Pedreira Ana Paula R V, Pegoraro Luiz Fernando, de Góes Mario Fernando, Pegoraro Thiago Amadei, Carvalho Ricardo Marins
Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Dent Mater. 2009 Jul;25(7):868-76. doi: 10.1016/j.dental.2009.01.096. Epub 2009 Feb 12.
To analyze the microhardness of four dual-cure resin cements used for cementing fiber-reinforced posts under the following conditions: after 7 days of storage in water, after additional 24h of immersion in 75% ethanol, and after 3 months of storage in water. Hardness measurements were taken at the cervical, middle and apical thirds along the cement line.
Root canals of 40 bovine incisors were prepared for post space. Fibrekor glass fiber-reinforced posts (Jeneric/Pentron) of 1mm in diameter were cemented using Panavia F 2.0 (Kuraray), Variolink (Ivoclar-Vivadent), Rely X Unicem (3M ESPE) or Duolink (Bisco) (N=10). After 7 days of water storage at 37 degrees C, half the sample (N=5) was longitudinally sectioned and the initial microhardness measured along the cement line from cervical to apex. These same samples were further immersed in 75% ethanol for 24h and reassessed. The remaining half (N=5) was kept unsectioned in deionized water at 37 degrees C for 3 months, followed by sectioning and measuring. Data were analyzed by a series of two-way ANOVA and Tukey tests at alpha=5%.
Statistically significant differences were identified among the cements, thirds and conditions. Significant interactions were also observed between cements and thirds and between cements and conditions. Panavia F exhibited significantly higher initial microhardness than the other three cements, which showed no statistical difference among themselves. Variolink and Duolink showed significantly higher microhardness values in the cervical third, without significant difference among the thirds for the other cements. Immersion in ethanol significantly reduced the hardness values for all cements, regardless of the thirds. Storage in water for 3 months had no influence on the hardness of most of the cements, with the exception of Unicem that showed a significant increase in the hardness values after this period.
Results showed heterogeneity in the microhardness of the cements inside the canal. All cements presented some degree of softening after ethanol treatment, which suggests instability of the polymer. The quality of curing of resin cements in the root canal environment seems unpredictable and highly material dependent.
分析四种双固化树脂水门汀在以下条件下用于粘结纤维增强桩时的显微硬度：在水中储存7天后、在75%乙醇中再浸泡24小时后以及在水中储存3个月后。沿着水门汀线在颈部、中部和根尖三分之一处进行硬度测量。
准备40颗牛切牙的根管以制作桩道。使用Panavia F 2.0（可乐丽）、Variolink（义获嘉伟瓦登特）、Rely X Unicem（3M ESPE）或Duolink（必思科）粘结直径为1mm的Fibrekor玻璃纤维增强桩（杰纳里克/彭特龙）（N = 10）。在37℃水中储存7天后，将一半样本（N = 5）纵向切片，并沿水门汀线从颈部到根尖测量初始显微硬度。将这些相同的样本进一步在75%乙醇中浸泡24小时并重新评估。其余一半（N = 5）在37℃的去离子水中未切片保存3个月，然后切片并测量。数据通过一系列双因素方差分析和Tukey检验进行分析，α = 5%。
在水门汀、三分之一部位和条件之间发现了统计学上的显著差异。在水门汀和三分之一部位之间以及水门汀和条件之间也观察到了显著的相互作用。Panavia F表现出比其他三种水门汀显著更高的初始显微硬度，而其他三种之间没有统计学差异。Variolink和Duolink在颈部三分之一处表现出显著更高的显微硬度值，其他水门汀在各三分之一部位之间没有显著差异。无论在哪个三分之一部位，浸泡在乙醇中都会显著降低所有水门汀的硬度值。在水中储存3个月对大多数水门汀的硬度没有影响，但Unicem在此期间后硬度值显著增加。
结果表明根管内水门汀的显微硬度存在异质性。所有水门汀在乙醇处理后都出现了一定程度的软化，这表明聚合物的不稳定性。树脂水门汀在根管环境中的固化质量似乎不可预测且高度依赖材料。
