Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

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 (mu CT) 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 mu CT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In mu CT, 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 mu m in SS-OCT. A correlation between mu CT 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 mu CT without the use of x-ray. (c) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)