Majkut Patrycja, Sadr Alireza, Shimada Yasushi, Sumi Yasunori, Tagami Junji
Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan.
University of Washington, School of Dentistry, Seattle, Washington.
J Endod. 2015 Aug;41(8):1349-52. doi: 10.1016/j.joen.2015.03.016. Epub 2015 May 1.
Optical coherence tomography (OCT) is a noninvasive modality to obtain in-depth images of biological structures. A dental OCT system has become available for chairside application. This in vitro study hypothesized that swept-source OCT can be used to measure the remaining dentin thickness (RDT) at the roof of the dental pulp chamber during excavation of deep caries.
Human molar teeth with deep occlusal caries were investigated. After obtaining 2-dimensional and 3-dimensional OCT scans using a swept-source OCT system at a 1330-nm center wavelength, RDT was evaluated by image analysis software. Microfocus x-ray computed tomographic (micro-CT) images were obtained from the same cross sections to confirm OCT findings. The smallest RDT values at the visible pulp horn were measured on OCT and micro-CT imaging and compared using the Pearson correlation. Pulpal horns and pulp chamber roof observation under OCT and micro-CT imaging resulted in comparable images that allowed the measurement of coronal dentin thickness.
RDT measured by OCT showed optical values range between 140 and 2300 μm, which corresponded to the range of 92-1524 μm on micro-CT imaging. A strong correlation was found between the 2 techniques (r = 0.96, P < .001).
Further analysis indicated linear regression with a slope of 1.54 and no intercept, closely matching the bulk refractive index of dentin. OCT enables visualization of anatomic structures during deep caries excavation. Exposure of the vital dental pulp because of the removal of very thin remaining coronal dentin can be avoided with this novel noninvasive technique.
光学相干断层扫描（OCT）是一种用于获取生物结构深度图像的非侵入性方法。一种牙科OCT系统已可用于临床椅旁应用。本体外研究假设，扫频源OCT可用于在深龋洞挖掘过程中测量牙髓腔顶部的剩余牙本质厚度（RDT）。
对患有深咬合面龋的人类磨牙进行研究。使用中心波长为1330nm的扫频源OCT系统获得二维和三维OCT扫描后，通过图像分析软件评估RDT。从相同横截面获取微焦点X射线计算机断层扫描（micro-CT）图像以确认OCT结果。在OCT和micro-CT成像上测量可见牙髓角处的最小RDT值，并使用Pearson相关性进行比较。OCT和micro-CT成像下对牙髓角和牙髓腔顶部的观察产生了可比的图像，从而能够测量牙冠部牙本质厚度。
OCT测量的RDT光学值范围在140至2300μm之间，这与micro-CT成像上92 - 1524μm的范围相对应。两种技术之间发现了很强的相关性（r = 0.96，P <.001）。
进一步分析表明线性回归斜率为1.54且无截距，与牙本质的体积折射率密切匹配。OCT能够在深龋洞挖掘过程中可视化解剖结构。使用这种新型非侵入性技术可以避免因去除非常薄的剩余牙冠部牙本质而暴露活髓。
