• 대한치과의사협회지
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• 제52권3호
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• pp.132-138
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• 2014

The emergence of Cone Beam Computed Tomography(CBCT) in the late 1990s represented an innovative advancement in the field of dental and maxillofacial radiology because it greatly reduced the radiation exposure to patients and offered 3D images easily. The 3D information generated by this technique brings the potential of improved diagnosis and treatment planning for a wide range of clinical applications in dentistry. The use of CBCT includes diagnosis and surgical assessment of the orofacial hard tissue lesions, dental implant treatment planning and postoperative evaluation, TMJ assessment, diagnosis of craniofacial fracture, orthodontics, endodontics, and so on. All CBCT examinations should be justified on an individualized needs. The clinical benefits to the patient for each CBCT scan must outweigh the potential risks associated with exposure to ionizing radiation. CBCT scans should be taken with initially obtained medical and dental histories of patients and a close clinical examination. CBCT should be considered as an imaging alternative of other conventional radiography in cases where the anatomical structures of interest may not be seen. The smallest possible field of view(FOV) and the lowest setting of tube current and scan time should be chosen, and the entire images scanned should be interpreted by a qualified expert.

• International Journal of Oral Biology
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• 제40권3호
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• pp.151-159
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• 2015

Odontogenic cells express many genes spatiotemporally through complex and intricate processes during tooth formation. Therefore, investigating them during the tooth development has been an important subject for the better understanding of tooth morphogenesis. The present study was performed to identify the genetic profiles which are involved in the morphological changes during the different stages of rat tooth development using the Agilent Rat Oligonucleotide Microarrays. Morphologically, the maxillary 3rd molar germ at 10 days post-partum (dpp) was at the cap/bell stage. In contrast, the maxillary 2nd molar germ showed the root development stage. After microarray analysis, there were a considerable number of up- or down-regulated genes in the 3rd and the 2nd molar germ cells during tooth morphogenesis. Several differentially expressed genes for nerve supply were further studied. Among them, neuroligin 1 (Nlgn 1) was gradually downregulated during tooth development both at the transcription and the translation level. Also, Nlgn 1 was mostly localized in the dental sac, which is an important component yielding the nerve supply. This genetic profiling study proposed that many genes may be implicated in the biological processes for the dental hard tissue formation and, furthermore, may allow the identification of the key genes involved in the nerve supply to the dental sac.

• 대한치과보철학회지
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• 제29권2호
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• pp.23-34
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• 1991

Even if we can recover the function of mastication, pronunciation and esthetic using the fixed or removable prosthesis in the loss of teeth or hard tissue in the oral cavity, we use several kinds of implants in order to solve the problem which can be occured when we can't install the denture because of excessive bone resolution or psychlogical affairs. At present Titanium implant plays a major role in this field and has osseointegrated. And the study on the modern material is going on, that result in developing and using the implant which is coated with HA, bone induced material. In this, I studied histologically the change of the bone tissue which is occured when three kinds of HA coated implants. Such as Integral, Sustain, Biovent implanted into mandible of dog and got a 8-weeks healing period. I got the conclusion as follows: 1. Most of the implant which is covered with serveral kinds of HA coating implant in bone after 8 weeks being implanted and has osseointegrated, partially converted into the connective tissue. 2. Biovent formed the connective tissue in the perforated area of inferior alveolar canal and has osseointegrated.

• 구강회복응용과학지
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• 제31권1호
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• pp.50-59
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• 2015

임플란트를 이용하여 심미 영역인 상악 전치부를 심미적, 기능적으로 수복하고 유지 관리하는 것은 어려운 일이다. 임플란트 주위염으로 인하여 치조골의 흡수, 치간유두의 수축 등과 같은 임플란트 주위 조직 문제와 금속 지대주의 노출로 인한 심미적 문제가 발생할 수 있기 때문이다. 본 증례에서는 기성지대주의 단점을 보완 가능한 맞춤형 지대주를 전통적인 제작 방식인 주조 방식으로 Co-Cr 합금을 이용하여 제작하고, 시멘트 유지형 보철물을 제작한 증례에 대해 보고하고자 한다.

• 대한치과보철학회지
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• 제38권3호
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• pp.366-374
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• 2000

FRC/ceromer system provides the clinician with a durable, flexible, and esthetic alternative to conventional porcelain fused to metal crowns. FRC is the matrix which is silica-coated and embedded in a resin matrix. The ceromer material which is a second generation indirect composite resin contains silanized, microhybrid inorganic fillers embedded in a light-curing organic matrix. FRC/ceromer restoration has a several advantages: better shock absorption, less wear of occluding teeth, translucency, color stability, bonding ability to dental hard tissues, and resiliency. It has versatility of use including inlay, onlay, single crown, and esthetic veneers. With adhesive technique, it can be used for single tooth replacement in forms of inlay adhesion bridge. In single tooth missing case, conventional PFM bridge has been used for esthetic restoration. However, this restoration has several disadvantages such as high cost, potential framework distortion during fabrication, and difficulty in repairing fractures. Inlay adhesion bridge with FRC/ceromer would be a good alternative treatment plan. This article describes a cases restored with Targis/Vectris inlay adhesion bridge. Tooth preparation guide, fabrication procedure, and cementation procedure of this system will be dealt. The strength/weakness of this restoration will be mentioned, also. If it has been used appropriately in carefully selected case, it can satisfy not only dentist's demand of sparing dental hard tissue but also patient's desire of seeking a esthetic restorations with a natural appearance.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.4137-4140
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• 2012

The authors present five cases of combined oral mucosa-mandible defects reconstructed with the vascularized internal oblique-iliac crest myoosseous free flap. This technique has many advantages compared to other conventional methods such as the radial flap, scapula flap, and fibula flap. Vascularized iliac crest flaps provide sufficient high-quality bone suitable for reconstructing segmental madibular defects. Although fibular flaps allow longer donor bone tissue to be harvested, the iliac crest can provide an esthetic shape for mandibular body reconstruction and also provides sufficient bone height for dental implants. Conventional vascularized iliac crest myoosseous flaps have excessive soft tissue bulk for reconstruction of intraoral soft tissue defects. The modification discussed in the present article can reduce soft tissue volume, resulting in better functional reconstruction of the oral mucosa. Another advantage is that complete replacement of the oral mucosa is observed in as early as one month post-operation. The final mucosal texture is much better than that obtained with other skin paddle flaps, which is especially beneficial for the placement of dental implant prostheses. Donor site morbidity looks to be similar to, if not less than that observed for other modalities in terms of function and esthetics. For combined oral mucosa-mandible defects, the vascularized internal oblique-iliac crest myoosseous free flap shows good results with respect to hard and soft tissue reconstruction.

• Journal of Periodontal and Implant Science
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• 제48권3호
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• pp.182-192
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• 2018

Purpose: The purpose of the present study was to validate an experimental model for assessing tissue integration of titanium and zirconia implants with and without buccal dehiscence defects. Methods: In 3 dogs, 5 implants were randomly placed on both sides of the mandibles: 1) Z1: a zirconia implant (modified surface) within the bony housing, 2) Z2: a zirconia implant (standard surface) within the bony housing, 3) T: a titanium implant within the bony housing, 4) Z1_D: a Z1 implant placed with a buccal bone dehiscence defect (3 mm), and 5) T_D: a titanium implant placed with a buccal bone dehiscence defect (3 mm). The healing times were 2 weeks (one side of the mandible) and 6 weeks (the opposite side). Results: The dimensions of the peri-implant soft tissue varied depending on the implant and the healing time. The level of the mucosal margin was located more apically at 6 weeks than at 2 weeks in all groups, except group T. The presence of a buccal dehiscence defect did not result in a decrease in the overall soft tissue dimensions between 2 and 6 weeks ($4.80{\pm}1.31$ and 4.3 mm in group Z1_D, and $4.47{\pm}1.06$ and $4.5{\pm}1.37mm$ in group T_D, respectively). The bone-to-implant contact (BIC) values were highest in group Z1 at both time points ($34.15%{\pm}21.23%$ at 2 weeks, $84.08%{\pm}1.33%$ at 6 weeks). The buccal dehiscence defects in groups Z1_D and T_D showed no further bone loss at 6 weeks compared to 2 weeks. Conclusions: The modified surface of Z1 demonstrated higher BIC values than the surface of Z2. There were minimal differences in the mucosal margin between 2 and 6 weeks in the presence of a dehiscence defect. The present model can serve as a useful tool for studying peri-implant dehiscence defects at the hard and soft tissue levels.

• Imaging Science in Dentistry
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• 제31권4호
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• pp.227-233
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• 2001

Purpose: The purpose of this study was to investigate the apoptosis induction in tissues constituting the craniofacial region of growing rat by irradiation. Materials and Methods: The submandibular gland, brain, articular cartilage of condylar head, and calvarium were extracted from 20-day-old rats irradiated 10 Gy. Apoptosis of each tissue was examined by DNA fragmentation and estimated quantitatively using apoptotic index on TUNEL assay. Apoptotic index of each tissue was calculated by the equation for apoptotic cells/total cells × 1,000 on the images of confocal laser scanning microscopy. Apoptotic index was analyzed statistically according to the time lapse after irradiation on the tissues. Results : In the submandibular gland, apoptotic index was significantly increased from 6 hours after irradiation showing the highest value at 12 hours and decreased to the control level at 3 days after irradiation. In the brain, apoptotic index was abruptly reached to the maximum value at 6 hours after irradiation and decreased to the control level at 4 days after irradiation. Articular cartilage and calvarium showed no or little apoptotic signals. The results obtained by the apoptotic index accorded with that of DNA fragmentation. Conclusion : Radiation was closely related with the apoptosis of submandibular gland and brain but, not related with the apoptosis of the articular cartilage of condylar head and calvarium. The changes induced by radiation of the hard tissues would not be explained by apoptosis.

• 구강회복응용과학지
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• 제36권4호
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• pp.289-295
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• 2020

비심미적인 임플란트유지형 보철물의 심미성 개선은 매우 어려운 문제이며 특히, 상악 전치부 임플란트와 관련되어 있는 경우는 더욱 그러하다. 본 증례는 상악전치부 임플란트의 주기적 배농과 비심미성을 주소로 보철과의사로부터 의뢰된 69세 남자 환자의 심미성 개선에 관한 보고이다. 임플란트는 다소 깊게 식립되어 긴 임상치관길이를 보였으며, 주변 연조직 양도 부족하였다. 임상 검사와 방사선검사 후, 깊게 식립된 임플란트의 제거 대신 예후가 불량한 인접 치아의 발치 후 임플란트를 추가 식립하여 임플란트 유지형 고정성보철물을 제작하고, 깊게 식립된 임플란트는 제거 대신 치조제 증대에 도움을 주기 위해 침수(submergence)시켜 치조제를 증대시키는 방식을 선택하였다. 적절한 진단이 동반된 임플란트 침수가 전치부의 임플란트 비심미성을 개선시킬 수 있는 또다른 대안이 될 수 있을 것이다.

• Imaging Science in Dentistry
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• 제51권4호
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• pp.341-350
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• 2021

Purpose: The use of micro-computed tomography (micro-CT) scans in biomedical and dental research is growing rapidly. This study aimed to explore the scientific literature on approaches and applications of micro-CT in restorative dentistry. Materials and Methods: An electronic search of publications from January 2009 to March 2021 was conducted using ScienceDirect, PubMed, and Google Scholar. The search included only English-language articles. Therefore, only studies that addressed recent advances and the potential uses of micro-CT in restorative and preventive dentistry were selected. Results: Micro-CT is a tool that enables 3-dimensional imaging on a small scale with very high resolution. In this method, there is no need for sample preparation or slicing. Therefore, it is possible to examine the internal structure of tissue and the internal adaptation of materials to surfaces without destroying them. Due to these advantages, micro-CT has been recommended as a standard imaging tool in dental research for many applications such as tissue engineering, endodontics, restorative dentistry, and research on the mineral density of hard tissues and bone growth. However, the high costs of micro-CT, the time necessary for scanning and reconstruction, computer expertise requirements, and the enormous volume of information are drawbacks. Conclusion: The potential of micro-CT as an emerging, accurate, non-destructive approach is clear, and the valuable research findings reported in the literature provide an impetus for researchers to perform future studies focusing on employing this method in dental research.