• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.467-476
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• 2009

The aim of this study was to measure the dentinal tubular fluid flow (DFF) during and after amalgam and composite restorations. A newly designed fluid flow measurement instrument was made. A third molar cut at 3 mm apical from the CEJ was connected to the flow measuring device under a hydrostatic pressure of 15 $cmH_2O$. Class I cavity was prepared and restored with either amalgam (Copalite varnish and Bestaloy) or composite (Z-250 with ScotchBond MultiPurpose: MP, Single Bond 2: SB, Clearfil SE Bond: CE and Easy Bond: EB as bonding systems). The DFF was measured from the intact tooth state through restoration procedures to 30 minutes after restoration, and re-measured at 3 and 7days after restoration. Inward fluid flow (IF) during cavity preparation was followed by outward flow (OF) after preparation, In amalgam restoration, the OF changed to IF during amalgam filling and slight OF followed after finishing. In composite restoration, application CE and EB showed a continuous OF and air-dry increased rapidly the OF until light-curing, whereas in MP and SB, rinse and dry caused IF and OF, respectively. Application of hydrophobic bonding resin in MP and CE caused a decrease in flow rate or even slight IF. Light-curing of adhesive and composite showed an abrupt IF. There was no statistically significant difference in the reduction of DFF among the materials at 30 min. 3 and 7 days after restoration (p > 0.05).

• Clinical and Experimental Reproductive Medicine
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• v.7 no.1_2
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• pp.11-20
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• 1980

Hysterosalpingograms (H.S.G.) have been done for several decades to determine causative factors in female infertility. However, the H.S.G. only reverals uterine cavity and tubal patency or inpatency. The author prefers to find more details in regard to the status and condition of the female reproductive organs and their surrounding tissue as they pertain to infertility. H.S.G. in combination with laparoscopic examination reveals the following results. Preparation and method of performance of H.S.G. during laparoscopy in a healthy reproductive age women are as follows. When laparoscopy is not contraindicated, NPO is ordered with routine bowel preparation. Analgesics administered by injection prior to procedure are valium 10mgs and pethidine 50-100mgs. The radiographic procedure is the same as for any HSG technique. During laparoscopy a solution of 3 to 10 ccs. of 60% hypaque sodium is used. Fluroscopic scout films are obtained A-P and oblique views as well as a delayed check film. 1. Age distribution of primary and secondary infertility in this studies involving tubal factors was as follows: 20-29 age group showed 46% incidence and in the 30-39 age group, 50% incidence. Duration of infertility in this study group was the following: 1-2 years showed 26.7%, 3-5 years 53.8%, and 6-9 years 13.3%. 2. Indications of laparoscopic examination were as follows: Secondary infertility in 35% of the cases, obscure tubal occlusion on previous H.S.G. in 25%, unknown origin in 11.7%, and the remaining cases included pelvic pain, small masses, dysmenorrhea, and uterine anomaly. The laparoscopic examination showed clearly the reproductive organs and the surrounding tissues in the pelvic cavity. The abnormal tubal findings there revealed were tuberculous salpingitis and hydrosalpinx in 10% each, endometriosis and peritubabl adhesions in 6.7% each, biconuate uterus in 3.3%. The remaining 58.3% of the cases showed normal findings. Laparoscopic observation for possible myoma nodules, streak ovary, and peritubal adhesions was also done at this time. 3. Comparative tubal findings in combined H.S.G. and laparoscopic examination revealed the following. Bilateral tubal occlusion was present in 14% (7cases) on laparoscopic examination but on H.S.G. 38% (19 cases) were noted. However, tubal occlusion and peritubal adhesions were found in 26% (13 cases) upon laparoscopy and only 8% (4 cases) on H.S.G. examination alone. Normal pelvic findings were present in 60% (27 cases).

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.59-66
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• 2015

A new concept of an inorganic foaming process at low temperature was demonstrated for the production of inorganic thermal insulating materials with the properties of flexible light-weight, the advantages of organic-based thermal insulation material. The foaming process was proceeded by establishing a skeleton of the foam body by using inorganic fibrous sepiolite and aluminum silicate. A cavity was formed by the expansion of fibrous skeleton body, by the gas which was generated from foaming agent at low temperature. Then the multi-vesicular expanded perlite with low thermal conductivity was filled into the cavity in a skeleton of the foam body. Finally through these overall process, a new inorganic foamed body could be obtained at low temperature without the hot melting of inorganic materials. In order to achieve this object, various preparations such as fibrous sepiolite fibrillation process, heat treatment process of the fibrous slurry were needed, and the optimal compositional condition of slurry was required. The foam body produced showed the properties of flexible light-weight thermal insulation materials such as bulk density, yield strength, flexural strength, and high heat resistance.

• Journal of Chest Surgery
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• v.28 no.11
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• pp.963-966
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• 1995

Ischemia reperfusion injury occurs in various diseases. The role of oxygen free radicals in IR injury of the lung has been spotlighted and many studies have been performed. In this study, we tried to prepare a stable rat lung model for IR injury, focusing on surrounding conditions as hilar stripped left lung, clamped left pulmonary artery and bronchus,and declamped after determined period was passed, and right main pulmonary aretery was clamped. Arterial blood gas analyes were performed at 1, 10, 20, 30, minutes after reperfusion. Before clamping, PaO2 was 95 to 120 mmHg in all animals. There were six groups; Group I : temperature 15o C, and 120 minutes clamping, Group II: 20 oC, and 120 minutes clamping, Group III : 25 oC, and 120 minutes clamping, Group IV : 15oC, 90 minutes clamping, Group V : 20 oC, 90 minutes clamping,Group VI: 20 oC, 75 minutes clamping. Each groups contained 10 Sprague Dayley rats. The humidity was maintained 100 % as circulation imerged isotonic Hartmann`s solution of the pleural cavity. In group IV, V, and VI, PaO2 decreased significantly in all animals immediately after reperfusion, but 43 % survived till 10 minutes after reperfusion, it was 74.0$\pm$5.7, 73.3$\pm$10.8,and 88.2$\pm$17.7 mmHg. Pulmonary edema was observed histologically in 2/10 animals in group IV, 6/10 in group V , 3/10 in group VI, 9/10 in group I, and the other lungs showed all edema. We established a stable model by setting ischemic time,and temperature, between 75 to 90 minutes,15 to 20o C, and isotemperature Hartmann`s solution immersion of the pleural cavity.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.490-498
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• 2010

The optimum mold design and the optimum process condition were constructed upon executing process simulation of rubber injection molding with the commercial CAE program of MOLDFLOW(Ver. 5.2) in order to solve the process-problems of K company relating to air-traps and short-shots. The former occurs at the cavity edge of torque-rod-bush and the latter takes place for the injection molding of dynamic dampers. As a result the process problem relating to air traps was solved by optimizing edge-angle and the number of gates to prevent the flow congestion of flow-front and to make the flow-front movement unaffected by congestion. For dynamic dampers of K company the unmolded flaw caused by their unfilled cavity was corrected by installing the air-vent at the confronting locations of both upstream and downstream of flow-front where air traps frequently occur. Besides the unmolded flaws were rectified by altering the position of gate from the upper to the middle or by increasing the number of gates. Thus the process problems of K company relating to air-traps and short-shots of torque-rod-bush and dynamic dampers, respectively, were solved by proper altering of mold design with process simulation of rubber injection molding.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.329-334
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• 2017

In this study, a new granular type mouthwash with equivalent antibacterial activity to marketed liquid type mouthwash was developed using a material called magnesium aluminometasilicate (Neusilin). This material adsorbs the surface of granules to improve the flowability of granules due to the formation of a eutectic mixture of the main constituents, which have improved flow properties and rapid disintegration time and little residue in the oral cavity. The characteristics of the granules were improved when the amount of Neusilin was 10% or more according to measurements of the granule properties, such as flowability. In addition, a disintegration test in artificial saliva and a sensory test in the human oral cavity were carried out to confirm the improved disintegration characteristics and sensory test results. The antimicrobial test confirmed similar antibacterial activity to that of the liquid oral cleanser already sold in the market. The granular oral cleanser composition prepared in this study can be used for the development of pharmaceuticals containing different drugs with similar characteristics as eutectic mixtures at the same time, which is considered to be useful in the development of medicines in the pharmaceutical industry.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.2
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• pp.259-267
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• 1998

For more than two decades, many investigators have tried a variety of methods for delivering antimicrobial agents to the oral cavity with the objective of eliminating mutans streptococci. In the belief that the effectiveness of chemotherapy might be improved by a more effective delivery system, the intention of the present study was to exploit a new drug delivery system delivering chlorhexidine to the oral cavity. The vehicle delivering chlorhexidine tested in this study was self-curing acrylic resin(polymethyl methacrylate). The powder of the acrylic resin was polymerized with the 5 different liquid preparations, in which $Chlorzoin^{(R)}$ was mixed with five different monomer/Chlorzoin ratios immediately prior to the polymerization, in a stainless steel mold ($40mm{\times}40mm{\times}2mm$). A total of 50 cured resin specimens were divided into 5 groups according to the different monomer preparations. Every specimen was soaked in an airtight container filled with distilled water (100 ml) and then kept in an incubator at $37^{\circ}C$. The solutions (0.8 ml) were collected from the container at every 24 hours, and the amount of released chlorhexidine in the solutions was measured in an ultraviolet spectrophotometer at 250nm. The container was refilled with distilled water every after measurement. This procedure was repeated for 14 days. It was found that chlorhexidine was continuously released from all of the 50 specimens during the experimental period. And it was noted that the pattern of chlorhexidine release was a type of sustained-release preparation, that is, the amount of the released chlorhexidine at the first day in all 5 groups was high (p<0.0001), and then the release was decreased during the rest of the experimental period (p<0.001).

• Journal of dental hygiene science
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• v.18 no.3
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• pp.147-154
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• 2018

This study aimed to evaluate the antimicrobial effects of Acanthopanax sessiliflorum fruit (ASF; Ogaza) extracts on Streptococcus mutans and Streptococcus sobrinus, which are agents that cause dental caries, and on Streptococcus mitis and Streptococcus salivarius, the microbial flora of the oral cavity. The ASF extracts obtained using 70% ethanol were fractionated in the order of ethyl acetate and n-Butanol, concentrated under reduced pressure, and lyophilized to give powdery solvent extracts. The antimicrobial activity of ASF extracts from each solvent was examined using the disk diffusion method. As a result, only those extracts obtained using an ethyl acetate solvent showed antimicrobial activity. These extracts were selected, and the minimum inhibitory concentration was measured by disk diffusion method at various extract concentrations. Results showed a minimum inhibitory concentration of 32 mg/ml. The viable cell count was measured to confirm the minimum bactericidal concentration. Results showed a minimum bactericidal concentration of 64 mg/ml. In the cytotoxicity test using normal human dermal fibroblast cells, the absorbance value of the test group was similar to that of the control group at 0.64, 1.28, and 6.4 mg/ml. The bacteria and their colonies were examined using a scanning electron microscope. Boundaries between the antimicrobial activity region and non-antimicrobial activity region were observed around the paper disk, which was immersed in the extract with 32 mg/ml concentration. Bacterial colonization was not observed in the area with antimicrobial activity. This finding suggests that ASF extracts can inhibit the growth of some microorganisms in the oral cavity, in addition to the effects of these extracts known to date. In particular, ASF extracts may be used as a preparation for preventing dental caries by adding the extract to the toothpaste or oral mouthwash.

• Restorative Dentistry and Endodontics
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• v.28 no.2
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• pp.127-133
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• 2003

The object of this study was to compare the microleakage between various composite resin systems of multistep, one-bottle, and self-etching systems using electrical conductivity. After making class V cavities ($4{\times}3{\times}1.5{\;}mm$ around CEJ), they were bulk filled with three kinds of resins of A3. Teeth were storaged in a saline solution for one day, after then, they were finished and polished using Sof-Lex system. Another stress of thermocycling was made for 500 times from $5^{\circ}{\;}to{\;}55^{\circ}C$ with each dwelling time of 10 seconds. Electrical conductivity (microamphere, $\mu\textrm{A}$) was checked four times: before and after cavity preparation, after filing, after thermocycling. One-way ANOVA and 95% Scheffe Post Hoc test was used for checking any statistical difference among groups. Another 95% Paired Samples T-test was also used for estimating any significant difference within group after cavity filling or thermocycling. The results were as follows: 1 Every specimen showed various range of microleakage after filing. There was, however, no difference between composite resin systems. 2. All composite resin systems showed marked increase in microleakage with a thermocycling (p<0.05), there was, however, no difference between composite resin systems. 3. Although there was no significant difference between groups (p=0.078), one-bottle and self-etching systems seemed to be unstable than multistep system. Within the limits of this study, it was concluded that much more consideration should be needed when using thermally unstable one-bottle and self-etching systems that have multi-advantages from simplified step. More studies will be needed to solve these kinds of problems.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.54-61
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• 2000

Amalgam, though a widely used dental material, does not bond to the tooth substrate Therefore, retentive preparation of the cavity is necessary. Such amalgam restorations, until corrosion products form and plug the margin, will show significant marginal leakage. Unless this is prevented early on, saliva and bacteria may enter the cavity causing postoperative hypersensitivity, dissolution and collapse of the restoration, discoloration of the margin and secondary caries, leading to shortened life-span of the restoration and pulpal pathosis. Recently, a method of restoration has been introduced whereby tooth material can be preserved, cavity margin can be sealed and preventive treatment of pit and fissure can be administered while retaining all the advantages of conventional amalgam restorations. Such sealed amalgams involve removing the carious lesion without extending the cavity for prevention and using pit and fissure sealants to seal cavity margins and pit and fissures to reduce microleakage. In this study, finishing of the amalgam and sealant application were performed after different intervals following of amalgam restoration to compare the microleakage of sealed and conventional amalgam restorations. Thirty bicuspids were prepared with Class V cavity preparations on the buccal and lingual surfaces. After amalgam placement, they were divided into the following groups and treated accordingly. Group 1 : Polishing after 24 hours Group 2 : Immediate sealant application without polishing Group 3 : No polishing, but sealant applied after thermocycling 500 times After treatment, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue kept in a $37^{\circ}C$ incubator at 100% humidity for 24 hours. The teeth were then embedded in resin and cut bucco-lingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage, The following results were obtained : 1. Group 2 showed the least microleakeage, while group 1 showed the greatest. 2. Group 1 showed significantly greater microleakage compared to group 2 (p<0.05). However, no significant differences were found between group 1 and 3(p>0.05). No significant differences in microleakage were also found between cup 2 and 3(p<0.05).