• YAKHAK HOEJI
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• v.29 no.5
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• pp.302-304
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• 1985

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.54-65
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• 2008

The purpose of this study was to determine the effect of sodium hypochlorite and steam autoclaving on the cyclic fatigue of nickel-titanium endodontic files. Two types of files with a .06 taper and #30 were used, $K3^{(R)}$ (SybronEndo, Glendora, California, USA) and Hero $642^{(R)}$(Micro-Mega, BesanCon, France). The files were divided into 6 experimental groups containing 10 files each group depending the soaking time in 6% sodium hypochlorite solution and number of cycles of steam autoclave. After sterilization, a cyclic fatigue test was performed on each file, and the fracture time was recorded in seconds. The control group underwent the cyclic fatigue test only. After the test, the surface characteristics of the files were observed using scanning electron microscopy (SEM). All groups containing the Hero 64~ files showed a similar cyclic fatigue fracture time. However, the cyclic fatigue fracture time with the $K3^{(R)}$ files was significantly shorter in groups which were treated with sodium hypochlorite than in the control group (P < 0.05), SEM revealed both Hero $642^{(R)}$ and $K3^{(R)}$ files to have significant corrosion on the file surface in groups treated with sodium hypochlorite, compared with the sharp and regular blades of the control group. $K3^{(R)}$ files showed more corrosion than the Hero $642^{(R)}$ files. Bluntness of the blades of the $K3^{(R)}$ file was observed in groups treated with steam autoclave. Although there was no obvious destruction on the surface of steam autoclaved Hero $642^{(R)}$ files, slight bluntness was observed. Sterilizing with a steam autoclave is much less destructive to $K3^{(R)}$ files than sodium hypochlorite. The longer time exposed to sodium hypochlorite, the more destructive pattern was shown on the blades of the files. Therefore, when using sodium hypochlorite solution, the exposure time should be as short as possible in order to prevent corrosion and increase the cyclic fatigue fracture time.

• 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.

• Culinary science and hospitality research
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• v.13 no.1 s.32
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• pp.55-61
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• 2007

This study was carried out to evaluate the growth characteristics of Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 and the production of propionic and acetic acids in 5% and 10% whey broth by mixed culture of L. acidophilus KCCM 32820 and P. freudenreichii KCCM 31227. Exponential phase of L. acidophilus KCCM 32820 was in the range of $6\sim12$ hrs and P. freudenreichii KCCM 31227 was in the range of $36\sim108$ hrs. In the mixed culture, production of propionic acid was shown to be greater value in the 10% whey broth than in the 5% whey broth and to be greater value in the low temperature for a long time than in sterilization by autoclave. Maximum production of propionic acid was 8.88 mg/mL in the 10% whey broth fermented at 120hrs. Production of acetic acid was revealed to be greater value in the 10% whey broth than in the 5% whey broth. The production quantity ratio of propionic acid to acetic acid was shown between $2:1\sim3:1$ during the fermentation process.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.297-302
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• 2003

고압증기멸균을 통해서 변형된 키토산을 FT-IR로 분석해 봤을 때, 기존의 키토산의 형태를 유지하고 있음을 알수가 있었고 분자량을 변화 시킨 키토산을 기존의 키토산과 납 흡착실험을 통해서 제거능 비교해 볼 때 15 min > 30 min > 10 min > 5min > 60 min > 0 min 순으로 나타났다 이로써 시간별로 autoclaving처리하여 분자량을 변화시킨 키토산의 제거율이 높음을 알 수가 있었다. 그 중에서도 15 min 동안 autoclaving처리하는 것이 가장 적당한 것으로 알 수가 있었다. 중금속 제거 전후의 키토산을 SAM과 TEM을 통해서 관찰해 보았다. SAM의 경우 autoclaving처리하지 않은 키토산의 표면보다는 autoclaving처리한 키토산의 표면에 보다 많은 기공이 생겨났음을 알 수 있었으며 그로 인해서 납 중금속이 보다 많이 흡착되어 있음을 알 수가 있었다. TEM의 결과로 봤을 때 높은 고압과 온도에 의해서 키토산 고유의 물결무늬가 사라졌음을 알 수가 있었다. 납 중금속이 내부에는 흡착이 이루어지지 않고 외부에 흡착이 이루어 진 것을 볼 수가 있었다.

• Journal of Korean society of Dental Hygiene
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• v.15 no.4
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• pp.713-718
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• 2015

Objectives: The purpose of the study was to investigate the bacterial morphology attached on ultrasonic scaler tips using no cleansing solution, alcohol cotton, liquid chemical disinfecting agent, and autoclave method. Methods: Scaling tip was applied to the mouth and the ultrasonic scaler tips were assigned to four groups. Group 1 was control group with no cleansing solution. Group 2 was treated with alcohol cotton. Group 3 was treated with 2% green Y-Na solution in liquid chemical disinfecting agent, and Group 4 was sterilized by autoclave method. Live bacteria were observed by phase contrast microscopy. The scanning electron microscopy(SEM) revealed the morphological characteristics of scaler surface. The type of attached bacteria were analyzed using SPSS 21.0 program. The data were analyzed by one-way analysis of variance(ANOVA) and Tukey's post-hoc test. Results: The types of sterilization methods had influences on the bacterial viability. The numbers of cocci, bacilli, spiral form bacteria, and filamentous bacteria was observed in $89.00{\pm}3.60%$, $29.67{\pm}3.51%$, $3.33{\pm}0.57%$ and $1.67{\pm}0.57%$ in control group, $31.67{\pm}3.51%$, $63.33{\pm}4.04%$, $2.00{\pm}1.00%$ and $1.67{\pm}0.57%$ in alcohol cotton group, $69.67{\pm}4.50%$, $12.33{\pm}2.51%$, 0% and 0% in liquid chemical disinfecting agent group, and 0.0%, 0.0%, 0.0% and 0.0% in autoclave method group. The clean surface of ultrasonic scaler tip was shown on SEM by autoclave method. Conclusions: The most effective sterilization method of ultrasonic scaler tip was the autoclave method. Autoclave method is the most effective sterilization method and can reduce the cross-infection in the dental clinic.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.8-13
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• 2016

Purpose: The aim of this study was to compare the accuracy of two different styles of mechanical implant torque wrenches before and after sterilization and repeated use. Materials and methods: Thirty new spring-style and friction-style mechanical implant torque wrenches from five different manufacturers were selected as subjects of study and assessed in terms of accuracy. Three manufacturers produced, spring-style (Dio, Neobiotech, Osstem) torque wrenches, and other three manufactures produced friction-style (Dentium, Osstem, Shinhung) torque wrenches. The procedure of target torque measurement was performed 10 times for each device and a digital torque gauge (MGT-12, Mark-10 Corp, USA) was used to record the measurements. All torque wrenches were used repeatedly for 20 times and then sterilized. This whole procedure was repeated 100 times and all torque wrenches were retested. The collected data was analyzed using a SPSS Statistics Analysis program to evaluate the accuracy of the torque wrenches and Mann-Whitney-U test was used for a comparative analysis. Results: After sterilization and repeated use procedure, results did not show any significant difference between error values in the spring-style torque wrench group. However, the results demonstrated an increase in error values within the friction-style torque wrench group (P<.05). Conclusion: There was no difference between the accuracy of new spring-style torque wrenches before and after 100 cycles of sterilization and repeated use (P>.05). There was significant difference between the accuracy of new friction-style torque wrenches before and after 100 cycles of sterilization and repeated use (P<.05). Within the limitation of this study, spring-style torque wrenches were more accurate than friction-style torque wrenches in delivering target torque values.

• Journal of Food Hygiene and Safety
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• v.13 no.1
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• pp.47-52
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• 1998

A rice cultivar (Japonica type), Cheong-cheong, was used to examine the ability as a substrate for aflatoxin production. Brown rice samples were inoculated with Aspergillus parasiticus, stored at various conditions, and observed the production of aflatoxin $B_1$ during storage. Enzyme-linked immunosorbent assay (ELISA) was performed to detect aflatoxin $B_1$ in the samples. A temperature of $28^{\circ}C$ favored the aflatoxin production in the samples. Remoisturizing brown rice to 15.8% encouraged the fungus to produce the aflatoxin significantly (p$B_1$ production in rice, and also indicated that other factors such as husking and storage periods were also risk determinants. This study provided evidence that rice could be an efficient medium for aflatoxin production.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.6-11
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• 2007

This study was carried out to evaluate the growth characteristics of Propionbacterium freudenreichii KCCM 31227 and production of organic acids in whey broth. Bacterial growth and increase rate of TTA (Total Titratible Acidity) were analysed. Log numbers of Propionibacterium freudenreichii KCCM 31227 was at the highest peak at 7.5${\times}10^7$ cfu/ml in fementation of 72 hr in 12% whey broth treated with low temperature long time method (60$^{\circ}C$, 30min) containing 1% yeast extract. TTA value of 12% whey broth treated with low temperature long time method and containing 1% yeast extract showed the highest peak at 5.2 in fermentation of 72 hr. The increase rate of cells and TTA in whey broth revealed almost the same tendency. Production of propionic and acetic acids showed higher value in the whey broth treated with low temperature long time method.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.122-134
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• 2002

목적 : 근관 치료의 최종 목적인 근관계의 영구적인 충전을 위해 사용되는 근관 봉함제는 많은 연구와 개선을 거쳐서 현재는 다양한 성분의 봉함제가 시판되고 있다. 이중에서 레진이 주성분인 봉함제는 조작이 편리하고 흐름성이 좋으며 근관의 벽에 높은 밀폐성을 보이고 충분한 작업시간과 높은 방사선 불투과성을 가지는 장점을 가짐에도 불구하고 높은 초기 생체 독성을 나타내는 단점을 가지고 있다. 본 실험에서는 기존의 상용화된 제품 중 레진이 주성분인 두 종류의 봉함제(AH 26, AH plus)와 산화아연이 주성분인 봉함제(Pulp Canal Sealer EWT)와 국내에서 새로이 개발한 제품으로서 레진이 주성분인 두 종류의 봉함제(Adseal-1,2)를 생체조직에 매식하여 국소적인 반응을 비교하여 생체친화성을 알아보고자 하였다. 방법 : 수종 봉함제의 생체 친화성을 알아보기 위하여 64마리의 Sprague-Dawley rat을 사용하였다. 봉함제의 피하조직 매식을 위해 길이와 직경이 각각 5와 1.5mm인 폴리에틸렌 테프론 관을 사용하였으며 이를 에탄올과 증류수로 세척 한 후 고압증기멸균을 시행하였다. Rat에 대하여 케타민으로 복강내 마취를 시행한 후 배부를 면도하고 iodine으로 소독한 다음 네 곳에 절개를 시행하였으며 blunt dissection을 통해 깊이 10mm이상의 피하조직 pocket을 형성하였다. 각각의 봉함제를 제조사의 지시 에 따라 혼합 후 즉시 멸균된 테프론 관에 주사기를 이용하여 담은 다음에 봉함제가 흐르지 않게 유의하며 pocket내로 삽입하였으며 이때 16개의 관을 대조군으로 사용하기 위해 봉함제를 넣지 않은 상태로 삽입하였다. 이 후 절개 부위를 surgical gut suture로 봉합하였으며 1주일 후에 발사하였다. Rat을 1, 2, 4, 12주 후에 각 군 당 세 마리 씩 에테르 흡입을 통해 희생하였으며 이 때 한 마리씩의 대조군도 포함시켰다. 이 후 매식된 관을 주위 조직과 함께 제거하고 포르말린에서 48시간 고정시킨 후 파라핀에 포매한 다음에 micro-tome을 사용하여 6$\mu\textrm{m}$로 serial section을 시행하였다. 정중선 부위의 시편에 Hematoxylin-Eosin staining을 시행한 후 Olsson, Orstavik 그리고 Mjor 등의 방법에 따라 조직학적 변화를 관찰한 후 slight(1), moderate(2), severe inflammation(3)의 단계로 분류하였다. 얻어진 결과를 통계처리 프로그램인 Jandel사의 Sigmastat을 이용하여 Kruskal Wallis Test로 통계처리를 하였다. 결과 : (Table omitted) 결론 : 1) Pulp Canal Sealer를 제외한 모든 군에서 시간이 지남에 따라 유의성 있게 염증이 감소되는 양상을 보였다(p<0.05). 2) Pulp Canal Sealer는 1주, 2주, 12주에서 강한 염증반응을 보였다. 3) AH 26과 AH Plus에서는 1주, 2주에서 강한 염증반응을 보였으나 12주에서는 염증반응이 감소하였다. 4) 새로 개발된 봉함제 Adseal-1,2는 1주, 2주에서는 가장 약한 염증반응을 보이나 4주, 12주 후에는 AH Plus와 비슷한 수준의 염증 반응을 보였다. 5) Pulp Canal Sealer를 제외한 모든 군에서 인정할 만한 생체친화성을 보였다. 6) Adseal-2가 Adseal-1에 비하여 전반적으로 낮은 염증반응을 보였다. 7) 각 군간 결과의 차이에 통계적 유의성은 없었다(p>0.05).