• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.97-109
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• 2022

Purpose: This study aims to investigate the risk indicators contributing to implant failure, and analyze the relationship between risk indicators and marginal bone loss (MBL) through long-term follow-up over 3 years. Materials and Methods: From 2003 to 2017, patients' medical charts with a history of dental implant surgery at Chonnam National University Dental Hospital were reviewed retrospectively. The patient's demographic variables, and clinical variables were recorded. Periapical radiographs were used to evaluated the changes in MBL around implants. And we analyzed implant survival rates. Multiple regression analysis with backward elimination was conducted to correlate the patient's clinical variables and implant failure and Pearson correlation analysis was performed to the correlated between implant long-term survival rates and MBL and initial stability. Results: In multiple regression analysis, there was a statistically significant negative correlation between abutment connection type (β = -.189, P < .05), with or without SPT (β = -.163, P < .05), diabetes (β = -.164, P < .05), osteoporosis (β = -.211, P < .05) and MBL. Anticoagulant medication influenced the long-term success rate of implants. PTV values at the second implant surgery showed a statistically significant negative correlation with long-term implant survival (P < .05). Conclusion: For the long-term success of the implant, the appropriate abutment connection type must be selected and the periodic SPT is recommended. Systemic diseases such as diabetes and osteoporosis and anticoagulant medication should be considered. Furthermore, since high PTV at the second implant surgery correlated with the long-term survival rates of the implant, initial stability should be carefully considered before undergoing the prosthetic procedure.

• Radiation Oncology Journal
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• v.29 no.1
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• pp.28-35
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• 2011

Purpose: Recently, the use of radiosurgery as a local therapy in patients with early stage non-small cell lung cancer has become favored over surgical resection. To evaluate the efficacy of radiosurgery, we analyzed the results of stereotactic body radiosurgery in patients with primary or recurrent non-small cell lung cancer. Materials and Methods: We reviewed medical records retrospectively of total 24 patients (28 lesions) with non-small cell lung cancer (NSCLC) who received stereotactic body radiosurgery (SBRT) at Inha University Hospital. Among the 24 patients, 19 had primary NSCLC and five exhibited recurrent disease, with three at previously treated areas. Four patients with primary NSCLC received SBRT after conventional radiation therapy as a boost treatment. The initial stages were IA in 7, IB in 3, IIA in 2, IIB in 2, IIIA in 3, IIIB in 1, and IV in 6. The T stages at SBRT were T1 lesion in 13, T2 lesion in 12, and T3 lesion in 3. 6MV X-ray treatment was used for SBRT, and the prescribed dose was 15~60 Gy (median: 50 Gy) for PTV1 in 3~5 fractions. Median follow up time was 469 days. Results: The median GTV was 22.9 mL (range, 0.7 to 108.7 mL) and median PTV1 was 65.4 mL (range, 5.3 to 184.8 mL). The response rate at 3 months was complete response (CR) in 14 lesions, partial response (PR) in 11 lesions, and stable disease (SD) in 3 lesions, whereas the response rate at the time of the last follow up was CR in 13 lesions, PR in 9 lesions, SD in 2 lesions, and progressive disease (PD) in 4 lesions. Of the 10 patients in stage 1, one patient died due to pneumonia, and local failure was identified in one patient. Of the 10 patients in stages III-IV, three patients died, local and loco-regional failure was identified in one patient, and regional failure in 2 patients. Total local control rate was 85.8% (4/28). Local recurrence was recorded in three out of the eight lesions that received below biologically equivalent dose 100 $Gy_{10}$. Among 20 lesions that received above 100 $Gy_{10}$, only one lesion failed locally. There was a higher recurrence rate in patients with centrally located tumors and T2 or above staged tumors. Conclusion: SBRT using a CyberKnife was proven to be an effective treatment modality for early stage patients with NSCLC based on high local control rate without severe complications. SBRT above total 100 $Gy_{10}$ for peripheral T1 stage patients with NSCLC is recommended.

• Radiation Oncology Journal
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• v.10 no.2
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• pp.205-212
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• 1992

Ninety five patients of rectal cancer treated with surgery with or without adjuvant radiation therapy since January 1982 to December 1990 at the Chonnam University Hospital were analysed retrospectively regarding local failure. Of these 95 patients 72 patients were treated with surgery alone and remaining 23 patients received postoperative radiation therapy to pelvis. There were 45 men and 50 women with 53 years of median age. Minimum follow-up period was 19 months and median was47 months (range, 19-125 months). Kaplan-Meier method was used to calculate actuarial risk of local recurrence and survival rate. Comparison between two groups was evaluated by Log rank test. Of total 95 patients twenty seven patients ($28.4\%$) developed local recurrence and 13 patients ($17.3\%$) developed local and distant metastasis concomitantly. Eighty nine percent (24/27) of patients developed local recurrence within 24 months. Pelvic organ adjacent to the primary tumor area was the most common site of initial local recurrence. Of 72 patients treated with surgery alone local recurrence developed in 24 patients. Of 17 patients with stage A and 81 (Gunderson-Sosin modification of Dukes' staging system) 6 patients experienced local recurrence ($31.2\%$). The local recurrence rate of B2 and B3 group was $29.9\%$ (7/33) and that of C2 and C3 was $54.7\%$ (11/19), respectively. There was statistically significant difference between two groups (p<0.05). Of 23 patients treated with definitive surgery and radiation therapy $10\%$ (1/10) recurred in B2 and B3 patients. This was slightly lower than C2 and C3 patients ($22.2\%$, 2/10) of similar policy, but revealed no statistically significant difference (p>0.05). In the patients of B2+3 local failure rate decreased when radiation therapy was added ($29.9\%$ vs $10\%$, p>0.05) and also similar results in C2+3 group ($34.7\%$ vs $22.2\%$, p<0.05). The local failure rate in relation to distance from the anal verge had no statistically significant difference.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.5
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• pp.1-13
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• 2015

The purpose of this research is to do exploratory analysis on the relationships between demographic characteristics of entrepreneurial candidates and their developmental level of entrepreneurial traits as well as the choice of business field. We analyzed gender, age, and educational level of the entrepreneurial candidates and their developmental level of entrepreneurial traits such as achievement tendencies, degree of awareness, planning skills, sincerity, interpersonal relationship, and problem-solving skills. Industry fields were classified into 4 types: restaurants, retail, services, internet business. Descriptive statistical analyses, logistic regressions, and variance analyses were performed about the sample data gathered from 1,441 persons since the year 2002 to 2014. Males and highly educated above university preferred service industry than restaurant, retail, and internet business. Females preferred internet business, retail, and restaurants than service industry field. The young persons under 20 showed higher probability to choose internet business. The college level and high school graduates preferred retail and restaurants than service industry. The developmental level of entrepreneurial traits were higher in male and highly educated. By this study, we could find the divide between groups with high and low probabilities of failure: restaurants and retail field showed higher failure probability than service industry in the business fields of self-employed. Furthermore, we could identify that entrepreneurial traits also had been developed differently depending on the groups. It is necessary to refrain from entering into the fields with high failure probabilities as well as to provide supporting policies to build the systems and environment to reduce the cases to begin new business without special knowledges and know-hows. The competency development training should be provided in the early stage of start-ups considering their entrepreneurial traits and aptitudes. Not only the assessment of the entrepreneurial traits but also professional counseling from initial stage are necessary.

• Childhood Kidney Diseases
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• v.4 no.2
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• pp.92-101
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• 2000

Purpose : We analyzed the demogaphic data md clinical course of Korean children with chronic renal failure (CRF) observed between 1990 and 1999. Patients and Methods : Questionnaires were mailed to all children's hospitals ail through the country. We asked for primary renal disease age and serum creatinine levels at first presentation with CRF and end-stage renal disease (ESRD), and modes of renal replacement therapy (RRT). Results : 401 children (254 boys, 147 girls) with CRF, defined as a permanent increase of serum creatinine above 1.2 mg/dl for at least 3 months or until death, were identified. This represents an incidence of 3.68 per million child population per year. Of these patients, 22$\%$ on younger than 5 years, 28$\%$ 5 to 10 years and 50$\%$ 10 to 15 year. Eight five $\%$ of the patients could be classified with a primary renal disease. The most frequent cause is glomerulonephritis (36$\%$), followed by chronic pyelonephritis (21$\%$), renal hrpo/dylplasia (9$\%$), and hereditary nephropathies (7$\%$). Reflux nephropathy (16$\%$) was the most common single cause of CRF. ESRD was reached in 70$\%$ of all patient. 99.3$\%$ of these started RRT. Hemodialysis (HD, 42$\%$), peritoneal dialysis (PD, 35$\%$) and transplantation (TP, 23$\%$) were performed as the initial mode of RRT. A total of 161 TPs were performed (159 first grafts, 2 second grafts). A total of 32 patients died. The main causes of death were dialysis related complication in HD patients and infections in PD patients. Survival rate on any form of RRT was 88.7$\%$ during the mean follow-up period of 37 months. Conclusion Major efforts should be directed toward earlier diagnosis and treatment of reflux nephropathy to prevent occurrence of Of. Dialysis and TP have now become well accepted forms of treatment in Korean children with ESRD.

• Journal of Chest Surgery
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• v.36 no.8
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• pp.559-565
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• 2003

By improving the flow pattern in Fontan circuit, total cavopulmonary connection (TCPC) could result in a better outcome than atriopulmonary connection Fontan operation. For the patients with impaired hemodynamics after atriopulmonary Fontan connection, conversion to TCPC can be expected to bring hemodynamic and functional improvement. We studied the results of the revision of the previous Fontan connection to TCPC in patients with failed Fontan circulation. Material and method: From October1979 to June 2002, eight patients who had failed Fontan circulation, underwent revision of previous Fontan operation to TCPC at Yonsei University Hospital. Intracardiac anomalies of the patients were tricuspid atresia (n=4) and other functional single ventricles (n=4). Mean age at TCPC conversion was 14.0$\pm$7.0 years (range, 4.6~26.2 years) and median interval between initial Fontan operation and TCPC was 7.5 years (range, 2.4~14.3 years). All patients had various degree of symptoms and signs of right heart failure. NYHA functional class was 111 or IV in six patients. Paroxysmal atrial fibrillation (n:f), cyanosis (n=2), intraatrial thrombi (n=2), and protein losing enteropathy (PLE) (n=3) were also combined. The previous Fontan operation was revised to extracardiac conduit placement (n=7) and intraatrial lateral tunnel (n=1). Result: There was no operative death. Major morbidities included deep sternal infection (n=1), prolonged pleural effusion over two weeks (n=1), and temporary junctional lachyarrhythrnia (n=1). Postoperative central venous Pressure was lower than the preoperative value (17.9$\pm$3.5 vs. 14.9$\pm$1.0, p=0.049). Follow-up was complete in all patients and extended to 50,1 months (mean, 30.3$\pm$ 12.8 months). There was no late death. All patients were in NYHA class 1 or 11. Paroxysmal supraventricular tachycardia developed in a patient who underwent conversion to intraatrial lateral tunnel procedure, PLE was recurred in two patients among three patients who had had PLE before the convertsion. There was no newly developed PLE. Conclusion: Hemodynamic and functional improvement could be expected for the patients with Fontan circulatory failure after atriopulmonary connection by revision of their previous circulation to TCPC. The conversion could be performed with low risk of morbidity and mortality.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.89-99
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• 2003

The purpose of this study was to investigate the bonding of resin- based root canal sealer, AH26 when the sealer was applied as a thin layer between dentine and gutta-percha surface. In this study forty non-caries extracted human molars and resin-based root canal sealer(AH 26, DeTrey/Dentsply, Germany) were used. Disks of gutta-percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for thermoplastic obturation were used and dentin surfaces were treated with 2% NaOCl(Group 1) or 2%NaOCl+17% EDTA(Group 3). Disks of gutta-Percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for conventional obturation were used and dentin surface were treated with 2% NaOCl(Group 2) or 2%NaOCl+17% EDTA(Group 4). Enamel was removed by a horizontal section 1mm below the deepest portion of the central occlusal groove by using a watercooled low speed diamond saw. A second horizontal section was done around cementoenamel junction. Exposed dentin surface was cut to approximately $8{\times}8{\;}mm$ rectangular shape and was ground against 320, 400, 600 grade silicon carbide abrasive paper serially. After grinding, the dentine surface were soaked in a solution of 2% NaOCl for 30 minutes and twenty of specimens were treated with 17% EDTA solution for 1 minute. The treated specimens were washed and dried, Root canal sealer, AH26 was prepared according to the manufacture's instructions The Gutta-percha and dentin surface were coated with a thin layer of the freshly mixed seal or. The specimens were left overnight at room temperature. After their initial set, they were transferred to an incubator at $37$^{\circ}C$ for 72 h. After 72 hours, resin blocks were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strength f3r each stick was measured with Microtensile Tester Failure patterns of the specimens at the interface between gutta-percha and dentin were observed under the SEM(x1000) and Stereomicroscope (LEICA M42O, Meyer Inst., TX U.S.A) at 1.25 x25 magnification. The results were statistically analysed by using a One-way ANOVA and Tukey's test. The results were as follows; 1. Tensile bond strengths($mean{\pm}SD$) were expressed with ascending order as follows: Group 1, $3.09{\pm}$ 1.05Mpa : Group 2, $6.23{\pm}1.16MPa$ : Group 3, $7.12{\pm}1.07MPa$ : Group 4, $10.32{\pm}2.06MPa$. 2. Tensile bond strengths of the group 2 and 4 used disks of gutta-percha for conventional obturation were significantly higher than that of the group 1 and 3 used fir thermoplastic obturation. (p < 0.05). 3. Tensile bond strengths of the group 3 and 4 treated with 2% NaOC1+17% EDTA were significantly higher than that of the group 1 and 2 treated with 2% NaOCl. (p < 0.05). 4. In analysis of failure patterns at the interface between sealer and gutta-percha, there were observed 49 (61%)cases of adhesive failure patterns and 31 (39%) cases of mixed failures patterns.

• Restorative Dentistry and Endodontics
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• v.32 no.2
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• pp.130-137
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• 2007

This in vitro study examined the effect of surface defects on cutting blades on the extent of the cyclic fatigue fracture of HEROShaper Ni-Ti rotary files using fractographic analysis of the fractured surfaces. A total of 45 HEROShaper (MicroMega) Ni-Ti rotary flies with a #30/.04 taper were divided into three groups of 15 each. Group 1 contained new HEROShapers without any surface defects. Group 2 contained HEROShapers with manufacturing defects such as metal rollover and machining marks. Croup 3 contained HEROShapers that had been clinically used for the canal preparation of 4-6 molars A fatigue-testing device was designed to allow cyclic tension and compressive stress on the tip of the instrument whilst maintaining similar conditions to those experienced in a clinic. The level of fatigue fracture time was measured using a computer connected the system. Statistical analysis was performed using a Tukey's test. Scanning electron microscopy (SEM) was used for fractographic analysis of the fractured surfaces. The fatigue fracture time between groups 1 and 2, and between groups 1 and 3 was significantly different (p<0.05) but there was no significant difference between groups 2 and 3 (p>0.05). A low magnification SEM views show brittle fracture as the main initial failure mode At higher magnification, the brittle fracture region showed clusters of fatigue striations and a large number of secondary cracks. These fractures typically led to a central region of catastrophic ductile failure. Qualitatively, the ductile fracture region was characterized by the formation of microvoids and dimpling. The fractured surfaces of the HEROShapers in groups 2 and 3 were always associated with pre-existing surface defects. Typically, the fractured surface in the brittle fracture region showed evidence of cleavage (transgranular) facets across the grains, as well as intergranular facets along the grain boundaries. These results show that surface defects on cutting blades of Ni-Ti rotary files might be the preferred sites for the origin of fatigue fracture under experimental conditions. Furthermore this work demonstrates the utility of fractography in evaluating the failure of Ni-Ti rotary flies.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.705-713
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• 1998

Background: An association between diabetes and tuberculosis has long been implied. The severity of diabetes appears to correlate with the degree of tuberculous activity. Methods: A retrospective chart review of 82 patients with active pulmonary tuberculosis in diabetics (DMTB) and 83 patients with active pulmonary tuberculosis in nondiabetics (Non-DMTB) admitted to the Kyung Hee Medical Center between January 1995 and December 1996 was underiaken. Results: The sex ratio of DMTB was 58 : 24, and that of Non-DMTB was 62 : 21. Male patients predominated in both groups. The highest incidence of DMTB was 6th and 7th decades and that of Non-DMTB was 3rd and 4th decades. In case which the tuberculosis developed after diagnosis of diabetes, the prevalence of pulmonary tuberculosis was the highest in diabetes for 5-10 years. On chest X-ray findings, the moderate advanced tuberculosis cases were the most common (60.9% in DMTTB and 50.6% in Non-DMTB). There was no relation between the degree of tuberculosis activity on chest x-ray(minimal, moderate, and far advanced tuberculosis) and presence of diabetes. The incidence of lower lung field tuberculosis in DMTB was significantly higher than Non-DMTB(p<0.05). The multiple lobe involvement was the predominant chest roentgenographic finding in both groups. There was no significant difference of treatment response between DMTB and Non-DMTB. There was no relationship between initial HbA1c and the severity of pulmonary tuberculosis on chest X-ray. During treatment of pulmonary tuberculosis in excellently and well controlled diabetes, the cure rate of pulmonary tuberculosis was significantly higher than the poorly controlled diabetes and the rate of treatment failure was significantly lower than poorly controlled diabetes. (p<0.05). Conclusion: Poor control of blood glucose is related with increased rate of treatment failure in pulmonary tuberculosis with diabetes mellitus. Further investigation will be needed to study the mechanisms of treatment failure in poorly controlled diabetics with pulmonary tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.233-238
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• 2006

Study objectives: To determine the factors associated with mortality after an in-hospital diagnosis of tuberculosis in a region with low levels of HIV coinfection. Methods: From January 2003 to December 2004, all subjects who were > 15 years of age and had received a diagnosis of tuberculosis were registered. The clinical, radiological and laboratory aspects of the patients who died (n=27) were compared with those of an age and gender matched control population(n=54). Logistic regression analyses were carried out, which included age, gender, hospital admission source, initial site of admission, dyspnea, general weakness and initial laboratory data. Results: The mean age of the patients was $60{\pm}16$ years and male patients outnumbered female patients. Univariate analysis identified hemoglobin, blood urea nitrogen, albumin, cholesterol, aspartate aminotransferase (AST), C-reactive protein and the risk factors for tuberculosis to be significantly associated with mortality. Among the characteristics of disease presentation and treatment, emergency department admission, intensive care unit, disease severity, general weakness and dyspnea at the time of admission were associated with mortality. Multiple regression analysis revealed the initial management in the intensive care unit and lower serum albumin to be independently associated with mortality. Conclusion: The markers of disease chronicity and severity appear to be associated with in-hospital mortality. Identifying potentially reversible factors such as malnutrition and respiratory failure suggests specific intervention that might lead to an improvement in the patients' outcomes.