Angker Linny, Nockolds Clive, Swain Michael V, Kilpatrick Nicky
Biomaterials Science Research Unit, Faculty of Dentistry, The University of Sydney, United Dental Hospital, 2 Chalmer St, Surry Hills, NSW 2010, Australia.
Arch Oral Biol. 2004 Feb;49(2):99-107. doi: 10.1016/j.archoralbio.2003.08.006.
Backscattered electron-scanning electron microscope (BSE-SEM) imaging has been recommended as a reliable tool to quantify the mineralisation state of calcified tissues and is commonly used in bone studies. The aim of this study is to investigate the use of BSE imaging to quantitatively analyse the mineral content of sound and carious dentine. Eight primary molars with untreated carious dentine were embedded in resin, axially sectioned and fine polished for this study. The BSE images were from a solid-state detector in an SEM operating at 1.5Torr gas pressure. BSE images of a number of different elements and compounds with atomic number ranged from 4 to 26 were analysed prior to the test to calibrate the experimental conditions and an enamel-carbon block. The mineral analysis was based on the change in BSE intensity (measured in graylevels). The results showed that variation in graylevels accurately represented difference in the atomic number and BSE coefficient of the test materials. The mineral content of sound primary dentine in the most regions was 59.3+/-5.5 wt.%, but it decreased gradually to be just 41.82+/-6.74 wt.% adjacent to the pulp. The carious dentine showed a marked reduction in mineral content which proceeded progressively toward the cavity floor, in which the minimum value of less than 10 wt.% was normally found in the outer layer of the lesion. The results show that BSE imaging is a simple and reliable technique that can be used to quantify the mineral content of sound and carious dentine. More importantly the variable pressure SEM offers an approach to minimize the impact of dehydration on carious dentine specimens.
背散射电子扫描电子显微镜（BSE-SEM）成像已被推荐为一种量化钙化组织矿化状态的可靠工具，常用于骨骼研究。本研究的目的是探讨使用BSE成像定量分析健康和龋坏牙本质的矿物质含量。将八颗患有未经治疗龋坏牙本质的乳牙嵌入树脂中，进行轴向切片并精细抛光用于本研究。BSE图像来自于在1.5托气压下运行的扫描电子显微镜中的固态探测器。在测试之前，分析了原子序数范围从4到26的多种不同元素和化合物的BSE图像，以校准实验条件和一个牙釉质-碳块。矿物质分析基于BSE强度的变化（以灰度级测量）。结果表明，灰度级的变化准确地反映了测试材料的原子序数和BSE系数的差异。大多数区域健康乳牙本质的矿物质含量为59.3±5.5 wt.%，但在靠近牙髓处逐渐降低至仅41.82±6.74 wt.%。龋坏牙本质的矿物质含量显著降低，且向龋洞底部逐渐减少，在病变外层通常发现其最小值小于10 wt.%。结果表明，BSE成像为一种简单可靠的技术，可用于定量分析健康和龋坏牙本质的矿物质含量。更重要的是，可变压力扫描电子显微镜提供了一种方法，可将脱水对龋坏牙本质标本的影响降至最低。
