• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.4
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• pp.379-382
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• 1998

The 44 years old man was consulted to our department due to restriction of mouth opening. On radiograph, we found bony expansive lesion at right mandibular ramus and temporal bone that it was suspected malignant tumor. So we had performed incisional bone biopsy at right ramus through skin incision. The result of biopsy was osteosarcoma. Then, he had experienced radiation therapy for the protection of recurrence after several times surgery of nasopharyngeal angiofibroma, 28 years ago. So, we concluded radiation induced osteosarcoma from his radiation therapy history. He had referred to the department of hematooncology because of severe expansion to skull base and was received 4 times chemotherapy with cisplatin and adriamycin, but he was expired just after 4th chemotherapy. Such radiation induced osteosarcoma have relative good prognosis due to rare metastasis from other reports. So if it will early detect from close follow up after radiation therapy, survival rate will rise up. But we missed early detection of our case. So, we report a case of rare radiation induced osteosarcoma. Ly detection of our case.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.31.1-31.5
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• 2015

Background: Pathologic fractures are caused by diseases that lead to weakness of the bone structure. This process sometimes occurs owing to bony change after radiation therapy. Treatment of pathologic fractures may be difficult because of previous radiation therapy. Methods: In this study, we analyzed clinical and radiographic data and progress of five patients with mandibular pathological fractures who had received postoperative radiation therapy following cancer surgery. Result: Patients received an average radiation dose of 59.2 (SD, 7.2) Gy. Four of five patients exhibited bone union regardless of whether open reduction and internal fixation (OR/IF) was performed. Patients have the potential to heal after postoperative radiation therapy. Treatment of a pathologic fracture following postoperative radiation therapy, such as traditional treatment for other types of fractures, may be performed using OR/IF or CR. OR/IF may be selected in cases of significant bone deviation, small remaining bone volume, or occlusive change. Conclusion: Patients have the potential to heal after postoperative radiation therapy.

• International Journal of Oral Biology
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• v.46 no.4
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• pp.168-175
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• 2021

To investigate the perceptions and attitudes of dental hygienists toward radiation safety management in Korea. A total of 800 dental hygienists were randomly selected for an anonymous survey, and 203 of them participated. The questionnaire items included the following: sex, career period, type of installed radiographic equipment, recognition of the diagnostic reference level (DRL), participation in radiation safety education, and attitudes toward radiation protection for both patients and dental hygienists. The participants were divided into two groups according to their years of experience (< 10 years versus ≥ 10 years). The difference between the groups was investigated according to frequency distribution. Fisher's exact test or Pearson's chi-square (𝛘²) test was used as appropriate. A regression analysis was performed to investigate the impact of wearing a thyroid collar for personnel protection during patient radiation exposure. The types of installed radiographic equipment included panoramic radiography (96.1%), cephalometric radiography (76.9%), intraoral radiography (72.9%), and cone-beam computed tomography (69.5%). Significant differences were observed in the learning pathway for the DRL (Fisher's exact test, p < 0.05), satisfaction with radiation safety education (Pearson's 𝛘² test = 5.3975, Pr = 0.02), and use of personnel radiation monitoring systems (Pearson's 𝛘² test = 18.1233, Pr = 0.000) between the groups. Significant differences were also observed in personnel protection using a thyroid collar and patient protection during panoramic radiography (odds ratio = 14.2). Dental hygienists with more than 10 years of experience were more satisfied with radiation safety education and more interested in radiation monitoring. Considering career experience, customized, continuous, and effective radiation safety management education should be provided.

• Restorative Dentistry and Endodontics
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• v.37 no.3
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• pp.160-164
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• 2012

Objectives: This study was aimed to investigate the methods to reduce operator's radiation dose when taking intraoral radiographs with portable dental X-ray machines. Materials and Methods: Two kinds of portable dental X-ray machines (DX3000, Dexcowin and Rextar, Posdion) were used. Operator's radiation dose was measured with an 1,800 cc ionization chamber (RadCal Corp.) at the hand level of X-ray tubehead and at the operator's chest and waist levels with and without the backscatter shield. The operator's radiation dose at the hand level was measured with and without lead gloves and with long and short cones. Results: The backscatter shield reduced operator's radiation dose at the hand level of X-ray tubehead to 23 - 32%, the lead gloves to 26 - 31%, and long cone to 48 - 52%. And the backscatter shield reduced operator's radiation dose at the operator's chest and waist levels to 0.1 - 37%. Conclusions: When portable dental X-ray systems are used, it is recommended to select X-ray machine attached with a backscatter shield and a long cone and to wear the lead gloves.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.18-23
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• 2000

The changes of the microorganism composition after therapeutic radiation for oral cancer patients are not well known and the long-term follow-up data are not reported. To obtain basic data for understanding of pathogenesis and prevention and treatment of dental caries and mucositis occuring after radiation therapy, 7 of the oral cancer patients presented at the Seoul National University Oral & Maxillofacial Department between 1997 and 1998 whose treatment plan included radiation therapy were recruited to investigate the changes in bacterial composition(total aerobic count, Candida, Staphylococci, Lactobacilli, S. mutans, and S. salivarius (mitis, sanguis)) of the saliva before, during, and after radiation therapy. The basic data obtained from this study on identification and composition change of the bacteria in saliva of patients treated with radiation therapy can be used (1) as a reference for deciding on the ideal anti-microbial spectrum of the oral rinsing agent to be used in patients treated with radiation therapy for malignant tumor of the head and neck region. (2) to enhance the understanding of increase of opportunistic infection after immunochemical changes of the saliva and its relation to specific bacterial infection. (3) as a reference in prescribing prophylactic antibiotics in immunodepressed patients after radiation therapy.

• Imaging Science in Dentistry
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• v.52 no.3
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• pp.283-288
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• 2022

Purpose: This study was conducted to measure the radiation exposure and image quality of various cone-beam computed tomography (CBCT) machines under common clinical conditions and to analyze the correlation between them. Materials and Methods: Seven CBCT machines used frequently in clinical practice were selected. Because each machine has various sizes of fields of view (FOVs), 1 large FOV and 1 small FOV were selected for each machine. Radiation exposure was measured using a dose-area product (DAP) meter. The quality of the CBCT images was analyzed using 8 image quality parameters obtained using a dental volume tomography phantom. For statistical analysis, regression analysis using a generalized linear model was used. Results: Polymethyl-methacrylate (PMMA) noise and modulation transfer function (MTF) 10% showed statistically significant correlations with DAP values, presenting positive and negative correlations, respectively (P<0.05). Image quality parameters other than PMMA noise and MTF 10% did not demonstrate statistically significant correlations with DAP values. Conclusion: As radiation exposure and image quality are not proportionally related in clinically used equipment, it is necessary to evaluate and monitor radiation exposure and image quality separately.

• Imaging Science in Dentistry
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• v.37 no.3
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• pp.117-126
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• 2007

Although the diagnostic information provided by radiographs may be of definite benefit to the patients, the radiographic examination does carry the potential for harm from exposure to ionizing radiation. Therefore we should try to expose radiation as low as reasonably achievable and to give diagnostic information to patients as much as possible. All of dentists should have competence in radiation protection. I wish to deal with what we should do for the optimization of radiation protection in dental clinic.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.22.1-22.12
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• 2021

Objectives: This study evaluated and compared the effects of radiation therapy on the dislocation resistance of AH Plus and BioRoot RCS applied to dentin and the sealer-dentin interface. Materials and Methods: Thirty single-rooted teeth were randomly assigned to 2 groups (n = 15 each): AH Plus (Dentsply DeTrey) and BioRoot RCS (Septodont). Each group was subdivided into control and experimental groups. The experimental group was subjected to a total radiation dose of 60 Gy. The root canals of all samples were cleaned, shaped, and obturated using the single-cone technique. Dentin slices (1 mm) were sectioned from each root third for the push-out test and scanning electron microscopy (SEM) was done to examine the sealer-dentin interface. The failure mode was determined using stereomicroscopy. Bond strength data were analyzed by the independent t-test, 1-way analysis of variance, and the Tukey post hoc test (α = 0.05). Results: Significantly lower bond strength was observed in irradiated teeth than non-irradiated teeth in the AH Plus group (p < 0.05). The BioRoot RCS group showed no significant reduction in bond strength after irradiation (p > 0.05) and showed a higher post-irradiation bond strength (209.92 ± 172.26 MPa) than the AH Plus group. SEM revealed slightly larger gap-containing regions in irradiated specimens from both groups. Conclusions: The dislocation resistance of BioRoot RCS was not significantly changed by irradiation and was higher than that of AH Plus. BioRoot RCS may be the sealer of choice for root canal treatment in patients undergoing radiation therapy.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.592.1-592
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• 2001

Conventional intraoral radiography continues to be the most widely used for the diagnosis of dental caries. But conventional intraoral film has several shortcomings, including processing error, increased radiation dose, etc. Recently, various digital radiographs substitude for conventional radiography to overcome these disadvantages. The digital radiographies are numerous advantages, including elimination of processing errors, lower radiation dose, image quality enhancements such as contrast and density modulation.(omitted)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.4
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• pp.288-291
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• 2020

Angiosarcoma is a rare malignant mesenchymal tumor of vascular or lymphatic origin and represents less than 1% of all malignant tumors. Radiation therapy is a standard treatment in many head and neck cancer cases, but ionizing radiation is associated with radiation carcinogenesis including radiation-induced angiosarcoma. In this article, we report a rare case of radiation-induced angiosarcoma found in a 58-year-old female patient who was previously diagnosed with an odontogenic keratocyst and mucoepidermoid carcinoma.