乙醇润湿对根部牙本质表面形貌及纳米粘附力的影响

Surface characterization of morphology and nano-scale adhesion force on ethanol saturated root dentin

目的利用原子力显微镜观察乙醇润湿处理后牙本质的表面形貌,并检测其表面纳米粘附力的改变,探讨乙醇润湿技术用于提高牙本质粘接效果的临床作用机制。方法将人单根管前磨牙制成根部牙本质片并打磨抛光、酸蚀冲洗后,随机分成5组,分别用无水乙醇处理0s(对照组)、20s、60s、3×60s或梯度乙醇处理样本;原子力显微镜在空气环境中检测乙醇润湿后的牙本质表面特性;利用SPSS 16.0对结果进行单因素方差分析和Tukey检验。结果和对照组相比,随着乙醇使用时间的延长,牙本质表面波浪形的形貌越不明显,逐渐趋于平滑,牙本质纳米粘附力明显降低(P<0.001),其中3×60s组和梯度乙醇组的值最低,且两组间差异无统计学意义(P>0.05)。结论在空气环境中采用原子力显微镜检测时,随着乙醇使用时间的延长,牙本质表面波浪形的形貌逐渐趋于平滑,纳米粘附力越低,表明增加乙醇润湿处理时间可使牙本质胶原纤维网中的水分置换越充分,提高牙本质粘接界面的疏水性。

Objective To observe the morphology of ethanol-wet dentin surfaces and detect their nano-scale adhesion force （Fad） by atomic force microscopy （AFM） in order to explore the potential mechanism of ethanol-wet bonding in improving clinical dentin bonding effectiveness. Methods Dentin slices from human premolar roots were prepared into flat ones, polished, and then randomly divided into five groups. All the specimens were acid- etched, rinsed, and left moist. They were then treated with 100% ethanol for 0 s （control group）, 20 s, 60 s, 3 X 60 s, or stepwise ethanol application. Afterwards, each group was scanned for the morphology in air and the Fad was probed by AFM. One-way ANOVA followed by Tukey＇s test was employed for multiple comparisons using SPSS16.0. Results Compared with control group, ethanol-wet dentine produced a less undulating and relatively smooth surface topography. Ethanol-wet protocol significantly decreased the value of Fad in the experimental groups （P〈0. 001）, in which 3 × 60 s and stepwise ethanol application groups showed the lowest Fad. No difference was found between these two groups （P〈0.05）. Conclusion When using AFM in air, ethanol-wet protocol with longer time can produce a less undulating and relatively smooth surface topography and decrease the Fad, which indicates that the water saturated in dentin matrix was replaced more thoroughly by longer ethanol application time. This will benefit hydrophobicity of the dentin bonding interface.