• 대한치과보철학회지
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• 제44권4호
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• pp.421-431
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• 2006

Statement of problem : Accurate impression is essential to success of implant prostheses. But there have been few studies about the accuracy of fixture-level impression technique in internal connection implant system. Purpose: This study evaluated the accuracy of splinted fixture-level impression technique using clinical methods and the effect of internal hex on fit of superstructure in internal connection implant system (Astra Tech). Material and method : Two metal master frameworks made from two abutments (Cast-to Abutment ST) each for parallel and divergent conditions and a corresponding. passively fitting, dental stone master cast with four future replicas (Fixture Replica ST) were fabricated. Ten dental stone casts were made with vinyl polysiloxane impressions from the master cast by acrylic resin splinted fixture-level impression technique. To evaluate the accuracy of impression technique, the fit of master frameworks for test models was evaluated using screw resistance test (SRT) and one-screw test. The results of SRT were recorded as SRT values from grade 1 to grade 5 by 1/4 turn. And to evaluate the effect of hex on fit of superstructure, the same tests were performed after removing hexes of master frameworks. Results: 1. There was only one case (2.5%) showing SRT value of test model below ade 2 in total before and after removing hexes of master frameworks. And, by removing hexes. SRT values decreased in only one test model (5%) and did not change in 17 test models (85%). 2. SRT values of the 1$^{st}$ screws were grade 2 in 80% of cases before, and grade 1 in 80% of cases after removing hexes. And, by removing hexes, SRT values decreased in 72.5% of cases. 3. SRT values of the 2$^{nd}$ screws were grade 3 in 85% of cases before, and grade 3 in 95% of cases after removing hexes. And, by removing hexes, SRT values did not change in 85% of cases. 4. There were only 2 cases regarded as acceptable fit by one-screw test, and SRT values of 2$^{nd}$ screws of both cases were grade 2. Conclusion. Within the limitations of this study, future-level impression of internal connection implant system is considered to obtain inaccurate working cast, even using acrylic resin splinted impression technique. And, it is considered to be unable improve the fit to remove the hexes of implant restoration.

• 대한치과의사협회지
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• 제46권4호
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• pp.222-231
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• 2008

Various maxillary sinus floor augmentation techniques were common performed and in the most cases, many kinds of bone graft materials were used. The graft materials are autogenous bone or other biomaterials of human, animal or synthetic origin. But these cases report describes a new surgical technique by which dental implants are inserted in a void space created by elevating the sinus membrane without additional graft material in atrophic posterior maxilla. We created lateral bony window using piezoelectric device and elevated the schneiderian membrane in five patients and was repositioned with bony window in five patients, without any bone graft. From the clinical and histological results, it is found there is potential capacity for bone formation and placement of implants in the maxillary sinus without the use of bone grafts or bone substitutes.

• 구강회복응용과학지
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• 제22권1호
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• pp.23-27
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• 2006

This case reports describe a new approach to the use of polymers in orthodontics, using a fiber reinforced composite(FRC). FRC was successfully used in a periodontal splints, fiber post for endodontic use, orthodontic retainer and space maintainers, implant prosthesis, large span bridge, management of cracked tooth, anchorage reinforcement in orthodontics. FRC has highly favorable mechanical properties, and its strength-to-weight ratios is superior to those of most alloys. FRC has potential for use in many applications in dentistry and is expected to gain increasing application and popularity in dentistry. These case reports show that FRC is a promising anchorage reinforcement material for use in orthodontic practice.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권2호
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• pp.51-67
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• 2019

As dental implant surgery and bone grafts were widely operated in Korean dentist, many bone substitutes are commercially available, currently. For commercially used in Korea, all bone substitutes are firstly evaluated by the Ministry of Health and Welfare (MOHW) for safety and efficacy of the product. After being priced, classified, and registration by the Health Insurance Review and Assessment Service (HIRA), the post-application management is obligatory for the manufacturer (or representative importer) to receive a certificate of Good Manufacturing Practice by Ministry of Food and Drug Safety. Currently, bone substitutes are broadly classified into C group (bone union and fracture fixation), T group (human tissue), L group (general and dental material) and non-insurance material group in MOHW notification No. 2018-248. Among them, bone substitutes classified as dental materials (L7) are divided as xenograft and alloplastic bone graft. The purpose of this paper is to analyze alloplastic bone substitutes of 37 products in MOHW notification No. 2018-248 and to evaluate the reference level based on the ISI Web of Knowledge, PubMed, EMBASE (1980-2019), Cochrane Database, and Google Scholar using the criteria of registered or trademarked product name.

• The Journal of Advanced Prosthodontics
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• 제10권2호
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• pp.147-154
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• 2018

PURPOSE. This study was performed to evaluate the osteogenic potential of 3mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) and niobium oxide containing Y-TZPs with specific ratios, new (Y,Nb)-TZPs, namely YN4533 and YN4533/Al20 discs. MATERIALS AND METHODS. 3Y-TZP, YN4533 and YN4533/Al20 discs (15 mm diameter and 1 mm thickness) were prepared and their average surface roughness ($R_a$) and surface topography were analyzed using 3-D confocal laser microscope (CLSM) and scanning electron microscope (SEM). Mouse pre-osteoblast MC3T3-E1 cells were seeded onto all zirconia discs and evaluated with regard to cell attachment and morphology by (CLSM), cell proliferation by PicoGreen assay, and cell differentiation by Reverse-Transcription PCR and Quantitative Real-Time PCR, and alkaline phosphatase (Alp) staining. RESULTS. The cellular morphology of MC3T3-E1 pre-osteoblasts was more stretched on a smooth surface than on a rough surface, regardless of the material. Cellular proliferation was higher on smooth surfaces, but there were no significant differences between 3Y-TZP, YN4533, and YN4533/Al20. Osteoblast differentiation patterns on YN4533 and YN4533/Al20 were similar to or slightly higher than seen in 3Y-TZP. Although there were no significant differences in bone marker gene expression (alkaline phosphatase and osteocalcin), Alp staining indicated better osteoblast differentiation on YN4533 and YN4533/Al20 compared to 3Y-TZP. CONCLUSION. Based on these results, niobium oxide containing Y-TZPs have comparable osteogenic potential to 3Y-TZP and are expected to be suitable alternative ceramics dental implant materials to titanium for aesthetically important areas.

• 대한치과보철학회지
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• 제31권3호
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• pp.423-446
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• 1993

Titanium and its alloys are finding increasing use in medical devices and dental implants. The strong selling point of titanium is its resistance to the highly corrosive body fluids in which an implant must survive. This corrosion resistance is due to a tenacious passive oxide or film which exists on the metal's surface and renders it passive. Potentiodynamic polarization measurement is one of the most commonly used electro-chemical methods that have been applied to measure corrosion rates. And the potentiodynamic polarization test supplies detailed information such as open circuit, rupture, and passivation potential. Furthermore, it indicates the passive range and sensitivity to pitting corrosion. This study was designed to compare the corrosion resistance of the commonly used dental implant materials such as CP Ti, Ti-6A1-4V, Co-Cr-Mo alloy, and 316L stainless steel. And the effects of galvanic couples between titanium and the dental alloys were assessed for their useful-ness-as. materials for superstructure. The working electrode is the specimen , the reference electrode is a saturated calomel electrode (SCE), and the counter electrode is made of carbon. In $N_2-saturated$ 0.9% NaCl solutions, the potential scanning was performed starting from -800mV (SCE) and the scan rate was 1 mV/sec. At least three different polarization measurements were carried out for each material on separate specimen. The galvanic corrosion measurements were conducted in the zero-shunt ammeter with an implant supraconstruction surface ratio of 1:1. The contact current density was recorded over a 24-hour period. The results were as follows : 1. In potential-time curve, all specimens became increasingly more noble after immersion in the test solution and reached between -70mV and 50mV (SCE) respectively after 12 hours. 2. The Ti and Ti alloy in the saline solution were most resistant to corrosion. They showed the typical passive behavior which was exhibited over the entire experimental range. Therefore no breakdown potentials were observed. 3. Comparing the rupture potentials, Ti and Ti alloy had the high(:st value (because their break-down potentials were not observed in this study potential range ) followed by Co-Cr-Mo alloy and stainless steel (316L). So , the corrosion resistance of titanium was cecellent, Co-Cr-Mo alloy slightly inferior and stainless steel (316L) much less. 4. The contact current density sinks faster than any other galvanic couple in the case of Ti/gold alloy. 5. Ag-Pd alloy coupled with Ti yielded high current density in the early stage. Furthermore, Ti became anodic. 6. Ti/Ni-Cr alloy showed a relatively high galvanic current and a tendency to increase.

• Radiation Oncology Journal
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• 제16권2호
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• pp.167-175
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• 1998

목적 : 원발성 혹은 재발한 부인과암(자궁경부암, 질암, 및 외음부암)에서 질부위의 병소에 추가선량를 조사하기 위한 기존의 방법들 즉, 실린더(cylinder)를 이용한 강내치료와 바늘(needle)을 사용한 조직내 평면삽입(Single plane Implant)만으로는 이상적인 선량분포를 얻기 힘든 경우가 많다. 저자들은 방광 및 직장에 대한 조사선량을 최소화하면서 질내의 병소에 국한하여 고선량의 방사선을 효과적으로 조사하기 위해 체적삽입(Volume Implant)이 가능한 기구(applicator 혹은 template)를 고안, 자체 제작하여 사용하고 있으며 이를 소개하고자 한다. 대상 및 방법 : 1994년 8월부터 1998년 2월까지 9명의 환자를 대상으로 아주대학교병원에서 조직내 방사선치료를 시행하였다 이들은 질벽에 재발한 자궁경부암(5명), 원발성 자궁경부암(3명), 원발성 질암(1명)으로 치료받았다. 첫 3명의 환자는 기구없이 바늘을 평면삽입하였고 이후에는 병변의 위치 및 크기 등을 고려할 때 주위정상조직에 대한 선량을 줄이면서 종양에는 균등한 선량 분포로 고선량의 방사선을 조사하기 위해서는 체적삽입이 유리할 것으로 판단되어 기구를 고안, 자체 제작하였다. 바늘은 일반적인 조직내 삽입용(Microselectron, Nucletron)을 사용하였고 이는 저선량율(LDR) 및 고선량율(HDR) 근접치료 모두에서 사용 가능하였다. 6명중 3명은 50cc 주사기를 이용하여 만든 초기 단계의 기구를 사용하였다(1차 형태). 이러한 초기 단계의 기구는 표면이 매끈하지 못하여 질점막을 손상시킬 수 있고 바늘 삽입후 기구가 움직이지 않도록 회음부에 고정시키는 날개부위가 없는 단점이 있었다. 나머지 3명의 환자는 이러한 단점을 보완하고 종양의 크기 및 위치에 따라 좀 더 많은 바늘을 삽입할 수 있도록 새롭게 고안한 기구를 사용하였다 (2차 형태). 재료는 투명 아크릴 혹은 치과용 몰드(mold) 소재($Provil^{(R)}$)를 사용하였으며 회음부에 기구를 고정시키기 위한 날개를 만들었다. 2차 형태의 기구를 사용한 환자중 마지막 1명은 종양의 위치를 고려하여 삽입할 수 있는 바늘의 갯수를 증가시켜서 새로이 제작하였다 실제로 환자에게 시술하기 전에 예비치료계획을 시행하여 필요한 동위원소의 수량 및 배열을 결정하였다. 결과 : 자체 제작한 기구를 사용함으로써 바늘을 일정간격으로 삽입하는 것이 용이해졌으며 시술시간을 단축시킬 수 있고 삽입방향이 잘못되어 여러번 바늘을 찌르는 경우가 적어져 조직에 대한 손상을 줄일 수 있었다. 손쉽게 구할 수 있는 재료를 사용하여 병소에 따라 개별화간 가능한 값싸고 유용한 기구의 제작이 가능함을 확인하였으며 이를 통해 좀 더 이상적인 선량분포곡선을 얻을 수 있었다. 3명의 환자에서 바늘 삽입후 컴퓨터 단층촬영을 시행하여 배열의 정확성과 방광 및 직장에 조사되는 선량을 감소시킬 수 있음을 확인하였다. 마지막 추적관찰시 원발성 종양으로 치료받았던 3명의 환자 모두가 국소제어되었으나 재발하여 치료하였던 경우에는 모두 국소재발하였다. 결론 : 저자들은 부인과암에서 근접치료시 환자의 종양 특성에 따라 기구를 적절하게 고안하여 적은 비용으로 비교적 손쉽게 자체 제작하여 사용함으로써 효과적인 조직내 삽입 방사선치료를 시행할 수 있었다.

• 구강회복응용과학지
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• 제30권3호
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• pp.259-264
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• 2014

역행성 임플란트 근단병소 주위염은 임상증상을 동반한 근단부의 방사선 투과성 병소로 정의되며 임플란트 식립부위 또는 인접한 치아의 잔존하고 있는 감염에서 유래한 세균감염, 골 삭제시의 열 발생 등의 다양한 원인에 의해 야기될 수 있고, 다양한 치료방법으로 임플란트를 제거하지 않고 유지할 수 있는 증례들이 보고되고 있다. 본 증례에서는 근관 치료 실패로 발치한 상악 우측 제2소구치 부위에 식립한 임플란트에서 발생한 역행성 임플란트 근단병소 주위염을 표면의 detoxification과 차폐막과 골이식재를 동반한 골유도재생술로 해결하여 기능을 회복하였으며, 7년간 장기적으로 안정적으로 유지되고 있는 증례에 대해 보고하고자 한다.

• Journal of Periodontal and Implant Science
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• 제40권6호
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• pp.283-288
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• 2010

Purpose: The aim of this case report is to present a case of incomplete bone formation after sinus augmentation. Methods: A patient having alveolar bone resorption of the maxillary posterior edentulous region and advanced pneumatization of the maxillary sinus was treated with sinus elevation using deproteinized bovine bone in the Department of Periodontology, Kyung Hee University School of Dentistry and re-evaluated with computed tomography (CT) follow-up. Results: Even though there were no significant findings or abnormal radiolucency on the panoramic radiograph, incomplete bone formation in the central portion of the augmented sinus was found fortuitously in the CT scan. The CT scan revealed peri-implant radiolucency in the apical portion of the implant placed in the augmented maxillary sinus. Nevertheless, the dental implants placed in the grafted sinus still functioned well at over 15 months follow-up. Conclusions: The result of this case suggests that patients who received maxillary sinus augmentation may experience incomplete bone formation. It is possible that 1) osteoconductive graft material with poor osteogenic potential, 2) overpacking of graft material that restricts the blood supply, and 3) bone microbial contamination may cause the appearance of incomplete bone formation after sinus augmentation. Further studies are needed to elucidate the mechanism of this unexpected result and care must be taken to prevent it.

• The Journal of Advanced Prosthodontics
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• 제11권2호
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• pp.105-111
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• 2019

PURPOSE. Limited data is available regarding the differences for possible microleakage problems and fitting accuracy of zirconia versus titanium abutments with various connection designs. The purpose of this in vitro study was to investigate the effect of connection design and abutment material on the sealing capability and fitting accuracy of abutments. MATERIALS AND METHODS. A total of 42 abutments with different connection designs [internal conical (IC), internal tri-channel (IT), and external hexagonal (EH)] and abutment materials [titanium (Ti) and zirconia (Zr)] were evaluated. The inner parts of implants were inoculated with $0.7{\mu}L$ of polymicrobial culture (P. gingivalis, T. forsythia, T. denticola and F. nucleatum) and connected with their respective abutments under sterile conditions. The penetration of bacteria into the surrounding media was assessed by the visual evaluation of turbidity at each time point and the number of colony forming units (CFUs) was counted. The marginal gap at the implant- abutment interface (IAI) was measured by scanning electron microscope. The data sets were statistically analyzed using Kruskal-Wallis followed by Mann-Whitney U tests with the Bonferroni-Holm correction (${\alpha}=.05$). RESULTS. Statistically significant difference was found among the groups based on the results of leaked colonies (P<.05). The EH-Ti group characterized by an external hexagonal connection were less resistant to bacterial leakage than the groups EH-Zr, IT-Zr, IT-Ti, IC-Zr, and IC-Ti (P<.05). The marginal misfit (in ${\mu}m$) of the groups were in the range of 2.7-4.0 (IC-Zr), 1.8-5.3 (IC-Ti), 6.5-17.1 (IT-Zr), 5.4-12.0 (IT-Ti), 16.8-22.7 (EH-Zr), and 10.3-15.4 (EH-Ti). CONCLUSION. The sealing capability and marginal fit of abutments were affected by the type of abutment material and connection design.