• Restorative Dentistry and Endodontics
• /
• v.12 no.1
• /
• pp.107-116
• /
• 1986

The primary aim of this study was to assess the effects of the margin designs and composite resins on the marginal leakage of Class V resin restorations. 60 Class V cavities with $90^{\circ}$ butt joint, 60 with $45^{\circ}$ bevel joint, and 60 with concave joint were prepared on the labial surfaces of 38 extracted anterior teeth and the buccal and lingual surfaces of 71 premolars, and classified as the butt group, bevel group and concave group, respectively. After completion of the cavity preparation, Heliosit${(R)}$ was filled in 20 butt joint cavities, 20 bevel joint cavities, and 20 concave cavities. And Hi-Pol$^{(R)}$ and Palfique$^{(R)}$ were filled in the same manner, respectively. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$, $37^{\circ}C$, and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours, and buccolingually sectioned with sectioning machine. The sectioned specimens were examined under the light microscope. The results indicated the following: 1. The bevel group showed the least amount of marginal leakage compared with the other two design groups, but the statistical analysis showed no significant difference at the 95% confidence level. 2. Hi-Pol$^{(R)}$ group showed the most severe marginal leakage compared with the other composite resin materials, but there was no significant difference in the groups. 3. The bevel-Heliosit$^{(R)}$ subgroup, which was filled with Heliosit$^{(R)}$ in the beveled cavities, showed the least amount of marginal leakage, but there was no significance in all the subgroups.

• Restorative Dentistry and Endodontics
• /
• v.37 no.1
• /
• pp.41-49
• /
• 2012

Objectives: The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.3
• /
• pp.61-71
• /
• 2018

The purpose of this study is to analyze the efficiencies of project management offices in large information system construction projects using the data envelopment analysis. In addition, we tried to estimate the confidence interval of those efficiencies using bootstrap DEA to give a statistical meaning. The efficiency by the CCR model is analyzed as eight project management offices are fully efficient and 22 project management offices are inefficient. On the other hand, there are 15 project management offices are fully efficient, but 15 project management offices are inefficient in the BCC model. As the result of the scale efficiencies, of the inefficient project management offices, 13 project management offices are inefficient in scale. It is possible to eliminate the inefficiency in the CCR model by improving their project performances. And, the nine project management offices showed that the inefficiency was due to pure technical efficiency, and these companies should look for various improvements such as improvement of project execution system and project management process. In order that the inefficient project management offices be efficient, it is analyzed that more efforts must be made for on-budget and on-time as a result of examining the potential improvement potentials of inefficient project management offices.

• YAKHAK HOEJI
• /
• v.46 no.4
• /
• pp.290-294
• /
• 2002

Cephradine is an orally absorbed cephalosporin with a broad spectrum of activity against gram-positive and gram-negative bacteria and is highly resistant to beta-lactamase degradation. The purpose of the present study was to evaluate the bioequivalence of two cephradine capules, Cephradine capsule (Donggu Pharmaceutical Co., reference drug) and Cephradine capsule (Shinpoong Pharmaceutical Co., test drug), according to the guidelines of Korea Food and Drug Administration. Twenty-six normal volunteers, 24.6 $\pm$ 3.70 years in age and 62.4 $\pm$ 8.99 kg in body weight, were divided into two groups and a randomized 2 $\times$ 2 cross-over study was employed. After one capsule containing 250 mg of cephrdine was orally administered, blood was taken at predetermined time intervals and the concentrations of cephrdine in serum were determined using HPLC with UV detector. The pharmacokinetic parameters such as AU $C_{t}$ to $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters. The results showed that the differences in AUCt, $C_{max}$ and $T_{max}$ between two products were 2.89％, 1.05％ and 1.06％, respectively, when calculated against the reference drug. The 90％ confidence intervals were within log0.8 $\leq$ $\delta$ $\leq$ log1.25 (e.g., log0.9803 $\leq$ $\delta$ $\leq$ log1.0734 and log0.9674 $\leq$ $\delta$ $\leq$ log1.220 for AU $C_{t}$, and $C_{max}$, respectively). Two parameters met the criteria of KFDA for bioequivalence, indicating that Cephradine capsules (Shinpoong Pharmaceutical Co.) is bioequivalent to Cephradine capsules (Donggu Pharmaceutical Co.).o.).o.).).o.).

• Journal of Korean Academy of Nursing
• /
• v.33 no.1
• /
• pp.122-129
• /
• 2003

Purpose: The purpose of this study is to examine the difference of direct nursing activity and patient outcomes as mortality rate, complication rate, readmission rate and length of stay related to graded fee of nursing management for inpatient. Method: The subjects of this study were 44 general hospitals with more than 500 beds. Data totaled to 86,044 claims provided to inpatients in Jan. 2001 requested by an electronic data interchange from a Health Insurance Review Agency. The data was analyzed by SPSS win(ver.10.0) and statistical methods used were frequency, one-way ANOVA, $X^2$-Test and regression. Result: Synthetic judgment through performance index and 95% confidence interval, direct nursing activity showed to provided adequate quality of nursing care on 2nd, 3rd, 4th and 6th nursing degree. Also, patient outcomes showed difference by graded fee of nursing management for inpatient. Mortality rate of 2nd was the lowest with P.I. 67.9, 3rd, 5th, 6th, 4th in order. In case of complication rate, 2nd, 3rd and 4th were lower than other nursing degree. Readmission rate of 4th and 5th was the lowest. Length of stay of 2nd was the shortest with P.I. 88.3, 3rd, 4th, 5th, 4th, 6th in order. Conclusion: The findings from this study showed that, the higher nurse-to-patient ratio, the greater amount of direct nursing care activity for the patient. Also, the more direct nursing activities influenced a lower mortality rate, complication rate and readmission rate, shorter length of stay.

• Imaging Science in Dentistry
• /
• v.33 no.1
• /
• pp.27-33
• /
• 2003

Purpose : The purpose of this experiment was to evaluate the diagnostic ability of a CCD-based digital system (CDX-2000HQ) in the detection of incipient dental caries. Materials and Methods : 93 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were radiographed using 4 imaging methods. Automatically processed No.2 Insight film (Eastman Kodak Co., U.S.A.) was used for conventional radiography, scanned images of conventional radiograms for indirect digital radiography were used. For the direct digital radiography, the CDX-2000HQ CCD system (Biomedisys Co. Korea) was used. The subtraction images were made from two direct digital images by Sunny program in the CDX-2000HQ system. Two radiologists and three endodontists examined the presence of lesions using a five-point confidence scale and compared the diagnostic ability by ROC (Receiver Operating Characteristic) analysis and one way ANOV A test. Results: The mean ROC areas of conventional radiography, indirect digital radiography, direct digital radiography, and digital subtraction radiography were 0.9093, 0.9102, 0.9184, and 0.9056, respectively. The diagnostic ability of direct digital radiography was better than the other imaging modalities, but there were no statistical differences among these imaging modalities (p > 0.05). Coclusion : These results indicate that new CCD-based digital systems (CDX-2000HQ) have the potential to serve as an alternative to conventional radiography in the detection of incipient dental caries.

• Journal of Periodontal and Implant Science
• /
• v.32 no.1
• /
• pp.249-255
• /
• 2002

Zea Mays L. has been known to be effective for improving tissue health and Magnoliae cortex to have effective antibacterial and antimicrobial activity against pathogenic microbes. The purpose of this study was to examine the antimicrobial effects of Zea Mays L. and Magnoliae cortex extract mixtures on periodontal pathogens(Prevotella intermedia, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Streptococcus mutans )and to examine the effects on human gingival fibroblast cellular activity. Zea Mays L. and Magnoliae cortex extracts and their mixtures were prepared with various mixing ratios (0.5:1, 1:1, 1.5:1, 2:1). These extracts were loaded to periodontal pathogen cultured petri dish for antimicrobial test and also loaded to cultured human gingival fibroblast for cellular activity test. Each test was repeated 3 times and data were analyzed by one-way ANOVA with 95% confidence level. Mixture of these two extracts showed greater amount of inhibition area on periodontal pathogen and more improved gingival fibroblast activity as Zea Mays L. ratio reduced. So, mixture ratio 0.5:1 (Zea Mays L. : Magnoliae cortex) group showed statistical significance in antimicrobial activity and cellular activity among various mixtures(p < 0.05). In conclusion, 0.5:1 (Zea Mays L. : Magnoliae cortex) mixture possessed best gingival fibroblast cellular activity and antimicrobial activity toward periodontal pathogens.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.2
• /
• pp.902-910
• /
• 2018

In recent times, development of nanofluid insulation for power transformers is a hot research topic. Many researchers reported the enhancement in dielectric characteristics of nano modified mineral oils. Considering the drawbacks of petroleum based mineral oil, it is necessary to understand the dielectric characteristics of nanofluids developed with natural ester based oils. Palm oil has better insulation characteristics comparable to mineral oil. However very few research reports is available in the area of nanofluids based on palm oil. Partial discharge (PD) is one of the major sources of insulation performance degradation of transformer oil. It is essential to understand the partial discharge(PD) characteristics by collecting huge data base of PD performance of nano modified palm oil which will increase its confidence level for power transformer application. Knowing these facts, in the present work, certain laboratory experiments have been performed on PD characteristics of nano $SiO_2$ modified palm oil at different electrode configurations. Influence of concentration of nano filler material on the PD characteristics is also studied. Partial discharge inception voltage, Phase resolved partial discharge (PRPD) pattern, PD signal time-frequency domain characteristics, PD signal equivalent timelength-bandwidth mapping, Weibull distribution statistical parameters of PRPD pattern, skewness, repetition rate and phase angle variations are evaluated at different test conditions. From the results of the experiments conducted, we came to understand that PD performance of palm oil is considerably enhanced with the addition of $nano-SiO_2$ filler at 0.01%wt and 0.05%wt concentration. Significant reduction in PD inception voltage, repetition rate, Weibull shape parameter and PD magnitude are noticed with addition of $SiO_2$ nanofillers in palm oil. These results will be useful for recommending nano modified palm oil for power transformer applications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.46 no.3
• /
• pp.183-190
• /
• 2020

Objectives: The purpose of this retrospective epidemiological study was to determine the etiology and pattern of maxillofacial injuries in a pediatric population. Materials and Methods: Data for pediatric maxillofacial trauma patients aged 12 years and younger who were registered at the Department of Pediatric and Preventive Dentistry, Dr. R. Ahmed Dental College and Hospital, Kolkata, India, were reviewed and examined. Patients who were treated between October 2016 and September 2018 were analyzed according to age, sex, cause of injury, frequency and site of facial fractures, and soft tissue injuries. The chi-square tests were carried out for statistical analyses with a significance level of 5%. Results: Of 232 patients with a mean age of 6.77±3.25 years, there were 134 males (57.8%) and 98 females (42.2%). The overall male to female ratio was 1.39:1. The most common causes of injuries were falls (56.5%) and motor vehicle accidents (16.8%). Incidence of falls decreased significantly with age (P<0.001). Dentoalveolar injuries (61.6%) and soft tissue injuries (57.3%) were more common than facial fractures (42.7%). Mandibular fractures (82.8%) were the most common facial fractures, and perioral or lip injuries were the most prevalent injuries in our patient population. There was a positive association between facial fractures and soft tissue injury (P<0.01) (odds ratio 0.26; confidence interval 0.15-0.46). Conclusion: Falls were the leading cause of maxillofacial trauma in our sample of children, and the most common site of fractures was the mandible.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.4
• /
• pp.655-661
• /
• 2020

In this study, the correlation between concrete core compressive strength and rebound hardness of urban railway underground structures was analyzed. The equations for the range of rebound hardness were derived and compared with the measured concrete core strengths for each range of rebound hardness to confirm the adequacy of the estimated compressive strength. As the result, the linear regression analysis results of the average compressive strength by the Gaussian probability density function (representative compressive strength estimation formula) and the estimation formula by the rebound hardness range were founded to match well within 3% of the experimental concrete core compressive strength test results. Therefore, the stochastic statistical analysis using the rebound hardness measurement results suggested in this study could be help to secure the confidence level of the correlation between the rebound hardness and the concrete compressive strength which are relatively large deviation according to the estimation equations.