Huang Lijia, Zhang Xiaoyue, Shao Jian, Zhou Ziyu, Chen Yanan, Hu Xiaoli
Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, SunYat-sen University, Guangzhou 510000, China.
Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510000, China.
J Adv Res. 2019 Dec 30;22:163-171. doi: 10.1016/j.jare.2019.12.004. eCollection 2020 Mar.
Human dentin, as an important calcified tissue in the body, plays significant roles in withstanding masticatory forces and has a complex hierarchical organization. Understanding the composition and ultrastructure of dentin is critical for elucidating mechanisms of biomineralization under healthy and pathological states. Here, atomic force microscope infrared spectroscopy (AFM-IR) and AFM-based amplitude modulation-frequency modulation (AM-FM) techniques were utilized to detect the heterogeneity in chemical composition and mechanical properties between peritubular and intertubular dentin at the nanoscale. AFM-IR spectra collected from peritubular and intertubular dentin contained similar vibrational bands in the amide regions (I, II and III), suggesting that collagen may exist in both structures. A distinctive band at 1336 cm indicative of S[bond, double bond]O stretching vibrations was detected only in peritubular dentin. AFM-IR imaging showed an uneven distribution of chemical components at different locations, confirming the heterogeneity of dentin. The Young's modulus of peritubular dentin was higher, and was associated to a higher mineral content. This study demonstrated distinctive chemical and mechanical properties of peritubular dentin, implying the different development and mineralization processes between peritubular and intertubular dentin. AFM-IR is useful to provide compositional information on the heterogeneity of human dentin, helping to understand the mineral deposition mechanisms of dentin.
人类牙本质作为人体中一种重要的钙化组织，在承受咀嚼力方面发挥着重要作用，并且具有复杂的层次结构。了解牙本质的组成和超微结构对于阐明健康和病理状态下的生物矿化机制至关重要。在此，利用原子力显微镜红外光谱（AFM-IR）和基于原子力显微镜的调幅-调频（AM-FM）技术在纳米尺度上检测管周牙本质和管间牙本质之间化学成分和力学性能的异质性。从管周牙本质和管间牙本质收集的AFM-IR光谱在酰胺区域（I、II和III）包含相似的振动带，表明两种结构中可能都存在胶原蛋白。仅在管周牙本质中检测到一个指示S=O伸缩振动的1336 cm处的独特谱带。AFM-IR成像显示不同位置的化学成分分布不均匀，证实了牙本质的异质性。管周牙本质的杨氏模量较高，且与较高的矿物质含量相关。本研究证明了管周牙本质独特的化学和力学性能，这意味着管周牙本质和管间牙本质之间不同的发育和矿化过程。AFM-IR有助于提供关于人类牙本质异质性的成分信息，有助于理解牙本质的矿物质沉积机制。
