Espigares J, Sadr A, Hamba H, Shimada Y, Otsuki M, Tagami J, Sumi Y.
J. Med. Imag. 2(1), 014001 (Feb 11, 2015). doi:10.1117/1.JMI.2.1.014001
A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography (μCT ) for assessment of natural enamel lesions in vitro. Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μCT , the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of increased signal intensity beneath the surface. An SS-OCT attenuation coefficient based on Beer–Lambert law could discriminate lesions from sound enamel. Lesion depth ranged from 175 to 606 μm in SS-OCT. A correlation between μCT and SS-OCT was found regarding lesion depth (R=0.81 , p<0.001 ) and also surface layer thickness (R=0.76 , p<0.005 ). The images obtained clinically in real time using the dental SS-OCT system are suitable for the assessment of natural subsurface lesions and their surface layer, providing comparable images to a laboratory high-resolution μCT without the use of x-ray.