Restoration of subsurface mineral in non-cavitated enamel lesions using bioactive nanoparticles: In Vitro Study

Abstract

Restoration of early-stage, non-cavitated caries lesions is a clinical challenge with few available options. Fluoride can stop the progression of caries at any stage, but it is ineffective at restoring enamel crystals lost within the lesion body. This study demonstrates the penetration of fluorapatite nanocrystals (nFA) into the subsurface of white spot lesions (WSL) using a calcium-binding fluorophore and two-photon microscopy (Fluo-4). Randomly divided into three groups, sixteen extracted human teeth with either active, natural or in vitrocreated carious lesions in enamel were analyzed. The teeth were treated with an emulsion of nFA crystals tagged with Fluo-4, Fluo-4 alone, or deionized water for 2 minutes and then left for 30 minutes before being washed with distilled water and analyzed using a two-photon microscope. At their deepest, in vitro and natural lesions treated with tagged nFA fluoresced at a depth of 80um. Lesions treated with Fluo-4 without crystals exhibited fluorescence primarily at the enamel's surface, whereas slabs treated with deionized water exhibited minimal to no fluorescence.