Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography

Abstract

Abstract. As dental caries is one of the most common diseases, the early and noninvasive detection of carious lesions plays an important role in public health care. Optical coherence tomography (OCT) with its ability of depth-resolved, high-resolution, noninvasive, fast imaging has been previously recognized as a promising tool in dentistry. Additionally, polarization sensitive imaging provides quantitative measures on the birefringent tissue properties and can be utilized for imaging dental tissue, especially enamel and dentin. By imaging three exemplary tooth samples ex vivo with proximal white spot, brown spot, and cavity, we show that the combination of polarization sensitive OCT and the degree of polarization uniformity (DOPU) algorithm is a promising approach for the detection of proximal carious lesions due to the depolarization contrast of demineralized tissue. Furthermore, we investigate different sizes of the DOPU evaluation kernel on the resulting contrast and conclude a suitable value for this application. We propose that DOPU provides an easy to interpret image representation and appropriate contrast for possible future screening applications in early caries diagnostics. © The Authors.Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Correlation between Lesion Progression and Depolarization Assessed by Polarization-Sensitive Optical Coherence Tomography

“…A detailed description of the PSOCT system used in this study can be found in a previously published paper [10]. In brief, it consists of a 1310 nm swept laser source with 110 nm spectral bandwidth and 50 kHz sweep rate, a Michelson interferometer with a single circularly polarized illumination of the sample, and a polarization-diverse balanced detection.…”

“…However, both native enamel birefringence and demineralization-induced depolarization contribute to an increased cross-polarization signal [5], which can be especially detrimental to the assessment of hidden caries, i.e., sound birefringent enamel with underlying depolarizing caries. In recent studies, we concluded that the representation of the degree of polarization (DOP) as a PSOCT-based measure of depolarization seems to be the most appropriate representation for the detection of early carious lesions in comparison with other measures such as co-and cross-polarization intensities, total reflectivity, retardation, and optic axis orientation [10,11]. Furthermore, we improved this approach by noise-immune processing, as introduced by Makita et al [12], and demonstrated that the DOP also supports the assessment of suspect occlusal enamel lesions [13].…”

Quantitative depolarization measurements for fiber‐based polarization‐sensitive optical frequency domain imaging of the retinal pigment epithelium

“…This characteristic property has enabled automated segmentation of pathologic features such as drusen and atrophic zones, and has allowed the assessment of age‐related macular degeneration (AMD) . Depolarization measured with OCT has also been used to monitor the healing process and scar formation of thermal injuries in rat skin and to detect lipid‐rich areas of coronary atherosclerotic lesions and dental caries .…”

Towards quantitative demineralization imaging for the assessment of carious lesions based on PS-OCT

“…The 1300 nm swept-source PS-OCT system [2] as well as the processing [3] of the depolarization images, based on calculating the noise-immune degree of polarization, have been described previously. After PS-OCT imaging of the extracted molar tooth samples, which were collected during clinical treatment and visually inspected by an experienced dentist, µCT volumes were acquired and pre-processed using a commercial high-resolution x-ray tomograph (Bruker Skyscan 1172, 85 kV source voltage).…”

“…utilizing polarization-sensitive OCT (PS-OCT), provides a more specific measure of those characteristics. We have recently shown that depolarization imaging based on PS-OCT is able to detect early stages of enamel demineralization [2] and facilitates the differentiation of surface staining and discoloration from carious lesions [3]. To assess the validity of this contrast mechanism, we acquired data sets of tooth samples with suspected occusal lesions using PS-OCT and X-ray micro-computed * e-mail: jonas.golde@tu-dresden.de tomography (µCT), an in dental research established radiographic imaging technique for demineralization imaging.…”