Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
J Biomed Mater Res A. 2010 Jul;94(1):288-97. doi: 10.1002/jbm.a.32692.
The objective was to determine absolute molar concentration of adhesive resin components in the hybrid layer by establishing methods based on Raman spectroscopy fundamentals. The hybrid layer was treated as a three-component system consisting of collagen and an adhesive resin containing two monomers. Adhesive standard specimens and Raman peak area ratios obtained with a 785 nm excitation wavelength were used to construct separate calibration curves for comonomer relative molar concentration and Bis-GMA absolute molar concentration. As collagen and water had no measurable peaks in the fingerprint region, a dilution coefficient K(j) was defined to describe their impact on Raman peak area and to calculate HEMA absolute molar concentration. Methodology was validated using an analogous system containing acetone/ethanol/water. The absolute molar concentration of Bis-GMA and HEMA decreased 87% and 83%, respectively, from the top quarter to the middle of the hybrid layer. Additionally, less Bis-GMA penetrated the hybrid layer than HEMA, as indicated by the approximately 20% decrease in comonomer molar concentration ratio between the adhesive resin layer and the top half of the hybrid layer. Lack of complete monomer infiltration will further challenge dentin-adhesive bond longevity. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.
目的是通过建立基于拉曼光谱基本原理的方法，来确定混合层中粘合树脂成分的绝对摩尔浓度。将混合层视为由胶原蛋白和含有两种单体的粘合树脂组成的三组分体系。使用 785nm 激发波长获得的粘合标准样品和拉曼峰面积比来构建两种单体相对摩尔浓度和 Bis-GMA 绝对摩尔浓度的单独校准曲线。由于胶原蛋白和水在指纹区域没有可测量的峰，因此定义了一个稀释系数 K(j)，用于描述它们对拉曼峰面积的影响，并计算 HEMA 的绝对摩尔浓度。该方法使用含有丙酮/乙醇/水的类似系统进行了验证。从混合层的上四分之一到中间，Bis-GMA 和 HEMA 的绝对摩尔浓度分别降低了 87%和 83%。此外，与粘合树脂层和混合层上半部分之间的单体摩尔浓度比相比，Bis-GMA 渗透到混合层的深度较小，表明 HEMA 的渗透深度较小。不完全的单体渗透将进一步挑战牙本质-粘合的耐久性。（c）2010 年 Wiley 期刊，生物医学材料研究，2010 年。
