Institute for Multiphase Processes, Leibniz University Hannover, Hannover, Germany.
Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway.
Int Endod J. 2021 Aug;54(8):1275-1288. doi: 10.1111/iej.13527. Epub 2021 May 3.
To introduce a methodology designed to simultaneously visualize dental ultrastructures, including cellular and soft tissue components, by utilizing phosphotungstic acid (PTA) as a contrast-enhancement agent.
Sound third molars were collected from healthy human adults and fixed in 4% buffered paraformaldehyde. To evaluate the impact of PTA in concentrations of 0.3%, 0.7% and 1% on dental soft and hard tissues for CT imaging, cementum and dentine-pulp sections were cut, dehydrated and stained with immersion periods of 12, 24 h, 2 days or 5 days. The samples were scanned in a high-resolution nano-CT device using pixel sizes down to 0.5 µm to examine both the cementum and pulpal regions.
Dental cementum and periodontium as well as odontoblasts and predentine were made visible through PTA staining in high-resolution three-dimensional nano-CT scans. Different segments of the tooth required different staining protocols. The thickness of the cementum could be computed over the length of the tooth once it was made visible by the PTA-enhanced contrast, and the attached soft tissue components of the interior of the tooth could be shown on the dentine-pulp interface in greater detail. Three-dimensional illustrations allowed a histology-like visualization of the sections in all orientations with a single scan and easy sample preparation. The segmentation of the sigmoidal dentinal tubules and the surrounding dentine allowed a three-dimensional investigation and quantitative of the dentine composition, such as the tubular lumen or the ratio of the tubular lumen area to the dentinal surface.
The staining protocol made it possible to visualize hard tissues along with cellular layers and soft tissues in teeth using a laboratory-based nano-CT technique. The protocol depended on both tissue type and size. This methodology offers enhanced possibilities for the concomitant visualization of soft and hard dental tissues.
介绍一种同时可视化牙齿超微结构的方法，包括细胞和软组织成分，利用磷钨酸（PTA）作为对比增强剂。
从健康成年人的第三磨牙中采集声音，并固定在 4%缓冲多聚甲醛中。为了评估 PTA 在 0.3%、0.7%和 1%浓度下对牙齿软、硬组织 CT 成像的影响，对牙骨质和牙髓-牙本质切片进行切割、脱水和染色，浸泡时间为 12、24、2 天或 5 天。使用像素大小低至 0.5µm 的高分辨率纳米 CT 设备对样品进行扫描，以检查牙骨质和牙髓区域。
通过 PTA 染色，在高分辨率三维纳米 CT 扫描中可以看到牙齿牙骨质和牙周组织以及成牙本质细胞和前期牙本质。牙齿的不同部位需要不同的染色方案。一旦 PTA 增强对比度使牙骨质可见，就可以计算出牙的长度上的牙骨质厚度，并且可以更详细地显示牙齿内部的附着软组织成分。三维图允许在所有方向上对切片进行类似于组织学的可视化，并且易于进行样本制备。可以对牙本质管的分形和周围牙本质进行分割，从而对牙本质成分进行三维研究和定量分析，例如管腔或管腔面积与牙本质表面的比值。
染色方案使得使用基于实验室的纳米 CT 技术可视化牙齿中的硬组织以及细胞层和软组织成为可能。该方案取决于组织类型和大小。该方法为同时可视化软、硬牙科组织提供了增强的可能性。
