Structure and mechanical properties of the soft zone separating bulk dentin and enamel in crowns of human teeth: Insight into tooth function
Structure and mechanical properties of the soft zone separating bulk dentin and enamel in crowns of human teeth: Insight into tooth function
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DOI：
10.1016/j.jsb.2005.10.010
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发表时间：
2006-02-01
影响因子：
3
通讯作者：
Weiner, S
中科院分区：
文献类型：
--
作者：
Zaslansky, P;Friesem, AA;Weiner, S
牙本质软区位于人类牙冠的釉质下，约200-300 μ m，被认为在牙齿功能中发挥重要作用。但对其结构-力学关系知之甚少。骨折表面的扫描电子显微镜图像显示，在牙本质-釉质交界处（DEJ）附近，管间牙本质的多孔网状基质包含小管，没有管周衬里。管周牙本质在离DEJ一定距离处，随着深度的增加逐渐变厚。同时，观察到胶原纤维的紧密堆积，纤维上和纤维之间的矿物质沉积逐渐增加。已知该结构梯度区在测试显微硬度时较软。当使用莫尔干涉法测量时，它经历比大块牙本质更大的应变。我们通过非接触式激光散斑干涉法（ESPI）研究了该区域的变形和刚度，并在水中进行压缩测试期间跟踪了纳米级变形。我们报告了一个显着降低刚度的这一地区相比，散装牙本质。中颊区域或牙齿平均为3.5 GPa，而中舌区域为9.7 GPa。我们的研究结果支持和扩展的假设，即整个牙齿的耐久性依赖于颊舌不对称匹配的刚度通过所有的界面：釉质和散装牙本质之间的缓冲软层。(C)2005年爱思唯尔公司All rights reserved.
The 200-300 mu m soft zone of dentin, found beneath enamel in crowns of human teeth, is thought to fulfill important roles in tooth function. but little is known about its structure-mechanical relations. Scanning electron microscopy images of fracture Surfaces showed that near the dentino-enamel junction (DEJ), a porous reticulate matrix of intertubular-dentin contains tubules with no peritubular lining. Peritubular-dentin however is found at some distance from the DEJ, and it gradually thickens kith increasing depth into the bulk dentin. Concurrently, tighter packing of the collagen fibers is observed with a gradual increase in mineral deposits on and between the fibers. This structurally graded zone is known to be softer when tested for micro-hardness. It undergoes greater strain compared to bulk dentin, when measured using Moire interferometry. We investigated the deformation and stiffness of this zone by means of non-contact laser-speckle interferometry (ESPI), and nanometer-scale deformations were tracked during compression-testing performed in water. We report a significantly reduced stiffness of this zone compared to bulk dentin. with mid-buccal regions or teeth averaging 3.5 GPa compared with 9.7 GPa in mid-lingual regions. Our results support and expand upon the hypothesis that the durability of the whole tooth relies upon a bucco-lingual asymmetric matching of stiffness by means of all interphase: a cushioning soft layer between enamel and bulk dentin. (C) 2005 Elsevier Inc. All rights reserved.