• Journal of Periodontal and Implant Science
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• 제37권2호
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• pp.165-180
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• 2007

Dental Implants have been proved to be successful prosthetic modality in edentulous patients for 10 years. However, there are few reports on the survival of implant according to location in molar regions. The purpose of this study was to evaluate the $4{\sim}5$ years' cumulative survival rate and the cause of failure of dental implants in different locations for maxillary and mandibular molars. Among the implants placed in molar regions in Gwangju Mir Dental Hospital from Jan. 2001 to Jun. 2002, 473 implants from 166 patients(age range; $26{\sim}75$) were followed and evaluated retrospectively for the causes of failure. We included 417 implants in 126 periodontally compromised patients, 56 implants in 40 periodontal healthy patients, and 205 maxillary and 268 mandibular molar implants. Implant survival rates by various subject factors, surgical factors, fixture factors, and prosthetic factors at each location were compared using Chi-square test and Kaplan-Meier cumulative survival analysis was done for follow-up(FU) periods. The overall failure rate at 5 years was 1O.2%(subject level) and 5.5%(implant level). The overall survival rates of implants during the FU periods were 94.5% with 91.3% in maxillary first molar, 91.1% in maxillary second molar, 99.2% in mandibular first molar and 94,8% in mandibular second molar regions. The survival rates differed significantly between both jaws and among different implant locations(p<0.05), whereas the survival rates of functionally loaded implants were similar in different locations. The survival rates were not different according to gender, age, previous periodontal status, surgery stage, bone graft type, or the prosthetic type. The overall survival rate was low in dental implant of too wide diameter(${\geq}5.75$ mm) and the survival rate was significantly lower for wider implant diameter(p

• 치과방사선
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• 제29권2호
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• pp.507-521
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• 1999

Osteopetrosis is an uncommon hereditary bone disorder whose prominent radiologic feature characterized by increased bone density. The authors reported a 7-year-old male patient who referred from local dental clinic for dental problems such as early exfoliation of deciduous teeth(#54,73,83) and delayed eruption of permanent teeth(#31.41.36.46). The patient appeared as a poorly developed. Dental X-ray films showed early exfoliation of deciduous teeth, delayed eruption of permanent teeth, and rampant caries. Lateral view of skull demonstrated increased opacity of calvarium, facial bones, and skull base. Generally the skeletal density is greatly increased throughout all bones. Facial CT showed poor development of paranasal sinuses and mastoid air cells. No hematopoietic and neurologic complications such as anemia, thrombocytopenia, blindness and deafness were found. Also mental retardation was not found. The final diagnosis of this case was a osteopetrosis tarda. Sometimes patient with osteopetrosis tarda may be developed dental problems prior to severe systemic symptoms. The dentist can be the first clinician to see the patient. It is very important for the dentist to have the knowledge of the osteopetrosis and to care the patient's dental problems to prevent complication such as osteomyelitis of jaws.

• 치과방사선
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• 제21권2호
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• pp.405-413
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• 1991

상악골 골수염을 수반한 골화석증에 이환된 33세의 남자환자에서 다음과 같은 사항이 관찰되었다. 1. 간비대, 비장비대, 궁다리소견 등을 볼 수 있었다. 2. X선사진상에서 전반적인 골밀도의 증가와 부비동의 폐색등을 볼 수 있었다. 3. 대퇴골과 좌골의 여러 부위에서 오래된 골절이 관찰되었으며 고관절의 아탈구도 관찰되었다. 4. 상ㆍ하악골 모두 골밀도가 증가되어 있었으며 다수의 기형치와 매복치가 관찰되었다. 5. 골주사 소견에서 큰 관절과 장골에서 다발성의 불규칙한 섭취증가를 볼 수 있었다.

• Geomechanics and Engineering
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• 제23권2호
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• pp.165-178
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• 2020

This paper investigates the effect of the jaw's curvature, also known by contact angle and jaw arc central angle (2α), of the Brazilian test apparatus on indirect tensile strength of various rock types. That's why, ten rock samples including limestone, marble, skarn, granite, diorite, and granodiorite were collected from some quarries in different provinces of Iran. Petrographic, mineralogical and textural investigations were performed using thin section analyses. Physical properties of the selected rock samples namely dry and saturated unit weights, porosity, water absorption, and specific gravity were determined for the rock samples. In addition, Brazilian tensile strength at different 2α angles (i.e., 2α = 0°, 10°, 15°, 20°, 45°, and 60°) were determined for the rocks in the laboratory. Results show that the parameter for the rocks is between 3.81 MPa at 2α=0° and 54.76 MPa at 2α=60°. This means that Brazilian tensile strength increased with increasing 2α angle from 0° to 60°. Also, it was found that the highest change rate of the Brazilian tensile strength occurs in range of 2α=15°-30° for most studied rock samples. In some tested samples, the parameter is decreased only at 2α = 60°. The values of Brazilian tensile strength of the rocks tested by flat and standard jaws are near to each other.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2514-2518
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• 2003

The KAERI Spent Fuel Remote Technology Development (SFRTD) Department is developing the remote maintenance and repair equipment, which is used in a hot cell in an intense radiation field, as part of a project to develop the Advanced spent fuel Conditioning Process (ACP). Although several mechanical master-slave manipulators (MSMs) is mounted on the hot cell wall, their reach will be limited and cannot access areas for all the ACP equipment maintenance. A Bridge Transported ServoManipulator (BTSM) has been designed to overcome the limitation of access areas that is a drawback of MSMs for the ACP equipment maintenance. The BTSM system consists of four components: a transporter with telescoping tubeset, a slave manipulator, a master manipulator, and a remote control system. The BTSM system has been designed by Solid Edge that is a 3D computer-aided design (CAD) software, except for the remote control system. The master manipulator and the slave manipulator are kinematically similar in design, except for the handle and the tong, respectively. The manipulators have 6 degrees of freedom (DOF) plus the jaws motion. The transporter has traveling, traverse, and hoisting motion to position the slave manipulator.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권5호
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• pp.440-444
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• 2011

Mucoepidermoid carcinoma generally arises from salivary glands and represents 5~10% of all salivary tumors. Arising within the jaws as primary central bony lesions, central mucoepidermoid carcinomas are extremely rare, accounting for only 2~3% of all mucoepidermoid tumors. Central mucoepidermoid carcinoma of the mandible was first reported in 1939 and since then approximately 100 cases have been documented in the literature. Several hypotheses have been proposed to explain the pathogenesis of intraosseous salivary tumors. The most likely source of most intraosseous tumors is odontogenic epithelium. Waldron and Mustoe suggested that central mucoepidermoid carcinoma be included in primary intraosseous carcinoma of the jaw. We report here on a case of central mucoepidermoid carcinoma affecting the mandible and discuss the clinical, radiographic, and histological findings.

• Imaging Science in Dentistry
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• 제46권4호
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• pp.245-249
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• 2016

Purpose: This study was designed to evaluate differences in the required visibility of anatomic structures according to the diagnostic tasks of implant planning and periapical diagnosis. Materials and Methods: Images of a real skull phantom were acquired under 24 combinations of different exposure conditions in a cone-beam computed tomography scanner (60, 70, 80, 90, 100, and 110 kV and 4, 6, 8, and 10 mA). Five radiologists evaluated the visibility of anatomic structures and the image quality for diagnostic tasks using a 6-point scale. results: The visibility of the periodontal ligament space showed the closest association with the ability to use an image for periapical diagnosis in both jaws. The visibility of the sinus floor and canal wall showed the closest association with the ability to use an image for implant planning. Variations in tube voltage were associated with significant differences in image quality for all diagnostic tasks. However, tube current did not show significant associations with the ability to use an image for implant planning. conclusion: The required visibility of anatomic structures varied depending on the diagnostic task. Tube voltage was a more important exposure parameter for image quality than tube current. Different settings should be used for optimization and image quality evaluation depending on the diagnostic task.

• Imaging Science in Dentistry
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• 제46권4호
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• pp.267-272
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• 2016

Gardner syndrome is known as a variant of familial adenomatous polyposis. This syndrome is characterized by multiple intestinal polyposes, osteomas, and epidermoid cysts. In addition, dental abnormalities include an increased frequency of multiple odontomas, as well as supernumerary and impacted teeth. The authors report the case of a 7-year-old male patient with Gardner syndrome. Radiographic findings revealed multiple osteomas in both sides of the maxilla, multiple diffuse enostoses in both jaws, and a complex odontoma in the left mandibular body. Two years later, multiple epidermoid cysts on the scalp were found. Since this patient was suspected to have Gardner syndrome, the authors recommended gastrointestinal endoscopy to check for intestinal polyposis. Gastrointestinal endoscopic examination revealed multiple polyposes in the upper gastrointestinal tract and fundus of the stomach. As a result, the final diagnosis was Gardner syndrome.

• 대한치과의사협회지
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• 제58권9호
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• pp.546-555
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• 2020

Allergic rhinitis is a specific IgE mediated inflammatory disease of the nasal mucosa, characterized by symptoms such as rhinorrhea, nasal congestion, nasal obstruction, nasal and eye itching, and sneezing. The prevalence of allergic rhinitis varies according to country, age, and surveying methods, but it seems to increase worldwide, also in Korea. Prolonged mouth breathing caused by allergic rhinitis can produce muscular and postural alterations, causing alterations on the morphology, position, growth direction of the jaws, and malocclusion. Also, mouth breathing leads to dryness of the mouth, causing various oral diseases; gingivitis, halitosis, inflammation of tonsil, increased risk of dental caries and dental erosion. In dental clinic, using rapid maxillary expansion to persistent allergic rhinitis patients with narrow maxilla can enlarge maxillary dental arch and nasal cavity anatomy, improving nasal breathing and reducing nasal cavity resistance. However, it is desirable to use along with otolaryngologic treatment. Dentists should be aware of the characteristics of allergic rhinitis and its effects on patients, and consider when planning dental treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권6호
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• pp.486-489
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• 2009

Odontogenic Myxoma of the jaws is a rare benign tumor derived from embryonic mesenchymal elements of dental anlage. It appears to originate from the dental papilla, follicle or periodontal ligament. Odontogenic Myxoma of the maxilla is less frequent but behaves more aggressively than that of the mandible, because it spreads through the maxillary sinus. Radiographically, the tumors present as unilocular or multilocular radiolucent lesions with well-defined borders with fine, bony trabeculae. On gross examination, the tumor appears as a smooth, glistening, gelatinous, lobulated mass. On microscopic examination, these neoplasms exhibit loose arrangement of stellate-shaped cells. The intercellular substance is a mucinous and homogeneous matrix. We report a case of odontogenic myxoma of the maxilla observed in our clinic with good prognosis after partial maxillectomy.