• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권6호
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• pp.337-342
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• 2012

Objectives: Implants connect the internal body to its external structure, and is mainly supported by alveolar bone. Stable osseointegration is therefore required when implants are inserted into bone to retain structural integrity. In this paper, we present an implant with a "wing" design on its area. This type of implant improved stress distribution patterns and promoted changes in bone remodeling. Materials and Methods: Finite element analysis was performed on two types of implants. One implant was designed to have wings on its cervical area, and the other was a general root form type. On each implant, tensile and compressive forces ($30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$) were loaded in the vertical direction. Stress distribution and displacement were subsequently measured. Results: The maximum stresses measured for the compressive forces of the wing-type implant were $21.5979N/m^2$, $25.1974N/m^2$, $29.7971N/m^2$, and $32.3967N/m^2$ when $30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$ were loaded, respectively. The maximum stresses measured for the root form type were $23.0442N/m^2$, $26.9950N/m^2$, $30.7257N/m^2$, and $34.5584N/m^2$ when $30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$ were loaded, respectively. Thus, the maximum stresses measured for the tensile force of the root form implant were significantly higher (about three times greater) than the wing-type implant. The displacement of each implant showed no significant difference. Modifying the design of cervical implants improves the strength of bone structure surrounding these implants. In this study, we used the wing-type cervical design to reduce both compressive and tensile distribution forces loaded onto the surrounding structures. In future studies, we will optimize implant length and placement to improve results. Conclusion: 1. Changing the cervical design of implants improves stress distribution to the surrounding bone. 2. The wing-type implant yielded better results, in terms of stress distribution, than the former root-type implant.

• Imaging Science in Dentistry
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• 제36권1호
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• pp.63-68
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• 2006

Desmoplastic ameloblastoma is a rare histologic variant of ameloblastoma. It shows important differences in anatomic distribution, histologic appearance, and radiographic findings compared with the general type of ameloblastoma. It is histologically characterized by an abundance of densely collagenous stroma and radiographically a mixed radiolucent-radiopaque lesion. We present three cases of desmoplastic ameloblastoma. All the patients complained on buccal swelling with or without pain and the sites of occurrence were the anterior and the premolar region. Plain radiographs showed mixed radiopaque-radiolucent lesion with ill-defined or diffuse sclerotic margin and no external root resorption. Additionally, CT scans revealetl buccal expansion and relatively well-defined margin of the lesions. The clinical and radiographic features of the presented cases were compared with those of the desmoplastic ameloblastoma in the previous literatures.

• 치과방사선
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• 제27권2호
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• pp.135-144
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• 1997

The primary intra-osseous carcinoma (PIOC) is a very rare lesion. PIOC is an odontogenic carcinoma defined as a squamous cell carcinoma arisinig within a jaw having no initial connection with the oral mucosa, and presumably developing from residues of the odontogenic epithelium. The authors diagnosed a 51-year-old female as primary intra-osseous carcinoma after undergoing clinical, radiological and histological examinations. The characteristics were as followed : 1. The patient complained of gingival bleeding on the premolar area in the left maxilla 2. The conventional radiograms showed a relatively well-defined unilocular radiolucent lesion from the mesial aspect of the upper left canine to the mesial aspect of the upper left 1st molar. The 2nd premolar was separated from the 1st molar and the floor of the maxillary sinus was elevated by the lesion. There was a external root resorption of the upper left canine, the 1st premolar, and the 2nd premolar. 3. On the computed tomograms, the osteolytic bony lesion expanded the cortical plate of the left maxilla and displaced the margin of the left maxillary sinus upwards. But the bony lesion was separated from the maxillary sinus by a bony septum. 4. Bone scintigram with /sup 99m/Tc demonstrated the increased uptake in the left maxilla. Sonograms in the neck area and chest P-A radiogram didn't show any abnormalities. 5. Histologically, the tumor islands infiltrating into the surrounding bone increased in alveolar pattern, composed of the malignant cells, and there was a necrosis in the center of the tumor islands.

• Imaging Science in Dentistry
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• 제44권3호
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• pp.249-252
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• 2014

Glandular odontogenic cyst (GOC) is a rare, potentially aggressive jaw lesion. The common radiographic features include a well-defined radiolucency with distinct borders, presenting a uni- or multilocular appearance. A cystic lesion in the posterior mandible of a 78-year-old female was incidentally found. Radiographs showed a unilocular lesion with a scalloped margin, external root resorption of the adjacent tooth, and cortical perforation. This lesion had changed from a small ovoid shape to a more expanded lesion in a period of four years. The small lesion showed unilocularity with a smooth margin and a well-defined border, but the expanded lesion produced cortical perforation and a lobulated margin. The provisional diagnosis was an ameloblastoma, whereas the histopathological examination revealed a GOC. This was a quite rare case, given that this radiographic change was observed in the posterior mandible of an elderly female. This case showed that a GOC can grow even in people in their seventies, changing from the unilocular form to an expanded, lobulated lesion. Here, we report a case of GOC with characteristic radiographic features.

• 대한장애인치과학회지
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• 제7권1호
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• pp.25-28
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• 2011

자폐증을 진단 받은 16세 남환이 하악 좌측 부위의 낭종 및 매복치를 주소로 내원하였다. 해당낭종은 함치성 낭종으 로 최종 진단 되었으며 일일 입원 및 전신 마취 하에 낭종의 적출 및 매복치의 발거와 자가 이식을 시행 후 치근단 형성 술 진행하였다. 2년 6개월 경과 관찰한 현재 주소 증상은 사라지고 재발 성향은 없으나, 치근단 염증 소견 및 발거 부 위 공간 소실 등의 합병증이 관찰된다. 저자는 본 증례를 통 해 다음과 같은 지견을 얻었다. 1. 함치성 낭종의 치료는 일반적으로 골 결손이 적고 매복치의 자발적 맹출을 유도할 수 있는 조대술이 추천된다. 2. 매복치의 자발적 맹출 가능성은 매복 깊이, 치축 각도, 환자의 나이, 치근 성숙도 등을 주의 깊게 고려하여 판단해야 한다. 3. 본 증례의 경우 매복치의 자발적 맹출 가능성이 낮으며 자폐증으로 인한 구강위생 불량, 저조한 협조도 등 을 고려하여 적출술을 시행하였다. 4. 치료 계획 설정 시 일반적 요인뿐만 아니라 환자의 의과 적, 전신적 병력에 따른 특별한 요구도 고려해야 한다.

• Restorative Dentistry and Endodontics
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• 제27권4호
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• pp.441-447
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• 2002

The bleaching of discolored nonvital teeth is conservative treatment that satisfy the cosmetic desire. The most common method for this treatment, walking bleaching, is using 30% hydrogen peroxide and sodium perborate. Many alternatives are suggested for preventing the external cervical root resorption that is the common complication of the nonvital teeth bleaching with 30% hydrogen peroxide The same extent of oxidation reactions as that resulted by the bleaching with the application of 30% hydrogen peroxide and sodium perborate can also be acquired more safely by materials that contain 10% carbamide peroxide, used primarily for the bleaching of vital teeth. Therefore, this study was performed to evaluate the efficacy of 10% and 15% carbamide peroxide bleaching gel in nonvatal teeth bleaching. The internal bleaching of intentionally discolored teeth was performed in vitro with 10% carbamide peroxide (Group 1), 15% carbamide peroxide (Group 2), mixture of distilled water and sodium perborate (Group 3), and mixture of 30% hydrogen peroxide and sodium perborate (Group 4). The bleaching materials were refreshed following 3, 6, 9 and 12 days. To evaluate the bleaching effect, the color change of the crowns was measured at 1, 2, 3, 4, 7 and 15 days of bleaching using the colorimeter. The results were as follows：1. L$^*$ and $\Delta$E$^*$ values were increased with time in all bleaching agents (p<0.01). 2. There was no significant difference in L$^*$ and $\Delta$E$^*$ value among bleaching agents. 3. $\Delta$E$^*$ value higher than 3 was shown after 3 days of bleaching with 10% carbamide peroxide gel, 1 day with 15% carbamide poroxide gel, 4 days with mixture sodium perborate and distilled water and 4 days with mixture sodium perborate and 30% hydrogen peroride, respectively. These results revealed that the use of 10% and 15% carbamide peroxide bleaching gel in non-vital teeth bleaching is as effective as mixture of distilled water and sodium perborate and mixture of 30% hydrogen peroxide and sodium perborate. Accordingly, carbamide peroxide could be used clinically to bleach discolored non-vital teeth.

• 대한소아치과학회지
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• 제30권3호
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• pp.515-519
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• 2003

과잉치는 정상치아의 수보다 더 많이 생기는 치아를 말하며 특히 상악 전방부에서 종종 발견되어진다. 상악 전방부에 발생하는 과잉치는 매복, 영구치의 이상위치, 정중부 이개의 형성, 낭종, 구강이나 비강으로의 맹출 등과 같은 다양한 합병증을 나타낼 수 있다. 임상적 연구에서 5세 이전에 과잉치를 발거하는 것이 7세 이후에 발거하는 것에 비해 영구치의 맹출 문제를 감소시킨다는 보고가 있으나 과잉치의 조기 발거가 인접 영구치의 손상 및 환아의 행동조절문제를 야기하므로 발거 시기를 늦추어야 한다는 주장도 있어 논란의 여지가 있다. 과잉치의 발거 시기를 결정할 때 병발종의 유, 무 및 양상은 치료의 시기, 치료 후의 예후를 판단하는데 중요한 영향을 미치게 된다. 이에 본 증례에서 과잉치에 의한 병발증 중 정중부 이개 맹출지연, 인접치근의 흡수, 비강으로의 맹출 및 낭종형성을 관찰하여 보고하였다.

• 대한소아치과학회지
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• 제29권1호
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• pp.38-43
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• 2002

15.5% ferric sulfate solution을 이용하여 유치치수절단술을 시행한 유구치의 상태를 임상적, 방사선학적으로 평가를 하여 이를 20%로 희석한 formocresol로 치수절단술을 시행한 경우와 비교하였다. 1997년부터 1998년까지 서울대학교병원 소아치과에서 치료를 받은 건강한 환아를 대상으로 하였고, ferric sulfate를 이용한 치수절단술을 치료받은 30개의 치아와 20%로 희석한 formocresol로 치수절단술치료한 23개의 치아, 총 53개의 치아를 평균 34개월 후 follow-up하여 그 임상적, 방사선학적 상태를 조사하였다. ferric sulfate군의 전체적인 성공률은 80.0%이었고, formocresol군의 성공률은 81.0%이었다. 두 군의 결과 차이를 카이제곱검정의 통계방법으로 분석하였다. ferric sulfate군의 4개와 formocresol군의 4개의 치아가 외흡수를 보였고 근단부 치조골파괴는 ferric sulfate군의 3개와 formocresol군의 2개에서 보였다. ferric sulfate군과 formocresol군 사이의 성공률은 통계학적으로 유의한 차이를 보이지 않았다.

• 대한소아치과학회지
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• 제25권1호
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• pp.127-133
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• 1998

An impacted tooth is defined pathologically as a tooth that remains under the mucosa of inside bone without eruption of the crown after a specific period of eruption. Clinically, the term includes those teeth, even before eruption period, that are not expected to erupt due to shape, position and alignment of tooth and lack of space. Canine is prone to impaction more than other teeth because it has the longest time to develop and a complex route from the place of formation to the site of eruption. The impaction incidence of maxillary canine is repoted 0.92$\sim$3.3% (Ferguson, 1990). In 1995 Orton reported that the incidence was 0.92$\sim$2.2% and palatal impaction was more frequent than labial impaction(85%:15%). In 1969 Johnston presented it was more common to woman than to man(3:1). The etiology includes systemic disease such as endocrine disorder, cleidocranial dysostosis, irradiation, Crouzon syndrome, ricketts, facial hemihypertrophy and hereditary and local problems such as ectopic position of the tooth, distance of tooth from its place of eruption, malformation of the tooth, presence of supernumerary teeth, trauma of tooth germ, infection of tooth germ, displacement of tooth germ or tooth by a neoplasm, ankylosis, overretention of deciduous predecessor, lack of space for the tooth in the dental arch and mucosal barrier due to gingival fibrosis. The maxillary canine is especially important as it has the longest root, provides guidance for lateral movement of the mandible and masticatory function and assumes an important role esthetically as it is located at mouth angle. If left untreated, it may cause migration and external, internal resorption of adjacent teeth, loss of arch length, formation of dentigerous cyst or tumors, infection and referred pain as well as malposition of the tooth. Therefore, periodic examination of the development and eruption of the maxillary canine is especially important in a growing child. This case study presents the results of treatment of palatally impacted maxillary canine utilizing surgical exposure and orthodontic tooth movement on patients visiting SNUDH dept. of pediatric dentistry.