A commercially available dental Glass Ionomer Cement (GIC) was studied after setting at room temperature (300 K) to understand its DC electrical conductivity, dielectric and thermal properties. The dental GIC’s are s...A commercially available dental Glass Ionomer Cement (GIC) was studied after setting at room temperature (300 K) to understand its DC electrical conductivity, dielectric and thermal properties. The dental GIC’s are supposed to have free mobile charge carriers like F- ions. Interestingly this material loses its conductivity above 80°C and behaves like a non-polar substance. The frequency dependent dielectric studies also indicate the loss of mobile charge carriers in the samples annealed at 80°C. The DSC and TGA studies indicate that the material loses H2O exothermically at 100°C. This is attributed to the onset of a secondary setting reaction.展开更多
A resin-modified glass-ionomer cement (RMGIC) was studied from a computational point of view. We suggest terpolymer formation by reaction of fixation through a combination of acrylic acid (AA), itaconic acid (IA) and ...A resin-modified glass-ionomer cement (RMGIC) was studied from a computational point of view. We suggest terpolymer formation by reaction of fixation through a combination of acrylic acid (AA), itaconic acid (IA) and an aminoacid derivative (AAD) in different positions. We found that AAD-AA-IA is thermodynamically more stable, but AA-IA-AAD is the combination which can react with glycidyl methacrylate (GM) to form a grafted polymer with two pendant methacrylate groups which can be used later in the process of light-curing. A RMGIC contains a glass powder of calcium-fluoroaluminosilicate acting as the source of cross linking, and for this reason, we have optimized two intramolecular Al3+ tricarboxylate complexes (salt-bridges) formed from the most stable grafted polymers. A possible reaction mechanism for the addition of (GM) to copolymer is proposed.展开更多
In vitro responses of human primary pulp cells (HPCs) and 3T3 mouse fibroblasts to six contempo-rary commercial dental restoratives were evaluated using the WST-1 assay. The results show that Fuji II is not cytotoxic ...In vitro responses of human primary pulp cells (HPCs) and 3T3 mouse fibroblasts to six contempo-rary commercial dental restoratives were evaluated using the WST-1 assay. The results show that Fuji II is not cytotoxic to both cells. Fuji II LC is not cyto-toxic to HPCs but cytotoxic to 3T3 cells, indicating that 3T3 cells are more vulnerable to 2-hydroxyethyl methacrylate (HEMA) than HPCs. Vitremer is very cytotoxic probably due to having diphenyliodonium chloride and HEMA in it. Z100 is very cytotoxic probably due to having triethylene glycol dimethacry-late (TEGDMA) in it. P60 is cytotoxic but less cyto-toxic than Z100 probably due to no TEGDMA in it. Durelon is the most cytotoxic among the six materials studied probably due to the high cytotoxicity of zinc ions. Additionally, the cytotoxcity of the tested mate-rials was found to be dose-dependent.展开更多
目的比较玻璃离子水门汀与流动树脂垫底对深龋近髓磨牙充填后的疼痛及术后敏感性。方法120颗深龋近髓磨牙,随机分为对照组,玻璃离子水门汀组和流动树脂组,每组40颗患牙。对照组采用dycal护髓,玻璃离子水门汀组采用dycal护髓和玻璃离子...目的比较玻璃离子水门汀与流动树脂垫底对深龋近髓磨牙充填后的疼痛及术后敏感性。方法120颗深龋近髓磨牙,随机分为对照组,玻璃离子水门汀组和流动树脂组,每组40颗患牙。对照组采用dycal护髓,玻璃离子水门汀组采用dycal护髓和玻璃离子水门汀垫底,流动树脂组采用dycal护髓和流动树脂垫底,酸蚀粘接后,3组上层均加压充填3M ESPE Filtek^(TM)P60复合树脂。分别于修复后1天,1周,1个月,3个月采用疼痛程度标尺(Visual Analog scales,VAS)记录自觉疼痛程度,采用Ryge评价标准记录对压缩空气刺激的敏感性。结果术后1天、1周、1个月和3个月,对照组与两个实验组之间自觉疼痛程度上差异有统计学意义(P<0.05),各观察期两实验组之间自觉疼痛程度差异无统计学意义(P>0.05)。术后1天和1周,3组之间的术后敏感发生率差异无统计学意义(P>0.05),术后1个月和3个月,玻璃离子水门汀组和流动树脂组与对照组之间差异有统计学意义(P<0.05),而玻璃离子组与流动树脂组之间差异没有统计学意义(P>0.05)。结论在深龋近髓磨牙充填中,双垫底治疗可以降低术后疼痛以及敏感的发生,玻璃离子水门汀和流动树脂之间没有本质区别。展开更多
文摘A commercially available dental Glass Ionomer Cement (GIC) was studied after setting at room temperature (300 K) to understand its DC electrical conductivity, dielectric and thermal properties. The dental GIC’s are supposed to have free mobile charge carriers like F- ions. Interestingly this material loses its conductivity above 80°C and behaves like a non-polar substance. The frequency dependent dielectric studies also indicate the loss of mobile charge carriers in the samples annealed at 80°C. The DSC and TGA studies indicate that the material loses H2O exothermically at 100°C. This is attributed to the onset of a secondary setting reaction.
文摘A resin-modified glass-ionomer cement (RMGIC) was studied from a computational point of view. We suggest terpolymer formation by reaction of fixation through a combination of acrylic acid (AA), itaconic acid (IA) and an aminoacid derivative (AAD) in different positions. We found that AAD-AA-IA is thermodynamically more stable, but AA-IA-AAD is the combination which can react with glycidyl methacrylate (GM) to form a grafted polymer with two pendant methacrylate groups which can be used later in the process of light-curing. A RMGIC contains a glass powder of calcium-fluoroaluminosilicate acting as the source of cross linking, and for this reason, we have optimized two intramolecular Al3+ tricarboxylate complexes (salt-bridges) formed from the most stable grafted polymers. A possible reaction mechanism for the addition of (GM) to copolymer is proposed.
文摘In vitro responses of human primary pulp cells (HPCs) and 3T3 mouse fibroblasts to six contempo-rary commercial dental restoratives were evaluated using the WST-1 assay. The results show that Fuji II is not cytotoxic to both cells. Fuji II LC is not cyto-toxic to HPCs but cytotoxic to 3T3 cells, indicating that 3T3 cells are more vulnerable to 2-hydroxyethyl methacrylate (HEMA) than HPCs. Vitremer is very cytotoxic probably due to having diphenyliodonium chloride and HEMA in it. Z100 is very cytotoxic probably due to having triethylene glycol dimethacry-late (TEGDMA) in it. P60 is cytotoxic but less cyto-toxic than Z100 probably due to no TEGDMA in it. Durelon is the most cytotoxic among the six materials studied probably due to the high cytotoxicity of zinc ions. Additionally, the cytotoxcity of the tested mate-rials was found to be dose-dependent.
文摘目的比较玻璃离子水门汀与流动树脂垫底对深龋近髓磨牙充填后的疼痛及术后敏感性。方法120颗深龋近髓磨牙,随机分为对照组,玻璃离子水门汀组和流动树脂组,每组40颗患牙。对照组采用dycal护髓,玻璃离子水门汀组采用dycal护髓和玻璃离子水门汀垫底,流动树脂组采用dycal护髓和流动树脂垫底,酸蚀粘接后,3组上层均加压充填3M ESPE Filtek^(TM)P60复合树脂。分别于修复后1天,1周,1个月,3个月采用疼痛程度标尺(Visual Analog scales,VAS)记录自觉疼痛程度,采用Ryge评价标准记录对压缩空气刺激的敏感性。结果术后1天、1周、1个月和3个月,对照组与两个实验组之间自觉疼痛程度上差异有统计学意义(P<0.05),各观察期两实验组之间自觉疼痛程度差异无统计学意义(P>0.05)。术后1天和1周,3组之间的术后敏感发生率差异无统计学意义(P>0.05),术后1个月和3个月,玻璃离子水门汀组和流动树脂组与对照组之间差异有统计学意义(P<0.05),而玻璃离子组与流动树脂组之间差异没有统计学意义(P>0.05)。结论在深龋近髓磨牙充填中,双垫底治疗可以降低术后疼痛以及敏感的发生,玻璃离子水门汀和流动树脂之间没有本质区别。
