• Title/Summary/Keyword: failure patterns

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Concurrent Chemoradiotherapy in Locally Advanced Carcinoma of The Uterine Cervix : A Phase I/II Prospective Study (국소적으로 진행된 자궁경부암의 방사선치료와 복합 항암화학요법의 동시치료 결과)

  • Kang One Chul;Choi Eun Kyung;Chung Weon Kuu;Kim Jong Hoon;Chang Hyesook;Kim Yong Man;Kim Young Tak;Nam Joo Hyun;Mok Jung-Eun;Lee Moo-Song
    • Radiation Oncology Journal
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    • v.16 no.3
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    • pp.311-323
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    • 1998
  • Purpose : Prospective, single arm, Phase I/II clinical trial was performed to assess the efficacy and toxicity of the concurrent chemotherapy and definitive radiotherapy (RT) in patients with previously untreated locally advanced carcinoma of the uterine cervix. Methods and Materials : From Mar 1992 to January 1997, a total of 73 patients with advanced cervical carcinoma were entered on the protocol but 5 patients were excluded in analysis because of patients' refusal of treatment. Their ages ranged from 31 to 77 years, median 58 years. The International Federation of Gynecology and Obstetrics (FIGO) stage distribution was as follows: IIB 46, IIIA 2, IIIB 15 and IVA 5. RT consisted of external beam irradiation to 4,140-5,040 cGy/23-28 fractions plus high dose rate intracavitary treatments to deliver a dose of 30-35 Gy to point A in 6-7 fractions. During the intracavitary treatments parametrial boost was delivered for point B dose of 60 Gy in stage IIB and 65 Gy in stage IIIB. Two cycles of concurrent 5-fluorouracil and cisplatin (FP) chemotherapy (5-fluorouracil 1,000 mg/$m^2$/day continuous infusion for 4 days, day 1-4, 29-32 and cisplatin 20 mg/$m^2$/day intravenous bolus for 3 days day 1-3, 29-31) administered starting on day 1 of RT. Results : The median follow-up was 24 months (range 4-68+). Sixty-four patients were evaluable for survival rate in this protocol: The 5-year actuarial and disease-free survival rate were 52$\%$ and 64$\%$, respectively. The 5-rear actuarial survival for stage IIB and III+IVA patients were 58$\%$ and 36$\%$, respectively The 5-year disease-free survival rate for stage IIB and III+IVA patients were 71$\%$ and 40$\%$, respectively. Of the 68 patients evaluated for patterns of failure, overall recurrence rate was 27.9$\%$ (19/68) : local failure in 5.9$\%$ (4/68), distant metastasis in 10.3$\%$ (7/68) and both in 11.8$\%$ (8/68). Of the 64 patients evaluated for response at one month after the completion of treatment the complete response rate was 78$\%$ (50/64). Concurrent chemoradiation appear to be a well-tolerated regimen but there were two treatment-related deaths. Conclusion : Concurrent chemotherapy of FP with high-dose definitive RT in locally advanced carcinoma of the uterine cervix is feasible and effective with acceptable toxicities. This chemoradiation regimen may offer a modest survival benefit for advanced stage. Further follow-up of these patients will evaluate the impact of this regimen on the long-term local control and their survival.

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The Results of Definitive Radiation Therapy and The Analysis of Prognostic Factors for Non-Small Cell Lung Cancer (비소세포성 폐암에서 근치적 방사선치료 성적과 예후인자 분석)

  • Chang, Seung-Hee;Lee, Kyung-Ja;Lee, Soon-Nam
    • Radiation Oncology Journal
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    • v.16 no.4
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    • pp.409-423
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    • 1998
  • Purpose : This retrospective study was tried to evaluate the clinical characteristics of patients, patterns of failure, survival rates, prognostic factors affecting survival, and treatment related toxicities when non-small cell lung cancer patients was treated by definitive radiotherapy alone or combined with chemotherapy. Materials and Methods : We evaluated the treatment results of 70 patients who were treated by definitive radiation therapy for non-small cell lung cancer at the Department of Radiation Oncology, Ewha Womans University Hospital, between March 1982 and April 1996. The number of patients of each stage was 2 in stage I, 6 in stage II, 30 in stage III-A, 29 in stage III-B, 3 in stage IV. Radiation therapy was administered by 6 MV linear accelerator and daily dose was 1.8-2.0 Gy and total radiation dose was ranged from 50.4 Gy to 72.0 Gy with median dose 59.4 Gy. Thirty four patients was treated with combined therapy with neoadjuvant or concurrent chemotherapy and radiotherapy, and most of them were administered with the multi-drug combined chemotherapy including etoposide and cisplatin. The survival rate was calculated with the Kaplan-Meier methods. Results : The overall 1-year, 2-year, and 3-year survival rates were 63$\%$, 29$\%$, and 26$\%$, respectively. The median survival time of all patients was 17 months. The disease-free survival rate for 1-year and 2-year were 23$\%$ and 16$\%$, respectively. The overall 1-year survival rates according to the stage was 100$\%$ for stage I, 80$\%$ for stage II, 61$\%$ for stage III, and 50$\%$ for stage IV. The overall 1-year 2-year, and 3-year survival rates for stage III patients only were 61$\%$, 23$\%$, and 20$\%$, respectively. The median survival time of stage III patients only was 15 months. The complete response rates by radiation therapy was 10$\%$ and partial response rate was 50$\%$. Thirty patients (43$\%$) among 70 patients assessed local control at initial 3 months follow-up duration. Twenty four (80$\%$) of these 30 Patients was possible to evaluate the pattern of failure after achievement of local control. And then, treatment failure occured in 14 patients (58$\%$): local relapse in 6 patients (43$\%$), distant metastasis in 6 patients (43$\%$) and local relapse with distant metastasis in 2 patients (14$\%$). Therefore, 10 patients (23$\%$) were controlled of disease of primary site with or without distant metastases. Twenty three patients (46$\%$) among 50 patients who were possible to follow-up had distant metastasis. The overall 1-year survival rate according to the treatment modalities was 59$\%$ in radiotherapy alone and 66$\%$ in chemoirradiation group. The overall 1-year survival rates for stage III patients only was 51$\%$ in radiotherapy alone and 68$\%$ in chemoirradiation group which was significant different. The significant prognostic factors affecting survival rate were the stage and the achievement of local control for all patients at univariate- analysis. Use of neoadjuvant or concurrent chemotherapy, use of chemotherapy and the achievement of local control for stage III patients only were also prognostic factors. The stage, pretreatment performance status, use of neoadjuvant or concurrent chemotherapy, total radiation dose and the achievement of local control were significant at multivariate analysis. The treatment-related toxicities were esophagitis, radiation pneunonitis, hematologic toxicity and dermatitis, which were spontaneously improved, but 2 patients were died with radiation pneumonitis. Conclusion : The conventional radiation therapy was not sufficient therapy for achievement of long-term survival in locally advanced non-small cell lung cancer. Therefore, aggressive treatment including the addition of appropriate chemotherapeutic drug to decrease distant metastasis and preoperative radiotherapy combined with surgery, hyperfractionation radiotherapy or 3-D conformal radiation therapy for increase local control are needed.

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The Role of Postoperative Pelvic Radiation Therapy in Rectal Cancer (직장암에 있어서 수술후 방사선치료의 역할)

  • Ahn, Yong-Chan;Kim, Jae-Sung;Yun, Hyong-Geun;Ha, Sung-Whan;Park, Charn-Il
    • Radiation Oncology Journal
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    • v.9 no.1
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    • pp.93-102
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    • 1991
  • To evaluate the role of postoperative pelvic radiation therapy in rectal cancer, a retrospective analysis was done on 189 patients with modified Astler-Coiler stages B2+3, Cl , and C2+3 who were treated from February 1979 to June 1980. Forty-seven patients were staged as B2+3,17 as Cl, and 125 as C2+3. As a curative resection,41 received low anterior resection,143 received abdomino-perineal resection, and five received pelvic exenteration. The survival and disease-free survival rates of the total patients at five year were $45.3\%\;and\;44.1\%$, respectively. The stage was an important prognostic factor for survival and disease-free survival: the survival rates at five year were $63.4\%$ in stage B2+3, $62.4\%$ in C1, and $37.2\%$ in C2+3 (p<0.005): the disease-free survival rates at five year were $55.7\%$ in B2+3, $65.7\%$ in C1, and $30.4\%$ in C2+3, respectively (p<0.01). The liver was the most frequently involved organ of recurrence followed by the lung and the perineum. The patients who received low anterior resection achieved better disease-free survival but were more prone to late radiation bowel morbidities than those who received abdominoperineal resection. Postperative Pelvic radiation therapy Proved to be effective in locoregional disease control but did not prevent the appearance of distant metastasis, which was of major concern in advanced stages. Patterns of treatment failure, and factros relating to radiation morbidity are discussed, and therapeutic options for better results are proposed.

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Twice Daily Radiation Therapy Plus Concurrent Chemotherapy for Limited-Stage Small Cell Lung Cancer (국한성병기 소세포폐암에서 하루 두 번 분할조사와 동시 화학방사선치료)

  • Yeo Seung-Gu;Cho Moon-June;Kim Sun-Young;Kim Ki-Whan;Kim Jun-Sang
    • Radiation Oncology Journal
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    • v.24 no.2
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    • pp.96-102
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    • 2006
  • Purpose: A retrospective study was performed to evaluate the efficiency and feasibility of twice daily radiation therapy plus concurrent chemotherapy for limited-stage small cell lung cancer in terms of treatment response, survival, patterns of failure, and acute toxicities. Materials and Methods: Between February 1993 and October 2002, 76 patients of histologically proven limited-stage small cell lung cancer (LS-SCLC) were treated with twice daily radiation therapy and concurrent chemotherapy. Male was in 84% (64/76), and median age was 57 years (range, 32-75 years). Thoracic radiation therapy consisted of 120 or 150 cGy per fraction, twice a day at least 6 hours apart, 5 days a week. Median total dose was 50.4 Gy (range, 45-51 Gy). Concurrent chemotherapy consisted of CAV ($cytoxan\;1000mg/m^2,\;adriamycin\;40mg/m^2,\;vincristine\;1mg/m^2$) alternating with PE ($cisplatin\;60mg/m^2,\;etoposide\;100mg/m^2$) or PE alone, every 3 weeks. The median cycle of chemotherapy was six (range, 1-9 cycle). Prophylactic cranial irradiation (PCI) was recommended to the patients who achieved a complete response (CR). PCI scheme was 25 Gy/10 fractions. Median follow up was 18 months (range, 1-136 months). Results: Overall response rate was 86%; complete response in 39 (52%) and partial response in 26 (34%) patients. The median overall survival was 23 months. One, two, and three year overall survival rate was 72%, 50% and 30%, respectively. In univariate analysis, the treatment response was revealed as a significant favorable prognostic factor for survival (p<0.001). Grade 3 or worse acute toxicities were leukopenia in 46 (61%), anemia in 5 (6%), thrombocytopenia in 10 (13%), esophagitis in 5 (6%), and pulmonary toxicity in 2 (2%) patients. Of 73 evaluable patients, 40 (55%) patients subsequently had disease progression. The most frequent first site of distant metastasis was brain. Conclusion: Twice daily radiation therapy plus concurrent chemotherapy produced favorable response and survival for LS-SCLC patients with tolerable toxicities. To improve the treatment response, which proved as a significant prognostic factor for survival, there should be further investigations about fractionation scheme, chemotherapy regimens and compatible chemoradiotherapy schedule.

Relationship Between IFN${\gamma}$ Production, Antibody and Hormone Levels in Naturally Neospora caninum-infected Pregnant Dairy Cows (Neospora caninum에 자연 감염된 임신우에서 IFN${\gamma}$, 항체 및 호르몬 수준의 상관관계)

  • Son, Jeong-Hoon;Park, Bae-Keun;Son, Hwa-Young;Jung, Ju-Young;Park, Sang-Joon;Kim, Tae-Hwan;Cho, Sung-Whan;Ryu, Si-Yun
    • Journal of Veterinary Clinics
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    • v.27 no.6
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    • pp.640-646
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    • 2010
  • Neosporosis is a widespread parasitic disease caused by Neospora caninum, an intracellular protozoan parasite. It causes economic losses due to reproductive failure. The potential relationship between pregnancy outcomes and levels of IFN${\gamma}$, hormones, and antibodies in naturally N. caninum-infected cows was examined in the blood samples collected every 2 or 4 weeks in 26 pregnant cows from 4 different farms. The mean S/P value of seropositive nonaborting animals (n = 14) reached peak levels 15 weeks prior to parturition, and declined thereafter to parturition. The S/P value 13 weeks prior to abortion in seropositive aborting cows (n=3) remained at high levels, and abortions occurred at 20 (142 days), 26 (185 days), and 28 weeks (199 days) after artificial insemination. IFN${\gamma}$ levels in the seropositive non-aborting group varied by individuals and gestational periods; IFN${\gamma}$ levels stayed at elevated levels or increased abruptly close to abortion in seropositive aborting cows. IFN${\gamma}$ level patterns in the seronegative group (n = 9) were similar to the seropositive non-aborting group, although IFN${\gamma}$ amounts were lower than the seropositive group. The mean progesterone levels in the seropositive non-aborting and seronegative groups decreased markedly 7 weeks prior to parturition. The mean progesterone levels 5 and 7 weeks prior to abortion were lower than the other groups 5 and 7 weeks prior to parturition. The mean 17${\beta}$-estradiol levels in the seropositive aborting cows increased close to abortion; the produced amounts were lower than those of seropositive non-aborting and seronegative groups close to parturition. These results suggested that lower levels of progesterone and ${\beta}$-estradiol in Neospora-infected cows may lead to increases in IFN${\gamma}$ production and in turn may result in abortion.

Epidemic acute interstitial pneumonia in children occurred during the early 2006s (2006년 초에 유행한 소아 급성 간질성폐렴)

  • Cheon, Chong Kun;Jin, Hyun-Seung;Kang, Eun Kyeong;Kim, Hyo Bin;Kim, Byoung-Joo;Yu, Jinho;Park, Seong Jong;Hong, Soo-Jong;Park, June Dong
    • Clinical and Experimental Pediatrics
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    • v.51 no.4
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    • pp.383-390
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    • 2008
  • Purpose : This study was aimed to analyze the clinical characteristics of patients with acute interstitial pneumonia who had presented similar clinical patterns from March to June, 2006 and to describe our experience of treatment and to identify risk factors associated with prognosis. Methods : The clinical characteristics, radiologic and histopathologic findings and response to steroids of 15 patients (non-survival group [n=7] and survival group [control, n=8]) with acute interstitial pneumonia were investigated through the review of medical records. Results : The mean age of the patients was 26 (range: 3-48) months. Cough, cyanosis and fever were frequent symptoms. The most frequent radiologic findings on admission were pneumomediastium and extensive ground glass opacity. Surgical lung biopsy was performed on 8/15 (53.3%) patients and diffuse alveolar damage was found. Mechanical ventilation was applied for 9/15 (60.0%) patients for 40 (range: 1-99) days. Five patients in survival group received steroid treatment and 7 patients in non-survivial group (P=0.20). One patient in survival group received steroid pulse treatment and 4 patients in non-survival group (P=0.12). Seven patients died all of respiratory failure. The survival rate was 53.4%. Conclusion : The patients with acute interstitial pneumonia which occurred on spring 2006 showed high mortality because of rapidly and extensively progressing pulmonary fibrosis and air leakage. Therefore, we should consider surgical lung biopsy and steroid application earlier. We should recognize this acute interstitial pneumonia occurring on spring in domestics and need to investigate the cause and treatment in large scale.

A Destructive Method in the Connection of the Algorithm and Design in the Digital media - Centered on the Rapid Prototyping Systems of Product Design - (디지털미디어 환경(環境)에서 디자인 특성(特性)에 관한 연구(硏究) - 실내제품(室內製品) 디자인을 중심으로 -)

  • Kim Seok-Hwa
    • Journal of Science of Art and Design
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    • v.5
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    • pp.87-129
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    • 2003
  • The purpose of this thesis is to propose a new concept of design of the 21st century, on the basis of the study on the general signification of the structures and the signs of industrial product design, by examining the difference between modern and post-modern design, which is expected to lead the users to different design practice and interpretation of it. The starting point of this study is the different styles and patterns of 'Gestalt' in the post-modern design of the late 20th century from modern design - the factor of determination in industrial product design. That is to say, unlike functional and rational styles of modern product design, the late 20th century is based upon the pluralism characterized by complexity, synthetic and decorativeness. So far, most of the previous studies on design seem to have excluded visual aspects and usability, focused only on effective communication of design phenomena. These partial studies on design, blinded by phenomenal aspects, have resulted in failure to discover a principle of fundamental system. However, design varies according to the times; and the transformation of design is reflected in Design Pragnanz to constitute a new text of design. Therefore, it can be argued that Design Pragnanz serves as an essential factor under influence of the significance of text. In this thesis, therefore, I delve into analysis of the 20th century product design, in the light of Gestalt theory and Design Pragnanz, which have been functioning as the principle of the past design. For this study, I attempted to discover the fundamental elements in modern and post-modern designs, and to examine the formal structure of product design, the users' aesthetic preference and its semantics, from the integrative viewpoint. Also, with reference to history and theory of design my emphasis is more on fundamental visual phenomena than on structural analysis or process of visualization in product design, in order to examine the formal properties of modern and post-modern designs. Firstly, In Chapter 1, 'Issues and Background of the Study', I investigated the Gestalt theory and Design Pragnanz, on the premise of formal distinction between modern and post-modern designs. These theories are founded upon the discussion on visual perception of Gestalt in Germany in 1910's, in pursuit of the principle of perception centered around visual perception of human beings. In Chapter 2, I dealt with functionalism of modern design, as an advance preparation for the further study on the product design of the late 20th century. First of all, in Chapter 2-1, I examined the tendency of modern design focused on functionalism, which can be exemplified by the famous statement 'Form follows function'. Excluding all unessential elements in design - for example, decoration, this tendency has attained the position of the international style based on the spirit of Bauhause - universality and regularity - in search of geometric order, standardization and rationalization. In Chapter 2-2, I investigated the anthropological viewpoint that modern design started representing culture in a symbolic way including overall aspects of the society - politics, economics and ethics, and its criticism on functionalist design that aesthetic value is missing in exchange of excessive simplicity in style. Moreover, I examined the pluralist phenomena in post-modern design such as kitsch, eclecticism, reactionism, hi-tech and digital design, breaking away from functionalist purism of modern design. In Chapter 3, I analyzed Gestalt Pragnanz in design in a practical way, against the background of design trends. To begin with, I selected mass product design among those for the 20th century products as a target of analysis, highlighting representative styles in each category of the products. For this analysis, I adopted the theory of J. M Lehnhardt, who gradated in percentage the aesthetic and semantic levels of Pragnantz in design expression, and that of J. K. Grutter, who expressed it in a formula of M = O : C. I also employed eight units of dichotomies, according to the G. D. Birkhoff's aesthetic criteria, for the purpose of scientific classification of the degree of order and complexity in design; and I analyzed phenomenal aspects of design form represented in each unit. For Chapter 4, I executed a questionnaire about semiological phenomena of Design Pragnanz with 28 units of antonymous adjectives, based upon the research in the previous chapter. Then, I analyzed the process of signification of Design Pragnanz, founded on this research. Furthermore, the interpretation of the analysis served as an explanation to preference, through systematic analysis of Gestalt and Design Pragnanz in product design of the late 20th century. In Chapter 5, I determined the position of Design Pragnanz by integrating the analyses of Gestalt and Pragnanz in modern and post-modern designs In this process, 1 revealed the difference of each Design Pragnanz in formal respect, in order to suggest a vision of the future as a result, which will provide systemic and structural stimulation to current design.

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THE EFFECTS OF SURFACE TREATMENTS ON SHEAR BOND STRENGTHS OF LIGHT-CURED AND CHEMICALLY CURED GLASS IONOMER CEMENTS TO ENAMEL (법랑질의 표면처리가 광중합형 및 화학중합형 글래스아이오노머 시멘트의 전단결합강도에 미치는 영향)

  • Shin, Kang-Seob;Lee, Ki-Soo
    • The korean journal of orthodontics
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    • v.25 no.2 s.49
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    • pp.223-233
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    • 1995
  • The purpose of this study was to evaluate the effects of surface conditioning with $10\%$ polyacrylic acid, etching with $38\%$ phosphoric acid, and polishing with a slurry of pumice on shear bond strengths of light-cured glass ionomer cement, chemically cured glass ionomer cement, and a composite resin to enamel, and to observe the failure patterns of bracket bondings. Shear bond strengths of glass ionomer cements were compared with that of a composite resin. Metal brackets were bonded on the extracted human bicuspids after enamel surface treatments, and samples were immersed in the $37^{\circ}C$ distilled water bath, and shear bond strengths of glass ionomer cements and a composite resin were measured on the Instron machine after 24hrs passed, and the deboned samples were measured in respect of adhesive remnant index. Scanning electron micrographs were taken of enamel surfaces after various treatments. The data were evaluated and tested by ANOVA and Duncan's multiple range test, and those results were as follows. 1. Shear bond strength of light-cured glass ionomer cement showed statistically higher than that of chemically cured glass ionomer cement. 2. Shear bond strengths of light-cured and chemically cured glass ionomer cements to enamel treated with $10\%$ polyacrylic acid and $38\%$ phosphoric acid showed statistically higher than those with a slurry of pumice. 3. According to scanning electron micrographs, enamel surface conditioned with $10\%$ polyacrylic acid is slightly etched and cleaned, that etched with $38\%$ phosphoric acid is severely etched, and that polished with a slurry of pumice is irregulary scretched and not completely cleaned. 4. After debonding, light-cured glass ionomer cement to enamel treated with $10\%$ polyacrylic acid showed less residual materials on the enamel solace than composite resin to enamel etched with $38\%$ phosphoric acid. 5. There was no significant difference in the shear bond strength of light-cured glass ionomer cement to enamel treated with $10\%$ polyacrylic acid and that of composite resin to enamel etched with $38\%$ Phosphoric acid.

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Effects of Smoking on Oral Health : Preliminary Evaluation for a Long-Term Study of a Group with Good Oral Hygiene (흡연이 구강 건강에 미치는 영향 : 구강 위생이 양호한 집단의 장기적 연구를 위한 예비 평가)

  • Lee, Hyun-Suk;Kim, Mee-Eun
    • Journal of Oral Medicine and Pain
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    • v.36 no.4
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    • pp.225-234
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    • 2011
  • Tobacco smoking is a major risk factor of systemic health and also impairs oral health, which is related to development of oral cancers, periodontitis, delayed wound healing, tooth loss, failure of implant, etc. Aside from smoking, many other risk factors can be related to oral health and long-term effects of smoking on salivary flow and taste threshold are still in controversy. Authors considered dental students to be an appropriate group with good oral hygiene for a long-term study to reveal effects of smoking on oral health. This study was performed to compare smoking patterns and current oral health conditions between smokers and nonsmokers in dental students prior to long-term evaluation. 192 volunteers (85.7%) of 224 male dental students in Dankook University were evaluated through questionnaires and clinical examination in 2010. Questionnaires included smoking pattern, alcohol use, nicotine dependence, preventive care, psychological profile and clinical examinations comprised assessment of teeth or periodontal status, nicotine pigmentation, salivary flow, electrical taste thresholds and halitosis. From the study, (current) smokers were older, and drank more frequently with more alcohol intake compared to former smokers and nonsmokers(p<0.05). There was no significant difference among them in salivary flow rate, halitosis and electrical taste threshold. However, there was significant difference in DMFT rate, periodontal treatment need, nicotinic pigmentation between smokers and nonsmokers(p<0.05), irrespective of their levels of preventive care. The smokers in this study, who are young dental students with relatively shorter duration of smoking, less use of cigarettes and low level of nicotine dependence, did not reveal significant impairment of oral health. However, their oral health was found to be relatively impaired compared to nonsmokers', which suggests negative effect of smoking on the oral health and a need of smoking cessation.

A study on the shear bond strengths of orthodontic brackets according to surface treatments and sizes of amalgam restorations (아말감 충전물의 크기와 표면 처리방법에 따른 교정용 브라켓의 전단접착강도에 대한 연구)

  • Kim, Hyeun-Hee;Cha, Kyung-Suk;Lee, Jin-Woo
    • The korean journal of orthodontics
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    • v.31 no.3 s.86
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    • pp.381-391
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    • 2001
  • In orthodontic patients, frequently, amalgam restorations are present on the buccal surface of molars. The ability to successfully bond orthodontic brackets and buccal tubes to amalgam restorations would therefore be of clinical value. But the bond strength to total amalgam surface is probably not critical in most instances. Because there is usually a considerable amount of sound enamel surrounding a buccal amalgam filling. The purpose of this study was to evaluate the bond strengths of orthodontic brackets according to surface treatments and size of amalgam restorations. Eighty tooth specimen were assigned to four groups according to amalgam size-1.5mm, 2.0mm, 2.5mm, 3.0mm diameter-and then divided into two groups : one half was sandblasting group the other half was no sandblasting group. After Bracket bonding, shear bond strength for each specimen was determined and bond failure patterns was evaluated. 1. Shear bond strength of amalgam size 1.5mm group was significantly higher than that of the other groups. (p<0.05) 2. There was no significant difference in the bond strength produced by sandblasting. (p<0.05) 3. Shear bond strength of G and H group of which amalgam restoration ratio to the bracket base sizes were $61\%$ were significantly decreased $50-60\% level of that of control group. (p<0.05) 4. There was positive correlation between sandblasting and mARI. (p<0.05) The results of the present study indicate that it may be feasible to bond orthodontic bracket clinically successfully to amalgam restoration with conventional orthodontic resin when its size is less than $50\%$ of that of bracket base.

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