• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.15 no.1
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• pp.7-12
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• 1985

Anatomical anomaly of temporo-madiblar joint and its dysfunction is becoming one of the important problem in dentistry because the number of these cases are increasing rapidly. Applying 'Lateral Transcranial Technic', 'Updegrave method' and 'Denar Accuard 100' to skull and adult with normal occlusion the author obtained following results: 1. Grewcock method combied with cephalostat as one of 'Lateral Transcranial Technic' revealed clear picture but the image of condyle head was tend to incline downward. 2. Direction of central radiation in 'Updegrave method' should be 2 recommended inch upward from auditorial mearus. 3. For functional analysis and correct diagnosis 'Denar Accuard 100' should be highly recommended.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.387-396
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• 1999

In dentistry. RadioVisioGraphy was introduced as a first electronic dental x-ray imaging modality in 1989. Thereafter. many types of direct digital radiographic system have been produced in the last decade. They are based either on charge-coupled device(CCD) or on storage phosphor technology. In addition. new types of digital radiographic system using amorphous selenium. image intensifier etc. are under development. Advantages of digital radiographic system are elimination of chemical processing, reduction in radiation dose. image processing, computer storage. electronic transfer of images and so on. Image processing includes image enhancement. image reconstruction. digital subtraction, etc. Especially digital subtraction and reconstruction can be applied in many aspects of clinical practice and research. Electronic transfer of images enables filmless dental hospital and teleradiology/teledentistry system. Since the first image management and communications system(IMACS) for dentomaxillofacial radiology was reported in 1992. IMACS in dental hospital has been increasing. Meanwhile. researches about computer-assisted diagnosis, such as structural analysis of bone trabecular patterns of mandible. feature extraction, automated identification of normal landmarks on cephalometric radiograph and automated image analysis for caries or periodontitis. have been performed actively in the last decade. Further developments in digital radiographic imaging modalities. image transmission system. imaging processing and automated analysis software will change the traditional clinical dental practice in the 21st century.

• Journal of Oral Medicine and Pain
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• v.41 no.3
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• pp.118-125
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• 2016

Purpose: The aims of this study were to evaluate the clinical characteristics of patients with altered sensation and/or pain, and to determine outcome predictors affecting persistent neuropathy. Methods: Patients who complained an altered sensation or pain following trigeminal nerve trauma were involved in this study. To determine outcome predictors affecting persistent neuropathy, the patients were divided into two groups; transient vs. persistent, and the clinical phenotypes are compared between groups. Data were analyzed with t-tests, chi-square, and multiple regression analyses with 95% confidence interval and p<0.05 significance level. Results: A total of 111 patients were included: 23 with transient and 88 persistent groups. The panoramic result and pin-prick test score were statistically different between the groups. Radiating symptoms after blunt and pinprick stimuli were also significantly different between groups. The results revealed that the presence of a neurologic lesion in the panoramic view result, reduced sensation in the pinprick test, and radiation in the pinprick test could affect the persistent group. Conclusions: The presence of a neurologic lesion in panoramic view result and reduced sensation and radiating symptoms in the pin prick test would be defining features of one of the main clinical features of persistent neuropathy. These features could serve as outcome predictors diagnosing the permanent nerve injury in trigeminal nerve.

• Imaging Science in Dentistry
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• v.34 no.3
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• pp.137-144
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• 2004

Purpose: To investigate the effects of low dose irradiation on the calcium content and calcific nodule formation of the MC3T3-El osteoblastic cell line. Materials and Methods: Cells were irradiated with a single dose of 0.2, 0.4 and 0.6 Gy at a dose rate of 5.38 Gy/min using Cs-137 irradiator. After irradiation, the calcium content and calcific nodule formation were examined on the 1st, 2nd, 3rd and 4th week. Results: We did not find any significant difference of total calcium content after irradiation of 0.2, 0.4 and 0.6 Gy when compared with the unirradiated control group. There was no significant difference of total calcium content between 0.2, 0.4 and 0.6 Gy irradiated groups. We found an increased tendency of the calcific nodule formation after irradiation of 0.2, 0.4 and 0.6 Gy when compared with the unirradiated control group without significant difference of calcific nodule formation between 0.2, 0.4 and 0.6 Gy irradiated groups. Conclusion : The results showed an increased tendency of the calcific nodule formation after low dose irradiation. However, this tendency did not increase with the increase of irradiation dose.

• Journal of Oral Medicine and Pain
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• v.25 no.2
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• pp.241-245
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• 2000

In this case report, I discussed the diagnosis and treatment of two pregnant women with temporomandibular disorders(TMD) who visited the Department of Oral Medicine, PNUH. Also, I reviewed some investigations of diagnosis and treatment of TMD in pregnant women. The obtained results were as follows; 1. No single X-ray diagnostic procedure for TMD results in radiation dose that threatens the well-being of the developing embryo and fetus. 2. Most non-steroidal anti-inflammatory drugs(NSAIDs) have commonly used because these drugs are considered to be nonteratogenic, but these agents are not recommended for routine use after 3rd trimester. 3. Electro-acupuncture stimulation therapy(EAST) is contraindicated for 1st trimester, and ultrasonic deep heat therapy, microwave deep heat therapy, low level laser therapy, myo-monitor are not contraindicated for pregnant women but clinician must consider some risk of adverse fetal effects. 4. The occlusal stabilization splint may be used for pregnant women, if it is fabricated indirectly. 5. Surgical treatment is contraindicated for pregnant women.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.1
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• pp.41-49
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• 2011

Purpose: This study is designed to investigate radiotherapic valuation of Paraffin Wax, which is newly formed for this study and generally utilized in dentistry, and Mouth Piece and Putty impression, which are commonly used in radiotherapy, for oral cavity as a compensator. Materials and Methods: Each compensator was formed by $10{\times}10{\times}1cm$ and measured radiation dose attenuation ratio with reference of water phantom which is made of tissue-equivalent materials. Two patients with oral cancer underwent DRR (Digitally Reconstructed Radiogrph) of Offline Review Program of Aria System and Portal vision for 5 times for each material to evaluate reproducibility by each filling materials. Moreover, MU (monitor unit) changes by dose absorption were considered in the case of inevitable implication of an filling materials in the range for radiotherapy. Results: Radiation dose attenuation ratios were shown -0.7~+3.7% for Mouth Piece, +0.21~+0.39% for Paraffin Wax and -2.71~-1.76% for Putty impression. Error ranges of reproducibility of positions were measured ${\pm}3mm$ for Mouth Piece, ${\pm}2mm$ for Paraffin Wax and ${\pm}2mm$ mm for Putty impression. Difference of prescription MU from dose absorption with an filling material increased +7.8% (250 MU) in Putty impression and -0.9% (230 MU) in Paraffin Wax as converted into a percentage from the standard phantom, Water 232 MU. Conclusion: Dose reduction of boundary between cavity and tissue was observed for Mouth Piece. Mouth Piece also had low reproducibility of positions as it had no reflection of anatomy of oral cavity even though it was a proper material to separate Maxilla and Mandible during therapy. On the other hand, Putty impression was a suitable material to correctly re-position oral cavity as before. However, it risked normal tissues getting unnecessary over irradiation and it caused radiation dose decrease by -2.5% for 1cm volume in comparison of it of water phantom. Dose reduction in Paraffin Wax, Fat Tissue-Equivalent Material, was smaller than other impressions and position reproducibility of it was remarkable as it was possible to make an anatomy reflected impression. It was also well fitted to oral cavity to transfer radiation dose planned in radiotherapy. Thus, Paraffin Wax will be an ideal material in radiotherapy for patients with oral cancer.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.4
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• pp.248-255
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• 2013

Reconstruction techniques of orofacial defects caused by wide excision of the intraoral malignant lesions are various. Although radial forearm free flap is a common donor site on reconstruction of soft tissue defect, anterolateral thigh (ALT) free flap also has an established site in orofacial soft tissue reconstruction as the favored donor flap with recent progress of the microsurgical technique. A 59-year-old female complained of hyperplastic mass on the right retromolar and buccal cheek, which was diagnosed as a squamous cell carcinoma (SCC) by an incisional biopsy. Before the operation, we planned a wide excision of the SCC lesion, supraomohyoid neck dissection, reconstruction with radial forearm free flap (RFFF), and split thickness skin graft. We accidentally found an arterial variation of the forearm area during elevation of RFFF, and changed the plan of reconstruction operation to reconstruction with ALT free flap. Operative sites was healed well during the post-operative period, and we referred to the department of radiation oncology for post-operative radiotherapy.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.265-272
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• 2019

Purpose: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel(PPA) and oblique projected periapical(OPA) radiography for the detection of different types of peri-implant bone defects. Materials and Methods: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects(10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. Results: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects(P<0.05). Conclusion: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.591-596
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• 2007

Neck node metastasis of oral cancer can be diagnosed by bimanual palpation, CT, MRI and neck sonography and the final diagnosis can be confirmed by pathologic evaluation of the neck nodes after elective neck dissection. When we meet clinically negative neck node(N0 neck) of oral squamous cell carcinoma, the treatment modality of the neck nodes with the primary lesions are so controversial. The usually used methods are various from close observation to elective radiation and elective neck dissection. The methods can be chosen by the primary size of the carcinoma, site of the lesions and the expected percentage of the occult metastasis to the neck. We reviewed the 86 patients from 1996 to 2006 who were diagnosed as oral squamous cell carcinoma, whose necks were diagnosed negative in radiographically and clinically. According to TNM stage, the patients were in the states of N0 and treated by surgery using mass excision and elective neck dissection. We compared the differences between the clinical diagnoses and pathologic reports and would discuss the needs for elective neck dissection.

• Imaging Science in Dentistry
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• v.38 no.1
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• pp.39-47
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• 2008

Purpose: The aim of this study was to observe a direct effect of irradiation on the periodontopathic Porphyromonas gingivalis (P. gingivalis). Materials and Methods: P. gingivalis 2561 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40Gy. Changes in viability and antibiotic sensitivity, morphology, transcription, and protein profile of the bacterium after irradiation were examined by pour plating method, disc diffusion method, transmission electron microscopy, RT-PCR, and immunoblot, respectively. Results: Viability of irradiated P. gingivalis drastically reduced as irradiation dose was increased. Irradiated P. gingivalis was found to have become more sensitive to antibiotics as radiation dose was increased. With observation under the transmission electron microscope, the number of morphologically abnormal cells was increased with increasing of irradiation dose. In RT-PCR, decrease in the expression of fimA and sod was observed in irradiated P. gingivalis. In immunoblot, change of profile in irradiated P. gingivalis was found in a number of proteins including 43-kDa fimbrillin. Conclusion: These results suggest that irradiation may affect the cell integrity of P. gingivalis, which is manifested by the change in cell morphology and antibiotic sensitivity, affecting viability of the bacterium.