Kinney J H, Habelitz S, Marshall S J, Marshall G W
Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, USA.
J Dent Res. 2003 Dec;82(12):957-61. doi: 10.1177/154405910308201204.
It is widely held that the hardness and modulus of dentin increase in proportion to the mineral concentration. To test this belief, we measured hardness and modulus of normal dentin and an altered form of dentin without gap-zone mineralization in wet and dry conditions by AFM nanoindentation to determine if the modulus and hardness scale linearly with mineral concentration. Mineral concentrations in the mid-coronal location of the normal and altered dentins were 44.4 vol% and 30.9 vol%, respectively. Surrounding the pulp of the altered dentin was a region of higher mineralization, 40.5 vol%. The indentation modulus of normal dentin was 23.9 (SD = 1.1) GPa dry and 20.0 (SD = 1.0) GPa wet. In mid-coronal regions of the altered dentin, the indentation modulus was 13.8 (SD = 2.0) GPa dry and 5.7 (SD = 1.4) GPa wet. In the more mineralized regions of the altered dentin, the modulus was 20.4 (SD = 1.8) GPa dry and 5.3 (SD = 0.8) GPa wet; the properties of the altered wet dentin did not correlate with mineral concentration. The results of this study raise doubt as to whether mineral concentration alone is a sufficient endpoint for assessing the success or failure of remineralization approaches in restorative dentistry.
人们普遍认为，牙本质的硬度和模量与矿物质浓度成正比。为了验证这一观点，我们通过原子力显微镜纳米压痕法在湿态和干态条件下测量了正常牙本质和一种无间隙区矿化的改变形式牙本质的硬度和模量，以确定模量和硬度是否与矿物质浓度呈线性关系。正常牙本质和改变后牙本质的冠中部位矿物质浓度分别为44.4体积%和30.9体积%。改变后牙本质牙髓周围是一个矿化程度较高的区域，为40.5体积%。正常牙本质的压痕模量在干态下为23.9（标准差 = 1.1）GPa，在湿态下为20.0（标准差 = 1.0）GPa。在改变后牙本质的冠中区域，压痕模量在干态下为13.8（标准差 = 2.0）GPa，在湿态下为5.7（标准差 = 1.4）GPa。在改变后牙本质矿化程度更高的区域，模量在干态下为20.4（标准差 = 1.8）GPa，在湿态下为5.3（标准差 = 0.8）GPa；改变后湿态牙本质的性能与矿物质浓度无关。这项研究的结果让人怀疑，仅矿物质浓度是否足以作为评估修复牙科中再矿化方法成败的终点指标。
