• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.247-256
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• 1998

To evalutate the change in shear bond strength according to dentin surface treatment, 4 materials were divided into control group(A) and experimental group(B). Group A was treated according to the instruction of manufacture. Group B was treated with 32% phosphoric acid. After dentin surface treatment, each material was bonded and stored in 100% humidity during 7 days, and then, the shear bond strength was evaluated. The results were as follows: 1. In the case of treatment according to the instruction of manufacture, the shear bond strength according to material showed Z-100 to be highest with 12.42 MPa, Compoglass had the lowest shear bond strength with 4.23 MPa and there was significant difference between Compoglass and Z-100, Dyract (p<0.01). 2. The group treated with 32% phosphoric acid showed lower shear bond strength than that of the group treated according to the instruction of manufacture but there was no statistical significance. 3. As a result of observation under SEM, the fracture pattern was a mixture of cohesive and adhesive failure in group 1, and there was more adhesive failure in group 2, and in group 3 and 4 there was cohesive failure of material or tooth structure. From the results above Dyract showed shear bond strength levels between resin and resin -modified glass ionomer but Compoglass showed much lower shear bond strength than that of resin-modified glass ionomer thus indicating that even though they are the same type of material they show evident differences in physical properties. And it is thought that the treatment of dentin surface with phosphoric acid did not increase the shear bond strength, unlike enamel.

• 대한치과교정학회지
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• 제34권4호
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• pp.351-362
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• 2004

고정식 교정 치료시 교정용 밴드가 장착된 치아의 치주조직 손상은 접착된 치아에서 보다 자주 발생한다. 일반 치과치료에 사용되는 시멘트는 세포독성을 지닌 것으로 알려져 있으므로 치주조직과 직접 접촉하거나 구강 내에서 밴드시멘트의 성분들이 용출되는 교정용 밴드 시멘트는 치주조직의 손상을 일으키는 원인이 될 수 있다 그러므로 교정용 밴드 시멘트의 생체 친화성은 재료의 물성과 함께 중요하게 고려되어야 할 사항이다. 이 연구의 목적은 교정용 밴드 시멘트의 세포독성을 평가하는 것으로 현재 임상에서 널리 사용되고 있는zinc phosphate cement (ZPC), glass ionomer (GI), resin modified glass ionomer (RMGI), compomer의 생체 친화성을 평가하기 위해 human gingiva fibroblast를 배양하고 이 세포에 대한 세포수 산정 및 세포 형태관찰, MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, 한천중층시험 등의 세포독성 검사를 시행하여 다음과 같은 결과를 얻었다. 1. 세포수 산정 및 형태 관찰 시험에서 Gl>ZPC, RMGI, RMG124, GI24>compomer24, ZPC24, compomer 순으로 세포독성이 높게 나타났다. 2. MTT assay 에서는 GI>ZPC, RMGI>GI24>ZPC24, compomer, RMGI24, compomer24 순으로 세포독성이 높게 나타났다. 3. 한천중층시험에서 는 GI>GI24, ZPC, ZPC24, RMGI>RMG124, compomer, compomer24 순으로 세포독성 이 높게 나타났다.

• 대한소아치과학회지
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• 제46권2호
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• pp.226-232
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• 2019

이 연구의 목적은 글라스 아이오노머 시멘트의 표면 보호가 미세경도와 마모저항성에 미치는 효과를 알아보고자 하는 것이다. 글라스 아이오노머와 레진강화형 글라스 아이오노머를 사용하려 각각 60개의 시편을 제작하였다. 각 시편을 표면 보호를 시행하지 않은 경우, 나노필러가 함유된 표면 보호재, 필러가 함유되어 있지 않은 표면 보호재에 따라 20개씩 나누었다. $37^{\circ}C$ 증류수에 24시간 보관한 후 각 군당 10개의 시편은 비커스 미세경도를 측정하였고, 10개의 시편은 마모 시험을 시행한 후 마모된 깊이를 측정하였다. 표면보호를 시행한 군들보다 표면 보호를 시행하지 않은 군들이 높은 표면경도를 보였다. 글라스아이오노머와 레진강화형 글라스아이오노머 모두에서 표면 보호를 시행한 경우에 마모저항성이 더 증가하였지만 유의한 차이는 아니었다. 나노필러의 유무는 마모도에 유의한 영향을 미치지 못하였다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.358-373
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• 1997

Resin modified glass ionomers were introduced in 1988 to overcome the problems of moisture sensitivity and low early mechanical strength of conventional glass ionomers and to maintain their clinical advantages. The purpose of this study was to evaluate the color stability of four resin modified glass ionomers(Fuji II LC, Vitremer, Dyract and VariGlass), one resin composite material(Z-100), and one conventional glass ionomer(GC Fuji II) under several conditions. These conditions were as follows: 1) before curing, 2) after curing, 3) after polishing, 4) after 500 thermocycling, 5) after 1,000 thermocycling, 6) after 1,500 thermocycling and 7) after 2,000 thermocycling. Three specimens of each material/shade combination were made. Materials were condensed into metal mold with a diameter of 10 mm and a thickness of 2.0 mm, and were pressed between glass plates. The material was polymerized using a light polymerizing unit(Visilux II, 3M, USA). After removal of excess, the surface was polished sequentially on wet sandpapers. A reflection spectrophotometer(Model TC-6FX, Tokyo Denshoku Co., Japan) was used to determine CIELAB coordinates($L^*,a^*$ and $b^*$) of each specimen. CIE standard illumination C was used as the light source. The results were as follows : 1. In comparing different shades of same material, CIELAB color difference(${\Delta}E^*$) value was not significantly different from each other(p>0.05). 2. CIELAB color difference(${\Delta}E^*$) values between after-curing and after-polishing were ranged from 5.53 to 27.08. These values were higher than those of other condition combinations. 3. CIELAB color difference(${\Delta}E^*$) values between before-thermocycling and after-thermocycling were ranged from 1.40 to 7.81. Despite the number of thermocycling increased, CIELAB color difference(${\Delta}E^*$) value was low. 4. The color stability of resin modified glass ionomers was more stable than that of conventional glass ionomers but less stable than that of Z100.

• 구강회복응용과학지
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• 제38권1호
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• pp.69-69
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• 2022

• 대한소아치과학회지
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• 제51권2호
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• pp.132-139
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• 2024

This study aimed to compare the fluoride-releasing ability and degree of microbial attachment of a newly developed glass-hybrid restorative material (GH) with those of a high-viscosity glass ionomer (HvGIC), resin-modified glass ionomer (RMGI), and composite resin (CR). In addition, the correlation between fluoride-releasing ability and microbial attachment between materials was evaluated. Specimens were prepared in a disc shape and divided into 4 groups according to the materials (GH, HvGIC, RMGI, and CR). The fluoride release experiments were performed in each group (n = 15). The amount of fluoride released was measured on days 1, 3, 7, 14, 28, and 42 after storage. For the microbial attachment experiment, 12 specimens were produced per group using Mutans Streptococci (S.mutans ), a cariogenic microorganism. S. mutans was cultured on the specimens for 24 hours, and the number of bacteria was measured. GH had the highest cumulative fluoride release and showed a significant difference when compared with RMGI (p = 0.001) and CR (p < 0.0001). Microbial attachment was the lowest in GH; however, no significant difference was observed between the materials (p = 0.169). There was no significant correlation between fluoride release from materials and microbial attachment (p > 0.05). From this perspective, remineralization of low-mineralized areas could be expected due to the high fluoride release of GH, and the effect of delaying the progression of dental caries could be predicted from the low cariogenic microbial attachment. Therefore, GH might be a useful restorative material for treating immature permanent teeth with hypomineralized enamel. However, further studies are needed about the degree of remineralization of hypomineralized areas after restoration and the capacity to recharge fluoride.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.255-261
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• 2016

Objectives: This study aimed to analyze the mineral composition of naturally- and artificially-produced caries-affected root dentin and to determine the elemental incorporation of resin-modified glass ionomer (RMGI) into the demineralized dentin. Materials and Methods: Box-formed cavities were prepared on buccal and lingual root surfaces of sound human premolars (n = 15). One cavity was exposed to a microbial caries model using a strain of Streptococcus mutans. The other cavity was subjected to a chemical model under pH cycling. Premolars and molars with root surface caries were used as a natural caries model (n = 15). Outer caries lesion was removed using a carbide bur and a hand excavator under a dyeing technique and restored with RMGI (FujiII LC, GC Corp.). The weight percentages of calcium (Ca), phosphate (P), and strontium (Sr) and the widths of demineralized dentin were determined by electron probe microanalysis and compared among the groups using ANOVA and Tukey test (p < 0.05). Results: There was a pattern of demineralization in all models, as visualized with scanning electron microscopy. Artificial models induced greater losses of Ca and P and larger widths of demineralized dentin than did a natural caries model (p < 0.05). Sr was diffused into the demineralized dentin layer from RMGI. Conclusions: Both microbial and chemical caries models produced similar patterns of mineral composition on the caries-affected dentin. However, the artificial lesions had a relatively larger extent of demineralization than did the natural lesions. RMGI was incorporated into the superficial layer of the caries-affected dentin.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.45.1-45.11
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• 2018

Objectives: This study was conducted to evaluate fluoride release and the micro-shear bond strength of resin-modified glass ionomer cement (RMGIC) in casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-remineralized caries-affected dentin (CAD). Materials and Methods: Exposed dentin surfaces of 30 human third molar teeth were divided into 2 equal groups for evaluating fluoride release and the micro-shear bond strength of RMGIC to CAD. Each group was subdivided into 3 equal subgroups: 1) control (sound dentin); 2) artificially demineralized dentin (CAD); 3) CPP-ACP remineralized dentin (remineralized CAD). To measure fluoride release, 15 disc-shaped specimens of RMGIC (4 mm in diameter and 2 mm in thickness) were bonded on one flat surface of the dentin discs of each group. Fluoride release was tested using ion chromatography at different intervals; 24 hours, 3, 5, 7 days. RMGIC micro-cylinders were built on the flat dentin surface of the 15 discs, which were prepared according to the assigned group. Micro-shear bond strength was measured after 24 hours water storage. Data were analyzed using 1- and 2-way analysis of variance and the post hoc least significant difference test (${\alpha}=0.05$). Results: Fluoride detected in solutions (at all intervals) and the micro-shear bond strength of RMGIC bonded to CPP-ACP-remineralized dentin were significantly higher than those bonded to artificial CAD (p < 0.05). Conclusions: Demineralized CAD consumes more fluoride released from RMGIC into the solution for remineralization than CPP-ACP mineralized dentin does. CPP-ACP increases the micro-shear bond strength of RMGIC to CAD.

• 대한소아치과학회지
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• 제38권3호
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• pp.244-249
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• 2011

글라스 아이오노머 시멘트는 초기 우식 치질에 재광화 효과가 있다고 알려져 있다. 본 연구에서는 시판되고 있는 세 가지 종류의 글라스 아이오노머 시멘트(Fuji IX $GP^{TM}$, $Vitremer^{TM}$, $F2000^{TM}$)를 실험군으로, 복합 레진(Filtek $Z250^{TM}$)을 대조군으로 사용하여 3개월간 인접면 우식증에 대한 재광화 효과를 시편의 파괴 없이 1개월 간격으로 QLF로 시편의 상을 얻고, 이렇게 얻은 상의 무기질 소실량(${\Delta}Q$)을 측정하여 ${\Delta}Q$의 변화량을 계산하여 시편의 재광화 정도를 평가하였다. 인접면 수복물은 인공 우식 병소가 있는 치아 시편과 수복재료(세 가지 글라스 아이오노머 및 복합 레진)를 접촉시켜 재현하였고, 이것을 인공 타액에 완전히 잠기도록 하여 pH 7.0, $37^{\circ}C$를 유지하였다. 치아 시편들은 실험 시작 후 30, 60, 90일 뒤에 꺼내어 QLF로 촬영하였다. 얻어진 영상을 QLF를 이용하여 시편 각각의 무기질 소실량(${\Delta}Q$)을 측정하였고, ${\Delta}Q$의 변화량(${\Delta}{\Delta}Q$), 즉 무기질 소실 변화량을 계산하여 얻어진 값을 ANOVA로 분석하고, Dunnett C multiple comparison test로 사후 검정을 시행하여 다음과 같은 결과를 얻었다. 1. 모든 군에서 병소의 무기질 소실량(${\Delta}Q$)이 증가하였다. 2. 무기질 소실량(${\Delta}Q$)의 변화량인 무기실 소실 변화량(${\Delta}{\Delta}Q$)은, 1 개월 후에는 글라스 아이오노머 시멘트가 복합레진에 비해 유의하게 컸으며(p<0.05), 글라스 아이오노머 중에서는 Fuji IX $GP^{TM}$가 $Vitremer^{TM}$, $F2000^{TM}$에 비해 유의하게 컸다(p<0.05). 2 개월 후에는 Fuji IX $GP^{TM}$가 나머지 군에 비해 ${\Delta}{\Delta}Q$가 유의하게 컸으며(p<0.05), 3 개월 후에는 모든 군간에 ${\Delta}{\Delta}Q$의 유의한 차이가 없었다. 3. 세 가지 글라스 아이오노머 시멘트에서 무기실 소실 변화량(${\Delta}{\Delta}Q$), 즉 재광화 정도는 시간이 지날수록 점차 감소하였다. 4. 대조군인 복합 레진 군에서도 무기실 소실 변화량(${\Delta}{\Delta}Q$)은 증가하였다.

• Restorative Dentistry and Endodontics
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• 제43권3호
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• pp.32.1-32.11
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• 2018

Objectives: This study evaluated the effects of a bleaching agent on the composition, mechanical properties, and surface topography of 6 conventional glass-ionomer cements (GICs) and one resin-modified GIC. Materials and Methods: For 3 days, the specimens were subjected to three 20-minute applications of a 37% $H_2O_2$-based bleaching agent and evaluated for water uptake (WTK), weight loss (WL), compressive strength (CS), and Knoop hardness number (KHN). Changes in surface topography and chemical element distribution were also analyzed by energy-dispersive X-ray spectroscopy and scanning electron microscopy. For statistical evaluation, the Kruskal-Wallis and Wilcoxon paired tests (${\alpha}=0.05$) were used to evaluate WTK and WL. CS specimens were subjected to 2-way analysis of variance (ANOVA) and the Tukey post hoc test (${\alpha}=0.05$), and KH was evaluated by one-way ANOVA, the Holm-Sidak post hoc test (${\alpha}=0.05$), and the t-test for independent samples (${\alpha}=0.05$). Results: The bleaching agent increased the WTK of Maxxion R, but did not affect the WL of any GICs. It had various effects on the CS, KHN, surface topography, and the chemical element distribution of the GICs. Conclusions: The bleaching agent with 37% $H_2O_2$ affected the mechanical and surface properties of GICs. The extent of the changes seemed to be dependent on exposure time and cement composition.