Tetracycline Enables Visualization of Remineralization Induced by Agents Penetrating Dental Enamel

The demineralization of tooth enamel caused by acid attack in dental biofilms is a significant challenge in dentistry. While fluoride varnishes are widely used to protect and restore the enamel surface, their actual ability to penetrate and treat the enamel in depth remains poorly understood. This study proposes an innovative in vitro approach to visualize the diffusion of remineralizing agents into enamel depth using by confocal laser scanning microscopy (CLSM). Four commercial fluoride varnishes (MI Varnish^®, Duraphat^®, FluoroCal^®, Clinpro Clear Fluoride^®) were applied to artificially demineralized bovine enamel samples in the presence of tetracycline. We used the tetracycline's properties to bind to calcium and form a fluorescent complex to track the remineralization activity of varnishes. The results demonstrate the absence of autofluorescence in the controls and the presence of a specific fluorescent emission for the active varnishes. MI Varnish^® demonstrated the most significant penetration in enamel depth (42.0 ± 11.6 μm), followed by Duraphat^®, FluoroCal^®, and Clinpro Clear Fluoride^®. This non-destructive method provides accurate three-dimensional visualization of remineralized areas and is a promising tool for evaluating fluoride varnishes effectiveness.