Automated analysis of lesion depth and integrated reflectivity in PS‐OCT scans of tooth demineralization

Abstract

Several studies have demonstrated that polarization sensitive optical coherence tomography (PS-OCT) can be used to nondestructively measure the severity of subsurface demineralization in enamel and dentin, track lesion progression over time and measure remineralization. The purpose of this study was to develop methods for the automated assessment of the depth and severity of demineralization in PS-OCT scans. Subsurface caries-like lesions of increasing depth and severity were produced in adjoining windows on 10 bovine enamel samples via exposure to demineralization for periods of 1-4 days. PS-OCT scans were acquired for each sample and analyzed using various methods to calculate the lesion depth and severity. Edge detection algorithms were most successful for measurement of the lesion depth for improved assessment of lesion severity. Edge-finding algorithms were able to detect significant differences (P<0.05) in the lesion depth and severity between each of the periods of demineralization and sound enamel. The lesion depth and mineral loss were also measured with polarized light microscopy and transverse microradiography after sectioning the teeth for comparison. This study demonstrates that the depth and severity of early lesions can be calculated automatically for rapid analysis of PS-OCT images.