• Progress in Medical Physics
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• v.22 no.2
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• pp.67-71
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• 2011

We evaluated the overall setup accuracy for the On-Board Imager (OBI, Varian Medical Systems Inc., Palo Alto, CA, USA), with attention to the laser, the gantry, and operator performance. We let experienced technicians place the marker block on the couch using a lock bar system, with alignment to the isocenter of the laser, every morning. A pair of radiographic images of the marker block was acquired at $0^{\circ}$ and $270^{\circ}$ angles to the kV arm to correct the position using a 2D/2D matching technique. Once the desired match was achieved, the couch was moved remotely to correct the setup error and the parameters were saved. The average for the vertical and the longitudinal displacements were 0.65 mm and 0.66 mm, and 0.01 mm for the lateral displacement. The average for the vertical and longitudinal displacements were statistically significant at the 0.05 level (p value=0.000 for both), while the p value for the lateral direction was 0.829. These results show that the tendencies to displacement in vertical and longitudinal directions occur through systematic error, while systematic error was not found in the lateral displacement. This daily overall evaluation is practical and easy to find the systematic and random errors in the setup system; however, a daily QA for laser and OBI alignment is still needed to minimize the systematic error in aligning patients.

• Journal of Periodontal and Implant Science
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• v.48 no.2
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• pp.103-113
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• 2018

Purpose: The purpose of this retrospective study with 4-12 years of follow-up was to compare the marginal bone loss (MBL) between external-connection (EC) and internal-connection (IC) dental implants in posterior areas without periodontal or peri-implant disease on the adjacent teeth or implants. Additional factors influencing MBL were also evaluated. Methods: This retrospective study was performed using dental records and radiographic data obtained from patients who had undergone dental implant treatment in the posterior area from March 2006 to March 2007. All the implants that were included had follow-up periods of more than 4 years after loading and satisfied the implant success criteria, without any peri-implant or periodontal disease on the adjacent implants or teeth. They were divided into 2 groups: EC and IC. Subgroup comparisons were conducted according to splinting and the use of cement in the restorations. A statistical analysis was performed using the Mann-Whitney U test for comparisons between 2 groups and the Kruskal-Wallis test for comparisons among more than 2 groups. Results: A total of 355 implants in 170 patients (206 EC and 149 IC) fulfilled the inclusion criteria and were analyzed in this study. The mean MBL was 0.47 mm and 0.15 mm in the EC and IC implants, respectively, which was a statistically significant difference (P<0.001). Comparisons according to splinting (MBL of single implants: 0.34 mm, MBL of splinted implants: 0.31 mm, P=0.676) and cement use (MBL of cemented implants: 0.27 mm, MBL of non-cemented implants: 0.35 mm, P=0.178) showed no statistically significant differences in MBL, regardless of the implant connection type. Conclusions: IC implants showed a more favorable bone response regarding MBL in posterior areas without peri-implantitis or periodontal disease.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.237-245
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• 2016

This study aimed to identify the characteristics of jaw cysts among children and adolescents treated at the Kyung Hee University Dental Hospital from 2005 to 2015. A retrospective observational study was conducted of 269 jaw cysts diagnosed in 253 patients. The following variables were recorded: gender, age, prevalence and location of lesions, clinical symptoms and treatment. Statistical analyses were performed using the SPSS (version 20.0). Our results suggest that the cysts are slightly more prevalent in males. Cystic lesions of the jaws in children are predominantly odontogenic and developmental in origin. Dentigerous cysts predominate in developmental cysts and the most frequent diagnosis is radicular cysts in inflammation cysts. The most common location of the cysts is in the mandible, particularly the lower molar region. In numerous cases, the patients have no clinical symptoms. Most cysts were surgically enucleated with tooth extraction. Furthermore, our findings demonstrate that the characteristics of jaw cysts in children are distinctive and differ in several respects from the corresponding distribution of jaw cysts in adult population. Therefore, knowledge of the clinical, radiological and histopathological behavior of jaw cysts and periodic radiographic examination are key factors for early diagnosis and adequate treatment of jaw cysts in children.

• Journal of Radiation Protection and Research
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• v.32 no.1
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• pp.27-34
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• 2007

In this paper, We are evaluated about bio-signal between general workers and nuclear medicine workers which is more radiation exposure relatively. In order to reciprocal evaluated two group, we experimented nuclear medicine workers in Chung-Buk National University Hospital at department of nuclear medicine and worker in Chon-Nam National University Hospital at CT room, general radiographic room, medical recording room, receipt room, general office room. Used of experimental Equipments as follows, for a level of radiation measurement by pocket dosimeter which made by Arrow-Tech company, for heart rate and blood pressure measurement by TONOPORT V which made by GE medical systems company, for heat flux and skin temperature and energy expenditure measurement by Armband senseware 2000 which made by Bodymedia company. Result of experiment obtains as follows: 1) Individual radiation exposure is recorded 3.05 uSv at department of nuclear medicine and order as follows CT room, general radiograpic room, medical recording room, receipt room, general office room. Department of nuclear medicine more 1.5 times than other places. 2) Radiation accumulated dose is not related to Heat flux, Skin temperature, Energy expenditure. 3) Blood pressure is recorded equal to nuclear medical workers, general officer, general people about systolic blood pressure and diastolic blood pressure. Compared to blood pressure between nuclear medical works which is more radiation exposure and other workers was not changed. Consequently, more radiation exposed workers at nuclear medicine field doesn't have hazard.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.219-225
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• 2003

Purpose: Platelet Rich Plasma(PRP) application is increasing with sinus inlay bone graft, but there is few research with radiographic ananlysis on effect of PRP in maxillary sinus. The author investigated the amount of bony changes of maxillary sinus for dental implantation among the patients with maxillary inlay graft. Materials and Methods: With 10 patients who were treated with sinus inlay autologous bone grafting combined with PRP technique, and with 5 patients who were treated with sinus inlay grafting only without PRP, the panoramic radiographys which were taken at preoperation, immediate postoperation, 3months postoperation, and 4 months postoperation(a month after dental implantation)periods were analysed. The films had been scanned, and then proceeded throughout image analysis system. The bone density of maxillary grafted sites was compared with adjacent tooth enamel density and remeasured according to density luminosity of each film. The density changes on PRP group and bone graft only group were analysed with non-parameteric statistics method. Results: In PRP combined patients group, bone density on postoperation periods was increased totally. The remarkable enhanced change of bone density was observed on 3 months postoperation period, thereafter the increasing rate was slightly reduced. In only bone graft patients group, bone density on postoperation periods was also increased compared with preoperation period, but the bone density of 4 months postoperation period was decreased compared with 3 months postoperation period. The amount of bone density on PRP group was significantly changed according to periods in contrast to bone graft only group. Conclusion: The bone density on PRP group was remarkably increased at 3 months postoperation compared to bone graft only group and it was seemed to be associated with more new bone formation, less grafted bone resorption at bone grafted sites with PRP.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.439-447
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• 2011

Introduction: In today's society, the rapid and appropriate care of the dental emergency patients is much more important. So, a retrospective study on the characteristics of emergency dental injuries and diseases will be very meaningful. Materials and Methods: This retrospective clinical study was carried by reviewing the radiographic films and emergency chart of 11,493 patients who had visited the emergency room of Hallym Sacred heart Hospital and were treated in the Department of Oral and Maxillofacial Surgery from January 2006 to December 2010. Results: The male to female ratio was 1.9:1. The highest monthly incidence was observed in May (10.4%) and June (8.9%) and the peak age distribution was the first decade (56.0%), followed by the second decade (16.0%). Trauma was the most common cause in dental emergency patients, followed in order by toothache, odontogenic infection, temporomandibular joint (TMJ) disorder and oral hemorrhage. Soft tissue injury was most prevalent in the trauma group, followed by tooth injury and facial bone fractures. In the tooth injury group, tooth fracture (56.7%) showed the highest incidence followed in order by tooth subluxation (18.2%), tooth concussion (16.9%), tooth avulsion (11.5%) and alveolar bone fractures (3.7%). In the facial bone fracture group, mandibular fractures (81.8%) showed the highest incidence followed in order by maxilla fractures (15.7%), nasal bone fractures (9.0%), zygomaticomaxillary complex fractures (5.4%), orbital bone fractures (2.5%). In mandibular bone fractures, the most common location was the symphysis (70.1%), followed in order by the mandibular angle (33.0%), mandibular condyle (22.8%) and mandibular body (13.6%). In the infection group, a submandibular space abscess (46.2%) was most common followed in order by a buccal space abscess (17.4%), canine space abscess (16.9%) and submental space abscess (12.3%). TMJ dislocation (89.3%) showed the highest incidence in the TMJ disorder group, followed by TMJ derangement (10.7%). In the other group, a range of specific symptoms due to post operation complications, trigeminal neuralgia, chemical burns and foreign body aspiration were reported. Conclusion: For the rapid and appropriate care of the dental emergency patients, well-organized system should be presented in oral and maxillofacial surgery. And it is possible under analysis of pattern and the variation of the dental emergency patients.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.114-119
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• 2018

Purpose: Patients who treated implant immediate loading within a week after implant placement at Wonkwang University Dental Hospital Implant Center were evaluated marginal bone resorption. These retrospective analyses are intended to reinforce the clinical evidence for the implant immediate loading. Materials and methods: Medical history and radiographic data were investigated, which were the patients' who treated implant immediate loading and restoration with provisional prostheses between January 2005 and June 2016, at Wonkwang University Dental Hospital Implant Center. Total number of implants was 70, marginal bone resorption was measured according to implant length, diameter and connection type. To measure marginal bone resorption, periapical radiographs were taken when the implants were placed and after 6 month. Statistical analysis was done in Mann-whitney U test and Kruskal-wallis test with SPSS 22.0 software (P<.05). Results: Mean marginal bone resorption around immediately loaded implants according to implant connection type was shown $1.24{\pm}0.72mm$ in internal hexagon connection type and $1.73{\pm}1.27mm$ in external hexagon connection type. There was no statically significant difference in marginal bone resorption with implant length and diameter. Conclusion: Implants with immediated loading in internal hexagon connection type showed less marginal bone resorption significantly than in external hexagon connection type.

• Tuberculosis and Respiratory Diseases
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• v.57 no.6
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• pp.604-608
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• 2004

A 47-year-old-man was admitted to the emergency department with dyspnea, right pleuritic pain, and high fevers for 3 days. He had a nonproductive cough that exacerbated the chest pain. A clinical examination revealed distressed and slightly tachypneic patient, with blood pressure of 110/90 mmHg, temperature of $39^{\circ}C$, pulse of 90 beats/min, respiratory rate of 24 breaths/min. A chest examination showed significantly diminished breath sounds in the right lung with dullness to percussion. Laboratory investigation demonstrated leukocytosis and a raised C-reactive protein. The results of arterial blood gas analysis revealed moderate hypoxemia. A radiograph and a CT scan of the chest showed extensive consolidation with multifocal low densities, and pleural effusion in the right lung. A diagnostic thoracentesis revealed straw-colored fluid, which was found to be a neutrophil-predominant exudate. At 7 days after admission, the clinical symptoms had not improved and the temperature was still $39^{\circ}C$ despite the aggressive therapy of community-acquired pneumonia. After comprehensive history taking, we realized then that he accidentally aspirated kerosene while siphoning from fuel tank to put into the boiler 3 days ago. Bronchoscopy with bronchial washings could be successful in establishing the diagnosis of hydrocarbon pneumonitis by demonstration of a high lipid-laden macrophage index. Thereafter, the symptoms and radiographic opacities gradually improved, and he was discharged several days later.

• The Journal of the Korean dental association
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• v.54 no.4
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• pp.296-305
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• 2016

Narrow zone of attached gingiva and shallow vestibule around the implants might contribute to difficulty of cleasing, periimplant mucositis caused by incomplete cleansing and further peri-implantitis. The aim of this case report is to present modification of soft tissue biotype around the implants by free gingival grafts according to timing of surgical intervention and shape of free gingiva. A 44 year-old male patient had a missing area on lower right second molar area with 1 to 2 mm of narrow attached gingiva zone and wanted to be treated by implant placement. In radiographic analysis, there was enough alveolar bone to install an implant, free gingiva from hard palate was grafted following implant placement using double layer flap. The width of attached gingival was increased to 4 to 5mm and well maintained during 5 months of follow up. A 69 year-old female patient also had a missing area on lower right first and second molar area with 1 to 2 mm narrow attached gingiva. Since she had systematically angina pectoris and dental phobia, minimal invasive free gingival graft after implants placement was planned. After 2 months of implant surgery, free gingival graft surgery was performed with healing abutments connection. The grafted gingiva was composed of two strip shaped free gingiva, and they were immobilized by periodontal pack. The width of attached gingival was increased to 4 to 5mm and well maintained during 10 months of follow up. With prosthesis delivery, the patients recovered ideal periodontal environment around implants and masticatory function. In conclusion, periodontal health and masticatory function could be achieved through implant placement and free gingival graft.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.432-439
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• 2018

The purpose of this study was to analyze the knowledge, attitudes, safety management behavior, and radiation anxiety of dental hygienists and to analyze affecting factors in order to improve the level of radiation safety management and reduce anxiety. The study period consisted of 280 dental hygienists working in Jeollabuk-do from September 10 to October 31, 2017 using the SPSS 12.0 program, frequency, descriptive statistics, and multiple regression analysis. The average knowledge level of radiation quality control was 8.07, and the correct answer rate was 75.3%. The attitude level was 96.1%, and the radiation safety management behavior was 4.11 for the photographer and 4.58 for the 'always wear a TLD (personal dosimeter) during radiography'. Patient radiation safety management behavior was 3.86, and the highest was '4.69' to confirm pregnancy of the woman before radiography. Radiation-covered lining was 3.86, and was the highest at 4.13 for 'I am concerned about fetal health when I am pregnant'. Factors affecting radiation exposure anxiety were lower radiation safety management behaviors, lower age, lower radiographic experience, higher educational background, higher monthly income, and higher job title (p<0.05). Based on the above results, dental hygienists had strong knowledge, attitudes, and safety management practices for radiation quality control. However, since anxiety related to radiation exposure was high, it is possible to improve radiation safety management level and reduce radiation exposure anxiety.