The anticariogenic effect of fluoride in primer, bonding agent, and composite resin in the cavosurface enamel area

The role of fluoride in the prevention of initial caries is well known in dentistry. This study was designed to evaluate the anticariogcnic effect of fluoride in primers, bonding agents, composite resins, and glass-ionomer cements in enamel. Twenty-five extracted teeth that had no cracks, white spots, or enamel defects were selected. A 2 × 3 × 1.5 mm cavity was prepared on either the buccal or the lingual surface of each tooth. After pumicing, tooth enamel was etched with 37% phosphoric acid gel for 30 seconds, and the samples were divided into five groups. The samples were primed, bonded, and filled using ART Bond and Brilliant Enamel in group A, OptiBond and Herculite XRV in group B, Syntac and Tetric in group C, Scotchbond Multi-Purpose and Z100 in group D, and a resin-modified glass ionomer (Fuji II LC) in group E. All surfaces except a 2 mm zone adjacent to the cavosurface margin of each sample was protected with nail varnish, and samples were then placed into a buffered solution for 3 days to develop the initial caries. The samples were then sectioned through the restoration faciolingually into wafers that were approximately 300 μm in thickness then thinned to 150 μm. These thin samples were then examined with a polarizing microscope underwater imbibition. The fluoride in primer, bonding agent, and composite filling material did not prevent the initial caries in the enamel area adjacent to the restoration, whereas the fluoride in the glass ionomer did prevent the initial-stage caries.