Cellular effects of silver diamine fluoride in oral cells

Silver diamine fluoride (SDF) is widely used for its caries-arresting, antimicrobial, and remineralizing effects. However, its cytotoxic, inflammatory, and genotoxic effects in oral cells are unclear. In this study, the effects of increasing concentrations of silver diamine fluoride SDF on cell viability, inflammation, DNA integrity, and functional properties, were evaluated.

Dental pulp stem cells (DPSCs), periodontal ligament fibroblasts (PDLFs), and gingival fibroblasts (GFs) were exposed to increasing concentrations of SDF. Cell viability and apoptosis were assessed using MTT and Annexin V assays. Inflammatory and DNA damage-related gene expression was analyzed by qRT-PCR. Wound closure and transwell migration assays were used to evaluate the functional effects. An indirect transwell diffusion system (0.4 μm pores) was used to evaluate the effects of soluble SDF components on DPSCs, without direct cell contact.

SDF exposure (0.005-0.01%, 24-48 h) caused a dose-dependent reduction in cell viability, confirming increased apoptosis across all cell types. qRT-PCR showed upregulation of inflammatory genes (IL-1β and COX2) and downregulation of DNA repair genes (RAD51, PARP1, and XRCC4). Functional assays revealed impaired wound closure and reduced cell migration. Notably, indirect exposure through the transwell diffusion barrier significantly reduced cell viability and wound healing.

SDF concentrations lower than those commonly used clinically, even under indirect exposure conditions using a transwell diffusion barrier, can induce inflammation, apoptosis, impaired wound healing, and suppression of DNA repair pathways in oral cells, including DPSCs. These findings emphasize the potential cytotoxic and genotoxic risks associated with SDF, and they highlight the necessity to re-evaluate SDF concentrations to balance therapeutic benefits with cellular safety in patients.