Polarization-sensitive optical coherence tomographic imaging of artificial demineralization on exposed surfaces of tooth roots

Abstract

Background and Objectives-The purpose of this study was to assess the potential of polarization sensitive optical coherence tomography (PS-OCT) to non-destructively measure the depth and severity of artificial demineralization on exposed root surfaces and measure the degree of inhibition by topical fluoride. Although PS-OCT imaging studies have demonstrated the utility of PS-OCT for imaging carious lesions on enamel and dentin surfaces the influence of the cementum layer that is present on intact root surfaces has not been investigated.Materials and Methods-In this study, extracted human tooth roots were partitioned into three sections with one partition treated with topical fluoride, one partition protected from demineralization with acid resistant varnish, and one partition exposed to a demineralization solution, producing artificial lesions approximately 200-µm deep in root dentin. The lesion depth, remaining cementum thickness and the integrated reflectivity for lesion areas was measured with PS-OCT. These measurements were also compared with more established methods of measuring demineralization, namely transverse microradiography (TMR) and polarized light microscopy (PLM)Results-PS-OCT was able to measure a significant increase in the reflectivity between lesion areas and sound root surfaces. In contrast to dentin, the cementum layer manifests minimal reflectivity in the PS-OCT images allowing nondestructive measurement of the remaining cementum thickness. The reflectivity of the cementum layer did not increase significantly after substantial demineralization, however it did manifest considerable shrinkage in a fashion similar to dentin and that shrinkage could be measured with OCT.Significance-This study demonstrates that PS-OCT can be used to measure demineralization nondestructively on root surfaces and assess inhibition of demineralization by anticaries agents.

Estimation of lesion progress in artificial root caries by swept source optical coherence tomography in comparison to transverse microradiography

“…Fried et al emphasized that the contrast of lesion images captured by PS-OCT was enhanced by depolarization of the incipient light by the lesion, 6 and that high reflectivity at the tooth surface interfered with the measurement of early enamel demineralization beneath the surface. 15 It was also indicated that the unfavorable strong reflections from the tooth surface were greatly reduced in the orthogonal polarization image, enabling better resolution of the surface zone of the lesion. 16,17 While a combination of PS-OCT with SS-OCT (PS-SS-OCT) would take advantage of both systems, 7,10 conventional SS-OCT may be still more affordable since PS-SS-OCT requires a more complicated design.…”

“…10 Nevertheless, various solutions have been addressed for each of these drawbacks and, therefore, it appears that the use of an optimized SS-OCT system as a clinical tool may be more feasible in terms of imaging resolution and speed. 8,[10][11][12] In dental literature, there have been several reports on the use of OCT, 6,7,[13][14][15] especially for polarization-sensitive OCT (PS-OCT). It was reported that the PS-OCT was able to quantify the lesion depth and mineral loss in enamel and dentin lesions with the aid of special image analysis algorithms, 6 in which the lesion depth and mineral loss were validated by transversal microradiography (TMR).…”

Theory of X-ray microcomputed tomography in dental research: application for the caries research

“…The latter has been a widely accepted method for determining mineral loss or gain in experimentally induced incipient carious lesions 17 and has been used for the comparison and validation of other newly developed caries detection techiniques. [23][24][25] Both of these methods require the tooth to be sectioned as thin as 100 ㎛, which introduces a variation in the results and prevents the longitudinal analysis or assessment of teeth by an examiner. Furthermore, the location of the original surface of a dentinal lesion may be hard to determine because air drying dentinal lesions can result in characteristic surface shrinkage.…”

1550 nm superluminescent diode and anti-Stokes effect CCD camera based optical coherence tomography for full-field optical metrology

“…Its ability to in vivo imaging both hard and soft tissues of dental cavity enables early detection and intervention with dental and periodontal diseases. What is more, an OCT modality, a polarization sensitive OCT (PS-OCT) is able to record not only magnitude of light backscattered from the sample, but can reveal polarization properties of tissues, that are difficult or impossible to obtain by using other diagnostic methods [134][135][136]. This includes i.e.…”