The effect of silver diamine fluoride treatment on dental pulp cells

Abstract

Dental caries is one of the most common global health issues. When left untreated, moderate to deep carious lesions can lead to pain and loss of aesthetics and function. Treating deep carious lesions involves a risk of pulp exposure and loss of pulp vitality. Therefore, selective or partial caries removal is now preferred. Eliminating microorganisms within the cavity is essential for the success of minimally invasive restorative techniques. However, achieving or maintaining an ideal seal with current restorative materials is challenging. Using antimicrobial agents for cavity conditioning or lining can eliminate cariogenic bacteria, inhibit further cariogenic biofilm development, reduce secondary caries risk, and potentially improve restoration longevity. This study commenced with a scoping review to explore silver-containing solutions for deep cavity disinfection and their effects on dental pulp. Silver, a broad-spectrum antimicrobial agent, shows promise for caries management. Silver fluoride, silver nitrate, silver diamine nitrate, silver diamine fluoride (SDF), and nano-silver fluoride were identified as effective antimicrobial agents but only SDF was suitable to be used as a cavity liner safely for carious cavities. A subsequent review evaluated the dental pulp response to SDF treatment, focusing on inflammatory response, pulp cell activity, dentinogenesis, silver penetration, and bacterial presence in dental pulp. Direct SDF application was found to cause pulp necrosis, while indirect application was generally biocompatible, eliciting a mild inflammatory response with reparative dentine formation. A key concern with using SDF in moderate and deep cavities is the diffusion of silver and fluoride ions through the remaining dentine to the pulp. This was addressed in a laboratory study measuring ion diffusion through different dentine thicknesses over 24 weeks post-SDF application. Results showed a decline in ion diffusion, with dentine thickness significantly influencing the diffusion process due to variations in dentinal tubule diameter and number. Another laboratory study assessed the impact of a 38% SDF solution and its serial dilutions on human dental pulp stem cells (hDPSCs), investigating proliferation, odontogenic differentiation, inflammatory response, and mineralization potential. The study indicated that 38% SDF is cytotoxic and unsuitable for direct pulp capping, leading to pulp death. However, diluted SDF (dSDF) enhanced hDPSCs proliferation, promoted odontogenic differentiation, controlled inflammatory response, and mineralized particle formation, all crucial for reparative dentine formation. Further investigation examined the effects of 38% SDF and its dilutions on the proliferation and angiogenic potential of human umbilical vein endothelial cells (HUVECs), commonly used in biomaterials research. The study also explored the role of hDPSCs in promoting angiogenesis by assessing the effects of mediators released after SDF treatment. Results indicated that dSDF significantly enhances angiogenesis, including vascular endothelial growth factor secretion from hDPSCs, endothelial cell proliferation, migration, and blood vessel-like structure formation by HUVECs. These findings enhance our understanding of the interactions between fluoride-containing dental materials and dental pulp, highlighting the potential therapeutic applications of SDF in restorative dentistry. SDF, particularly in diluted form, shows promise as an effective approach in minimally invasive restorative dentistry, offering benefits such as biocompatibility, enhanced pulp cell activity, controlled inflammatory response, and improved angiogenesis. (Word count: 498)