Imaging Artificial Caries on the Occlusal Surfaces with Polarization-Sensitive Optical Coherence Tomography

Abstract

Polarization-sensitive optical coherence tomography (PS-OCT) is a nondestructive imaging system that can utilize near-infrared (IR) light to produce depth-resolved images of dental enamel and has the potential to monitor early enamel occlusal caries. The objective of this study was to investigate the relationship between the magnitude of backscattered light and depolarization recorded by PS-OCT with changes in the enamel mineral volume in an artificial caries model. Artificial lesions were created on a selected region on the occlusal surfaces of sound posterior teeth (n = 10) using a well-characterized 14-day pH cycling model. An all-fiber-based PS-OCT system operating at 1,310 nm was used to collect serial images at day 0 and day 14 prior to tooth sectioning. The quantitative mineral content profile and relative mineral loss, ΔZ (%vol × µm), of the carious enamel samples were obtained from transverse sections using high-resolution digital microradiography (DM). Line profiles of PS-OCT and DM images were used to evaluate the artificial caries severity and depth. The integrated reflectivity of the perpendicular-axis PS-OCT image, quantifying lesion severity, was correlated to the ΔZ of the caries lesions. There was also a strong correlation between the lesion depth calculated from both imaging modalities. PS-OCT can image and quantify artificial occlusal caries by measuring the increase in backscattering and depolarization of near-IR light. This optical method has promising applications for in vivo detection and monitoring of early enamel occlusal caries.

Use of new minimum intervention dentistry technologies in caries management

“…Monitoring in vivo carious lesion changes could be helpful with this device. [34][35][36] A combination of near infrared radiation (NIR) imaging with PS-OCT was also described to acquire depthresolved images. Combining this technology with a short-pulsed CO 2 laser ablation system would allow for the selective removal of dental caries.…”

“…37 Whatever numerical values given by the device, 35,36 visual inspection remains an essential component in making the final decision: to drill or not to drill. Indeed it is more the complexity of the shape, depth and the width of the grooves which governs clinical decision, meaning that before the diagnostic step the pits need to be perfectly clean.…”

Optical coherence tomography examination of the effect of S-PRG filler extraction solution on the demineralization of bovine enamel

“…Based on this finding, it has been suggested that the reflectivity from the lesion area can be directly determined and then used as a measure of the lesion severity 19,20) . It has also been shown that shallow lesions exhibit a loss of penetration depth in OCT images and this is correlated with the mineral loss that can be detected with microradiography 21) .…”

Early caries detection using optical coherence tomography: a review of the literature

“…65 After that, a series of studies using an artificial caries model and PS-OCT was performed to evaluate caries under composite sealants and restorations, the severity of interproximal caries lesions, occlusal surface caries, remineralization of the lesion, inhibition of demineralization by anticaries tools such as fluoride or lasers, demineralization of enamel by CO2 lasers, demineralization of exposed root surfaces, and de-/re-mineralization of dentin. 7,[66][67][68][69][70][71][72][73][74][75] In addition, this group compared the near-infrared (NIR) transillumination to PS-OCT and combined these methods with other optical techniques into image-guided laser ablation systems. [76][77][78] Recently, the study of automated analysis algorithms to assess enamel demineralization and the use of novel cross-polarization OCT were reported.…”

“…6 The effectiveness of this nonsurgical therapy is contingent on detecting the lesion in the outer enamel and requires imaging modalities that can safely and accurately monitor the success of such treatment. 7 Visual examination and probing with a sharp explorer is a rather subjective method depending on the examiner' s experience and training. 8 Early caries detection using optical coherence tomography: a review of the literature Clinical radiology is another widely used method that has poor sensitivity for detecting early carious lesions since the lesions are too shallow and do not provide enough contrast.…”