Xie Z, Swain M V, Hoffman M J
Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
J Dent Res. 2009 Jun;88(6):529-33. doi: 10.1177/0022034509337130.
Tooth enamel is the hardest tissue in the human body and is directly responsible for dental function. Due to its non-regenerative nature, enamel is unable to heal and repair itself biologically after damage. We hypothesized that with its unique microstructure, enamel possesses excellent resistance to contact-induced damage, regardless of loading direction. By combining instrumented indentation tests with microstructural analysis, we report that enamel can absorb indentation energy through shear deformation within its protein layers between apatite crystallites. Moreover, a near-isotropic inelastic response was observed when we analyzed indentation data in directions either perpendicular or parallel to the path of enamel prisms. An "effective" crystal orientation angle, 33 degrees -34 degrees , was derived for enamel microstructure, independent of the loading direction. These findings will help guide the design of the nanostructural architecture of dental restorative materials.
牙釉质是人体中最坚硬的组织，直接负责牙齿功能。由于其不可再生的特性，牙釉质受损后无法自行进行生物愈合和修复。我们推测，凭借其独特的微观结构，无论加载方向如何，牙釉质都具有出色的抗接触损伤能力。通过将仪器化压痕测试与微观结构分析相结合，我们发现牙釉质能够通过磷灰石微晶之间蛋白质层内的剪切变形来吸收压痕能量。此外，当我们在垂直或平行于牙釉质棱柱路径的方向上分析压痕数据时，观察到了近各向同性的非弹性响应。对于牙釉质微观结构，得出了一个与加载方向无关的“有效”晶体取向角，为33度至34度。这些发现将有助于指导牙科修复材料纳米结构的设计。
