Imaging inhibitory effect of fissure sealants on demineralization of adjacent enamel with cross polarization OCT

摘要

Dental fissure sealants were shown to be effective for prevention of fissure caries in individuals with high caries risk.However, their inhibitory effect on enamel at a distance from sealant margin has not been thoroughly investigated.Previous studies have confirmed effectiveness of optical coherence tomography (OCT) for imaging of sound anddemineralized enamel. The purpose of this study was to assess the potential of cross-polarization OCT (CP-OCT) asa non-destructive tool to evaluate the efficacy of fissure sealants on inhibition of demineralization of adjacentenamel.In this study, fissure sealants were applied to bovine enamel preparations (0.5×3×1 mm~3, width× length× depth) andspecimen surface was covered with varnish with the exception of 0.5 mm of peripheral enamel around the fissuremargins. Then, demineralized enamel lesions were produced by immersion of specimens in demineralizing solution(pH 4.5) for 7 days and serial cross-sectional OCT images were obtained from each specimen. The OCT imageswere acquired using a high scan rate (30 kHz) continuous wavelength scanning diode laser centred near 1310 nm(Santec, Japan). In addition, stereomicroscope was used to observe enamel inhibition zones on histological sectionsafter trimming the specimens to certain OCT cross-sectional slices for confirmation. CP-OCT images showeddemineralized subsurface enamel lesions adjacent to fissure sealants. Also, demineralized lesions were formed awayfrom the fissure sealants in some specimens as enamel margins resisted demineralization, forming zones ofinhibition at enamel-sealant interface. This study suggests that CP-OCT could be used to nondestructively evaluatedemineralization inhibition effect of dental materials in enamel.