Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
J Endod. 2012 Sep;38(9):1269-74. doi: 10.1016/j.joen.2012.05.008. Epub 2012 Jul 20.
Current methods for the detection of enamel cracks are not very sensitive. Optical coherence tomography (OCT) is a promising diagnostic method for creating cross-sectional imaging of internal biological structures by measuring echoes of backscattered light. In this study, swept-source OCT (SS-OCT), a variant of OCT that sweeps the near-infrared wavelength at a rate of 30 kHz over a span of 110 nm centered at 1,330 nm, was examined as a diagnostic tool for enamel cracks.
Twenty extracted human teeth were visually evaluated without magnification. SS-OCT was conducted on locations in which the presence of an enamel crack was suspected under visual inspection using a photocuring unit as transillumination. The teeth were then sectioned with a diamond saw and directly viewed under a confocal laser scanning microscope (CLSM).
Using SS-OCT, the presence and extent of enamel cracks were clearly visualized on images based on backscattering signals. The extension of enamel cracks beyond the dentinoenamel junction could also be confirmed. The diagnostic accuracy of SS-OCT was shown to be superior to that of conventional visual inspection--the area under the receiver operating characteristic curve--for the detection of enamel crack and whole-thickness enamel crack; visual inspection: 0.69 and 0.56, SS-OCT: 0.85 and 0.77, respectively).
Enamel cracks can be clearly detected because of increased backscattering of light matching the location of the crack, and the results correlated well with those from the CLSM.
目前用于检测釉质裂纹的方法并不十分敏感。光学相干断层扫描（OCT）是一种有前途的诊断方法，通过测量背向散射光的回波，可以对内部生物结构进行横截面成像。在本研究中，作为一种诊断釉质裂纹的工具，我们研究了扫频源 OCT（SS-OCT），这是一种 OCT 的变体，它以 30 kHz 的速率在 1330nm 中心波长处扫过 110nm 的近红外波长。
二十颗离体人牙未经放大肉眼观察。SS-OCT 是在视觉检查怀疑有釉质裂纹的位置进行的，使用光固化单元作为透照光源。然后，用金刚石锯将牙齿切割，并用共聚焦激光扫描显微镜（CLSM）直接观察。
使用 SS-OCT，可以根据背向散射信号清楚地观察到釉质裂纹的存在和程度。还可以确认釉质裂纹延伸至牙本质-釉质交界处以外。SS-OCT 的诊断准确性优于传统的视觉检查--检测釉质裂纹和全层釉质裂纹的接收者操作特征曲线下面积；视觉检查：0.69 和 0.56，SS-OCT：0.85 和 0.77。
由于与裂纹位置相匹配的光背散射增加，釉质裂纹可以被清楚地检测到，并且结果与 CLSM 的结果很好地相关。
