Aksornmuang Juthatip, Nakajima Masatoshi, Foxton Richard M, Tagami Junji
Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
Dent Mater. 2007 Feb;23(2):226-34. doi: 10.1016/j.dental.2006.01.014. Epub 2006 Feb 21.
To evaluate the regional mechanical properties of dual-cure resin composites and their regional bond strengths to root canal dentin.
One of the following dual-cure resin composites was placed in artificial post spaces: Unifil Core (UC), Clearfil DC Core (DC), Build-It FR (BI), Clearfil DC Core-automix (DCA), and photo-cured for 60s. After 24h storage, each specimen was serially sliced to harvest eight hour-glass shaped specimens for measurement of regional ultimate tensile strength (UTS), and the remaining eight semi-circular slabs were polished for the measurement of Knoop Hardness Number (KHN). For the microtensile bond strength (muTBS) test, post cavities were prepared in human premolar roots, and the cavity surfaces treated with Clearfil SE Bond and photo-cured for 10s. The post spaces were then filled with one of the above resin composites and photo-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6x0.6 mm-thick beams for the muTBS test. The data were divided into coronal and apical regions and analyzed using ANOVA and post hoc test (alpha=0.05).
UTS and KHN were affected by the type of dual-cure resin composite and region (p<0.0001). There was no relationship between UTS and KHN for each material. The auto-mix type of resin composite possessed superior UTS to that of the hand-mix type. muTBS among the four composite materials were not significantly different at both apical and coronal regions (p>0.05). Regional differences in bond strengths were found for all materials (p<0.05).
The UTS and KHN of the dual-cure resin composites varied among each material, however, differences in the mechanical properties of the resin core materials did not affect their adhesion to root canal dentin.
评估双固化树脂复合材料的区域力学性能及其与根管牙本质的区域粘结强度。
将以下双固化树脂复合材料之一置于人工桩道内：Unifil Core（UC）、Clearfil DC Core（DC）、Build-It FR（BI）、Clearfil DC Core-automix（DCA），并光固化60秒。储存24小时后，将每个标本依次切片，获取八个沙漏形标本以测量区域极限拉伸强度（UTS），其余八个半圆形板进行抛光以测量努氏硬度值（KHN）。对于微拉伸粘结强度（muTBS）测试，在人前磨牙牙根中制备桩腔，并用Clearfil SE Bond处理腔面并光固化10秒。然后用上述树脂复合材料之一填充桩道并光固化60秒。储存24小时后，将每个标本依次切成8个0.6×0.6毫米厚的梁用于muTBS测试。数据分为冠部和根尖部区域，并使用方差分析和事后检验进行分析（α=0.05）。
UTS和KHN受双固化树脂复合材料类型和区域的影响（p<0.0001）。每种材料的UTS和KHN之间没有关系。自动混合型树脂复合材料的UTS优于手工混合型。四种复合材料在根尖部和冠部区域的muTBS均无显著差异（p>0.05）。所有材料的粘结强度均存在区域差异（p<0.05）。
双固化树脂复合材料的UTS和KHN在每种材料之间各不相同，然而，树脂核材料力学性能的差异并未影响它们与根管牙本质的粘结。
