• Imaging Science in Dentistry
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• v.30 no.2
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• pp.132-137
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• 2000

Actinomycosis is defined as a chronic, specific, suppurative, granulomatous disease caused mainly by the anaerobic, gram positive organism, Actinomyces israelii. Actinomycosis in the salivary gland is a rare disease that is caused by an inhabitant of the normal flora. We report the case of the actinomycosis of submandibular gland. A 53-year old man presented with the swelling on left submandiblar area. The lesion was not painful but had been increasing for about 10 days. In the CT view, the internal portion of the mass showed homogeneous moderate signal. The mass had continuities with the inferior portion of the left enlarged submandibular gland. In the MRI, there was a mass that showed a buldging pattern inferiorly in the left submandibular gland without bony invasion sign. The biopsy shows the colony of special organism. Many filaments are discovered with clubbed ends diffused from center of colony. We diagnosed this disease as actinomycosis in the submandibular gland by the postoperational biopsy.

• Imaging Science in Dentistry
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• v.38 no.2
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• pp.117-120
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• 2008

The odontogenic keratocyst (OKC) is a developmental odontogenic cyst typically occurring in the jaws. Since the first description of OKC was published in 1956, the lesion has been of particular interest because of its specific histopathologic features, high recurrence rate, and aggressive behavior. Recurrences most commonly arise within bone at the site of the original cyst. However, as lining cells may find their way into surrounding tissues either from implantation during surgery or from cortical perforation recurrences may arise at a distance from the original cyst. Here, we report a rare case of recurrent OKC which was first developed in mandible and recurred within the masticatory space.

• Imaging Science in Dentistry
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• v.38 no.4
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• pp.229-231
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• 2008

Brown tumor is a histologically benign lesion that is a serious complication of renal osteodystrophy because it may result in severe deformity and discomfort. We report a case of brown tumor, which occurred in a 35-year-old woman with chronic renal failure, who had been treated with hemodialysis for 14 years. The lesion was found on the lingual side of the mandible. Standard panoramic radiograph showed generally decreased bone mineral density, loss of lamina dura, and thin cortical plates. Computed tomography (CT) revealed multilocular expansile lesions with heterogeneous attenuation in the anterior mandible, as well as generalized trabecular alteration with homogeneous sclerosis, and thinning or obliteration of cortical plates. Excision of the mandibular lesion and curettage of the affected bone were performed. (Korean J Oral Maxillofac Radiol 2008; 38: 229-31)

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.209-216
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• 2021

Sjögren syndrome is a chronic autoimmune inflammatory disease characterized by lymphocytic infiltration of exocrine glands, predominantly the parotid and lacrimal glands, thereby resulting in oral and ocular dryness. It has been reported to occur most frequently in women between 40 and 50 years of age. Sjögren syndrome has an insidious onset, is slowly progressive, and presents a wide range of clinical manifestations, leading to delays or challenges in the diagnosis. Early diagnosis of this condition is essential to prevent the associated complications that affect patients' quality of life. This report presents 3 cases of Sjögren syndrome in female patients aged between 40 and 75 years who presented with complaints of persistent dry mouth and burning sensation. The cases highlight the diagnostic value of 3-dimensional cone-beam computed tomographic sialography in the detection of salivary gland pathologies at an early stage.

• Imaging Science in Dentistry
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• v.33 no.2
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• pp.97-105
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• 2003

Purpose : To evaluate the effect of all-trans-retinoic acid (ATRA) on the radiosensitivity of normal human oral keratinocyte (NHOK). Materials and methods: Relative cell survival fraction including SF2 (survival fraction at 2 Gy) was calculated on the basis of colony formation assay. Data were fitted to the linear-quadratic model to establish the survival curve and calculate α and β values. Using flow cytometry at 1, 2, 3, 4, and 5 days after exposure to 2 and 10 Gy irradiation, cell cycle arrest and apoptosis were analysed. To understand the molecular mechanism of the radiosensitization of ATRA on NHOK, proteins related with apoptosis and cell cycle arrest were investigated by Western blot analysis. Results: Treatment with ATRA resulted in a significant decrease of SF2 value for NHOK from 0.63 to 0.27, and increased α and β value, indicating that ATRA increased radiosensitivity of NHOK. ATRA increased LDH significantly, but increasing irradiation dose decreased LDH, suggesting that the radiosensitizing effect of ATRA is not directly related with increasing cell necrosis by ATRA. ATRA did not induce appotosis but increased G2 arrest after 10 Gy irradiation, implying that the increased radiosensitivity of NHOK may be due to a decrease in mitosis casued by increasing G2 arrest. ATRA inhibited the reduction of p53 at 3 days after l0Gy irradiation and increased p21 at 1 day after 10 Gy irradiation. Further study is required to determine the precise relationship between this effect and the radiosensitizing effect of A TRA. Conclusion: These results suggested that ATRA increase radiosensitivity by inhibiting mitosis caused by increasing G2 arrest.

• Imaging Science in Dentistry
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• v.44 no.3
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• pp.207-212
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• 2014

Purpose: This study aimed to investigate the deviation of landmarks from horizontal or midsagittal reference planes according to the methods of establishing reference planes. Materials and Methods: Computed tomography (CT) scans of 18 patients who received orthodontic and orthognathic surgical treatment were reviewed. Each CT scan was reconstructed by three methods for establishing three orthogonal reference planes (namely, the horizontal, midsagittal, and coronal reference planes). The horizontal (bilateral porions and bilateral orbitales) and midsagittal (crista galli, nasion, prechiasmatic point, opisthion, and anterior nasal spine) landmarks were identified on each CT scan. Vertical deviation of the horizontal landmarks and horizontal deviation of the midsagittal landmarks were measured. Results: The porion and orbitale, which were not involved in establishing the horizontal reference plane, were found to deviate vertically from the horizontal reference plane in the three methods. The midsagittal landmarks, which were not used for the midsagittal reference plane, deviated horizontally from the midsagittal reference plane in the three methods. Conclusion: In a three-dimensional facial analysis, the vertical and horizontal deviations of the landmarks from the horizontal and midsagittal reference planes could vary depending on the methods of establishing reference planes.

• Imaging Science in Dentistry
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• v.45 no.2
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• pp.73-80
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• 2015

Purpose: This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Materials and Methods: Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. Results: Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. Conclusion: Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7075-7080
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• 2013

Background: Oral submucosal fibrosis (OSMF) is one of the most prevalent premalignant conditions in India which is easy to diagnose but difficult to manage. At present it is considered as irreversible and incurable. It has also been referred to as an epidemic in India. Aims and Objectives: To correlate the frequency and duration of habits with clinical staging, functional staging and histopathological grading and to correlate the clinical and functional staging with histopathological grading. Materials and Methods: The study included a total of 90 subjects, 80 with OSMF in the experimental group and 10 patients in the control group. Patient personal history was recorded with chewing habits, including frequency and duration of chewing. The site of keeping the quid, time duration and whether he/she swallows it or spits it were also noted. Clinical staging was done on the presence of palpable fibrous bands. Functional staging was accomplished by measuring mouth opening. Incisional biopsy was done for all the patients for histopathological examination. Histopathological grading was according to Pindborg and Sirsat. Results: The experimental group comprised 71 males and 9 females, the majority of which were in the age group of 21-30 years. Correlation of habits with clinical staging, functional staging and histopathological grading were significant (p<0.05). Clinical and functional staging did not correlate with histopathological grading, but the correlation of clinical and functional staging was highly significant (p<0.01). Conclusions: The widespread habit of chewing gutkha is a major risk factor for OSMF, especially in the younger age group. In this study, it was found that with increase in the duration and frequency of the habit the severity of the disease increased.

• Imaging Science in Dentistry
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• v.37 no.3
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• pp.157-163
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• 2007

Purpose: To evaluate the characteristics of (widely used) cone beam computed tomography (CBCT) images. Materials and Methods: Images were obtained with CT performance phantoms (The American Association of Physicists in Medicine; AAPM). CT phantom as the destination by using PSR $9000N^{TM}$ dental CT system (Asahi Roentgen Ind. Co., Ltd., Japan) and i-CAT CBCT (Imaging Science International Inc., USA) that have different kinds of detectors and field of view, and compared these images with the CT number for linear attenuation, contrast resolution, and spatial resolution. Results: CT number of both PSR $9000N^{TM}$ dental CT system and i-CAT CBCT did not conform to the base value of CT performance phantom. The contrast of i-CAT CBCT is higher than that of PSR $9000N^{TM}$ dental CT system. Both contrasts were increased according to thickness of cross section. Spatial resolution and shapes of reappearance was possible up to 0.6 mm in PSR $9000N^{TM}$ dental CT system and up to 1.0 mm in i-CAT CBCT. Low contrast resolution in region of low contrast sensitivity revealed low level at PSR $9000N^{TM}$ dental CT system and i-CAT CBCT. Conclusion: CBCT images revealed higher spatial resolution, however, contrast resolution in region of low contrast sensitivity was the inferiority of image characteristics.

• Imaging Science in Dentistry
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• v.38 no.4
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• pp.189-194
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• 2008

Picture archiving and communication system (PACS) is an image information technology system for the transmission and storage of medical images. In Korea the first full PACS was installed at Samsung Medical Center in 1994, but, the rate of distribution was very slow. The government's approval for the medical insurance reimbursement for full PACS examinations in November 1999 became the turning point. Thereafter the number of hospitals with full PACS has steeply increased. In September of this year, PACS was installed at 906 medical institutes, including most of university hospitals and general hospitals. The first full dental PACS was installed at Wonkwang University Dental Hospital in 2002. Now ten out of eleven university dental hospitals implemented full dental PACS. The current status and technological factors of dental PACS in Korean university dental hospitals and the future perspectives of dental PACS are described. (Korean J Oral Maxillofac Radiol 2008; 38: 189-94)