Effect of radiation dose variation on expression of caspase-3 in rat submandibular glands / 대한구강악안면방사선학회지

PURPOSE: To investigate the caspase-3 expression in the acinar and ductal cells of rat submandibular glands after the irradiation of various doses. MATERIALS AND METHODS: The male Sprague-Dawley rats weighing approximately 250 gm were used for this study. The experimental group was irradiated with a single absorbed dose of 2, 5, 10, and 15 Gy on the head and neck region. The rats were sacrificed on the 1st, 3rd, 7th, 14th, 21st, and 28th day after irradiation. The specimens including the submandibular gland were sectioned and observed using histopathological and immunohistochemical methods. RESULTS: The local destruction of the acinar and ductal cells and the karyopyknotic nuclei of the acinar cells were observed in the 2 Gy and 5 Gy irradiation groups later than in the 10 Gy and 15 Gy irradiation groups. And the expression of caspase-3 was prominent only in the ductal cells in the 2 Gy and 5 Gy irradiation groups. CONCLUSION: This experiment suggests that radiation-induced apoptosis in the ductal cells of rat submandibular glands was induced by a low dose radiation associated with the activation of caspase-3 and radiation-induced necrosis was induced by a high dose radiation.

Metastatic gastric adenocarcinoma to the mandible / 대한구강악안면방사선학회지

Metastatic tumors to the jaw bones are uncommon. The most common metastatic tumors to the jaw bones are the breast, lung and kidney. In the jaw bones, the common location of the lesions is the mandible, and the posterior area of the mandible is more commonly affected. The radiographic appearance is quite variable. In this report, a very rare case of metastatic gastric adenocarcinoma to the mandible is presented. The patient had undergone a gastrectomy 3 years ago.

Comparison of MRI findings with clinical symptoms in temporomandibular joint internal derangement / 대한구강악안면방사선학회지

PURPOSE: To determine the clinical correlation of magnetic resonance imaging (MRI) findings of temporomandibular joint internal derangements. MATERIALS AND METHODS: The MR images of 150 TMJs in 75 patients were analyzed. The clinical symptoms were pain in the preauricular area and masticatory muscles and TMJ sounds. RESULTS: There was a statistically significant relationship between the MRI diagnoses of different types of disc displacements and clinical findings of pain, clicking, and crepitus. The risk of TMJ pain was increased when the disc displacement without reduction occurred at the same time in combination with the osteoarthrosis and effusion. CONCLUSION: Regardless of the results, the data indicate that each of these MR imaging variables may not be regarded as the unique and dominant factor in defining TMJ pain occurrence.

Effects of irradiation on the calcific nodule formation in MC3T3-E1 osteoblastic cell line / 대한구강악안면방사선학회지

PURPOSE: To investigate the effects of irradiation on the calcium content and calcific nodule formation in the MC3T3-E1 osteoblastic cell line. MATERIALS AND METHODS: Cells were irradiated with a single dose of 2, 4 and 8 Gy at a dose rate of 5.38 Gy/min using a Cs-137 irradiator. After irradiation, the calcium content and calcific nodule formation were examined on the 1st, 2nd, 3rd and 4th week. RESULTS: A decreasing dose-dependent tendency of the cell proliferation rate was found in all irradiated groups of this experiment when compared with the unirradiated control group. In accordance with the duration of culture, there was no significant difference in the cell proliferation rate after irradiation of 2 Gy when compared with the unirradiated group, however a decreasing tendency was found in 4 Gy- and 8 Gy-irradiated groups. While an increase in total calcium content after irradiation of 2 Gy was found at week 1, week 2, and week 4, there was a decrease in calcium content at week 1 through 4 in the 8 Gy- irradiated group. Calcific nodule formation was increased in irradiated experimental groups when compared with the unirradiated control group in the 2 Gyirradiated group, but decreased in the 4Gy- and 8Gy-irradiated groups at the same stage. CONCLUSION: The results showed a mild increasing tendency of the calcific nodule formation after irradiation of 2 Gy. However, a decreased calcific nodule formation in 4Gy- and 8Gy-irradiated groups was found. Taken together, the irradiation of 2 Gy mildly activated bone formation, however 4 Gy or 8 Gy suppressed bone formation by decreasing cell numbers in the MC3T3-E1 osteoblastic cell line.

Diagnostic accuracy of artificially induced vertical root fractures: a comparison of direct digital periapical images with conventional periapical images / 대한구강악안면방사선학회지

PURPOSE: To compare the diagnostic accuracy for the detection of root fractures in CMOS-based digital periapical images with conventional film-based periapical images. MATERIALS AND METHODS: Sixty extracted single-root human teeth with closed apices were prepared endodontically and divided into two groups; artificially induced vertical root fracture group and control group. All radiographs were obtained using the paralleling technique. The radiographs were examined by 4 observers three times within a 4 week interval. Receiver operating characteristic (ROC) analysis was carried out using data obtained from four observers. Intra- and inter-examiner agreements were computed using kappa analysis. RESULTS: The area under the ROC curve (Az) was used as an indicator of the diagnostic accuracy of the imaging system. Az values were as follows: direct-digital images; 0.93, film-based images; 0.92, and inverted digital images; 0.91. There was no significant difference between imaging modalities (P< 0.05). The kappa value of interobserver agreement was 0.42 (range: 0.28-0.60) and intra-observer agreement was 0.57 (range: 0.44-0.75). CONCLUSION: There is no statistical difference in diagnostic accuracy for the detection of vertical root fractures between digital periapical images and conventional periapical images. The results indicate that the CMOS sensor is a good image detector for the evaluation of vertical root fractures.

Effects of irradiation on the mRNA expression of osteonectin and bone sialoprotein in MC3T3-E1 osteoblastic cell line / 대한구강악안면방사선학회지

PURPOSE: To investigate the effects of irradiation on the phenotypic expression of the MC3T3-E1 osteoblastic cell line, especially on the osteonectin and bone sialoprotein. MATERIALS AND METHODS: Cells were irradiated with a single dose of 0.5, 1, 4 and 8 Gy at a dose rate of 5.38 Gy/min using Cs-137 irradiator. After specimens were harvested, total RNA was extracted on the 3rd, 7th, 14th, 21st day after irradiation. The total RNA was reverse-transcribed and the resulting cDNAs were subjected to amplification by PCR with a pair of primers. RESULTS: The irradiated cells showed a dose-dependent increase in osteonectin mRNA expression when compared with the unirradiated control group. The irradiated cells showed no difference in bone sialoprotein mRNA expression when compared with the unirradiated control group. In accordance with the duration of culture period after irradiation, the level of osteonectin mRNA expression showed no difference, but it increased a little at the 21st day in the 4 and 8 Gy exposure groups. In the case of bone sialoprotein, however, the level of mRNA expression increased significantly at the 3rd and 7th day after irradiation, but it showed no difference at the 14th and 21st day when compared with the control group. CONCLUSION: These results showed that each single dose of 0.5, 1, 4 and 8 Gy influenced the mRNA expression of osteonectin and bone sialoprotein at the calcification stage of osteoblastic cells, suggesting that single dose of irradiation affected the osteoblastic bone formation at the cell level.

Comparative study on the osseous changes of the TMJ and mandibular asymmetry after conservative or operative treatment in condylar fracture patients / 대한구강악안면방사선학회지

PURPOSE: To compare the effects of the conservative treatment and operative treatment by observation of osseous changes of the TMJ and mandibular asymmetry in condylar fracture patients. MATERIALS AND METHODS: 33 condylar fracture patients (17 with conservative and 16 with operative treatment) were included in this study. After a minimum of 6 months after the surgical procedure, patients were given a follow up examination of the osseous changes using a transcranial view. Differences in the osseous changes of both groups were compared and the asymmetry indices were calculated on a postero-anterior skull view. RESULTS: The TMJ of the operative treatment group showed more significant osseous changes than the conservative treatment group. The affected TMJ showed more significant osseous changes than the unaffected TMJ in the both groups. The unaffected TMJ of the conservative group and the affected TMJ of the operative group showed significant osseous changes. The mandibular asymmetry indices in the conservative and operative group were 5.12 and 7.30 respectively at the time of treatment, and 2.39 and 3.41 respectively at the follow-up. But the mandibular asymmetry between the both groups showed no statistical differences. CONCLUSION: The TMJ of the operative group showed more significant osseous changes than the conservative group, but the mandibular asymmetry between the both groups showed no statistical difference.

Tomographic study of temporomandibular joints before orthodontic treatment / 대한구강악안면방사선학회지

PURPOSE: To determine whether there is a relationship between abnormal temporomandibular joint radiographic findings and age or gender in a sample of preorthodontic patients. MATERIALS AND METHODS: Individualized corrected sagittal tomographs of 188 temporomandibular joints in 94 preorthodontic patients, aged 11 to 29 years, were taken and viewed by an observer blinded to clinical records. The study population was divided into 2 aged groups (11-15 years and 16-29 years) for comparative purposes. Temporomandibular joint radiographic findings were classified as normal or abnormal. RESULTS: There was no difference in ratio of abnormal to normal findings between the both aged groups. The frequency of osseous abnormalities was similar with that of abnormalities of condylar position. Abnormalities in CP and JS were most frequent in all aged groups. CONCLUSION: There is no significant difference between ages or genders for temporomandibular joint radiographic abnormalities.