School of Materials Science and Engineering, Clemson University, 161 Sirrine Hall, Clemson, SC 29634, United States.
J Mech Behav Biomed Mater. 2010 May;3(4):339-46. doi: 10.1016/j.jmbbm.2010.01.005. Epub 2010 Feb 21.
The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation analysis with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0 GPa versus 113.4 GPa), while smaller increases were observed in the dentin (17.9 GPa versus 27.9 GPa). Likewise, there was an increase in the hardness of enamel (2.0 GPa versus 4.3 GPa) and dentin (0.5 GPa versus 0.7 GPa) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in the literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips, Opalescence or UltraEtch caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips showed a reduction in the elastic modulus of enamel (55.3 GPa to 32.7 GPa) and increase in the elastic modulus of dentin (17.2 GPa to 24.3 GPa). Opalescence treatments did not significantly affect the enamel properties, but did result in a decrease in the modulus of dentin (18.5 GPa to 15.1 GPa). Additionally, as expected, UltraEtch treatment decreased the modulus and hardness of enamel (48.7 GPa to 38.0 GPa and 1.9 GPa to 1.5 GPa, respectively) and dentin (21.4 GPa to 15.0 GPa and 1.9 GPa to 1.5 GPa, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy.
牙本质和牙釉质的机械性能会影响牙齿的可靠性和磨损性能。本研究探讨了临床牙科治疗和程序的影响，如美白治疗或修复前的蚀刻。为了允许与已发表的值进行比较，并提高临床相关性，研究了高压灭菌和非高压灭菌的牙齿。使用奥利弗-菲尔模型的纳米压痕分析提供了贯穿牙本质-釉质交界处（DEJ）的弹性模量和硬度。在经过高压灭菌的牙齿中，牙釉质的弹性模量观察到较大的增加（52.0 GPa 对 113.4 GPa），而牙本质的增加较小（17.9 GPa 对 27.9 GPa）。同样，牙釉质的硬度也有所增加（2.0 GPa 对 4.3 GPa）和牙本质（0.5 GPa 对 0.7 GPa）随着高压灭菌而增加。这些变化表明，文献中以前报道的弹性模量和硬度值范围可能部分归因于灭菌程序。使用 Crest Whitestrips、Opalescence 或 UltraEtch 处理非高压灭菌牙齿的外表面会导致牙釉质和牙本质的机械性能发生变化。用 Crest Whitestrips 处理的牙齿，牙釉质的弹性模量降低（55.3 GPa 至 32.7 GPa），牙本质的弹性模量增加（17.2 GPa 至 24.3 GPa）。Opalescence 处理对牙釉质特性没有显著影响，但确实导致牙本质的模量降低（18.5 GPa 至 15.1 GPa）。此外，如预期的那样，UltraEtch 处理降低了牙釉质和牙本质的模量和硬度（分别为 48.7 GPa 至 38.0 GPa 和 1.9 GPa 至 1.5 GPa，以及 21.4 GPa 至 15.0 GPa 和 1.9 GPa 至 1.5 GPa）。机械性能的变化与牙齿内蛋白质浓度的变化有关，这可以通过荧光显微镜和傅里叶变换红外光谱来证明。
