incisors. 2. The stimulant thresholds of the carious teeth were lower than that normal contralateral teeth. 3. There were no difference stimulant threshold at 10:00 A.M. and 3:00 P.M.