• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.331-341
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• 1995

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. For this study, cell surviving curves were obtained for murine melanoma Bl6 cell line using semiautomated M1T assay. 2,4,6,8, 10Gy were irradiated at a dose rate of 210cGy/min using /sup 60/Co Irradiator ALOORADO 8. After irradiatior, B16 cell lines(2.5×10⁴ cells/ml) were exposed to bleomycin and cisplatin at concentration of 0.2㎍/㎖, 2㎍/㎖ and 20㎍/㎖ for I hour respectively. The viable cells were determined for each radiation dose and/or each concentration of drug. And they were compared to control values. The obtained results were as follows : 1. There was significant difference of surviving fraction at 4, 6, 8, 10Gy on B16 cell line(P<0.05). 2. There was significant difference of cytotoxicity between bleomycin and cisplatin at concentration of 0.2㎍/㎖ and 2㎍/㎖(P<0.05) on B16 cell line, but there was no significant difference of cytotoxicity at concentration of 20㎍/㎖ on B16 cell line. 3. There was significant difference of cytotoxicity of bleomycin after irradiation of 2Gy and 10Gy on B16 cell line(P<0.01). 4. There was significant difference of cytotoxicity of cisplatin at concentration of 20㎍/㎖ after irradiation on B16 cell line.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.501-511
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• 1995

The purpose of this study was to evaluate the position and shape of mental foramen in periapical radiographs. For this study, periapical radiographs of premolar areas were obtained from the 200 adults. Accordingly, the positional and shape changes of mental foramen were evaluated. The authors obtained radiographs according to changes in radiation beam direction in periapical radiographs of premolar areas, and then evaluated the positional and shape changes of mental foramen. The following results were obtained: 1. Shapes of mental foramen were observed elliptical(34.3％), round or oval(28.0％), unidentified(25.5％) and diffuse(12.2％) type in descending order of frequency. 2. Horizontal positions of mental foramen were most frequently observed at the 2nd premolar area(55.3％), the area between the 1st premolar and 2nd premolar(39.6％), the area between the 2nd premolar and 1st molar(3.4％), the 1st premolar area(1.0％), the area between the canine and 1st premolar(0.7％) in descending order of frequency. 3. Vertical positions of mental foramen were most frequently observed at the inferior to apex(67.1％), and at apex(24.8％), overlap with apex(6.4％), superior to apex(1.7％) in descending order of frequency. 4. Shapes of mental foramen were more obviously observed at the upward 10° positioned periapical radiographs. And according to the changes of horizontal and vertical position, they were observed similar to normally positioned periapical radiographs.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.125-133
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• 1990

It is known that radiation therapy is a kind of treatment choices of the maxillofacial tumors. This study is designed to investigate the effects of irradiation on rat's tongue tissues as functional tissues which relate to taste, mastication, and pronunciation. 88 rats (Sprague Dawley branch, male) were divided into control group of 4 and experimental group of 84. Experimental group was singly exposed to Co-60 irradiation with 8, 13, 18 Gy in the head and neck region. Animals were sacrificed on 1 hour, 3 hours, 6 hours, 1day, 3 days, 7 days, and 28 days after the irradiation. The specimens were observed by histopathological examination employing H-E stain and Van-Gieson stain. The results were follows; 1. The tongue tissue were severely swollen on the 1 hour after irradiation, but gradually decreased in course of time. 2. The basal cells of epithelium of tongue proliferated at initial stage of irradiation, but gradually decreased. The Keratin layer were gradually increased. 3. The muscles within the tongue were severely degenerated at initial stage of irradiation, but gradually recovered almost normally. 4. The tissue changes after irradiation were gradually increased by the degree of irradiation.

• Journal of The Korean Dental Society of Anesthesiology
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• v.11 no.2
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• pp.177-182
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• 2011

There are five principal causes for excessive bleeding in the immediate postextraction phase ; (1) Vascular wall alteration (wound infection, scurvy, chemicals, allergy) (2) Disorders of platelet function (genetic defect, drug-aspirin, autoimmune disease) (3) Thrombocytopenic purpuras (radiation, leukemia), (4) Inherited disorders of coagulation (hemophilia, Christmas disease, vitamin deficiency, anticoagulation drug-heparin, coumarin, aspirin, plavix). If the hemorrhage from postextraction wound is unusually aggressive, and then dehydration and airway problem are occurred, the socket must be packed with gelatine sponge(Gelfoam) that was moistened with thrombin and wound closure & pressure dressing are applied. The thrombin clots fibrinogen to produce rapid hemostasis. Gelatine sponges moistened with thrombin provide effective coagulation of hemorrhage from small veins and capillaries. But, in dental alveoli, gelatine sponges may absorb oral microorganisms and cause alveolar osteitis (infection). This is a case report of bleeding and infection control by the circumferential suture and iodoform gauze drainage on infected active bleeding extraction socket under sedation and local anesthesia in a 71-years-old male patient with anticoagulation drug.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.28.1-28.4
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• 2020

Background: This clinical case presented a novel method of segmental mandible reconstruction using 3D-printed titanium implant with pre-mounted dental implants that was planned to rehabilitate occlusion. Case presentation: A 53-year-old male who suffered osteoradionecrosis due to the radiation after squamous cell carcinoma resection. The 3D-printed titanium implant with pre-mounted dental implant fixtures was simulated and fabricated with selective laser melting method. The implant was successfully inserted, and the discontinuous mandible defect was rehabilitated without postoperative infection or foreign body reaction during follow-ups, until a year. Conclusions: The 3D-printed titanium implant would be the one of the suitable treatment modalities for mandible reconstruction considering all the aspect of mandibular functions.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.161-168
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• 2023

Nasopalatine duct cysts (NPDCs), the most common non-odontogenic cysts of maxilla, are often incidental findings on diagnostic imaging. When symptomatic, they usually present as a painless swelling with possible fistula. Conventional radiography shows a round-to-ovoid or heart-shaped radiolucency between the roots of central maxillary incisors. While the radiographic features of NPDCs in X-ray-based modalities have been well described, their magnetic resonance imaging (MRI) features have rarely been reported. Developments in dental MRI in recent years and the introduction of various dental MRI protocols now allow a wide range of applications in dental medicine. MRI is becoming an important tool for the detection and diagnosis of incidental or non-incidental dentomaxillofacial cysts. This report presented and discussed the characteristics of 2 NPDC cases visualized on MRI using both conventional and newly implemented specific dental MRI protocols with a novel 15-channel mandibular coil, demonstrating the use of these protocols for radiation-free maxillofacial diagnoses.

• Polymer(Korea)
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• v.39 no.3
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• pp.418-425
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• 2015

Polycaprolactone (PCL) and biphasic calcium phosphate (BCP) have been considered as useful materials for orthopedic devices and osseous implants because of their biocompatibility and bone-forming activity. However, PCL-based scaffolds have hydrophobic surfaces reducing initial cell adhesion or proliferation. To overcome the limitation, we fabricated surface-modified PCL/BCP nanofibers using gamma-irradiation for bone tissue engineering. PCL/BCP nanofibers were prepared by electrospinning and then we supplemented hydrophilicity by introducing acrylic acid (AAc) through gamma-irradiation. We confirmed the surface of nanofibers by SEM, and then the initial viability of MG63 was significantly increased on the AAc grafted nanofibers, and alkaline phosphatase activity($1.239{\pm}0.226nmole/{\mu}g/min$) improved on the modified nanofibers than that on the non-modified nanofibers($0.590{\pm}0.286nmole/{\mu}g/min$). Therefore, AAc-grafted nanofibers may be a good tool for bone tissue engineering applications.

• Radiation Oncology Journal
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• v.38 no.2
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• pp.99-108
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• 2020

Purpose: The probability of recurrence of cancer after adjuvant or definitive radiotherapy in patients with human papillomavirus-negative (HPV(-)) head and neck squamous cell carcinoma (HNSCC) varies for each patient. This study aimed to identify and validate radiation sensitivity signature (RSS) of patients with HPV(-) HNSCC to predict the recurrence of cancer after radiotherapy. Materials and Methods: Clonogenic survival assays were performed to assess radiosensitivity in 14 HNSCC cell lines. We identified genes closely correlated with radiosensitivity and validated them in The Cancer Genome Atlas (TCGA) cohort. The validated RSS were analyzed by ingenuity pathway analysis (IPA) to identify canonical pathways, upstream regulators, diseases and functions, and gene networks related to radiosensitive genes in HPV(-) HNSCC. Results: The survival fraction of 14 HNSCC cell lines after exposure to 2 Gy of radiation ranged from 48% to 72%. Six genes were positively correlated and 35 genes were negatively correlated with radioresistance, respectively. RSS was validated in the HPV(-) TCGA HNSCC cohort (n = 203), and recurrence-free survival (RFS) rate was found to be significantly lower in the radioresistant group than in the radiosensitive group (p = 0.035). Cell death and survival, cell-to-cell signaling, and cellular movement were significantly enriched in RSS, and RSSs were highly correlated with each other. Conclusion: We derived a HPV(-) HNSCC-specific RSS and validated it in an independent cohort. The outcome of adjuvant or definitive radiotherapy in HPV(-) patients with HNSCC can be predicted by analyzing their RSS, which might help in establishing a personalized therapeutic plan.

• International Journal of Oral Biology
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• v.37 no.1
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• pp.1-7
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• 2012

Opioid receptors have been pharmacologically classified as ${\mu}$, ${\delta}$, ${\kappa}$ and ${\varepsilon}$. We have recently reported that the antinociceptive effect of morphine (a ${\mu}$-opioid receptor agonist), but not that of ${\beta}$-endorphin (a novel ${\mu}/{\varepsilon}$-opioid receptor agonist), is attenuated by whole body irradiation (WBI). It is unclear at present whether WBI has differential effects on the antinociceptive effects of ${\mu}-$, ${\delta}-$, ${\kappa}-$ and ${\varepsilon}$-opioid receptor agonists. In our current experiments, male ICR mice were exposed to WBI (5Gy) from a $^{60}Co$ gamma-source and the antinociceptive effects of opioid receptor agonists were assessed two hours later using the hot water ($52^{\circ}C$) tail-immersion test. Morphine and $D-Ala^2$, $N-Me-Phe^4$, Gly-olenkephalin (DAMGO), [$D-Pen^2-D-Pen^5$] enkephalin (DPDPE), trans-3,4-Dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide (U50,488H), and ${\beta}$-endorphin were tested as agonists for ${\mu}$, ${\delta}$, ${\kappa}$, and ${\varepsilon}$-opioid receptors, respectively. WBI significantly attenuated the antinociceptive effects of morphine and DAMGO, but increased those of ${\beta}$-endorphin. The antinociceptive effects of DPDPE and U50,488H were not affected by WBI. In addition, to more preciously understand the differential effects of WBI on ${\mu}-$ and ${\varepsilon}$-opioid receptor agonists, we assessed pretreatment effects of ${\beta}$-funaltrexamine (${\beta}$-FNA, a ${\mu}$-opioid receptor antagonist) or ${\beta}$-$endorphin_{1-27}$ (${\beta}$-$EP_{1-27}$, an ${\varepsilon}$-opioid receptor antagonist), and found that pretreatment with ${\beta}$-FNA significantly attenuated the antinociceptive effects of morphine and ${\beta}$-endorphin by WBI. ${\beta}$-$EP_{1-27}$ significantly reversed the attenuation of morphine by WBI and significantly attenuated the increased effects of ${\beta}$-endorphin by WBI. The results demonstrate differential sensitivities of opioid receptors to WBI, especially for ${\mu}-$ and ${\varepsilon}$-opioid receptors.

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.71-79
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• 2000

Purpose : This study was aimed to evaluate the cell cycle arrest and apoptosis induction after irradiation and epidermal growth factor (EGF) treatment in three human epithelial tumor cell lines (A431, Siha, KB). Materials and Methods: Single irradiation of 2, 5 and 10 Gy was done on three cell lines with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. Also, EGF of 10 ng/ml was added immediately after 10 Gy irradiation. Cell growth was evaluated by counting the living cell number using a hemocytometer at 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Cell cycle arrest and apoptosis induction were assayed with the flow cytometry at 8 hours, 12 hours, 1 day, 2 days, 3 days, 4 days and 5 days after irradiation. Results : Growth of irradiated three cell lines were inhibited in proportion to radiation dose. EGF treatment after irradiation showed various results according to cell lines. On all cell lines, G2 arrest was detected after 8 hours and maximized after 12 hours or 1 day. Amount of G2 arrest was positively dose dependent. However, EGF showed no significant change on G2 arrest. G2 arrest was recovered with time at 2 Gy and 5 Gy irradiation. However, at 10 Gy irradiation, G2 arrest was continued. Apoptosis was detected at 10 Gy irradiation. On EGF treated group after irradiation, A431 and Siha cell lines showed slightly increased apoptosis but there was no statistically significant difference. KB cell line showed no marked change of apoptosis induction. Conclusion : Irradiation effects on cell cycle arrest and apoptosis induction in three human epithelial tumor cell lines, however epidermal growth factor doesn't effect on.