Fluoride activity of antibacterial ammonium hexafluorosilicate solution for the prevention of dentin caries

Purpose: To evaluate the acid resistance of various antibacterial ammonium hexafluorosilicate (SiF) solutions. Methods: Antibacterial SiF solutions were prepared with the addition of chlorhexidine (CHX), cetylpyridinium chloride (CPC), isopropyl methylphenol (IPMP), or epigallocatechin gallate (EGCG). Hydroxyapatite pellets were treated with SiF solution with or without antibacterial agents for 3 minutes. The demineralized depth of hydroxyapatite pellets after SiF treatment was measured using a surface roughness analyzer. Results: SiF+CPC solution showed equivalent acid resistance to SiF and AgF treatment. In contrast, the original acid resistance activity of SiF solution was diminished by the addition of other antibacterial agents (CHX, IPMP and EGCG). SiF with the addition of CPC was the most effective for reducing the demineralized depth, showing the same levels as those of SiF and AgF.