• Restorative Dentistry and Endodontics
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• 제43권2호
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• pp.23.1-23.9
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• 2018

Objectives: This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. Materials and Methods: Sixty maxillary canines were divided into 6 groups (n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. Results: Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA (p < 0.05). US improved the push-out bond strength for all the cements (p < 0.05). Conclusions: The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.69-70
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• 2023

The development of advanced 3D printing technologies has opened up new opportunities for customized digital designs in the construction industry. Using nano- and micro-scale additives is expected to improve the performance of cement-based materials in 3D printing. TiO₂ particles have been widely used as reinforcing additives in cement-based materials. Therefore, this study aims to investigate the application of cement-based materials containing multi-size TiO₂ particles in binder jet 3D printing and the effect of different-size TiO₂ particles on the performance of printed samples. TiO₂ particles exhibit an excellent filling effect, which increases the density of the printed samples and promotes hydration, thereby improving the compressive strength of the samples. In addition, larger TiO₂ particles exert more pronounced filling and photocatalytic effects on the resulting samples.

• Restorative Dentistry and Endodontics
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• 제11권1호
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• pp.53-61
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• 1985

This study was conducted to evaluate and compare the apical leakage in the following retrograde techniques; apicoectomys, retrograde filling with zinc oxide eugenol cement, non-zinc and zinc amalgam, and cold-burnished gutta-percha method. One hundred twenty five upper anterior and lower premolar teeth were divided into five above mentioned groups and each tooth was individually prepared for its particular group. The specimens were incubated at $37^{\circ}C$ for 14 days and then were infiltrated by 2% methylene blue for 24 hours. The apical leakage was evaluated by measuring the degree of dye penetration between the filling material and the canal wall. The results were as follows: 1. The cold-burnished gutta-percha group showed the least amount of apical leakage and the apicoectomy group showed the greastest amount of apical leakage. 2. Statistics showed that there were significant differences among the groups (P<0.05), however there was no difference between the zinc oxide eugenol cement retrograde filling group and the non-zinc amalgam retrograde filling group (P>0.05).

• Restorative Dentistry and Endodontics
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• 제18권1호
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• pp.1-26
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• 1993

The purpose of this study was to investigate the effect of acid etching on the surface appearance and fracture toughness of five glass ionomer cements. Five kinds of commercially available glass ionomer cements including chemical curing filling type, chemical curing lining type, chemical curing metal reinforced type, light curing tilling type and light curing lining type were used for this study. The specimens for SEM study were fabricated by treating each glass ionomer cement with either visible light curing or self curing after being inserted into a rubber mold (diameter 4mm, depth 1mm). Some of the specimens were etched with 37% phosphoric acid for 0, 15, 30, 60, go seconds, at 5 minutes, 1 hour and 1 day after mixing of powder and liquid. Unetched ones comprised the control group and the others were the experimental groups. The surface texture was examined by using scanning electron microscope at 20 kV. (S-2300, Hitachi Co., Japan). The specimens for fracture toughness were fabricated by curing of each glass ionomer cement previously inserted into a metal mold for the single edge notch specimen according to the ASTME399. They were subjected to a three-point bend test after etching for 0, 30, 60, and 90 seconds at 5 minutes-, 1 hour-and 1 day-lapse after the fabrication of the specimens. The plane strain fracture toughness ($K_{IC}$) was determined by three-point bend test which was conducted with cross-head speed of 0.5 mm/min using Instron universal testing machine (Model No. 1122) following seven days storage of the etched specimens under $37^{\circ}C$, 100% humidity condition. Following conclusions were drawn. 1. In unetched control group, crack was present, but the surface was generally smooth. 2. Deterioration of the surface appearance such as serious dissolving of gel matrix and loss of glass particles occured as the etching time was increased beyond 15 s following Immediate etching of chemical curing type of glass ionomer cements. 3. Etching after 1 h, and 1 d reduced surface damage, 15 s, and 30s etch gave rough surface appearance without loss of glass particle of chemical curing type of glass ionomer cements. 4. Light curing type glass ionomer cement was etched by acid, but there was no difference in surface appearances according to various waiting periods. 5. It was found that the value of plane stram fracture toughness of glass ionomer cements was highest in the light curing filling type as $1.79\;MNm^{-1.5}$ followed by the light curing lining type, chemical curing metal reinforced type, chemical curing filling type and chemical curing lining type. 6. The value of plane stram fracture toughness of the chemical curing lining type glass ionomer cement etched after 5 minutes was lower than those of the cement etched after 1 hour or day or unetched (P < 0.05). 7. Light curing glass ionomer cement showed Irregular fractured surface and chemical curing cement showed smooth fractured surface.

• Restorative Dentistry and Endodontics
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• 제33권6호
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• pp.553-559
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• 2008

이 연구의 목적은 레진 코팅된 표면과 레진인레이 사이의 자가-접착 레진시멘트를 이용한 결합 시 임시가봉제에 따른 미세인장결합강도를 평가하는 것이었다. Caviton(GC, Tokyo, Japan), Provifil(Promedica, Neumunster, Germany), Provifil(Promedica, Neumunster Germany) & petrolatum, and Eugenol-based cement, Tembond(Kerr, Orange. CA, USA) 이 임시가봉재로 사용되었다. Tescera(Bisco, Schamburg IL, USA) 로 제작하였고 자가-접착 레진시멘트인 Rely X unicem (3M, St. Paul. Minn, USA) 를 이용하여 접착하였다. 이후 미세인 장결합강도를 측정하였고 one-way anova 와 Duncan test 를 이용하여 분석하였다.(p<0.05) Caviton 군이 다른 그룹과 비교하여 유의성 있는 차이를 보여주었다(p<0.05). Provifil, Provifil & petrolatum, Tembond 군 등은 상대적으로 낮은 값을 보여주었다.

• 대한토목학회논문집
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• 제37권4호
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• pp.637-645
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• 2017

제주도는 여러 차례의 화산활동에 의해 형성된 섬으로 불규칙한 화산암층 구조를 가지고 있다. 해상풍력발전기와 같은 구조물은 기초에서부터 하중 작용점까지의 거리가 멀고 상대적으로 큰 수평하중이 작용하여 매우 큰 전도모멘트를 지지해야 한다. 이러한 구조물을 경제적으로 지지하기 위해서는 암반층이라도 말뚝기초를 시공해야 한다. 따라서 본 연구에서는 암반매입말뚝을 위한 주면고정액의 적정배합비를 찾기 위하여 물, 시멘트, 모래의 배합비를 달리하여 역학적 성능을 평가하고, 실험 결과와 기존 연구 결과를 비교분석하였다. 동일한 배합조건에서 시멘트풀과 소일시멘트보다 모르타르(잔골재 비=20~40%)의 역학적 성능이 우수하게 나타났다. 이 결과를 바탕으로 적정배합범위와 강도추정식을 제안하였다.

• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.39-44
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• 2014

Objectives: The purpose of this study was to evaluate in vitro cytotoxicity of the pozzolan cement and other root-end filling materials using human periodontal ligament cell. Materials and Methods: Endocem (Maruchi), white ProRoot MTA (Dentsply), white Angelus MTA (Angelus), and Super EBA (Bosworth Co.) were tested after set completely in an incubator at $37^{\circ}C$ for 7 days, Endocem was tested in two ways: 1) immediately after mixing (fresh specimens) and 2) after setting completely like other experimental materials. The methods for assessment included light microscopic examination, cell counting and WST-1 assay on human periodontal ligament cell. Results: In the results of microscopic examination and cell counting, Super EBA showed significantly lower viable cell than any other groups (p < 0.05). As the results of WST-1 assay, compared with untreated control group, there was no significant cell viability of the Endocem group. However, the fresh mixed Endocem group had significantly less cell viability. The cells exposed to ProRoot MTA and Angelus MTA showed the highest viability, whereas the cells exposed to Super EBA displayed the lowest viability (p < 0.05). Conclusions: The cytotoxicity of the pozzolan cement (Endocem) was comparable with ProRoot MTA and Angelus MTA. Considering the difficult manipulation and long setting time of ProRoot MTA and Angelus MTA, Endocem can be used as the alternative of retrofilling material.

• 한국건설순환자원학회논문집
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• 제7권1호
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• pp.29-36
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• 2019

본 연구는 투수시험 실시 후 고로 슬래그 자극제로 $Na_2SO_4$를 첨가한 고로 슬래그 시멘트 페이스트 시편의 자기치유 특성으로서 충진율과 자기치유 생성물을 고찰하였다. 실시한 시편에 대해 충진율과 자기치유 생성물을 분석하였다. 자기치유 정도는 충진율로 평가하였으며 충진율은 객관성을 갖기 위해 BSE-DIP를 이용한 파노라마 분석법으로 실시하였다. 평균 충진율은 Top 부분은 평균 18%, Middle 부분은 평균 7%, Bottom 부분은 평균 5%로 시편의 윗부분에서 아래 부분으로 갈수록 충진율은 감소되는 경향을 나타냈다. 또한 구간별 최대 충진율은 44%이었고 최소 충진율은 3%이었다. 투수시험 후 잔존하는 자기치유생성물은 기본적으로 Ca 원소와 고로 슬래그에서 유래된 Al 원소를 다량 함유하고 있었으며 Si 원소는 균열 표면으로부터 가깝게 위치한 곳에 주로 존재하였다. 자기치유 생성물 중에서 가장 많이 존재하는 광물은 C-A-H로 68% 정도 존재하였다. $CaCO_3$는 13%, C-A-S-H는 8% 순으로 3가지 물질이 자기치유 생성물의 90% 정도를 차지하고 있었다. C-A-H는 주로 균열 표면에서 약간 떨어진 부분에서 존재하였으며 각진 형태 이거나 침상 형태의 형상을 나타냈다. C-A-S-H는 기존의 시편과 자연스럽게 이어지게 표면을 타고 생성되었으며 $CaCO_3$는 시편의 표면이나 균열의 내부 등 위치에 상관없이 전반적으로 보였다.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.97-105
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• 1990

When conventional root canal treatment is failed or contraindicated, retrograde root canal filling following apicoectomy is a valuable procedure, aimed at hermetically sealing the root canal against leakage of irritants from the canal into the periapical tissue. In this in vitro investigation, to analyze apical microleakage electrochemically in teeth with different retrograde filling materials and preparation types, single - rooted tooth was cut 2mm from the apex and each Class I and Slot preparation was prepared. Experimental groups : Group 1. Amalgam filling with cavity varnish in Class I preparation Group 2. Scotchbond 2+Silux filling in Class I preparation Group 3. Gutta percha filling with ZOE cement in Class I preparation Group 4. Amalgam filling with cavity varnish in Slot preparation Group 5. Scotchbond 2+Silux filling in Slot preparation Each specimens was immersed in 1% solution of KCl, and applied a potential of 9V external power supply. Measurements of the current flow were obtained at 1, 2, 3, 7, 9, 12, 14, 18, 21, 25 and 28 day after immerson. Marginal microleakage were compared and evaluated. The results were as follows ; 1. The group filled with composite resin with dentin bonding agent shows lower apical microleakage value than the group filled with amalgam following varnish application (P<0.01). 2. In the group filled with gutta percha, apical microleakage value was the hightest 3. There was no significant difference between Class I cavity and Slot type cavity regardless of the used materials.

• Restorative Dentistry and Endodontics
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• 제12권1호
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• pp.131-147
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• 1986

The purpose of this study was to observe the color matching of lining or filling materials according to the remaining tooth material. Twenty-seven freshly extracted human central incisors were used in this experiments. The teeth were stored in saline solution at room temperature after extraction. All teeth were cut parallel to the tangent to height of contour on labial surface from the lingual surface until the pulp were completely removed. Then 27 teeth were devided into 0.5mm, 1.0mm and 1.5mm reduction groups according to the thickness of cutting the lingual surfaces of teeth. The specimens of control group were three teeth of 27 teeth with cutting the lingual surface same mode as above described. In the specimens of experimental groups, 8 kinds of lining and filling materials; FUJI IONOMER TYPE II (G-C Co. Japan), LINING CEMENT (G-C Co. Japan), Dycal (Caulk, U.S.A.), CLEARFIL F II (Kuraray Co. Japan), Crown Bridge & Inlay Cement (G-C Co. Japan), Copalite (Harry J. Bosworth Co. U.S.A.), HY-BOND (G-C Co. Japan) and LIV-CENERA (G-C Co. Japan); applied on the back of 24 teeth with 0.5mm, 1.0mm and 1.5mm cut thickness of lingual surfaces. Three teeth of control group did not applied linging or filling materials on the back of 3 kinds of different thickness of cutting the lingual surfaces. The absorbances of total 27 specimens were obtained by reflection spectrophotometer. (Cary 17 D, Varian Co, U.S.A.) The following conclusions were drawn from above the results; 1. The absorbance patterns in both experiment and control groups were gradually decreased with increasing wavelength of spectra. 2. The absorbance patterns were not decreased in relation to the kinds of lining or filling materials, but the amount of the remaining tooth materials. 3. In 0.5mm reduction group, FUJI IONOMER TYPE II, LINING CEMENT, LIV-CENERA and Copalite applied on the back of cut lingual surface showed similar absorbance patterns as control group. 4. The specimens which were reduced up to 1.0mm thickness and lined with FUJI IONOMER TYPE II and LINING CEMENT showed the comparable absorbance patterns to the control group. 5. In case of HY-BOND application after 1.5mm reduction were observed the similar absorbance pattern as compared with control group. 6. When Dycal, CLEARFIL and Crown Bridge & Inlay Cement were applied to cut teeth surfaces, there were much differences of absorbance between control groups and experimental groups.