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

Abstract

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 ([Formula: see text]) 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 [Formula: see text], 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 [Formula: see text] in SS-OCT. A correlation between [Formula: see text] and SS-OCT was found regarding lesion depth ([Formula: see text], [Formula: see text]) and also surface layer thickness ([Formula: see text], [Formula: see text]). 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 [Formula: see text] without the use of x-ray.

Comparison of resin-based and glass ionomer sealants with regard to fluoride-release and anti-demineralization efficacy on adjacent unsealed enamel

“…The region of interest (ROI; width×optical depth: 500×400 µm), extending from the surface of the enamel to deeper levels adjacent to the sealant, was selected, converted to a signalintensity depth profile, and µ t values were recorded for each average signal-intensity profile, as described in previous studies [18][19][20] . The ∆µt value of the specimen for each demineralization interval was calculated as follows:…”

“…Quantitative measurement of light propagation in tissues, measured as the attenuation coefficient (µ t) parameter in OCT, has shown promising results with regard to its ability to discriminate between sound and demineralized tooth structures [18][19][20] . We believe that OCT may also be useful for clinically assessing the inhibitory effects of sealants on the demineralization of adjacent unsealed enamel surfaces.…”

Observation of white spot lesions using swept source optical coherence tomography (SS-OCT): <i>in vitro</i> and <i>in vivo</i> study

“…2D OCT scans of the lesions were compared according to two parameters derived from the images using specially developed code in ImageJ (ImageJ version 1.45S, Wayne Rasband, NIH, Bethesda, MD, USA). OCT lesion depth is the depth of the boundary that is observable between bright, highly-scattering area of the lesion and the darker region beneath the lesion 17,18) . Using Image J, the obtained OCT image was rotated to compensate for the tilting and reach a horizontal surface.…”

“…The intensity value was then checked and adjusted by the operator to ensure that it matched visible boundary of the lesions. The cut off value was then applied to the ROI to calculate an average optical lesion depth (LD OCT) by the software subsequently 18) . The measurements were repeated 4 times for each OCT image and the average value was reported.…”

Effect of a calcium phosphate and fluoride paste on prevention of enamel demineralization

“…The optical principle in evaluation of enamel demineralization by OCT is increased backscatter signal intensity, induced by multiple scattering and depolarization of the incident light through the demineralized enamel, typically projected from a near infrared laser source. This optical behavior of demineralized enamel is explained by the increased porosity and decreased density of the tissue 14) . The purpose of this study was to examine the potential anti-demineralization capacities of (a) TTCP and DCPA and 950 ppm fluoride paste, (b) CPP-ACP paste and (c) 950 ppm fluoride solution in comparison to (d) control solution (deionized water) in an artificial enamel demineralization model through in-depth monitoring of enamel using swept-source OCT followed by CLSM imaging.…”