• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6098-6105
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• 2013

In the present study, the characteristics of corrosion and thermal conductivity of thermal spray coatings for seawater heat exchangers were examined experimentally. The coating types of theZn and Al thermal spray coatings with additional epoxy and silicone sealers were tested. To examine the corrosion characteristics of the thermal spray coating, the cyclic voltamogram curve was measured followed by SEM imaging for surface characterization. The laser flash method was usedto measure the thermal conductivity of the specimen. The conductivity test results showed that thermal conductivity decreased by3 ~ 4% with the silicone sealer and decreased by 70 ~ 75% with the epoxy sealer.

• Health Policy and Management
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• v.26 no.1
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• pp.63-70
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• 2016

Background: Selective health benefit was introduced for decreasing economic burden of patients. Medical devices with economic uncertainty have been covered as selective health benefit by National Health Insurance since December 2013. We aimed to analyze impact of selective health benefit to medical expenditure and provider behavior focused on electrosurgery (ultrasonic shears, electrothermal bipolar vessel sealers) for gastric cancer patients covered since December 2014. Methods: We used the National Health Insurance claims data of 2,698 patients underwent gastric cancer surgery between August 2014 and March 2015. Medical cost and patient sharing per inpatient day were analyzed to verify that covering electrosurgery increased medical expenditure and changed provider behavior from open surgery to endoscopic or laparoscopic surgery. Additionally, we analyzed the claim rate of medical device or goods relating gastric endoscopic and laparoscopic surgery. Results: Medical cost and patient sharing per inpatient day were increased after covering electosurgery as selective health benefit (39,724/1,421 won). However, there were no medical expenditure increases after adjusting claim of electosurgery and patient sharing was decreased 1,057 won especially. The coverage of selective health benefit did not increase the claim rate of medical device or goods related endoscopic or laparoscopic surgery, either. Conclusion: Covering electosurgery decreased patient economic burden and did not change of provider behavior. Expanding selective health benefit is needed to decrease economic burden of severe patients. Further study should evaluate the long term effect with accumulated data.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.161-171
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• 1989

The purpose of this study was to evaluate and compare the sealing ability of ZOE, FR and Sealapex, as a root canal sealer. Ninety six extracted anterior or premolar human teeth with single root were instrumented by using conventional method. After instrumentation, the teeth were divided into three groups and thirty two teeth in each group were filled as follows: ZOE group: ZOE cement as a root canal sealer in combination with guttapercha cone FR group: FR root canal sealer in combination with guttapercha cone Sealapex group: Sealapex root canal sealer in combination with guttapercha cone $^{45}Ca$ in the form of calcium chloride, was employed as the tracer in this study and produce the auto-radiograph. The depth of isotope penetration into the root canal was evaluated by method by Yates and Hembree at the intervals of 1 day, 7 days, 14 days and 30 days. The following conclusions were derived from the results obtained; 1. After 1 day, ZOE group exhibited the greatest penetration degree of radioisotope (p < 0.05). 2. After 14 days, there was some difference of the radioisotope penetration between each group, but its difference was not significant statistically. 3. After 30 days Sealapex group exhibited the least penetration degree of radioisotope (p < 0.025). 4. In ZOE and Sealapex groups, there was no change of the degree of radioisotope penetration with time.

• Restorative Dentistry and Endodontics
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• v.28 no.4
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• pp.295-302
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• 2003

본 연구에서는 인산 칼슘 근관 봉함재 [Apatite Root Sealer (ARS) Type I, II, III]의 세포독성을 혼합후의 시간 경과에 따라서 다른 4계열의 근관 봉함재 (Pulp Canal Sealer EWT, AH Plus, Sealapex, Ketac Endo)와 비교하여 평가하였다. 근관 봉함재를 혼합한 후 1시간, 8시간, 24시간, 48시간, 1주, 2주,4주의 기간동안 배양액을 이용하여 추출액을 얻었다. L929 쥐섬유아세포를 24시간동안 각 시간군에서 얻은 추출액과 함께 배양한 후 dimethylthiazol diphenyltetrazolium (MTT) assay와 neutral red (NR) assay를 이용하여 세포독성(%)을 평가하였다. 실험 결과 ARS Type I, II, III는 전 시간군에 걸쳐 낮은 세포독성을 보였고 (23.65-0.55%) 특히 경화 초기에 다른 계열의 근관 봉함재보다 유의성 있게 낮은 세포독성을 나타내었다. ARS Type I, II, III간의 세포독성은 각 시간군에서 유의성 있는 차이를 보이지 않았다. AH Plus와 Ketac Endo는 초기에 높은 세포독성을 보였으나 AH Plus는 8시간 이후에, Ketac Endo는 24시간 이후에 독성이 급격히 감소하여 ARS와 유의성 있는 차이를 보이지 않았다. Pulp Canal Sealer EWT와 Sealapex는 4주까지 지속적인 세포독성을 나타내었다. 그리고 MTT assay와 NR assay를 이용하여 얻은 각 근관봉함재의 세포독성은 시간 경과에 따라서 비슷한 변화 양상을 나타내었다. 인산 칼슘 근관 봉함재는 생체적합성이 우수한 재료로써 앞으로 지속적인 개발과 평가가 필요할 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.34.1-34.7
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• 2020

Objectives: This study evaluated by using micro-computed tomography (micro-CT) the filling ability and sealer apical extrusion promoted by a new Sealer Injection System (SIS; Angelus) with side openings needle, in comparison with the conventional injection system, associated with a new ready-to-use calcium silicate-based sealer (Bio-C Sealer). Materials and Methods: Acrylic resin models containing a main curved artificial canal and 3 simulated lateral canals in apical, middle and cervical thirds were used. The main root canals were prepared using a rotary system up to size 35.05. The canals were filled with Bio-C sealer by using a single cone technique and the conventional delivery system or SIS. Samples were scanned in micro-CT. The percentage of voids throughout the entire extension of the main root canal and in each third of the lateral canals, besides the apical extrusion of the sealer was calculated. Data were submitted to t-test (p < 0.05). Results: There was no difference between both systems in the main root canals filling. Although the volume percentage of voids was similar in the apical and middle thirds of lateral canals, SIS had the greatest filling ability of the cervical third lateral canal. Moreover, the conventional system showed the highest apical extrusion of the sealer. Conclusions: The conventional and SIS obturation systems had an appropriate filling ability of the main root canal. SIS had the best filling of the cervical third of the lateral canals, besides lower sealer apical extrusion, suggesting its clinical indication.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.7-16
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• 1980

The author observed the periodontal tissue reactions to the root canal sealers after root perforations were made intentionally in dogs. The perforations were made on 74 teeth from 7 dogs. The experiments were performed in two different modes of procedure: In Group I, the perforations were made through the root canal to the alveolar bone. In Group II, the perforations were made from site of alveolar bone to the root canals. The perforated canals in Group I were filled with gutta-percha and root canal cements; Calxyl (Calcium Hydroxide in Ringer's solution), Zinc Oxide -Eugenol cement (Z.O.E.), Kerr sealer (Rickert's paste) and AH 26 (Epoxy Resin preparations). The perforated canals in Group II were sealed with Calxyl, Z.O.E, Kerr sealer and AH26. Histologic examinations of periodontal tissue reactions were observed at various time intervals. The results were as follows; l. Cementum deposition on the perforated root surface in Group II cases showed slightly earlier than that of Group I. Healing tendency of injured alveolar bone in Group II was greater than that of Group I. 2. According to the time increase after experiment, the cementum deposition on the site of perforated dentin in Group II with intact pulp was notably thickened. Secondary dentin deposition on the root canal surface where the dentinal tubles were cut was also found in similar pattern. 3. In the cases of perforated canals sealed with Calxyl both in Group I and Group II, It revealed the earliest cementum-deposition among 4 different root canal cements. In the cases of perforated canals sealed with Kerr sealer and AH26, the cementum-deposition on the root surface was not found. 4. Proliferation of epithelium around the perforated area was first seen at 5-week cases in Group I, and at 3-week cases in Group II. 5. In all cases, dentin resorption on the site of perforated root surface was always occured.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.36-54
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• 1992

The purpose of this study was to compare the shear bond strengths to ground dentin surfaces of four dentinal bonding agents in 193 teeth. Various dentin surfaces treated with four dentin bonding agents were attached with two restorative composite resins. The effectiveness of the bonding were tested by the monitoring the shear bond strength. The shear bond strengths were measured after 2 hours and 24 hours after surface conditioning with four dentin bonding agents. Effects of EDTA, the additive illumination, and sealer treatments without primer on bond strength to dentin surfaces were assessed. In addition the effects of the thickness of specimens ranging from 0.65 mm to 1.95 mm and the ratio of catalyst and base paste on the bond strength of chemical cure composite resin were estimated. The shear bond strength was determined by testing specimens in the Instron universal testing machine (Model No. 1122) at a crosshead speed of 1.0 mm/min. Following condusions were drawn: 1. The highest mean shear bond strengths of chemical cure composite resin to dentin conditioning with dentin bonding agents aged 2 hours were obtained, and then that was decreased with time followed by EDTA treatment. 2. In light cure composite resin, the shear bond strength was increased following dentin conditioning with bonding agents with time, irradiation time and EDTA treatment except in SB group. 3. The thicker the composite resin specimen was, the less the shear bond strength in chemical cure composite resin was. 4. In light cure composite resin, there was a little change in shear bond strength following dentin conditioning with bonding agents. 5. In chemical cure composite resin, the shear bond strength was the highest in the ratio of 1/1 of catalyst and base part. 6. Without a dentin primer, shear bond strength to dentin conditioned only with UB sealer was the highest among four sealers in light cure composite resin.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.677-687
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• 1996

This study was conducted to evaluate the tissue responses histologically to three root canal cements : Sealapex, AH-26, and zinc oxide-eugenol cement. Twelve white female Sprague-Dawley rats, weighing between 350 and 400 gm, were anesthetized with an intraperitoneal injection of Ketamine hydrochloride(0.4 ml). After shaving the sites selected(left and right scapular areas, left and right pelvic areas), the animal's backs were scrubed with soap and water, and sterilized with absolute alcohol. Each material was mixed to a thin consistency to flow out easily through a 24-guage needle, and loaded into a sterile, disposable plastic 1-ml syringe. All of the rats were injected subcutaneously with 0.1 ml of the three test sealers. Normal saline was used as a control. Animals were sacrificed after 48hr, 1, 4, and 12 weeks by overanesthetization using jars containing anesthetic ether. The tested sites were surgically removed with the surrounding tissue and fixed with 10% formalin. After 48 hours specimens were embedded in paraffin, sectioned to an average thickness of $6{\mu}m$ thick, stained with hematoxylin-eosin. The slides were examined under the light microscope. The results were obtained as follows 1. All material except the control showed various degree of inflammation on 48 hr. 2. Sealapex : In early stage, severe inflammatory cell infiltration was observed. At the 4th weeks observation, graunlomatous tissue with macrophage and foreing body giant cells containing many dark particles in their cytoplasm was observed. 3. AH-26 : Mild inflammatoy reaction was observed with AH-26 throughout the experimental period. 4. Zinc oxide-eugenol cement : Severe inflammatory cell infiltration, necrosis along the material, edema could be seen in early stage. Zinc oxide-eugenol cement maintained a moderate/severe reaction throughout the experimental period.

• Restorative Dentistry and Endodontics
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• v.46 no.1
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• pp.4.1-4.16
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• 2021

Objectives: This study evaluated the biocompatibility and bioactive potential of NeoMTA Plus mixed as a root canal sealer in comparison with MTA Fillapex. Materials and Methods: Polyethylene tubes filled with NeoMTA Plus (n = 20), MTA Fillapex (n = 20), or nothing (control group, CG; n = 20) were inserted into the connective tissue in the dorsal subcutaneous layer of rats. After 7, 15, 30 and 60 days, the specimens were processed for paraffin embedding. The capsule thickness, collagen content, and number of inflammatory cells (ICs) and interleukin-6 (IL-6) immunolabeled cells were measured. von Kossa-positive structures were evaluated and unstained sections were analyzed under polarized light. Two-way analysis of variance was performed, followed by the post hoc Tukey test (p ≤ 0.05). Results: At 7 days, the capsules around NeoMTA Plus and MTA Fillapex had more ICs and IL-6-immunostained cells than the CG. However, at 60 days, there was no significant difference in the IC number between NeoMTA Plus and the CG (p = 0.1137) or the MTA Fillapex group (p = 0.4062), although a greater number of IL-6-immunostained cells was observed in the MTA Fillapex group (p = 0.0353). From 7 to 60 days, the capsule thickness of the NeoMTA Plus and MTA Fillapex specimens significantly decreased, concomitantly with an increase in the collagen content. The capsules around root canal sealers showed positivity to the von Kossa stain and birefringent structures. Conclusions: The NeoMTA Plus root canal sealer is biocompatible and exhibits bioactive potential.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1289-1298
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• 2014

Pavement crack sealing method, which is one of the methods to maintain and repair the road, prevents the extending of cracks by repairing cracks in its early occurrence and has already been applied to many roadworks in advanced foreign country for a long time. But in the conventional crack sealing method, traffic accidents occur frequently during the repair because it's commonly performed on the heavy traffic road or highway. It also has some difficulties in securing the safety of workers from the risk of burns caused by heated sealant. In an effort to solve these problems, automated pavement crack sealing machines such as ARMM, OCCSM, TTLS have been developed in advanced foreign country since early 1990s. Also APCS in 2004 and ACSTM in 2013 were already developed domestically. However, since these automated crack sealers developed from a number of research institutions have different test-bed conditions and productivity measurement models, it's difficult to compare and evaluate them objectively. In this study, the image processing time of the respective machines and the movement time of each motion on the work process were estimated by using fully autonomous mapping and semi-automatic mapping in order to measure the productivity in the same environmental conditions. In addition, the productivity measurement test-bed reflected domestic road characteristics was designed to estimate and compare the productivity of the automated crack sealing machines.