• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.10 no.1
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• pp.57-61
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• 1980

In dental roentgenograph it is of mutual benefit to the patient and the dentist to use the minimum amount of radiation capable of producing roentgenograms with maximum interprtive informations. Recent increases in the number of diagnostic x-ray examinations made in this country have caused attention to be paid to the quantity of radiation delivered to the population and operator. The purposes of this study was to assess the quality of dental x-ray units, the amount of films, the average processing procedures and the radiation protection methods in korea. The results were as following: 1. Most of radiation generating system were used in low voltage such as 60Kvp, 10㎃. 2. High sensitivity films such as 'D' group of Kodak or Rinn were mainly used and average 14.7 films used per weeks. 3. Some dentists practiced visual processing technic in simple dark room, and others used instant films. 4. 68.26% of patient held the film themselves, but 27.30% were assisted by dentists film holding. 5. In radiation protection method, 7.85% of dentists had protection equipments such as protective barrier, 2.73% wore protective apron, 27.9% made it a rules to avoid beam, and 7.51% used to maintain a distance from the radiation source.

• Imaging Science in Dentistry
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• v.35 no.4
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• pp.191-198
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• 2005

Purpose: To characterize the effects of 2-deoxy-D-glucose (2DG) and quercetin (QCT) on cytokine secretion of IL-6, $TGF-\beta$ and gene expression of Col I in irradiated MC3T3-E1 cells Materials and Methods: The MC3T3-El cells were cultured in an a-MEM supplemented with 5mM 2DG or 10mM QCT and then the cells were incubated 12h before irradiation with 2, 4, 6, and 8Gy X-ray using a linear accelerator delivered at a dose rate of 1.5Gy/min. Level of IL-6 and $TGF-\beta$ was determined by ELISA. Also expression of Col I was examined by RT-PCR. Results: In accordance with the radiation dose, the amount of $TGF-\beta$ was not different in RA + QCT, but it showed a peak value in control and RA + 2DG at 4Gy on the 3rd day. However, all groups showed a decreasing tendency dose-dependently in RA+QCT on the 7th day (p<0.01). In accordance with the radiation dose, the amount of IL-6 increased dose-dependently in all groups on the 3rd day. On the 7th and 21st day, all groups showed peak values at 4Gy. RA+QCT showed a slightly increased amount of IL-6 at 2Gy, but it showed a slightly decreased amount at 4, 6, and 8Gy. In accordance with the period of culture after irradiation, the expression of Col I increased dose-dependently in RA+QCT. Conclusion: The result showed that QCT acted as radiosensitizer in the secretion of $TGF-\beta$ and gene expression of Col I during differentiation in irradiated MC3T3-E1 cells at the cellular level.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.24.1-24.6
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• 2017

Background: Tunneled transposition of the facial artery myomucosal (FAMM) island flap on the lingual side of the mandible has been reported for intraoral as well as oropharyngeal reconstruction. This modified technique overcomes the limitations of short range and dentition and further confirms the flexibility of the flap. This paper presents a case of reconstructing secondary soft palatal defect due to flap necrosis following two-flap palatoplasty in irradiated patient with lingually transposed facial artery myomucosal island flap. Case presentation: The authors successfully reconstructed secondary soft palatal defect due to flap necrosis following two-flap palatoplasty in an irradiated 59-year-old female patient with tunnelized-facial artery myomucosal island flap (t-FAMMIF). Conclusions: Islanding and tunneling modification extends the versatility of the FAMM flap in the reconstruction of soft palatal defects post tumor excision and even after radiation, giving a great range of rotation and eliminating the need for revision in a second stage procedure. The authors thus highly recommend this versatile flap for the reconstruction of small and medium-sized oral defects.

• Journal of Oral Medicine and Pain
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• v.43 no.3
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• pp.84-86
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• 2018

Salivary and lacrimal gland dysfunction is relatively frequent after radioiodine therapy. In most cases this is a transient side effect, but in some patients it may persist for a long period or appear late. Radioiodine ($^{131}I$) therapy is often administered to patients following total thyroidectomy to treat well-differentiated follicular cell-derived thyroid cancer. In addition to the thyroid, $^{131}I$ accumulates in the salivary glands, giving rise to transient or permanent salivary gland damage. Salivary gland dysfunction following radioiodine therapy can be caused by radiation damage. But, it also may be associated with $Sj{\ddot{o}}gren$ syndrome (SS) developed after radioiodine therapy. It would be recommended that the evaluation for SS including anti-SSA/Ro and anti-SSB/La should be considered before and after radioiodine therapy.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.141-165
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• 1997

Radiation-impaired wound healing in animal experiments was believed to be an another logical experimental model to understand the wound healing mechanism in patients. The purpose of this study was to reveal the block point which would result in impaired healing. Twenty four rats(Sprague-Dawley strains) were divided into two groups according to the time interval between irradiation and wounding. Group I, observing the healing effect on the 1st day and Group II are the healing effects on the 7th days after irradiation to the wound of the rat tongue. Experimental animals were sacrificed 3, 6, 12, and 24 hours after wounding. The specimens were examined by the light microscope and transmission electron microscope. The following results were obtained 1. Fibroblasts in both groups showed degenerative changes which were dilated mitochondria and rER, reduced microorganelle, vacuoles and little cytoplasmic process. 2. Average length between bands and Quantity of the newly produced collagen fibers around fibroblasts remained unchanged against control group. 3. The severity of degenerative change of the fibroblast and impairment of wound healing including shortening of the thickness of collagen fibers were more severe in the group II than in the group I.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.327-333
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• 1994

The purpose of this study was to investigate the irradiation effects on the palatal mucosa. For this study, Sprague-Dawley strain rats were irradiated to their head and neck region with the dose of 5Gy and l0Gy by 6MV X -radiation and sacrificed on the experimental periods after irradiation. The authors observed the histological changes of the hard and soft palatal mucosae. The results were as follows: In the light microscopic examination, hydropic change on the basal cells, increased cell size of the epithelium, and decreased epithelial cell layers were observed on the 3hours, 6hours, and 12hours groups after irradiation. But, basal cell hyperplasia, increased epithelial cell layers, and elongated rate pegs were observed on the 3days group after irradiation. After then, these changes were recovered in the mucosa of the hard palate on the 7days and 14days groups, and in the mucosa of the soft palate on the 14days and 2&lays groups after irradiation. And such changes were greater in the mucosa of the soft palate than in that of the hard palate, and more prominent in l0Gy irradiated groups than in 5Gy irradiated groups.

• Imaging Science in Dentistry
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• v.37 no.3
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• pp.149-156
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• 2007

Purpose: The purpose of this study was to measure the absorbed dose and to calculate the effective dose for periapical radiography done by portable intraoral x-ray machines. Materials and Methods: 14 full mouth, upper posterior and lower posterior periapical radiographs were taken by wall-type 1 and portable type 3 intraoral x-ray machines. Thermoluminescent dosemeters were placed at 23 sites at the layers of the tissue-equivalent ART woman phantom for dosimetry. Average tissue absorbed dose and radiation weighted dose were calculated for each major anatomical site. Effective dose was calculated using 2005 ICRP tissue weighted factors. Results: On 14 full mouth periapical radiographs, the effective dose for wall-type x-ray machine was 30 Sv; for portable x-ray machines were 30 Sv, 22 Sv, 36 Sv. On upper posterior radiograph, the effective dose for wall-type x-ray machine was 4 Sv; for portable x-ray machines doses were 4 Sv, 3 Sv, 5 Sv. On lower posterior radiograph, the effective dose for wall type x-ray machine was 5 Sv; for portable x-ray machines doses were 4 Sv, 4 Sv, 5 Sv. Conclusion: Effective doses for periapical radiographs performed by portable intraoral x-ray machines were similar to doses for periapical radiographs taken by wall type intraoral x-ray machines.

• Imaging Science in Dentistry
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• v.39 no.4
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• pp.199-203
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• 2009

Purpose : To measure dose-width product (DWP) values used for dental panoramic radiography in Anyang city, Korea. Materials and Methods : Thirty-six panoramic dental radiographic sets (17 analogue panoramic sets and 19 digital panoramic sets) in 36 dental clinics in Anyang city were included in the study. Each patient's panoramic exposure parameters were simulated and the panoramic radiation doses were measured at the secondary collimator using a Mult-O-Meter (Unfors Instruments, Billdal, Sweden) at each dental clinic during 2006. The third quartile DWP was determined from 310 surface dose measurements on adult. Results : The third quartile DWP for adult panoramic radiograph was 106.7 mGy mm. For analogue and digital panoramic radiograph, 3/4 DWP were 116.8 mGy mm and 72 mGy mm respectively. The overall third quartile DWP of panoramic radiography was 106.7 mGy mm. Conclusion : The measured 3/4 DWPs were higher than the 3/4 DWP of 65 mGy mm recommended by NRPB. Dentists who are operating above the reference dose should lower their panoramic exposure doses below the recommended reference value by changing the exposure parameters and/or their panoramic equipments.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.75-83
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• 2013

PURPOSE. Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment. MATERIALS AND METHODS. Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment, and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of $+37^{\circ}C$. Color measurements were made with a spectrophotometer and registered according to the CIELAB $L^*a^*b^*$ color model system. The changes in $L^*$, $a^*$ and $b^*$ values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant. RESULTS. The UV exposure resulted in visually noticeable and statistically significant color changes in the $L^*$, $a^*$ and $b^*$ values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the $a^*$ and $b^*$ values of the specimens containing thermochromic pigment, compared to those stored at room temperature. CONCLUSION. The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.5
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• pp.455-461
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• 2000

Malignant tumors of the head and neck frequently require treatment with both radiotherapy and surgery. Reconstruction of the defect in previously irradiated field is a challenge to surgeon, who must produce both a functional and an esthetic result. Hyperbaric oxygen therapy(HBO) has been used in an attempt to reduce the deleterious effects of radiation. But the issue of whether prior irradiation and HBO of the recipient site of a free flap affects the result of reconstruction continues to generate controversy. So, the effects of irradiation and hypergbaric oxygen therapy on microvascular anastomosis was evaluated in an experimental study in femoral vessels of rats. The experimental groups were divided into 3 groups, contorol group, irradiation group, and irradiation and HBO group. Preoperative irradiation was delivered in the left groin field with single dose corresponding 2,000cGy and total 48 hours of HBO was given 100% oxygen at 2.4 atmosphere for 4 weeks. The femoral vessels of 60 rats were anastomosed after irradiation and HBO treatment. Three days, 1 week, 2 weeks and 4 weeks after surgery, the femoral vessels were evaluated for patency and histopathologic changes. There was no notable effect of irradiation on patency of femoral vessels in rats and the radiation effects were obvious on histological examination which showed the sloughing of the endothelial cells, subintimal hyperplasia and fibrosis on the media and adventitia of femoral arteries. The histologic changes of the femoral veins were mild and not typical. But the effects of hyperbaric oxygen therapy after irradiation was seen not marked difference in irradiation group.