• The Journal of the Korean dental association
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• v.53 no.5
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• pp.326-347
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• 2015

목적: 노인 환자에서 식립된 임플란트의 생존율을 조사하고 다양한 요인에 따라 생존율에 미치는 영향을 후향적으로 평가하고자 하였다. 재료 및 방법: 2001년 1월부터 2007년 12월까지 조선대학교 치과병원 치주과에 내원한 65세 이상 노인 환자 56명에게 식립된 138개의 임플란트를 대상으로 하였다.(남자 38명, 여자 18명, 평균 연령$69.38{\pm}3.91$세) 임플란트 생존율은 환자 성별 및 연령, 전신질환 유무, 치아 상실 원인, 식립 위치, 임플란트 직경 및 길이, 골질, 골이식 여부, 상부 보철물 유형에 따라 조사되었다. Kaplan-Meier survival analysis을 통해 각 요인에 따른 누적 생존율을 조사하였고, chi-square test를 통해 누적 생존율과 각각의 요인 간의 통계학적 유의성을 평가하였다. 결과: 보철물 시적 후 5 ~ 140개월 간 추적 관찰을 시행하였다. 65세 이상 노인 환자 56명에게 식립된 총 138개의 임플란트 중 추적 관찰 기간 동안 5개의 임플란트가 실패하였다. 그 중 63개의 임플란트는 환자가 정기적인 내원 약속에 응하지 않아 도중에 조사대상에서 제외되었으며, 결과적으로 5년간 누적 생존율은 94.9%였다. 임플란트 생존율에 영향을 미치는 다양한 요인 중 골질 (P=0.037) 및 상부 보철물 유형 (P=0.015) 간에 누적 생존율이 통계적으로 유의한 차이가 있었다. 그외 연령, 성별, 전신질환 유무, 치아상실 원인, 식립 위치, 임플란트 직경 및 길이, 골이식 유무 관련 요인과 누적 생존율 사이에는 통계적으로 유의한 차이가 없었다. 결론: 여러 한계가 있었지만 노인 환자의 무치악 부위에 있어 임플란트는 장기간에 걸쳐 예지성 있고 받아들여질 만한 치료이면서 적은 합병증과 실패율을 가진다.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.61-66
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• 2012

Purpose: This study was to compare the cumulative survival rate (CSR) of Br${\aa}$nemark machined surface implants and TiUnite$^{TM}$ imlants and to analyze association between risk factors and the CSR of the implants. Materials and methods: A retrospective study design was used to collect long-term follow-up clinical data from dental records of 156 patients treated with 541 Br${\aa}$nemark machined and TiUnite$^{TM}$ implants at Korea University Guro hospital in South Korea from 1993 through 2008. Machined implant and TiUnite$^{TM}$ implant were compared by CSR. Exposure variables such as gender, systemic disease, location, implant length, diameter, prosthesis type, opposing occlusion type, date of implant placement, type of edentulous space, abutment type, existence of splinting with natural teeth, and existence of cantilever were collected. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR (${\alpha}$=.05). Results: Patient ages ranged from 16 to 75 years old (mean age, 51 years old). Implants were more frequently placed in men than women (94 men versus 63 women). Since 1993, 264 Br${\aa}$nemark machined implants were inserted in 79 patients and since 2001, 277 TiUnite$^{TM}$ implants were inserted in 77 patients. A total survival rate of 86.07% was observed in Br${\aa}$nemark and Nobel Biocare TiUnite$^{TM}$ during 15 years. A survival rate of machined implant during 15 years was 82.89% and that of TiUnite$^{TM}$ implant during 5 years was 98.74%. The implant CSR revealed lower rates association with several risk factors such as, systemic disease, other accompanied surgery, implant location, and Kennedy classification. Conclusion: Clinical performance of Br${\aa}$nemark machined and TiUnite$^{TM}$ implant demonstrated a high level of predictability. In this study, TiUnite$^{TM}$ implant was more successful than machined implant. The implant CSR was associated with several risk factors.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.1
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• pp.10-19
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• 2015

Purpose: The aim of the present study was to evaluate the long-term survival of implants retrospectively and determine the risk factors associated with implant failure. Materials and Methods: Of all implants that were placed at the Department of Periodontology of the Dental Hospital of Gangneung-Wonju National University from January 1998 to December 2012, 2265 implants that were followed up until June 2013 were included in this study. Data were collected from clinical and radiographic examinations from previous visits. The information gathered included gender, age, smoking status, implant diameter, implant length, surface of implant, location of implant within the dental arch, surgical techniques and existence of complications. Results: The survival rate before loading was 98.9%. The cumulative survival rate after 5 years of loading was 97.2%, and after 15 years of loading was 95.2%. In a simple logistic regression analysis, gender (P = 0.016), smoking status (P = 0.001), location of implant (P = 0.020) and existence of complications (P = 0.002) were statistically associated with implant failure and included in the multiple regression analysis. As a result of multiple logistic regression analysis, the variables statistically associated with implant failure (P < 0.05) were smoking status (P = 0.049) and existence of complications (P < 0.001). Conclusion: The cumulative survival rate of dental implants after 15 years of loading was 95.2% and that the variables statistically associated with implant failure were smoking status and existence of complications.

• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.395-406
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• 2006

Long-term survival rates are the most commonly used outcome measures for patients with cancer. However, traditional long-term survival statistics, which are derived by cohort analysis or complete analysis, essentially reflect the survival expectations of patients diagnosed many years ago. They are often outdated at the time they become available. In this article, we propose a modified product-limit method to obtain up-to-date estimates of long-term survival rates via a period analysis. The proposed method is illustrated with cancer registry data collected from January 1993 to December 1997.

• Journal of radiological science and technology
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• v.37 no.1
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• pp.21-28
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• 2014

Cultured pancreatic beta cells and nerve cells, it is given normal condition of 10% FBS (fetal bovine serum), 11.1 mM glucose and hyperglycemia codition of 1% FBS, 30 mM glucose. For low LET X-ray irradiated with 0.5 Gy/hr dose-rate(total dose: 0.5 to 5 Gy). Survival rates were measured by MTT assay. When non irradiated, differentiated in the pancreatic beta cells experiment is hyperglycemia conditions survival rate compared to normal conditions survival rate seemed a small reduction. However increasing the total dose of X-ray, the survival rate of normal conditions decreased slightly compared to the survival rate of hyperglycemia conditions, the synergistic effect was drastically reduced. When non irradiated, undifferentiated in the nerve cells experiment is hyperglycemia conditions survival rate compared to normal conditions survival rate seemed a large reduction. As the cumulative dose of X-ray normal conditions and hyperglycemia were all relatively rapid cell death. But the rate of decreased survivals by almost parallel to the reduction proceed and it didn't show synergistic effect.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.3
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• pp.272-278
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• 2017

Purpose: The aim of the present prospective clinical study was to assess the cumulative survival rate (CSR) of Neobiotech implants restored with fixed partial prosthesis in relation to its potential risk factors. Materials and methods: Thirty six partially edentulous patients received Neobiotech implants and implant supported fixed partial prosthesis at Korea University Guro Hospital Dental Center from November 2009 until November 2011. The observation period was set from the implant placement and the last clinical visit until December 2015. Implant survival rate was determined using the Kaplan-Meier method. The relationship between implant survival rate and the potential risk factors were analysed using the multi Cox proportional analysis (P<.05). Results: A total of 69 implants were placed in 36 patients after a mean observation period of 45.9 months. Two out of 69 implants failed before loading, yielding a 5-year cumulative survival rate of 97.1%. The maxillary implants have a lesser CSR than the mandibular implants based on log rank test analysis (maxilla=91.3%; mandible=100% P<.05). However, the multi Cox proportional analysis showed that implant location has no significant correlation with implant failure (P>.05). Conclusion: Neobiotech implants showed predictable results with a 5 year cumulative survival rate of 97.1%.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.28-40
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• 2010

Purpose: The aim of this retrospective study was to provide long-term data about the correlation between multifactorial local factors and the survival of implants. Material and methods: During 19 years (1991 to 2009), 2796 implants were placed in 879 patients. From dental charts and radiographs, the following data were collected: patient's age at implant placement, gender, implant system, surface, length, diameter, location of implant placement, bone quality, primary stability, type of prosthesis. The correlations between these data and implant survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival analysis, Chi-square test, odds ratio. Results: 1. Among the 2796 implants, 150 implants failed that resulted in a cumulative survival rate of 94.64%. The cumulative survival rate of smooth surface implants (91.76%) was lower than rough surface implants (96.02%). 2. Anatomic location, implant surface, diameter of smooth surface implant, primary stability, type of prosthesis, patient's age and gender were significantly associated with implant survival (P < .05). 3. No significant difference in implant survival was found in relation to the following factors: implant length, bone quality, diameter of rough surface implants and type of rough surface according to implant manufacturer (P < .05). Conclusions: Local factors such as anatomic location, implant surface, diameter of smooth surface implant, primary stability and type of prosthesis have a significant effect on implant survival.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.101-112
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• 2023

Purpose. This retrospective study was to investigate the survival and complication rates of posterior single implant according to the implant diameters, lengths and position. Materials and methods. Patients who had been restored single implant prosthesis in the posterior area by the three prosthodontists in the department of prosthodontics, Daejeon dental hospital of Wonkwang university, in the period from February 2014 to May 2018 were selected for the study. A total of 505 patients with 697 implants were observed. The survival and complications of implants were investigated using electronic medical records and radiographs. Fixture diameters, lengths, position, patient's sex and age were assessed as possible factor affecting the survival and complications of implants. Results. 3-year cumulative survival rates of posterior single implants were 98.5% and 5-year cumulative survival rates were 94.4%. 5-year cumulative survival rates were higher in implants with diameter > 4.0 mm (97.0%) than implants with diameter ≤ 4.0 mm (89.5%), and in females (98.8%) than males (92.4%). There were statistically significant differences (P < .05). The mechanical complication rate was 20.1% and the biological complication rate was 4.7%. Complications occurred in order of abutment screw loosening (7.5%), decementation (6.3%), proximal contact loss (3.7%) and so on. Abutment screw loosening occurred more frequently in the lower molar region (10.5%), in males (9.5%) than females (5.1%), and in patients aged < 65 years (9.4%) than patients aged ≥ 65 years (5.1%). There were statistically significant differences (P < .05). Conclusion. The 5-year cumulative survival rates were higher in implants with diameter > 4.0 mm than implants with diameter ≤ 4.0 mm and in females than males. Abutment screw loosening which was the most commonly occurring complication occurred more frequently in the lower molar region, in males than females, and in patients aged < 65 years than patients aged ≥ 65 years. There were statistically significant differences.

• Journal of Aquaculture
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• v.17 no.1
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• pp.39-45
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• 2004

Three experiments were conducted to determine utilization of Song-Gang(equation omitted) stone as the dietary additive for growth and immune stimulant in juvenile olive flounder. In the feeding trial, four diets were formulated to contain 0, 0.5, 1.0 and 2.0% Song-Gang(equation omitted) stone per kg diet (SGS$_{0}$ , SGS$_{0.5}$, SGS$_{1.0}$ , SGS$_{2.0}$ ). Fish averaging 5.0$\pm$0.04 g (mean$\pm$SD) were fed one of four experimental diets in triplicate groups for 8 weeks. There were no significant differences in weight gain, feed efficiency, protein efficiency ratio, hematosomatic index, condition factor and survival among fish fed all the diets. In chanlenge test, fish were infected by intraperitoneal injection of 0.1 $m\ell$ bacterial suspension with Edwardsielia tarda per fish after the feeding trial. Fish fed SGS$_{0.5}$ diet have a significantly higher cumulative survival rate than did fish fed the other diets (P<0.05). In the anti-mold test, Asprrgiilus niger, Penicillium pinophiltfm, Chaeromium globosum were inoculated with Song-Gang(equation omitted) stone using ASTM G-21 method. The amount of Α. niger, Ρ. pinuphiium. C. globosum didn't increase in Song-Gang(equation omitted) stone for 4 weeks for the test period. Therefore, these results indicate that 0.5% Song-Gang(equation omitted) stone per kg diet could increase immune resistance in juvenile olive flounder and Song-Gang(equation omitted) stone could be used as the anti-mold additive in fish feed.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.342-349
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• 2019

Purpose: The purpose of this study was to retrospectively investigate the survival and success rate of implant-supported fixed prosthesis according to the materials in the posterior area. Other purposes were to observe the complications and evaluate the factors affecting failure. Materials and methods: Patients who had been restored implant prosthesis in the posterior area by the same prosthodontist in the department of prosthodontics, dental hospital, Chonbuk National University, in the period from January 2011 to June 2018 were selected for the study. The patient's sex, age, material, location, type of prosthesis and complications were examined using medical records. The KaplanMeier method was used to analyze the survival and success rate. The Log-rank test was conducted to compare the differences between the groups. Cox proportional hazards model was used to assess the association between potential risk factors and success rate. Results: A total of 364 implants were observed in 245 patients, with an average follow-up of 17.1 months. A total of 5 implant prostheses failed and were removed, and the 3 and 5 year cumulative survival rate of all implant prostheses were 97.5 and 91.0, respectively. The 3 and 5 year cumulative success rate of all implant prostheses were 61.1% and 32.9%, respectively. Material, sex, age, location and type of prosthesis did not affect success rate (P>.05). Complications occurred in the order of proximal contact loss (53 cases), retention loss (17 cases), peri-implant mucositis (12 cases), infraocclusion (4 cases) and so on. Conclusion: Considering a high cumulative survival rate of implant-supported fixed prostheses, regardless of the materials, implant restored in posterior area can be considered as a reliable treatment to tooth replacement. However, regular inspections and, if necessary, repairs and adjustments are very important because of the frequent occurrence of complications.