• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.172-179
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• 2014

Objectives: This study aimed to assess the effect of 38% carbamide peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites. Materials and Methods: A total of 96 class V cavities were prepared on the buccal surface of extracted human teeth with both enamel and dentin margins and were randomly assigned into three groups of Filtek P90 (3M-ESPE) + P90 system adhesive (3M-ESPE)(group A), Filtek Z250 (3M-ESPE) + Adper Prompt L-Pop (3M-ESPE)(group B) and Filtek Z350XT (3M-ESPE) + Adper Prompt L-Pop (group C). Half of the teeth were randomly underwent bleaching (38% carbamide peroxide, Day White, Discus Dental, applying for 15 min, twice a day for 14 day) while the remaining half (control) were not bleached. Dye penetration was measured following immersion in basic fuchsine. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at a level of 0.05. Results: No significant differences were found between composites in the control groups in enamel (p = 0.171) or dentin (p = 0.094) margins. After bleaching, microleakage of Z250 (in enamel [p = 0.867] or dentin [p = 0.590] margins) and Z350 (in enamel [p = 0.445] or dentin [p = 0.591]margins) did not change significantly, but the microleakage of P90 significantly increased in both enamel (p = 0.042) and dentin (p = 0.002) margins. Conclusions: No significant differences were noted between the bleached and control subgroups of two methacrylate-based composites in enamel or dentin margins. Microleakage of silorane-based composite significantly increased after bleaching.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.749-752
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• 1988

In this paper, the delay margins of the LQ and the LQG regulators are obtained in the time domain. These margins are represented in terms of the singular values of system matrices and the solutions of a Riccati equation and a Lyapunov one. And their asymptotical properties when gains tend to infinity are investigated.

• Korean Journal of Radiology
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• 제20권6호
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• pp.999-1000
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• 2019

• Journal of Ecology and Environment
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• 제32권1호
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• pp.61-65
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• 2009

We compared two nondestructive methods for leaf area estimation using leaves of 16 common plant species classified into six types depending on leaf shape. Relatively good linear relationships between actual leaf area (LA) and leaf length (L), width (W), or the product of length and width (LW) were found for ordinary leaves with lanceolate, oblanceolate, linear and sagitttate shapes with entire margins, serrate margins, mixed margins with a entire form and shallow lobes, and ordinary incised margins. LA was better correlated with LW than L or W, with $R^2$ > 0.91. However, for deeply incised lobes, LA estimation using LW showed low correlation coefficient values, indicating low accuracy. On the other hand, a method using photographic paper showed a good correlation between estimates of area based on the mass of a cut-out leaf image on a photographic sheet (PW) and actual leaf area for all types of leaf shape. Thus, the PW method for LA estimation can be applied to all shapes of leaf with high accuracy. The PW method takes a little more time and has a higher cost than leaf estimation methods using LW based on leaf dimensions. These results indicate that researchers should choose their nondestructive LA estimation method according to their research goals.

• 대한소아치과학회지
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• 제3권1호
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• pp.33-39
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• 1976

The present in vitro study was undertaken to evaluate the initial marginal sealing ability of the sealant known as Nuva-Seal to seal cavity margins when used in conjunction with Adaptic and Nuva-Fil restorative materials. The results were as follows; 1. Where each Adaptic and Nuva-Fil restorative material was filled, showed the greatest degree of marginal leakage. 2. Where Adaptic and Nuva-Fil restorative materials were filled after acid etched surrrounding enamel surface adjoining the cavity margins, showed some degree of marginal leakage. 3. Where the Nuva-Seal was applied after acid etching a) to the cavity walls and the peripheral enamel surface adjoining the cavity margins, b) only to the surrounding enamel surface adjoining the cavity margins, and c) over the restorations and the peripheral enamel surface, showed complete absence of marginal leakage of Adaptic and Nuva-Fil restorative materials. 4. Where the Nuva-Seal was applied with the same methods as above, and restorations were placed on thermal stress also showed complete absence of marginal leakage of Adaptic and Nuva-Fil restorative materials.

• 대한치과보철학회지
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• 제41권1호
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• pp.20-34
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• 2003

Novel methods producing supplementary and prosthetic material by cutting or discharge processing via computer design have been proposed as alternatives for traditional casting methods and are being utilized for commercial purposes. The CAD/CAM system used in dentistry can be classified into three-dimensional input of target values, restoration design, and material processing. The marginal fidelity in production of In-Ceram core has important clinical implications and is a key consideration issue in CAD/CAM production as well. Through this research, the author arrived at the following conclusion aaer conducting comparison analysis of marginal fidelities between the In-Ceram core produced via CAD/CAM and that produced through the traditional method ; 1. In the cases of mesial, distal, and lingual margins, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 2. In the case of labial flange, the core margins via CAD/CAM produced lower values than those via the traditional method and the differences were found to be statistically significant. (p<0.05) 3. In comparision with overall marginal fidelity, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 4. Among the core margins produced via the traditional method did not have statistically significant differences but fir those produced via CAD/CAM had statistically significant differences between labial and lingual sides and between labial and mesial sides. (p <0.05).

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.261-274
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• 1995

This study aimed to evaluate the marginal microleakage of Class V cavities of All-bond 2 (Wet - bonding system), Gluma (Adhesion of resin to exposed collagen fibers), and Scotchbond Multi-purpose(Mild Etching System). Hundred extracted human teeth divided into a control and three experimental groups consisting of eight teeth. The experimental group was further subdivided into All- bond2, Gluma and Scotchbond MP groups, Vitrebond served as the control. The positive control group consisted of specimens filled with resin and with no etching, primer and bonding procesure. Polished specimens underwent temperature changed from $5^{\circ}C$ to $55^{\circ}C$ a thousand times. After thermocycling, speciemens were placed in 2 % methylene blue dye solution for 24 hours in an incubator set at $37^{\circ}C$. The teeth were sectioned buccolingually and the degree of dye penetration was observed with a stereomicroscoped(*20). The following results were obtained. 1. Both the control and the experimental group showed a lower degree of dye penetration on enamel than on dentin margins(p<0.05) 2. Gluma exhibited a statistically significant lower degree of dye penetration than All-bond 2 on enamel margins(p<0.05) Scotchbond MP also exhibited a lower degree of dye penetration than All-bone 2 but was no statistically significant. Gluma and Scotchbond MP exhibited a similar degree of dye penetration. 3. The degree of dye penetration of All-bond 2, Gluma and Scotch bond MP showed no statistically singnificance on enamel margins but was significantly lower than in the control using Vitrebond. 4. All-bond 2 exhibited a statistically significant lower degree of dye penetration than Gluma on dentin margins. All- bond 2 and Scotchbond MP showed a similar degree of dye penetration. 5. The degree of dye penetration of All-bond 2, Gluma and Scotchbond MP showed no statistically significance on dentin margins. There was neither a statistical significance with the control.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.349-360
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• 2020

The study aims to empirically examine the determinants of bank margins from Pakistan, an emerging South Asian economy. To elucidate the importance of the Pakistani banking sector, secondary data has been used, which was extracted from the annual accounts of twenty-four Pakistani scheduled commercial banks (20 conventional, four full-fledged Islamic) over a sample period of 2006 to 2017. The factors identified in the dealership model and the subsequent empirical developments in the dealership model categorized as bank-specific, diversification, regulatory, and industry concentration are analyzed by applying the most-common linear dynamic panel-data estimator, the Generalized Method of Moments (GMM) estimator, developed by Arellano and Bond (1991). The findings reveal that, among the bank-specific variables, funding cost, credit risk, managerial efficiency, market share, and operating cost are significant predictors of bank margins. For diversification variables employed in the study, both variables including net non-interest income and asset diversity are as well significant predictors of bank margins. It is also found that the market concentration variable proxied by the Herfindahl-Hirschman Index (HHI) is significantly predicting bank margins. Subsequently, one of the regulatory variables, the opportunity cost of holding reserves, and one bank-specific variable, the degree of risk aversion, are insignificant in the model.

• Restorative Dentistry and Endodontics
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• 제14권2호
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• pp.5-19
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• 1989

The purpose of this study was to observe the microleakage of composite resin filling using several glass ionomer cements. The Class V cavities of eighty noncarious human molars were prepared at the cementoenamel juction on the facial and lingual surfaces of each tooth with a No.330 carbide bur in a high speed handpiece. The cavity dimensions were $3.0{\pm}0.5mm$ wide, $2.0{\pm}0.5mm$ high, and $1.5{\pm}0.5mm$ deep and all enamel cavosurface margins were beveled with a No.558 carbide bur in low speed handpiece. The bevel was approximately $45^{\circ}$ and 0.5-1.0mm in width. A total of the 160 cavities was divided into four groups, and then 144 cavities among them were three experimental groups and remaining sixteen cavities were control group. All of the prepared cavities were restored as follows: group 1 : Preparations were restored with there three glass ionomer cements. group 2 : Preparations were restored with a composite resin with three glass ionomer cement bases placed $0.2{\pm}0.1mm$ short of the cavosurface margin. group 3 : Preparations were restored with a composite resin with three glass ionomer cement bases extened to the cavosurface margin. group 4 : As control group, preparations were restored with a composite resin, PALFIQUE. The specimens were then thermocycled in a range of $6^{\circ}C-60^{\circ}C$ and immersed in a bath of 2.0% aqueous basic fuchsin solution for 24 hours. Dye penetration was read on a scale of 0 to 4 by Tani and Buonocore's method. The following conclusions were derived from the results obtained; 1. All groups showed significantly more leakage at the gingival margins than at the occlusal margins(p<0.0005). 2. At the gingival margins, group 1 showed less leakage than group 3(p<0.01) and group 4(p<0.0005), while group 3 exhibited less leakage than group 2(p<0.01) and group 4(p<0.0005). 3. At the occlusal margins, group 4 showed less leakage than group 3(p<0.1) and group 1(p<0.005), while group 3 exhibited less leakage than group 2(p>0.1) and group 1(p<0.025).

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.702-709
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• 1997

To compare the marginal leakage of CAD/CAM-fabricated ceramic inlay, gold inlay and amalgam, forty extracted caries-free premolars were prepared with Class II MO cavity design. The teeth were divided into four groups of ten samples each. Group 1 was restored with CAD/CAM-fabricated ceramic inlays cemented with Scotchbond Resin Cement / Scotchbond Multi-purpose plus. Group 2 was restored with gold inlays cemented with Scotchbond Resin Cement / Scotchbond Multi-purpose plus. Group 3 was restored with gold inlays cemented with zinc phosphate cement. And, Group 4 was restored with amalgam. All samples were thermocycled, and stored in 1 % methylene blue. Marginal leakage was examined at four margins, that is, occlusal distal, priximal gingival, occlusal facial and occlusal lingual margins from sectioned samples under stereomicroscope(x15). The results were as follows : 1. Group 1 and 2 showed no statistically significant difference among marginal leakage at all four examined margins(p>0.05). 2. Group 3 and 4 showed significant marginal leakage at proximal gingival margin compared with other margins(p<0.05). 3. Significantly increased marginal leakage at priximal gingival, occlusal facial and occlusal lingual margins in group 3 were observed compared with other groups (p<0.05).