• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.188-197
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• 2010

The purpose of this study was to compare radiopacity and radiographic discriminability of various FRC-Posts. Six FRC-Posts were investigated ; 1) FRC Postec Plus (Ivoclar Vivadent AG, Schaan, Liechtenstein), 2) Snowlight (Carbotech, Lewis center, OH, USA), 3) Dentin Post (Komet Brasseler, Lamgo, Germany), 4) Rely-X Fiber Post (3M ESPE, St.paul, MN, USA), 5) D.T.-Light Post (BISCO, Schaumburg, IL,USA), 6) Luxapost (DMG, Hamburg, Germany) The radiographs of each post with a reference 1 mm / 2 mm aluminum step-wedge was taken using digital sensor. The optical density were calculated by gray value of $10{\times}10$ pixel and compared in mm Al equivalent at five points. Six maxillary incisors of similar radiopacity were used. Radiographs of posts in Mx. incisors of lingual side of dry mandible were taken. We showed radiographs and asked the questionnaire to 3 radiologists, 3 endodontists, 3 general practitioners. The questionnaire was comprised of choices of the highest, lowest radiopaque individual post and the choices of best discriminable post at apical, coronal area. The following results were obtained. 1. Each post system showed various radiopacity. 2. There was change of discriminability between each post and simulated specimens regardless of examiner. Although each post showed various radiopacity, the difference of radiopacity did not affect on discriminability.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.4
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• pp.338-345
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• 1993

Mandibular discontinuity defect due to benign tumor, malignant tumor, infection, or truma results in major esthetic and biologic compromise. The primary goal of reconstruction is full restitution of function, which secondarily lead to normalization of the cosmetic deformity. The authors make a clinical study of 61 consecutive bone graft cases for mandibular reconstruction of discontinuity defect which were studied retrospectively using clinical data and radiographic findings. The cases were reviewed to evaluate the clinical success in the period from 1981 to 1990 in the Dept. of Oral & maxillofacial Surgery, Seoul National University Hospital. The criteria of the success in bone graft, are no residual infection, graft in with maintain its integrity, and remain over a half of its original size of graft in the radiographic features. The purpose of this clinical survey is to study of the mandibular discontinuity defects and success rate of free bone graft in mandibular defects. To summarize the clinical study of free bone graft, the main type of autogenous bone graft is iliac bone and corticocancellous type. Overall success rate is 80.3% in 61 followup cases over 6 months. Wire fixation and Extraoral approach has realtively better prognosis than other methods. It showed relatively poor prognosis in symphysis defects than other recipient site.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.3
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• pp.249-256
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• 1999

This study was performed to investigate the changes in flow and composition of saliva in oral cancer patients after radiation therapy. Stimulated whole saliva was collected from 7 patients who were scheduled for over 6,000cGy irradiation (180 - 225cGy fraction $Co^{60}$ therapy, 5 times a week). The flow rate of saliva, and concentration of total protein and IgA were measured before irradiation and 1, 2, 3, 4, 5 days and 1, 2, 3, 4, 6 weeks and 3, 6, 12 months after. The followings are results we obtained: 1. The salivary flow rate before irradiation was $0.8671{\pm}0.4057ml/min$. Significant decrease started 3 days after irradiation and reached a minimum at 4 weeks ($0.2621{\pm}0.2858ml/min$). Afterwards, flow rate started to increase and was on the way to recover at 1 year. 2. The concentration of total protein and IgA before irradiation were $137.2000{\pm}16.9912mg%$ and $3.4200{\pm}1.4114mg%$, respectively. After irradiation, these figures increased significantly and reached a maximum of $366.4000{\pm}174.0583mg%$ and $43.4800{\pm}29.1207mg/ml$, respectively at 6 weeks. Recovery towards normal values started following the end of irradiation and figures at 12 months had lowered to $165.400{\pm}21.1495mg%$ and $4.6200{\pm}2.1580mg/ml$ each. 3. The ratio of IgA to the amount of total protein was 2.5% before irradiation. This began to increase from 1 week following irradiation as the total dose of radiation received was increased (11.9% at 6 weeks). After 1 year from the start of radiation therapy, the ratio was reduced to such level that was before irradiation.

• The Journal of the Convergence on Culture Technology
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• v.5 no.2
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• pp.123-138
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• 2019

The clinical institution of some dental hygiene students and the degree of practice and performance according to the practice contents are identified, so as to develop clinical practice guidelines and to improve the education of universities and practical institutions. From November 2016 to March 2017, the questionnaire was prepared by self-inclusion after explaining the purpose of research and how to prepare questionnaire to some dental hygiene students. This material has been analyzed using PASW Statistics 18.0. As for the clinical practice content items of basic care and infection control, the frequency of "execution" among practice methods was high, and the distribution rate was high in oral evil face radiation, preventive dentistry, prosthesis, periodontology, orthodontics, and oral internal medicine. The conservation department has conducted various practical methods such as "executing," "observing" and "preparing." Oral surgery showed similar distribution rates, such as "observation," "preparation," and "execution" in the "preparation and cooperation of the feet." In pediatric dentistry, "observation" was the most common practice, and among them, "observation," "preparation," and "execution" were performed in "preparation and cooperation for infantile development." In addition, students with more experience in clinical practice showed statistically significant differences in basic care, oral hygiene, preventative dentistry, conservation, dental dentistry, oral surgery, orthodontics, and oral internal medicine(p<0.05). Most clinical practice shows that it is more observable than performed.It is expected that the goal of clear clinical practice content should be set by grade or number of clinical practice experiences, as well as the practice method that can be performed by the trainees.

• Journal of Oral Medicine and Pain
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• v.37 no.1
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• pp.33-45
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• 2012

This study was designed to assess follow-up study of condylar bone changes using cone beam computed tomography in patients with osteoarthritis. The author performed clinical examination for osteoarthritis patients who visited Orofacial Pain Clinic, Department of Oral Medicine, Pusan National University Hospital. CBCT(Cone beam computed tomography) was taken for 228 joints in 114 subjects. After average 10 months, CBCT was retaken. A Oral medicine and Oral radiologist evaluated CBCT each other. Condyle bone changes were classified by no bone change, flattening, erosion, osteophyte and sclerosis. The obtained results were as follow. 1. The condylar bone changes of osteoarthritis in temporomandibular disorder were as follow: 1) The transitions of each types of condylar bone changes was maintained at the initial state of the majority. 2) The transition of erosion was distributed erosion, flattening, sclreosis, osteohyte in order. 3) The transition of flattening was distributed flattening, osteohyte, normal, sclreosis in order. 4) The transition of osteohyte was distributed osteohyte, erosion, sclreosis, flattening in order. 5) The transition of sclreosis was distributed sclreosis, osteohyte, erosion, normal in order. 2. The signs and symptoms according to transition of each types of condylar bone changes were as follow 1) In the transition of condylar bone changes from erosin to erosion, pain, noise, LOM and MCO had symptomatic improvement. In the transition of condylar bone changes from erosin to flattening, pain, LOM, MCO had symptomatic improvement. In the transition of condylar bone changes from erosin to no bony change, pain, noise, LOM had symptomatic improvement. In the transition of condylar bone changes from erosion to flattening than the maintenance of eosion, MCO had symptomatic improvement. 2) In the transition of condylar bone changes from flattening to flattening, pain, noise and MCO had symptomatic improvement. In the transition of condylar bone changes from flattening to sclerosis, LOM had symptomatic improvement. 3) In the transition of condylar bone changes from osteophyte to osteophyte, pain, LOM and MCO had symptomatic improvement.

• Journal of Oral Medicine and Pain
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• v.36 no.1
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• pp.39-51
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• 2011

The aims of this study were to investigate whether the facial skeletal patterns previously reported to be related to temporomandibular disorder (TMD) in other studies could be consistently observed in the TMD patients diagnosed according to Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) Axis I and evaluate its usability in the orthodontic clinics to examine the patients with TMD related symptoms. The clinical records and radiographs of female patients who visited the TMD and Orofacial Pain Clinic of Seoul National University Dental Hospital and were diagnosed as TMD were consecutively filed for this study. Patients were clinically examined and diagnosed according to the revised diagnostic algorithms of RDC/TMD Axis I and the lateral cephalogram, panoramic orthopantomogram, temporomandibular joint (TMJ) orthopantomogram, and transcranial radiograph of each patient were taken and digitalized. The data of patients who were under 18 years of age or had any systemic disease, trauma history involving the TMJ, or skeletal deformity at the time of the first examination were excluded. The remaining data of 96 female patients were finally analyzed. The obtained results were as follows: 1. There are no significant differences of cephalometric measurements between RDC I (muscle disorders) diagnostic groups. 2. Only the articular angle of the RDC group IIc (disk displacement without reduction without limited opening) patients was larger than patients of the no diagnosis of RDC II group (disk displacement). 3. Larger articular angle and smaller facial height ratio were observed in RDC IIIc group (osteoarthrosis) compared to IIIa group (arthralgia). Larger articular angle, larger Bjork sum, smaller posterior facial height, and smaller facial height ratio were observed in RDC group IIIc compared to no diagnosis of RDC III group (arthralgia, arthritis, and arthrosis). 4. According to the results of cephalometric analysis in simplified RDC groups, smaller overjet was observed in muscle disorders (MD) group. Facial height ratio and IMPA were smaller and articular angle was larger in disk displacements (DD) group than in no diagnosis of DD group. In arthrosis (AR) group, posterior facial height, and facial height ratio were smaller, and articular angle, gonial angle, facial convexity, FMA, Bjork sum, and ANB were larger than in no diagnosis of AR group. In joint pain (JP) group, only posterior facial height was smaller than no diagnosis of JP group. In conclusion, Facial morphologic patterns showing posterior-rotated mandible and lower posterior facial height is related to RDC group II and III diagnosis of the TMJ in female TMD patients. RDC/TMD Axis I diagnosis can provide a good clinical diagnostic tool for the standardized examination of the TMJ in orthodontic clinics.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.2
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• pp.78-86
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• 2010

Introduction: Cone beam computed tomography (CBCT) has various advantages and is used favorably in many fields in dentistry. Especially, CBCT is being used as basic diagnostic tool for 3-dimensional analysis in orthognathic patient. Two-dimensional cephalograms can be synthesized from CBCT digital imaging and communications in medicine (DICOM) data. In this study, conventional cephalograms and CBCT were taken simultaneously, and representative landmarks were located and analyzed in its accuracy and reproducibility. Materials and Methods: Ten patients who had orthognathic surgery in Wonkwang University Daejeon Dental Hospital participated in this study. For each patient, CBCT and conventional cephalogram was taken. By using Ondemand (Cybermad, Korea), 2-dimensional cephalograms was established on CBCT. In addition, 19 landmarks were designated and measured by 3 orthodontists twice a week. After these landmarks were transferred to a coordinate, distance of landmark and axis, standard error, distribution degree were measured, compared and analyzed. Results: Comparing the CT ceph group and conventional cephalogram group, CT ceph group had shown shorter distance of landmark and axis in S, Hinge axis, Bpt, Ba, Or, Corpus left. Standard error of the mean shows that CT ceph group has better reproducibility in Or, Corpus left, Hinge axis at X axis and Na, U1R, U1T, Bpt, PNS, Ba Corpus left, Hinge axis at Y axis. In both groups, mean error was less than 1.00 mm, no significant difference were found between CT ceph group and conventional cephalogram group in all measurements. Furthermore, comparing two groups, each 17 landmarks out of 19 had its characteristic in distribution degree. Conclusion: No significant difference were found between CBCT composed cephalographic radiograph and conventional cephalograghic radiograph, clinical application may be possible if improved.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.497-501
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• 2010

Primary nasal type natural killer (NK)/T cell (NKTC) lymphoma, a specific form of malignant lymphoma, has a higher geographic incidence in Oriental, Mexican, and South American populations than the Western population. In Koreans, it comprises 9-12% of all cases of non-Hodgkin's lymphoma. This type of lymphoma has also been named as angiocentic lymphoma and lethal midline granuloma because the most common site is the upper airway area and its clinical aggressiveness presents with a necrotic and destructive pattern. NKTC lymphoma can also be detected in different organs (testis, spleen, parotid gland, skin, gastroinstinal tract, central nervous system, lungs, bone marrow, etc.) other than the upper airway including the oral cavity. The lymphoma detected in the oral cavity shows various destructive and inflammatory changes, similar to the signs of inflammation and infection from periodontitis and pulpal disease, making a diagnosis difficult with just the clinical signs. For early detection, clinical, radiological, and pathological examinations are required. This report describes the clinical, radiological and histological characteristics with a case report for the early detection of NKTC lymphoma in the oral cavity.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.222-225
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• 2006

The treatment objective of mandibular fracture is a return to normal function. According to Champy, a rigid fixation of mandibular angle fracture is performed by using 4 or 6 holes titanium miniplates on the external oblique ridge of mandible. However, the limitations of metal plate such as hypersensitivity, interference with the cranio-facial growth of growing child, secondary bone resorption around the plate, foreign body reaction, declination of primary callus formation, and bone atrophy due to the lack of normal stress reaction of the bone have been reported. Recently, biodegradable miniplate has been introduced and used as an alternative to the metal plate despite its lower strength than that of the titanium plate and the side effect caused by the resorption in the body. In this study, 61 patients diagnosed as mandibular angle fracture and treated from Jan. 1998 to Dec. 2004 in our department have been reviewed. Metal plate fixation was used in 50 patients and biodegradable plate fixation in 11 patients on the external oblique ridge around the fractured mandibular angle according to the principle of monocortical osteosynthesis by Champy. We compared the incidence of side effects and the degree of bony union at the mandibular inferior border in two different fixation methods. In conclusion, we have found that one miniplate regardless of matter could provide enough strength to grasp bony fragments of the tension site and compress the inferior border of mandible without any complications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.550-554
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• 2008

Bisphosphonates (BPs) are a class of agent used to treat patient with osteoporosis or malignant bone metastases. BPs can be categorized into 2 groups: nitrogen-containing and non-nitrogen containing. Nitrogen-containing BPs are considered to have more toxicity. Despite their clinical benefits, bisphosphonate-related osteonecrosis of jaw(BRONJ) is a significant complication to patients receveing these drugs. Since the first description of BRONJ in 2003 by Marx, the number of reports on BRONJ has been rapidly increasing. BRONJ is considered as an emerging problem in oral & maxillofacial surgery. Generally, osteonecrosis in the maxilla is rare, however BRONJ is found both in the maxilla and the mandible. This is an important feature of BRONJ compared to common infectious osteomyelitis of the jaw. Growing number of case reports, suggest that bisphosphonate therapy may cause exposed, necrotic bone. BRONJ has simillar features compared to IORN (infected osteoradionecrosis). BRONJ has meaningful features established through the interestigation on histopathologic and radiographic findings. These features have an impact on treatment plan and prognosis. This presentation contemplates on features of histopathologic and radiographic findings in bisphosphonate-related osteonecrosis of the jaw.