Structural modifications of dentinal microcracks with human aging
Structural modifications of dentinal microcracks with human aging
复制标题
牙本质微裂纹随人类衰老的结构改变
DOI：
10.1093/jmicro/dft028
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发表时间：
2013
期刊：
影响因子：
1.8
通讯作者：
Ryuji Nishi and Fumio Takeshige
中科院分区：
文献类型：
--
作者：
Mizuho Kubo;Jiro Miura;Takao Sakata;Ryuji Nishi and Fumio Takeshige
一些研究报道了裂纹随老化扩展的机制。尽管已经通过使用扫描电子显微镜（SEM）观察裂纹表面来评估牙本质微裂纹随老化的结构变化，但很少尝试使用透射电子显微镜（TEM）对牙本质内部微裂纹进行截面观察。本研究的目的是：(1) 使用 TEM 检查牙本质微裂纹形成的过程；(2) 从形态学角度评估牙本质微裂纹扩展与人类衰老之间的关系。对“年轻”（16-28 岁）和“老年”（62-76 岁）受试者的臼齿进行了评估。牙本质块用压头破裂，并在包埋在环氧树脂中后使用金刚石刀和超薄切片机切片。通过TEM和超高压电子显微镜断层扫描观察微裂纹，以确定年轻和老化牙齿中裂纹扩展的特征。结果表明，在年轻牙齿中，裂纹扩展倾向于穿过牙本质小管，而在老年牙齿中，裂纹扩展倾向于偏向管周牙本质（PTD）外侧，特别是在冠状牙本质中。该方法的优点是它可以可视化和评估牙本质中微裂纹的超微结构传播。年轻牙本质和老化牙本质之间裂纹扩展的差异可以通过 PTD 厚度的差异来解释。
Several studies have reported the mechanism of crack propagation with aging. Although structural modifications of dentinal microcracks with aging have been evaluated by observing the cracked surface using scanning electron microscope (SEM), very few attempts have been made at sectional observation of the microcracks inside dentine using transmission electron microscopy (TEM). The objectives of this study were to: (1) examine the process of dentinal microcrack formation using TEM and (2) to morphologically evaluate the relation between dentinal microcrack propagation and human aging. Molars from ‘young’ (16–28 years) and ‘aged’ (62–76 years) subjects were evaluated. Dentine blocks were cracked with an indenter and sectioned using a diamond knife and ultramicrotome after embedding in epoxy resin. Microcracks were observed by TEM and ultra-high-voltage electron microscope tomography to determine the characteristics of crack propagation in the young and aged teeth. The results show that, in young teeth, crack propagation tended to pass through the dentinal tubules, while in aged teeth, it tended to deflect to the outer side of peritubular dentine (PTD), especially in coronal dentine. The advantage of this method is that it allows visualization and evaluation of the ultrastructural propagation of microcracks in dentine. The differences in crack propagation between young and aged dentine could be explained by differences in PTD thickness.