Detection of early changes in caries lesion using QLF-D and OCT

Abstract

Objectives: We aimed to compare the differences in caries lesion changes when measured by QLF-D as fluorescence loss and by SS-OCT as lesion depth with respect to demineralized time, during formation of artificial early caries lesion. We also demonstrated that QLF-D and SS-OCT can be used effectively in monitoring the longitudinal progression of simulated caries lesions. Methods: Ten bovine incisors were sectioned (5×4 mm) and embedded in epoxy resin. An acidresistant nail varnish was applied to a part of the tooth surfaces to protect sound enamel (2×4 mm). To generate lesions, each specimen was immersed in 40 ml of a demineralizing gel for 20 days at 37 o C. To measure mineral loss of the demineralized specimens, fluorescence loss (∆F, %) was measured by QLF-D and lesion depth (μm) was determined by SS-OCT from the captured cross-sectional image. All the specimens were analyzed daily by QLF-D image analysis software and SS-OCT image analysis program for 20 days. The repeated measures analysis of ∆F and lesion depth was used. The paired t-test was used to assess differences between each day. The correlation between ∆F and lesion depth was determined using the Pearson's correlation coefficient. Results: On the 5th, 10th, and 15th day, compared to baseline values, ∆F decreased in 12.7%, 25.0%, and 33.6% of the specimens, respectively, and the lesion depth increased in 9.9%, 16.0%, and 22.6% of the specimens, respectively. However, after 15 days, there was no change in the ∆F and lesion depth. High significant correlation was identified between the resultant values of ∆F obtained by QLF-D and those of lesion depth obtained by SS-OCT (r = -0.811, P<0.0001). Conclusions: The QLF-D and SS-OCT could detect subtle changes in mineral loss and lesion depth with respect to demineralized time. Furthermore, these devices were useful for monitoring changes in mineral amount and lesion depth.

The Use of Optical Coherence Tomography in Dental Diagnostics: A State-of-the-Art Review

“…This solution has been published in work [ 72 ]. There are also a few other possibilities for using the quantitative analysis of the intraoral structures and tissue conditions such as dental enamel and dental caries [ 86 ], dental abfraction and attrition [ 98 ], enamel erosion [ 101 ], enamel demineralization [ 109 ], thickness of dentin layer [ 121 ], and soft tissues [ 173 ].…”

Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography

“…Hye‐Min et al. comparing lesions extension also found high correlation between OCT lesion depths and variation of fluorescence by QLF. Comparing OCT and QLF potential to identify minimal erosive challenge, Chew et al.…”

“…Comparison between QLF and OCT has been done previously, analyzing caries lesions , and in some recent publications it has been applied to evaluate initial enamel erosion, each based on different parameters.…”

Characterisation of mineral loss as a function of depth using confocal laser scanning microscopy to study erosive lesions in enamel: A novel non-destructive image processing model

“…OCT is a non-destructive technique which has been utilised to image erosive and carious lesions [17][18][19]54]. The use of long wavelength light does not damage the sample, but it is affected by artefacts from reflections and scattering.…”

“…One study by Fowler et al [16] used a similar procedure to TMR to quantify mineral loss as function of depth using SEM, showing increases in sensitivity by the greater resolving power attributed to SEM [16]. OCT is a non-destructive method used clinically to assess carious lesions by use of long wavelength light and optical scattering to create 3D images of the lesion [17][18][19]. OCT has been shown capable of detecting erosive lesions by the intensity of backscattered light as a function of depth accomplished by Chew et al [20], but OCT suffers from limited spatial resolution for reliable use in erosion studies [21].…”