Lippert F, Parker D M, Jandt K D
Department of Oral and Dental Science, University of Bristol, Bristol, UK.
Caries Res. 2004 Sep-Oct;38(5):464-72. doi: 10.1159/000079628.
The aim of the present in vitro study was to investigate the toothbrush abrasion of surface softened enamel using tapping mode atomic force microscopy (TM-AFM) and AFM nanoindentation. TM-AFM investigations showed that the typical prismatic pattern as observed after demineralisation was retained after toothbrushing. The exposure to artificial saliva resulted in the deposition of a 'sausage-shape' material with random orientation. Brushing of these samples did not lead to a complete removal of this deposited material. Enamel mineral loss increased with increasing demineralisation time and increased further, although only to a small extent, due to subsequent toothbrushing. Exposure to artificial saliva did not alter the amount of enamel mineral lost due to the brushing treatment. AFM nanoindentation investigations showed that the three different demineralisation treatments caused three statistically different reductions in both surface hardness and reduced elastic modulus values, with the shortest exposure time having the least effect on the nanomechanical properties of the enamel samples. Toothbrushing did result only in a small increase in hardness and reduced elastic modulus. The present study has shown that toothbrushing of surface softened enamel leads to minor changes in the surface morphology and nanomechanical properties. The amount of enamel lost due to toothbrushing was independent of the demineralisation time and was lower compared to the mineral loss caused by the demineralisation treatments. Furthermore, the exposure to artificial saliva offers minimal protective effect to the softened enamel surface against toothbrushing.
本体外研究的目的是使用轻敲模式原子力显微镜（TM-AFM）和AFM纳米压痕技术研究表面软化牙釉质的牙刷磨损情况。TM-AFM研究表明，脱矿后观察到的典型棱柱图案在刷牙后得以保留。暴露于人工唾液会导致“香肠状”物质随机沉积。刷洗这些样品并不会导致这种沉积物质被完全去除。牙釉质矿物质流失随着脱矿时间的增加而增加，并且由于随后的刷牙，流失量进一步增加，尽管增加幅度较小。暴露于人工唾液并不会改变因刷牙处理导致的牙釉质矿物质流失量。AFM纳米压痕研究表明，三种不同的脱矿处理在表面硬度和降低的弹性模量值方面均导致了三种具有统计学差异的降低，暴露时间最短对牙釉质样品的纳米力学性能影响最小。刷牙仅导致硬度和降低的弹性模量有小幅增加。本研究表明，刷洗表面软化的牙釉质会导致表面形态和纳米力学性能发生微小变化。刷牙导致的牙釉质流失量与脱矿时间无关，并且与脱矿处理导致的矿物质流失相比更低。此外，暴露于人工唾液对软化的牙釉质表面抵抗刷牙的保护作用极小。
