Pattern of Hydroxyapatite Crystal Growth on Bleached Enamel Following the Application of Two Antioxidants: An Atomic Force Microscope Study

Cross-sectional visual comparison of remineralization efficacy of various agents on early smooth surface caries of primary teeth with swept source optical coherence tomography

Purpose

Sweptsource optical coherence tomography (SS-OCT) permits cross-sectional observation of surface/subsurface characteristics of enamel including early carious lesions (ECL) or remineralization non-invasively.This study aimed to visually compare the cross-sectional remineralizing efficacy of various agents on ICDAS-II scores-1&2 by using SS-OCT and histology.

Methods

Baseline SS-OCT (grey-scale/false-colour) and histology was performed on the randomly selected two samples with scores-1&2. Four remineralizing agents [fluoride-varnish (FV), CPP-ACP, nanohydroxy-paste (NHP) and silver-diamine-fluoride (SDF)]were evaluated for 2-or 6-weeks post-remineralization using SS-OCT and histology.

Results

Score-1&2 baseline SS-OCT images showed a linear-shaped demineralization with dentino-enamel junction (DEJ) visible; and bowl-shaped demineralization with DEJ invisible respectively. Remineralizing agents were assessed on the basis of their ability to remineralize the surface, subsurface and made visualize the DEJ in score-2. SS-OCT showed an outer growth layer in post-remineralization score-1, 2-weeks samples with FV and NHP. All the agents showed progressive subsurface remineralization in 6 weeks. Active lesions showed rapid uptake of minerals on surface. Subsurface mineralization in pigmented score-2 matched sound enamel with NHP and SDF. Surface remineralization was comparable in FV and SDF followed by NHP. SDF demonstrated deeper subsurface remineralization followed by NHP and CPP-ACP.

Conclusion

SS-OCT images correlated to histology. SS-OCT could monitor surface/subsurface in-situde/remineralization activity non-invasively.

Histologic validation of ICDAS-II and polarization sensitive optical coherence tomography to detect smooth surface early carious lesions

AIM

This in vitro study aimed to histologically validate and compare the methods for detection of smooth surface early carious lesions (ECLs) that is, International caries detection and assessment system for the smooth surface (ICDAS-II-SSC), Polarization sensitive optical coherence tomography (PS-OCT), and radiography.

METHODOLOGY

PS-OCT images for scores 0-3 of ICDAS-II-SSC were standardized according to ECLs' depth. Preliminary PS-OCT images for ICDAS-II-SSC score-2 of pigmented ECLs showed reduced lesion depth and therefore were dichotomized into scores 2 and 2p for white and pigmented lesions (ICDAS-II-SSCm). ECLs on one hundred freshly extracted teeth were scored by three examiners for ICDAS-II-SSCm, PS-OCT, radiography, and histology.

RESULTS

Compared to histology, ICDAS-II-SSCm showed a strong positive correlation followed by PS-OCT and radiographic evaluation. ICDAS-II-SSCm had a strong positive correlation with PS-OCT, while both variables had a weak positive correlation with radiography. PS-OCT detected the activity of ECLs by directly relating the image depth of ECLs to their mineral volume content.

CONCLUSION

The current scope of ICDAS-II should be reviewed since the pigmentation can be misinterpreted as an active lesion. Till then, ICDAS-II-SSC is an effective visual method for early caries detection. PS-OCT has the potential to become a probe with the proper algorithm for diagnostic purposes.