• Title/Summary/Keyword: RFA

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Histomorphometry and stability analysis of early loaded implants with two different surface conditions in beagle dogs

  • Kim, Dong-Seok;Kim, Dae-Gon;Park, Chan-Jin;Cho, Lee-Ra
    • The Journal of Advanced Prosthodontics
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    • v.1 no.1
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    • pp.10-18
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    • 2009
  • STATEMENT OF PROBLEM. Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. PURPOSE. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in early loading conditions. MATERIAL AND METHODS. A total of 36 solid screw implants(diameter 3.75 mm, length 10 mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium implants served as control. Gold crowns were inserted 4 weeks after implant placement and the dogs were immediately put on a food diet. Implants were observed for 10 weeks after loading. Radiographic assessments and stability tests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 4 weeks after loading, and 10 weeks after loading. Histological observations and morphometrical measurements were also performed. RESULTS. Of 36 implants, 33 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels(P=.46) and RFA values. The mean BIC % in the Mg-implants was $54.5{\pm}8.4%$. The mean BIC % in the turned implant was $45.3{\pm}12.2%$. These differences between the Mg-implant and control implant were statistically significant(P=.005). CONCLUSIONS. The anodized, Mg-incorporated implant demonstrated significantly more bone-to-implant contact(BIC) in early loading conditions. CLINICAL IMPLICATIONS. The results of this study in beagle dogs suggest the possibility of achieving predictable stability of early loaded free-standing dental implants with Mg-incorporated surface.

Sustainable controlled low-strength material: Plastic properties and strength optimization

  • Mohd Azrizal, Fauzi;Mohd Fadzil, Arshad;Noorsuhada Md, Nor;Ezliana, Ghazali
    • Computers and Concrete
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    • v.30 no.6
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    • pp.393-407
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    • 2022
  • Due to the enormous cement content, pozzolanic materials, and the use of different aggregates, sustainable controlled low-strength material (CLSM) has a higher material cost than conventional concrete and sustainable construction issues. However, by selecting appropriate materials and formulations, as well as cement and aggregate content, whitethorn costs can be reduced while having a positive environmental impact. This research explores the desire to optimize plastic properties and 28-day unconfined compressive strength (UCS) of CLSM containing powder content from unprocessed-fly ash (u-FA) and recycled fine aggregate (RFA). The mixtures' input parameters consist of water-to-cementitious material ratio (W/CM), fly ash-to-cementitious materials (FA/CM), and paste volume percentage (PV%), while flowability, bleeding, segregation index, and 28-day UCS were the desired responses. The central composite design (CCD) notion was used to produce twenty CLSM mixes and was experimentally validated using MATLAB by an Artificial Neural Network (ANN). Variance analysis (ANOVA) was used for the determination of statistical models. Results revealed that the plastic properties of CLSM improve with the FA/CM rise when the strength declines for 28 days-with an increase in FA/CM, the diameter of the flowability and bleeding decreased. Meanwhile, the u-FA's rise strengthens the CLSM's segregation resistance and raises its strength over 28 days. Using calcareous powder as a substitute for cement has a detrimental effect on bleeding, and 28-day UCS increases segregation resistance. The response surface method (RSM) can establish high correlations between responses and the constituent materials of sustainable CLSM, and the optimal values of variables can be measured to achieve the desired response properties.

Effects of an Agro-healing Program on Promoting Mental Health of the Middle-aged

  • Kim, Jae Soon;Yoo, Eunha;Jeong, Sun-Jin;Jang, Hye Sook
    • Journal of People, Plants, and Environment
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    • v.24 no.6
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    • pp.573-584
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    • 2021
  • Background and objective: This study was conducted with 10 men and women in their 50s-60s to investigate the effect of agro-healing activities on the improvement of mental health. Methods: The experimental group participated in total 8 sessions of agro-healing activities, once a week for 2 hours each, at a care farm in Wanju-gun. Physiological measurements were taken with an electroencephalogram (EEG), Salivettes samples, and blood pressure before and after the activities. Results: As a result of analyzing the changes in brainwaves of the experimental group before and after agro-healing activities, relative slow alpha (RSA), relative fast alpha (RFA), and ratio of alpha to high beta (RAHB), the indices of stability and relaxation, increased after the program with statistical significance. Also, the ratio of SMR to theta (RST) of the attention index increased on the right frontal lobes, temporal lobes, and left occipital lobes, and relative low beta (RLB) increasd on the frontal lobes, temporal lobes, and occipital lobes after the program with statistical significance. The sympathetic nervous system activity, which is a stress index, decreased after the program, whereas the parasympathetic nervous system activity, which is a relaxation index, increased, showing statistical significance (p < .05). As a result of analyzing the changes in blood pressure after the program, systolic blood pressure and diastolic blood pressure decreased from prehypertension to normal blood pressure, showing statistical significance. SThese results indicate that participating in agro-healing activities at a care farm for the 50-60s helps reduce stress and improve stability and relaxation as well as attention. Conclusion: Thus, developing and applying customized agro-healing programs for participants will have a positive effect on brain activity and psychophysiological improvement by relieving tension and stress. However, there are limitations in generalizing the results of this study since most of agro-healing farms have low accessibility that leads to a low level of participants.

Clinical Practice Guidelines for Hepatocellular Carcinoma: Current and Future Perspectives (간암 진료가이드라인의 현재와 전망)

  • Bo Hyun Kim;Joong-Won Park
    • Journal of Digestive Cancer Research
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    • v.4 no.1
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    • pp.21-28
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    • 2016
  • Hepatocellular carcinoma (HCC) is rather unique. Most of HCC patients have underlying chronic liver diseases with or without cirrhosis and the prognosis of HCC depends on the liver function, as well as the tumor extent. Non-invasive diagnosis of HCC can be made with certain risk factors and specific imaging findings (e.g. hypervascularity). Patients with HCC can receive surgical resection, radiotherapy, and systemic chemotherapy as other solid malignancies. HCC has more treatment options such as liver transplantation, transarterial chemoembolization (TACE) and radiofrequency ablation (RFA). A variety of practice guidelines for HCC has been published by many academic societies. Different healthcare systems and availability of resources also affect the practice guidelines; therefore, practice guidelines have similarities and dissimilarities. Herein, we review the current status of practice guidelines for HCC and future perspectives for the improvement of guidelines are also discussed.

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Prognostic Significance of Pre-operative FDG-PET in Colorectal Cancer Patients with Hepatic Metastasis (대장직장암 간전이 환자에서 수술전 FDG PET의 예후인자로서의 중요성)

  • Lee, Hyo-Sang;Lee, Won-Woo;Kim, Duck-Woo;Kang, Sung-Bum;Lee, Kyoung-Ho;Lee, Keun-Wook;Kim, Jee-Hyun;Kim, Sang-Eun
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.5
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    • pp.429-435
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    • 2009
  • Purpose: The purpose of this study was to assess the prognostic value of preoperative FDG-PET in colorectal cancer (CRC) patients with hepatic metastasis (HM). Materials and Methods: 24 CRC patients (M:F=14:10; age, $63{\pm}10$ yrs) with HM who had undergone preoperative FDG PET were included. Cure-intent surgery was performed in all the patients and HMs were controlled using resection (n=13), radio-frequency ablation (RFA) (n=7), and resection plus RFA (n=4). Potential prognostic markers tested were maxSUV of primary tumor, maxSUV of HM, maxSUV ratio of HM over primary tumor (M/P ratio), histologic grade, CEA level, venous/lymphatic/nerve invasion, T stage, N stage, no. of HM, no. of lymph node metastasis, and treatment modality of HM. Results: 14 CRC patients developed a recurrence with a median follow-up duration of 244 days, whereas 10 patients did not develop recurrence with a median follow-up duration of 504 days. M/P ratios but other potential prognostic markers were significantly higher in the recurrent patients ($0.72{\pm}0.14$) than recurrence-free patients ($0.54{\pm}0.23$) (p=0.038). M/P ratio only was found to predict recurrence by Cox multivariate analysis (hazard ratio 37.7, 95% confidence interval 2.01-706.1, p=0.016). The 11 patients with lower M/P ratio of <0.61 had significantly better disease-free survival rate than the 13 patients with higher M/P ratio (${\geq}0.61$) (p=0.026). Conclusion: maxSUV ratio of HM over primary tumor (M/P ratio) may be useful for prognosis prediction of CRC patients with HM. Higher FDG uptake of HM than that of primary tumor may indicate a more advanced status in stage IV CRC.

Histomorphometry and Stability Analysis of Loaded Implants with two Different Surface Conditions in Beagle Dogs (하중을 가한 두 가지 표면의 임플란트에 관한 조직형태학적 분석 및 안정성 분석 (비글견을 이용한 연구))

  • Kim, Sang-Mi;Kim, Dae-Gon;Cho, Lee-Ra;Park, Chan-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • v.24 no.4
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    • pp.337-349
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    • 2008
  • Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in delayed loading conditions. A total of 36 solid screw implants (diameter 3.75 mm, length 10mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium Implants served as control. Gold crowns were inserted 3 months. Radiographic assessments and stabilitytests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 1 and 3 months after loading. Histological observations and morphometrical measurements were also performed. Of 36 implants, 32 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels (p=0.413) and RFA values. The mean BIC % in the Mg-implants was $54.4{\pm}20.2%$. The mean BIC % in the turned implant was $48.9{\pm}8.0%$. These differences between the Mg-implant and control implant were not statistically significant (P=0.264). In the limitation of this study, bone-to-implant contact (BIC) and bone area of Mg-incorporated oxidized implant were similar to machine-turned implant. The stability analysis showed no significantly different ISQ values and marginal bone loss between two groups. Considering time-dependent bone responses of Mg-implant, it seems that Mg-implants enhanced bone responses in early loading conditions and osseointegrated similarly to cp Ti implants in delayed loading conditions. However, further investigations are necessary to obtain long-term bone response of the Mg-implant in human.

A study of $Smartpeg^{TM}'s$ lifetime according to sterilization for implant stability (임플랜트 안정성을 위한 자기공명막대의 소독방법에 따른 수명에 관한 연구)

  • Won, Ho-Yeon;Cho, In-Ho;Lee, Joon-Seok
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.1
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    • pp.42-52
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    • 2008
  • Purpose: Resonance Frequency Analysis(RFA) technique can be used as an effective method in measuring the implant stability and documenting the clinical results. This technique also determines how stable the implant is before performing a prosthetic practice. Having become one the guidelines of the implant therapy whose final objective is the immediate loading, the $Osstell^{TM}$ mentor is giving a lot of information to the clinicians recently. In this communication, experiments were performed to investigate how reliable the measured ISQ values by $Osstell^{TM}$ mentor are, and to see if those are also stable even after sterilization. As five objectives: 1) How stable measured ISQ values after fixation $Smartpeg^{TM}s$ for 400 times. 2) How stable measured ISQ values after 'attach-detach'$Smartpeg^{TM}'s$ for 400 times. 3) How stable measured ISQ values after clinical sterilization methods. 4) How stable measured ISQ values after repeatedly sterilization in autoclave for 10 times. 5) What is the critical temperature which is lost the magnetism of $Smartpeg^{TM}$. Materials and Methods: Clinical sterilization methods(Autoclave sterilization, Dentistar sterilization, Ultra violet sterilization, Vacuum dry unit sterilization, Boiling water sterilization, combined $H_{2}O_{2}$ and Alcohol sterilization).$Smartpeg^{TM}s$. D3 Block bone($3{\times}9{\times}2cm$). Osstem implant(${\emptyset}4.1$-10mm).$Osstell^{TM}$ mentor. Individual experiment was used 8 number of $Smartpeg^{TM}s$ and they had measured to ISQ values of before experiment and after experiment. Results: 1. The measured ISQ values did not change after fixation $Smartpeg^{TM}s$ for 400 times. 2. There was no significant changes in the measured ISQ values of 'attach-detach $Smartpeg^{TM}s'$ for 400 times. 3. The measured ISQ values did not change after the usual clinical sterilization methods. 4. The measured ISQ values did not change after sterilization in autoclave for 10 times. 5. It was impossible to exactly measure the critical temperature which is lost the magnetism of $Smartpeg^{TM}s$. But, the results was resulted to lost its magnetism in higher temperature than $150^{\circ}C$/10 minute. Conclusion: The measured ISQ values showed insignificant differences in case of no changes in the magnetism of the $Smartpeg^{TM}s$. It seems that the $Smartpeg^{TM}s$ can be used repeatedly in every measurement if the original magnetisms of the $Smartpeg^{TM}s$ can be recognized. There seems to be no significant changes in the measured ISQ values of 'attach-detach $Smartpeg^{TM}s'$ only if the screw pitches were unimpaired. The clinical sterilization methods seems acceptable because the result was resulted to lost its magnetism in higher temperature than $150^{\circ}C$/10minute.

Combined effects of rhBMP-2 and rhVEGF coated onto implants on osseointegration: pilot study (양극산화 임플란트 표면에 적용된 골형성단백질과 혈관내피세포성장인자가 골유착에 미치는 영향: 예비연구)

  • Huh, Jung-Bo;Yun, Mi-Jung;Jeong, Chang-Mo;Shin, Sang-Wan;Jeon, Young-Chan
    • The Journal of Korean Academy of Prosthodontics
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    • v.51 no.2
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    • pp.82-89
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    • 2013
  • Purpose: The present study is aimed to evaluate the combined effect of recombinant human bone morphogenetic protein 2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF) coated onto anodized implants on osseointeration. Materials and methods: Six New Zealand white rabbit were used in this study. Each animal received 4 implants that were either coated with rhBMP-2 and rhVEGF (Study group) or anodized implant (Control group) in both tibia. This was performed using a randomized split-mouth design. A total 24 implants were used. The implant stability quotient (ISQ) value using resonance frequency analyser and removal torque (RTQ) measurement were investigated at 2 and 8 weeks. The t-test was used for statistical analysis (${\alpha}$=.05). Results: Control and study group showed good osseointegration at 8 weeks. The ISQ and RTQ values of study group were significant compared with the control group at 8 weeks (P<.05). However, No statistical significance was observed at 2 weeks (P>.05). Conclusion: It was concluded that rhBMP-2 with rhVEGF coated onto anodized implants can induce better osseointegration at late healing period.

Ablation Characteristics of Bovine Liver According to Cool-Tip Temperature of RFA Equipment (고주파 열치료 장비의 Cool-Tip 온도에 따른 소간의 소작 특성)

  • Choi, Young-Jae;Kim, Jeong-Koo
    • Journal of radiological science and technology
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    • v.38 no.2
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    • pp.155-161
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    • 2015
  • This study confirmed the correlation between the change of the cooling water in internal cooling system and the size of the ablation site of bovine liver in RF heat treatment equipment. The bovine liver was resection with $4{\times}4{\times}4cm^3$ in 2cm cool-tip and with $6{\times}6{\times}6cm^3$ in 3cm cool-tip for the experiments. Area and perimeter of the ablation site for bovine liver were measured by Freehand techniques of MRI. It showed area and perimeter decreased during cool-tip temperature rises 6 and 12 minutes ablation using a 2cm and 3cm cool-tip. The correlation of cool-tip temperature and area and perimeter was statistically significant the result are shown(p=.000). The measurements of area and perimeter were more accurate with MRI in actual measurements and MRI for ablation range. The statistical results using Paired sample T-test was also significant(p=.038). The ablation range of bovine liver decreased according as cooling water temperature increases in RF heat treatment equipment for reason of carbonization occurred due to does not accurately pass the RF energy. Therefore, it is considered the effect of RF heat treatment would be increased if the temperature of the cooling water consistently maintain the low temperature in order to reduce the generation of carbide at RF heat treatment and RF energy is delivered accurately.

A comparative study on the accuracy of the devices for measuring the implant stability

  • Cho, In-Ho;Lee, Young-Il;Kim, Young-Mi
    • The Journal of Advanced Prosthodontics
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    • v.1 no.3
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    • pp.124-128
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    • 2009
  • STATEMENT OF PROBLEM. How the ISQ values measured by $Osstell^{TM}$ and $Osstell^{TM}$ Mentor are related, and whether the ISQ values acquired from the two machines changes in accordance with changes in implant stability are not yet fully understood. PURPOSE. The aim of this study was to find out correlation between the ISQ values acquired from $Osstell^{TM}$ and $Osstell^{TM}$ Mentor, and to evaluate the clinical effectiveness and accuracy of two devices. MATERIAL AND METHODS. Sixty two implants were inserted into 47 patients, and their ISQ values were measured using $Osstell^{TM}$ and $Osstell^{TM}$ Mentor. In the first stage surgery, the ISQ values of forty four implants inserted into thirty five patients were measured. In the second stage surgery, the values of fifty implants inserted into thirty seven patients were measured. The values were analyzed to determine the difference between the mean ISQ values of $Osstell^{TM}$ and $Osstell^{TM}$ Mentor. In addition, the correlation between implants used in the first and second stage of surgery with regard to their types and areas of insertion were analyzed. The difference between the ISQ values of 32 implants in each patient during the first and second stage was analyzed. The statistical assessment was carried out using SPSS V. 12.0 for Win. (SPSS Inc., Chicago, USA). The Pearson correlation coefficient was used to examine the correlation between $Osstell^{TM}$ and $Osstell^{TM}$ Mentor in the first and second stages of surgery, whereas the difference between their ISQ values was evaluated using a paired t-test. RESULTS. In the first stage, the mean ISQ value for $Osstell^{TM}$ and $Osstell^{TM}$ Mentor was 70.84 and 75.09, respectively, showing a significant difference (P < .01). In the second stage, the mean ISQ value of $Osstell^{TM}$ and $Osstell^{TM}$ Mentor was 71.76 and 75.94, respectively, also showing a significant difference (P < .01). The difference between the ISQ values in patients in the first and the second stages was significant with both instruments. CONCLUSION. The significant difference in the values obtained using the $Osstell^{TM}$ and $Osstell^{TM}$ Mentor between the first and second stages of implant surgery indicates that these values can be a convenient and precise way for evaluating the implant stability in clinical practice.