Meng Xiangfeng, Yoshida Keiichi, Atsuta Mitsuru
Division of Applied Prosthodontics, Nagasaki University, Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
Dent Mater. 2008 May;24(5):594-9. doi: 10.1016/j.dental.2007.06.014. Epub 2007 Jul 31.
To investigate the influence of ceramic thickness on the mechanical properties and polymer structure (degree conversion and cross-linking density) of three dual-cured resin luting agents.
Three dual-cured resin luting agents [Linkmax HV (GC), Nexus 2 (Kerr), and Variolink IIHV (Ivoclar-Vivadent)] were polymerized with or without 800 mW/cm2 irradiation through 0-3-mm-thick GN-I (GC) machinable ceramic. Bar-shape specimens were subjected to three-point bending to determine flexural strength (FS) and elastic modulus (EM) after dry storage at 37 degrees C for 24 h. Knoop hardness was measured on the irradiated surface of disk-shaped specimens before (KHN1) and after (KHN2) storage of 100% ethanol solution at 37 degrees C for 24 h. KHN1 and KHN2 were estimated as indirect indicators of degree of conversion (DC) and cross-linking density, respectively. Data were analyzed by one-way ANOVA and Student-Newman-Keuls test for each luting agent, and four mechanical properties were subjected to regression analysis.
For three resin luting agents with dual-cured mode, FS, EM, KHN1, and KHN2 decreased with the increase of ceramic thickness. FS except for Nexus 2 and EM for three resin luting agents had a positive linear relationship with both KHN1 and KHN2.
The variables tested behaved differently. When the ceramic thickness increased, the chemical cured components of dual-cured resin luting agents did not produce significant compensation for all variables. Mechanical properties and polymer structure of dual-cured resin luting agents was dependent on the intensity of light irradiation.
研究陶瓷厚度对三种双固化树脂粘结剂机械性能和聚合物结构（转化率和交联密度）的影响。
三种双固化树脂粘结剂[Linkmax HV（GC）、Nexus 2（Kerr）和Variolink II HV（Ivoclar-Vivadent）]通过0 - 3毫米厚的GN-I（GC）可加工陶瓷进行有无800 mW/cm²照射聚合。条形试样在37℃干燥储存24小时后进行三点弯曲以测定挠曲强度（FS）和弹性模量（EM）。在盘形试样的照射表面上，在37℃ 100%乙醇溶液中储存24小时之前（KHN1）和之后（KHN2）测量努氏硬度。KHN1和KHN2分别被估计为转化率（DC）和交联密度的间接指标。对每种粘结剂的数据进行单因素方差分析和Student-Newman-Keuls检验，并对四种机械性能进行回归分析。
对于三种双固化模式的树脂粘结剂，FS、EM、KHN1和KHN2均随陶瓷厚度的增加而降低。除Nexus 2外的FS和三种树脂粘结剂的EM与KHN1和KHN2均呈正线性关系。
所测试的变量表现不同。当陶瓷厚度增加时，双固化树脂粘结剂的化学固化成分并未对所有变量产生显著补偿。双固化树脂粘结剂的机械性能和聚合物结构取决于光照射强度。
