• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.9-18
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• 2022

In vitro studies are essential to predict the clinical performance of ceramic widely used as restorative materials. Traditional experiments such as fracture toughness and flexural strength have been used to evaluate the properties of brittle ceramics. However, these experiments have a limitation that the load conditions, failure patterns, and load values at which failure occurs are not similar to human occlusal force ranges or clinical failures. On the other hand, the edge chipping test (ECT), which was recently introduced to study chipping fracture of ceramics, has similar failure patterns to clinical trials. In addition, the failure loads from ECT were similar to human occlusal force. ECT can be usefully used in the study of ceramic properties. In this literature review, a more clinically meaningful experimental study of ceramics by examining the meaning and limitations of traditional ceramic failure tests and comparing them with ECT.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.16-22
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• 1999

Purpose : This study was done to analyze prognostic factors and patterns of failure of patients with histologically confirmed adenocarcinoma of the uterine cervix. Materials and Methods : From June 1988 to December 1990, a retrospective analysis was undertaken for 45 patients who were treated with curative radiation therapy for adenocarcinoma of the uterine cervix at the department of Therapeutic Radiology of Keimyung University Hospital. According to FIGO staging classification, f2 patients were stage Ib, 9 patients were lla, 19 patients were IIB, and 5 patients were lIIb. Median age of the patients was 54 years. The radiation therapy consisted of a combination of external and intracavitary irradiation. Only the pelvis was treated for external irradiation, but 6 patients were treated with extended field irradiation including paraaortic nodes. Intracavitary irradiation was performed with high dose rate sources (Co-60). Neoadiuvant chemotherapy was undertaken for 10 patients. Median and maximum follow-up duration was 64 and 116 months, respectively. Results : The overall 5-year survival rate was 55.2$\%$, and the 5-year survival rates for stage Ib, IIa, IIb, and IIIb were 100$\%$, 50.8$\%$, 46.8$\%$, and 40$\%$ (3-year survival rate), respectively. Of the many clinicopathologic variables evaluated for prognosis, only the stage and the tumor size were significant prognostic factors. Statistically, pelvic failure rates for stage Ib, IIa, IIb, and IIIb were 0$\%$, 33.3$\%$, 57.9$\%$, and 60$\%$, respectively. Distant metastasis rates were 0$\%$, 33.3$\%$, 21.1$\%$, and 40$\%$ for stage Ib, IIa, IIb, and IIIb, respectively. Especially the 6 patients who were irradiated with extended field to treat the paraaortic nodes were free of distant metastasis all. But, 9 patients (23.1$\%$) of the 39 patients who were not irradiated the paraaortic nodes were suffered and expired from uncontrolled distant metastasis. Conclusions : As compared with other studies, the survival rates were similar, but distant metastasis rates including paraaortic nodes metastasis were likely somewhat higher than expected, especially for patients with stage II. So, we think that the effect of prophylactic paraaortic nodes irradiation should be studied prospectively, especially for patients with pelvic nodes involvement or advanced stage of disease.

• Tuberculosis and Respiratory Diseases
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• v.66 no.5
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• pp.358-364
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• 2009

Background: The appropriate empirical antimicrobial choice in the treatment of community-acquired pneumonia (CAP) should be advocated by community-based information on the etiologic pathogens, their susceptibility to antimicrobials, clinical characteristics and outcomes. Jeju is a geographically isolated and identical region in Korea. However, there is no regional reference on adult CAP available. This study investigated the etiologic agents and clinical outcomes of adult patients diagnosed with CAP in Jeju, Korea, to help guide the empirical antimicrobial choice. Methods: A prospective observational study for one year in a referral hospital in Jeju, Korea. Patients diagnosed with CAP were enrolled with their clinical characteristics. Microbiological evaluations to identify the etiologic agents in the adult patients with CAP were performed with blood culture, expectorated sputum smear and culture, antibody tests for mycoplasma, chlamydophila, and antigen tests for legionella and pneumococcus. The clinical outcomes of the initial empirical treatment were analyzed. Results: Two hundred and three patients with mean age of 64 and 79 females were enrolled. Ten microbials from 90 cases (44.3%) were isolated and multiple isolates were confirmed in 30. Among the microbial isolates, S. pneumoniae (36.3%) was the most common, followed by M. pneumoniae (23.0%), C. pneumoniae (17.0%), S. aureus (9.6%) and P. aeruginosa (5.9%). The initial treatment failure (23.8%) was related to the isolation of polymicrobial pathogens, elevated inflammatory markers, and the presence of pleural effusion. Among the 30 isolates of S. pneumoniae, 16 (53.3%) were not susceptible to penicillin, and 19 isolates (63.3%) to erythromycin and clarithromycin. However, 29 isolates (96.7%) were susceptible to levofloxacin and ceftriaxone. Conclusion: S. pneumoniae, M. pneumoniae, S. aureus, and P. aeruginosa are frequent etiologic agents of adult CAP in Jeju, Korea. The clinical characteristics and antibiotic resistance should be considered when determining the initial empirical antimicrobial choice. Respiratory quinolone or ceftriaxone is recommended as an empirical antimicrobiotic in the treatment of adult CAP in Jeju, Korea.

• Radiation Oncology Journal
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• v.27 no.3
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• pp.153-162
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• 2009

Purpose: To evaluate the long-term results after breast-conserving surgery and radiation therapy in early breast cancer in terms of failure, survival, and cosmesis. Materials and Methods: One hundred fifty-four patients with stage I and II breast cancer were treated with conservative surgery plus radiotherapy between January 1992 and December 2002 at the Keimyung University Dongsan Medical Center. According to TNM stage, 93 patients were stage I, 50 were IIa, and 11 were IIb. The affected breasts were irradiated with 6 MV photons to 50.4 Gy in 28 fractions over 5.5 weeks with a boost irradiation dose of 10~16 Gy to the excision site. Chemotherapy was administered in 75 patients and hormonal therapy in 92 patients with tamoxifen. Follow-up periods were 13~179 months, with a median of 92.5 months. Results: The 5- and 10-year overall survival rates were 97.3% and 94.5%, respectively. The 5- and 10-year disease-free survival (5YDFS and 10YDFS, respectively) rates were 92.5% and 88.9%, respectively; the ultimate 5YDFS and 10YDFS rates after salvage treatment were 93.9% and 90.2%, respectively. Based on multivariate analysis, only the interval between surgery and radiation therapy ($\leq$6 weeks vs. >6 weeks, p=0.017) was a statistically significant prognostic factor for DFS. The major type of treatment failure was distant failure (78.5%) and the most common distant metastatic site was the lungs. The cosmetic results were good-to-excellent in 96 patients (80.7%). Conclusion: Conservative surgery and radiation for early stage invasive breast cancer yielded excellent survival and cosmetic results. Radiation therapy should be started as soon as possible after breast-conserving surgery in patients with early breast cancer, ideally within 6 weeks.

• Radiation Oncology Journal
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• v.18 no.3
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• pp.187-193
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• 2000

Purpose : DNA ploidy pattern was shown to correlate with several clinicohistologic findings in several tumors. Aim of this study was to evaluate the correlation of the clinicohistologic findings in colorectal cancer and the failure pattern in rectosigmoid cancer with DNA ploidy. Materials and Methods DNA flow cytometry using the Hedley methods on paraffin embedded specimen from 117 patients with colorectal cancers after curative resection was peformed. We tried to find the correlation between DNA ploidy and various clinicohistologic findings. And then the correlation DNA ploidy and the failure pattern in 75 patients of rectosigmoid cancer was analized. Results : Forty samples (34.2%) from tumors gave aneuploidy histogram. There was no significant difference in the frequency of DNA aneuploidy in terms of age, sex, depth of invasion, location and Dukes stage. But there was a significant correlation between DNA ploidy and the failure rates in Dukes stage B rectosigmoid cancer (P=0.048). Conclusions : These findings suggest that DNA ploidy pattern shows the correlation with the treatment failure rates in Dukes stage B rectosigmoid, but not with many other clinicohistologic findings. However,more patients will be needed to disclose these findings.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.283-289
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• 1998

Purpose : This study was performed to analyze the efficacy of induction chemotherapy fellowed by radiation therapy in locally advanced non-small cell lung cancer Materials and Methods : Eighty patients with locally advanced non-small cell lung cancer treated from 1989 to 1995 at Pusan Paik hospital were analyzed retrospectively. Twenty-one patients were treated with induction chemotherapy followed by radiation therapy and Fifty-nine Patients were treated with radiation therapy alone. Chemotherapy regimen consisted of cisplatin-based combination (2 or 3 drugs). All patients were treated by Co-60 or 6 MV linear accelerators. Radiation dose ranged from 50 Gy to 80 Gy (median 64.8 Gy). We evaluated response rate, survival rate, and pattern of failure in both treatment groups. Results : Overall response rate in induction chemotherapy group and radiotherapy alone group were 48% and 45%, respectively. Of the 80 patients, 46 patients were evaluable for pattern of failure. Initial failure pattern in induction chemotherapy group was as follows: 8 (67%) at locoregional, 4 (33) in distant metastasis. Radiation alone group was 21 (71%) and 5 (29%), respectively. Results showed no difference of distant failure between induction chemotherapy group and radiation alone group. The 1 and 2 year survival rate in induction chemotherapy group were 43% and 14%, respectively and in radiotherapy alone group, 31% and 7%, respectively (p=0.135). Conclusion : In stage III non-small cell lung cancer, induction chemotherapy and radiation therapy showed increased tendency in survival with no statistical significance Induction chemotherapy seems to have no effect of decreasing distant failure and no survival advantage compared with radiotherapy alone.

• 대한두경부종양학회:학술대회논문집
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• 2005.11a
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• pp.214-214
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• 2005

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.297-309
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• 2010

The objective of the present study was to perform a fracture analysis on fractured implant fixture after use in vivo and make clear the cause & mechanisms of failure. In case of fatigue fracture, the fractured surface represents fatigue striation. Fatigue striation indicate the progression of the crack front under cyclic loading, are characteristic of stage 2 crack growth. The site of crack initiation and stage 1 crack growth were not easily identified in any of the failure, presumably because of the complex microstructural features of the polycrystalline sample. In case of fractured by overload, dimpled or cleavage surface were observed. Using the interpretation of characteristic markings(ratchet mark, fatigue striation, dimple, cleavage et al) in fracture surfaces, failure events containing the crack origin, crack propagation, material deficiency could be understand.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.357-367
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• 1997

Purpose : To identify variable prognostic factors and analyse failure patterns in the uterine cervix cancer after radical operation and adjuvant radio-therapy, a retrospective analysis was undertaken. Materals and Methods : I analysed one hundred and twenty four patients with uterine cervix cancer, FIGO stage IB, IIA and IIB, treated with radical hysterectomy and pelvic lymph node dissection followed by adjuvant radio-therapy between May 1985 and May 1994. Minimum follow up period was 24 months. All of them were treated with full dose external radiotherapy with linear accelerator and/or high dese rate intracavitary radiation. Results : Overall 5 year survival rate and relapse free survival rate were $75.4\%,\;73.5\%$, respectively. Significant prognostic factors by relapse free survival were wall involvement thickness, lymph node location and number, parametrium involvement, tumor size, stage, uterine body involvement, vaginal resection margin involvement. By multivariate analysis, lymph node matastasis. tumor size and vaginal resection margin involvement were significant prognostic factos. Treatment related failure were 33 cases. Locoregional failure were more likely in the stage IIB, lymph node positive or vaginal resection margin positive patients whereas distant failures were relatively more frequent in stage IB, IIA and lymph node, vaginal resection negative patients. In stage IIB, 5 year relapse free survival rate was only $56\%$ and nine of twenty two patients recurred. Conculsion : Postoperative radiotherapy results are good for patients with relatively low risk factor. But the results are poor for patients with multiple, high risk factors or stage IIB. To control recurrence for patients with high risk factors, postoperative adjuvant radiotherapy is not sufficient treatment method. To raise control rate adding other methods such as radiosensitizing agent or chemotherapy is necessary and prospectively randomized study is needed for evaluation of postoperative radiotherapy efficacy and /or other methods. And it is reasonable to treat primary radical radiotherapy for patients with stage IIB cervical cancer instead of radical operation and adjuvant radiotherapy and/or chemotherapy regimen.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.369-376
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• 1993

226 patients with carcinoma of the uterine cervix treated with curative radiation therapy at the Department of Therapeutic Radiology, Dongsan hospital, Keimyung university, School of medicine, from July,1988 to May,1991 were evaluated. The patients with all stages of the disease were included in this study. The maximum and mean follow up durations were 60 and 43 months. The radiation therapy consisted of external irradiation to the whole pelvis (2700~4500 cGy) and boost parametrial doses (for a total of 4500~6300 cGy)with midline shild $(4{\times}10\;cm),$ and combined with intracavitary irradiation (5700~7500 cGy to point A). The distribution of patients according to the stage was as follows: stage IB 37 $(16.4\%),$ stage IIA 91 $(40.3\%),$ stage IIB 58 $(25.7\%),$ stage III 32 $(13.8\%),$ stage IV 8 $(3.5\%).$ The overall failure rate was $23.9\%$ (54 patients). The failure rate increased as a function of stage from $13.5\%$ in stage IB to $15.4\%$ in stage IIA, $25.9\%$ in stage IIB, $46.9\%$ in stage III, and $62.5\%$ in stage UV. The pelvic failure alone were 32 patients and 11 patients were as a components of other failure, and remaining 11 patients had distant metastasis only. Among the 43 patients of locoregional failure,28 patients were not controlled initially and in other words nearly half of total failures were due to residual tumor. The mean medial paracervical (point A) doses were 6700 cGy in stage IIB,7200 cGy in stage IIA,7450 cGy in stage IIB,7600 cGy in stage III and 8100 cGy in stage IV. The medial paracervical doses showed some correlation with tumor control rate in early stage of disease (stage Ib, IIA), but there were higher central failure rate in advanced stage in spite of higher paracervical doses. In advanced stage, failure were not reduced by simple increment of paracervical doses. To improve a locoregional control rate in advanced stages, it is necessary to give additional treatment such as concomitant chemoradiation.