Effect of Zinc on improving silver diamine fluoride-derived tooth discoloration in vitro

Background: Silver Diamine Fluoride (SDF) is effective for arresting dental caries, presenting a valuable non-invasive treatment option in dentistry. Despite its therapeutic advantages, a significant drawback is the tooth discoloration that follows its application, which can affect patient acceptance. Addressing this aesthetic concern without diminishing the treatment's efficacy remains challenging in dental practice. This study explores strategies to improve the aesthetic outcomes of SDF treatments. Methods: This in vitro study assessed the efficacy of Zinc in reducing SDF-induced discoloration on dentin blocks and examined its impact on the physical properties of dentin, including hardness and roughness. Dentin blocks were pre-treated with various concentrations of Zinc, followed by SDF application. Color changes were analyzed using Image J software, and cytotoxicity was evaluated using the CytoTox-ONE™ Homogeneous Membrane Integrity Assay. Dentin surface characteristics, including micro-hardness and roughness, were assessed using scanning electron microscopy. Results: The study results revealed a dose-dependent efficacy of Zinc in reducing discoloration caused by SDF on dentin, with higher Zinc concentrations showing better improvement in color outcomes. The application of a 20 M Zinc solution prior to SDF treatment significantly reduced discoloration compared to SDF alone, measured on day 14. Additionally, no significant changes in the hardness or roughness of etched dentin were observed in Zinc + SDF group compared to the SDF alone group. Zinc treatments demonstrated a desirable outcome on mucosal cytotoxicity, comparable to that of the negative control. Conclusion: Zinc significantly reduced SDF-induced tooth discoloration in a dose-dependent manner without affecting the etched dentin's micro-hardness and roughness, potentially improving patient acceptance, especially in visible areas of the mouth. Further research is warranted to validate the effectiveness of this zinc-enhanced treatment protocol in vivo. Clinical significance: Zinc-enhanced SDF treatments could enhance patient acceptance, especially in visible areas of the mouth, offering an improved option for caries management.