• 대한치과보철학회지
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• 제36권6호
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• pp.832-845
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• 1998

The purpose of this study was to compare the marginal fit of all ceramic crowns prepared from alumina slip casting, which is consistent with the conventional In-ceram system, and those fabricated from alumina tapes which is currently under development in an effort to alleviate complexities involved in the forming procedure of the In-ceram crown core. All ceramic crowns, made of In-ceram(slip casting) and alumina tapes(Doctor blade casting), were prepared with $90^{\circ}\;and\;135^{\circ}$ shoulder margins. The crowns were cemented with a glass ionomer cement and embeded in epoxy resin. The embedded crowns were sectioned faciolingually and mesiodistally and marginal discrepancies and marginal gaps were measured under the Measurescope MM II. The measurements were analyzed using Wilcoxon rank sum test and Kruskal-Wallis test and the results were as follows: 1. In the case of $90^{\circ}$ shoulder margin, the combined marginal discrepancies and marginal gaps were $78.3{\mu}m\;and\;44.4{\mu}m$ respectively, for the all ceramic crowns fabricated using the alumina tapes. In comparison, the values were $65{\mu}m\;and\;25.5{\mu}m$ for the In-ceram crowns. For the marginal gaps a statistical difference existed (p<0.05) but no significant difference was observed for the marginal discrepancy (p>0.05). 2. In the case of $135^{\circ}$ shoulder margin, the combined marginal discrepancy and marginal gaps were $82.1{\mu}m\;and\;40.2{\mu}m$ respectively, for the all ceramic crowns formed with the tapes. As compared with the marginal discrepancy and gaps of the $90^{\circ}$ shoulder margin in the fabricated from the alumina tapes, no significant statistical differencies were discerned in both cases (p>0.05). 3. There was no statistically significant difference in the fits among four locations around the margins of the all ceramic crowns fabricated using the alumina tapes. The results obtained in this study showed that the marginal fits of the glass infiltrated alumina cores fabricated from the alumina tapes are slightly higher value than those prepared using the In-ceram but the difference is within a clinically acceptable range.

• Journal of Korean Biological Nursing Science
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• 제4권2호
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• pp.19-40
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• 2002

The purpose of this study was to determine the effect of DHEA on Type I(soleus) and II muscles(plantaris, gastrocnemius) in a focal brain ischemia model rat. Thirty-seven male Sprague-Dawley rats with $200{\sim}250g$ body weights were randomly divided into four groups : CINS(cerebral ischemia + normal saline), CIDH(cerebral ischemia + DHEA), SHNS(sham + normal saline), SHDH (sham + DHEA). Both the CINS and CIDH groups were undergone a transient right middle cerebral artery occlusion operation. In the SHNS and SHDH groups, a sham operation was done. DHEA was administered daily at a dose of 0.34mmol/kg, and normal saline was administered daily at the same dose by intraperitoneal injection for 7days after operation. Cerebral infarction in the CINS and CIDH groups was identified by staining with 2% triphenyltetrazolium chloride solution for 60 minutes. The data were analyzed by Kruskal-Wallis test and Mann-Whitney U test using the SPSSWIN 9.0 program. The results were summarized as follows: 1) The muscle weights of soleus(Type I), plantaris and gastrocnemius(Type II) in CINS group were significantly less than those of the SHNS group(p<.01). The muscle fiber cross-sectional area of the CINS group was significantly less than that of the SHNS group in Type I muscle fiber of the soleus and Type II muscle fiber of the plantaris and gastrocnemius(p<.05). The myofibrillar protein content of the CINS group was significantly less than that of the SHNS group in the left gastrocnemius and right soleus(p<.05). 2) The muscle weights of the soleus, plantaris and gastrocnemius except the unaffected side of the plantaris in the CIDH significantly increased compared to those of the CINS group(p<.05). The muscle fiber cross-sectional area of the CIDH group significantly increased compared to that of the CINS group in Type II muscle fiber of the plantaris and gastrocnemius(p<.05). The myofibrillar protein content of the CIDH group significantly increased compared to that of the CINS group in the left soleus(p<.05). 3) On the post-op 8 day, the body weight of the CINS group was significantly less than that of the CIDH, SHNS and SHDH groups(p<.01). Total diet intake of the CINS and CIDH groups was significantly less than that of the SHNS and SHDH groups(p<.01). Based on these results, it was identified that muscle atrophy could be induced during the 7 days after cerebral infarction, and DHEA administration during the early stage of cerebral infarction might attenuate muscle atrophy.

• The Journal of Advanced Prosthodontics
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• 제9권4호
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• pp.244-251
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• 2017

PURPOSE. The purpose of this study was to determine fracture resistance and failure modes of three-unit fixed dental prostheses (FDPs) made of lithium disilicate pressed on zirconia (LZ), monolithic lithium disilicate (ML), and monolithic zirconia (MZ). MATERIALS AND METHODS. Co-Cr alloy three-unit metal FDPs model with maxillary first premolar and first molar abutments was fabricated. Three different FDPs groups, LZ, ML, and MZ, were prepared (n = 5 per group). The three-unit FDPs designs were identical for all specimens and cemented with resin cement on the prepared metal model. The region of pontic in FDPs was given 50,000 times of cyclic preloading at 2 Hz via dental chewing simulator and received a static load until fracture with universal testing machine fixed at $10^{\circ}$. The fracture resistance and mode of failure were recorded. Statistical analyses were performed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni's correction (${\alpha}=0.05/3=0.017$). RESULTS. A significant difference in fracture resistance was found between LZ ($4943.87{\pm}1243.70N$) and ML ($2872.61{\pm}658.78N$) groups, as well as between ML and MZ ($4948.02{\pm}974.51N$) groups (P<.05), but no significant difference was found between LZ and MZ groups (P>.05). With regard to fracture pattern, there were three cases of veneer chipping and two interfacial fractures in LZ group, and complete fracture was observed in all the specimens of ML and MZ groups. CONCLUSION. Compared to monolithic lithium disilicate FDPs, monolithic zirconia FDPs and lithium disilicate glass ceramics pressed on zirconia-based FDPs showed superior fracture resistance while they manifested comparable fracture resistances.

• 대한소아치과학회지
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• 제40권3호
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• pp.177-184
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• 2013

수산화칼슘 근관충전제는 뛰어난 항균작용과 낮은 세포독성으로 우수한 유치 근관충전제로 평가되고 있다. 하지만 수산화칼슘을 근관 내 장기간 적용할 경우 치근 상아질에 미치는 부정적인 영향이 논의되고 있으며 많은 연구에서 영구치 근관에 수산화칼슘을 적용 후 상아질 경도의 감소가 확인되었다. 본 연구에서는 수산화칼슘 제제의 적용 기간에 따라 유치 치근 상아질의 미세경도를 측정하여, 수산화칼슘의 적용이 유치 치근 상아질의 미세경도에 미치는 영향을 평가하고자 하였다. 생리적 치근 흡수가 1/3이상 진행되지 않은 시기에 발거된 60개의 상악 유전치를 각각 20개 씩 대조군, 수산화칼슘과 요오드포름의 혼합제제(Vitapex, Neodent., Japan), 수산화칼슘과 증류수의 혼합제제를 적용하는 3개의 군으로 분류하였다. 각 치아는 같은 과정의 치수 절제술을 시행한 후 교정용 레진에 매몰하여 군당 5개 치아를 배정하고 24시간, 7일, 30일, 90일 후 치근 중앙부에서 2 mm 두께의 시편을 획득하여 비커스 미세경도 측정기를 통해 미세경도를 측정하였다. 측정된 미세경도 값은 Kruskal-Wallis test로 변수 간의 상호관계를 확인하였으며 사후 검정으로 Mann-Whitney test를 시행하였다. 시간에 따른 미세경도 값의 감소량은 선형 회귀분석을 통해 추이를 분석하였다. 수산화칼슘 근관 충전제가 유치의 치근 상아질의 미세경도에 미치는 영향을 조사한 결과, 다음과 같은 결론을 얻을 수 있었다. 수산화칼슘 근관 충전제를 유치의 근관에 적용 시 기간에 따라 치근상아 질의 미세경도가 감소하였으며, 이는 통계적으로 유의하였다(p < 0.05). 수산화칼슘과 요오드화포름의 혼합제제에 비해 수산화칼슘을 증류수에 혼합하여 적용한 경우 유치 치근상아질의 미세경도가 더 급격하게 감소하였으며, 이는 통계적으로 유의하였다(p < 0.05). 수산화칼슘을 적용하지 않은 대조군에서도 7일, 30일, 90일 후 기간에 따라 치근상아질의 미세경도가 감소하였으며, 이는 통계적으로 유의하였다(p < 0.05).

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5705-5711
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• 2013

Background: Embryonic stem cells (ESCs) have the potential to form teratomas when implanted into immunodeficient mice, but data in immunocompetent mice are limited. We therefore investigated teratoma formation after implantation of three different mouse ESC (mESC) lines into immunocompetent mice. Materials and Methods: BALB/c mice were injected with three highly germline competent mESCs (129Sv, BALB/c and C57BL/6) subcutaneously or under the kidney capsule. After 4 weeks, mice were euthanized and examined histologically for teratoma development. The incidence, size and composition of teratomas were compared using Pearson Chi-square, t-test for dependent variables, one-way analysis of variance and the nonparametric Kruskal-Wallis analysis of variance and median test. Results: Teratomas developed from all three cell lines. The incidence of formation was significantly higher under the kidney capsule compared to subcutaneous site and occurred in both allogeneic and syngeneic mice. Overall, the size of teratoma was largest with the 129Sv cell line and under the kidney capsule. Diverse embryonic stem cell-derived tissues, belonging to the three embryonic germ layers, were encountered, reflecting the pluripotency of embryonic stem cells. Most commonly represented tissues were nervous tissue, keratinizing stratified squamous epithelium (ectoderm), smooth muscle, striated muscle, cartilage, bone (mesoderm), and glandular tissue in the form of gut- and respiratory-like epithelia (endoderm). Conclusions: ESCs can form teratomas in immunocompetent mice and, therefore, removal of undifferentiated ESC is a pre-requisite for a safe use of ESC in cell-based therapies. In addition the genetic relationship of the origin of the cell lines to the ability to transplant plays a major role.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1943-1948
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• 2012

Introduction: Prostate cancer in Indonesia is the $3^{rd}$ ranking cancer among males and the $5^{th}$ rank for their cancer mortality. Prognostic markers that can identify aggressive prostate cancer in early stages and help select appropriate therapy to finally reduce the mortality are therefore urgently needed. It has been suggested that stem cells in the prostate gland have a role in initiation, progression, and metastasis of cancer, although controversy continues to exist. Maintenance of normal stem cell or reserve cell populations in several epithelia including prostate has been shown to be regulated by p63 and alteration of p63 expression is considered to have an oncogenic role in prostate cancer. We hypothesize that the expression of cytoplasmic aberrance of p63 is associated with high ALDH1A1 expression as a cancer stem cell marker, thus leading to progression of prostate cancer. Methods: Using a cross-sectional study during two years (2009-2010), a total of 79 paraffin embedded tissues of benign prostatic hyperplasia, PIN prostatic intraepithelial neoplasia, low and high Gleason score prostate cancer were investigated using immunohistochemistry. Associations between cytoplasmic p63 and ALDH1A1, as well as with pathological diagnosis, were analyzed by Chi-Square test using SPSS 15.0. Links of both markers with cell proliferation rate (KI-67) and apoptotic rate (cleaved caspase 3) were also analyzed by Kruskal-Wallis test. Results: The mean age of patient at the diagnosis is 70.0 years. Cytoplasmic aberrance of p63 was associated with ALDH1A1 expression (p<0.001) and both were found to have significant relationships with pathological diagnosis (including Gleason score), (p=0.006 and p<0.001 respectively). Moreover, it was also found that higher levels of cytoplasmic p63 were significantly associated with the frequency of proliferating cells and cells undergoing apoptosis in prostate cancers (p=0.001 and p=0.016 respectively). Conclusion: p63 cytoplasmic aberrance is associated with high ALDH1A1 expression. These components are suggested to have an important role in prostate cancer progression and may be used as molecular markers.

• Restorative Dentistry and Endodontics
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• 제27권5호
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• pp.535-542
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• 2002

The purpose of this study was to evaluate the effect of EDTA irrigant according to application time and temperature. 31 human mature extracted teeth with a single canal were sectioned with microtome in 3mm thickness and gained 62 samples of root canals. They were distributed randomly into 6 groups of 10 specimens each and control group of 2 specimens. Each specimen was prepared with GT rotary file (Dentsply, Maillefer Co., Swiss) and irrigated with 3 ml sodium hypochlorite every minute. Then smear layer was removed with EDTA solution (PULPDENT$^{\circledR}$, PULPDENT Co., USA.) except two control specimens. Specimens of each group were irrigated with 17% EDTA. The time and temperature of application were as follows : (Table omitted) All specimens were split longitudinally and prepared for examination by scanning electron microscopy. A set of reference micrographs was used to award a debris score as follows: 0 = no smear layer, all tubules clean and open; 1 = no superficial smear layer, tubule openings visible, but some contain debris plug or soft tissue remnants: 2 = moderate smear layer, some tubules open and others closed; 3 = heavy smear layer, most/all tubule openings obscured. Results were evaluated with Kruskal-Wallis test to determine whether there was statistically significant difference among six groups. Pairs of groups were analyzed using the Student-Newman-Keuls Method and Mann-Whitney test. The results were as follows : 1. Control specimens showed heavy smear layer at the canal walls 2. Among the groups applied with EDTA for 2 minutes, group 1 showed the heaviest smear layer, and there was statistically significant difference between group 1 and the other groups(p<0.05). 3. Among the groups applied with EDTA for 5 minutes, group 4 and group 6 showed smear layer but there was no significant difference between them. 4. Among the groups applied with EDTA for the same temperature, group 1 showed heavier smear layer than group 4, and there was statistically significant difference(p<0.05). 5. Among the groups applied with EDTA for the same temperature, group 2 showed heavier smear layer than group 5 and group 3 showed heavier smear layer than group 6. But there was no statistically significant difference among them. From the results above, it could be concluded, EDTA solution is effective in removing of smear layer when it is applied for 5 minutes. If EDTA is applied for 2 minutes, it should be applied above room temperature.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.44-53
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• 2002

목적 : 최근 개발된 bonding agent 중 일부는 다양한 함량의 filler를 포함하고 있으며 filler의 첨가는 bonding agent의 기계적인 물성을 향상시킴으로써 접착력의 향상에 기여한다는 주장이 있다. 본 연구에서는 다양한 함량의 filler를 포함한 adhesive를 실험적으로 만들어, filler의 함량이 전단접착강도에 미치는 영향을 살펴보고 임상적으로 가장 적절한 filler의 함량을 알아보고자 하였다. 또 adhesive의 간접인장강도를 측정하여 adhesive의 기계적인 물성과 접착력과의 상관관계를 알아보았다. 방법 : 발거된 건전한 70개의 대구치를 투명 레진에 매몰하고 상아질면을 노출시켰다. 3M사의 Scotchbond Multipurpose의 etchant와 primer를 제조사의 지시대로 적용하고 1$\mu\textrm{m}$크기의 barium glass filler를 0, 5, 10, 15, 20, 30, 45wt% 포함하도록 실험적으로 제작한 adhesive를 도포한 후 레진을 충전하여 시편을 완성하였다. Instron으로 0.5mm/min의 속도에서 전단접착강도를 측정하고 그 단면을 입체현미경으로 관찰하여 파절의 양상을 확인하였다. Filler함량에 따른 adhesive의 후경을 측정하기 위해 상기한 방법으로 시편을 제작하여 주사 전자현미경으로 관찰한 후 Sigmascan을 이용하여 그 후경을 측정하였다. 또, 지름 4mm 높이 6mm의 원통형 시편을 제작하여 Instron로 간접인장강도의 측정을 시행하였다. 얻어진 결과는 Kruskal-Wallis test와 Mann-Whitney test를 시행하여 분석하였으며, 상관관계를 분석을 위해 Pearson Product Moment Correlation Coefficient를 구하였다. 결과 : 1) Filler함유량에 따라 전단접착강도는 유의할 만한 차이를 보였다(p<0.05). 2) Filler함량의 증가에 따라 전단접착강도는 유의하게 증가하여 15% 수준에서 가장 높은 갈(19.9$\pm$1.38Mpa)을 보였으며 20% 이상의 수준에서는 유의하게 감소하였다(p<0.05). 3) Adhesive의 간접인장강도는 20% 수준까지는 증가하는 양상을 보였으나 통계적 유의성은 없었으며(p>0.05), 30% 이상에서는 유의할 만한 감소를 보였다(p<0.05). 4) Adhesive의 후경은 0% 수준에서 5.97$\pm$1.23$\mu\textrm{m}$부터 45%수준에서 73.37$\pm$11.7$\mu\textrm{m}$까지 유의하게 증가하였다(p<0.05). 5) Filler함량에 따른 Adhesive의 간접인장강도와 전단접착강도는 상관관계가 없었다.

• 한국산업보건학회지
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• 제26권3호
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• pp.324-333
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• 2016

Objectives: We aimed to compare the sampling performance of different flow-based impactor samplers for collecting fungal spores and bacteria and to explore the association of the level of bioaerosols with activity patterns of occupants in daycare center settings. Methods: For comparison of sampling performance, two different flow-based samplers (greater than 100 L/min or not) were selected; a low flow-based sampler (one-stage Andersen sampler) and two high flow-based samplers (DUO SAS SUPER 360 sampler, BUCK bio-culture sampler). We collected airborne mold and bacteria in 30 daycare centers with various levels of contaminated air. Three repeat samplings per each sampler were performed. Mold and bacteria were grown for 96 hours at $25{\pm}1^{\circ}C$ and 48 hours at $35{\pm}1^{\circ}C$, respectively. The Andersen and SAS samplers were used for investigating the association between the level of bioaerosols and the activity patterns of occupants in daycares. Particular matters 10($PM_{10}$), temperature, and relative humidity were monitored as well. Samplings were carried out with one-hour interval from 9 to 5 O'clock. For statistical comparisons, Kruskal-Wallis test, Wilcoxon's signed rank test, and multiple regression analysis were carried out. Results: The airborne level of molds by the low flow-based sampler were significantly higher than that of high flow-based samplers (indoor, P=0.037; outdoor, P=0.041). However, no statistical difference was observed in the airborne level of bacteria by each sampler. Also the level of bioaerosols varied by the time, particularly with different activity patterns in daycare centers. The higher level of mold and bacteria were observed in play time in indoor. Similarly, the concentrations of $PM_{10}$ were significantly associated with the level of bioaerosols (P<0.05). Conclusions: Our findings indicate that the flow rate of sampler, rather than total air volume, could be able to affect the results of sampling. Also, the level of airborne mold and bacteria vary behavior patterns of occupants in indoor of daycare settings. Therefore, different samplers with other flow rate may be selected for mold or bacteria sampling, and activity patterns should be considered for bioaerosol sampling as well.

• Restorative Dentistry and Endodontics
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• 제28권1호
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• pp.1-10
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• 2003

This study investigated the influence of IRM on marginal microleakage of 5th generation adhesives. Class V cavities with gingival margins in dentin were prepared on both buccal and lingual surfaces of 60 extract-ed human molar teeth. Prepared teeth were randomly divided into six groups. Group 1 and 4 received no temporary restoration with IRM. Group 2 and 5 were covered with IRM mixed at P/L ratio(10g/1g). Group 3 and 6 were covered with IRM mixed at P/L ratio(10g/2g). The temporary restorations were removed mechanically with an ultrasonic scaler after one-week storage in distilled water. The cavities were restored using one of two adhesives and composites ; Single Bond/Filtek Z 250(Croup 1, 2 and 3), UniFil Bond/UniFil F(Group 4, 5 and 6). Following one day storage in distilled water, the restored teeth were thermocycled for 500 cycles(between $5^{\circ}C{\;}and{\;}55^{\circ}C$) and immersed in 2 % methylene blue for dye penetration testing. The results were analysed using Kruskal-Wallis Test, Mann-Whitney and Wilcoxon signed ranked test at a significance level of 0.05. The results of this study were as follows 1. Ranking of mean microleakage scores at the enamel margins was Group 10.05) 4. At the dentin margins, the microleakage of the group not pretreated with IRM was lower than that of the group pretreated with IRM. And the microleakage of UniFil Bond was lower than that of Single Bond. 5. Compared with microleakages between the enamel and dentin margins of each groups, Group 1, 2, 3, 4, 5 and 6 at dentin margin were higher microleakage than those at enamel margin. There were significant difference between enamel and dentin microleakage of Group 2 and 3(p<0.05).