Silver Releasing from Dental Alloys: Cytotoxic and Inflammatory Response in Vitro
Abstract:
Background: Although silver used in dental alloys is not classified as mutagenic, carcinogenic, or toxic to reproduction, the European Chemicals Agency (ECHA) has listed both ionic silver and silver nanoparticles as biocidal substances. In this context, the present study aimed to assess silver release and evaluate the cytotoxic and pro-inflammatory potential of various silver-containing dental alloys from the manufacturers operating within the European Union.
Methods: Eight dental alloys, containing between 6.4% and 58% silver, were subjected to standardized extraction tests using a racemic lactic acid and sodium chloride solution at 37 °C for 7 days. In parallel, cytotoxicity was assessed using the MTT/MTS assay on L929 fibroblasts and THP-1 monocytes, following ISO 10993-5 guidelines. Additionally, TNF-α secretion by THP-1 cells was quantified to evaluate potential inflammatory responses.
Results: Extraction tests revealed low levels of silver release, ranging from 11 μg/L to 314 μg/L. In vitro cytotoxicity assays showed minimal to no cytotoxic effects on both L929 and THP-1 cells. Interestingly, some alloys even promoted slight proliferative responses in THP-1 cells. No significant induction of TNF-α was observed following exposure to any of the tested alloys.
Conclusions: Despite the inclusion of ionic silver in the ECHA’s list of biocidal substances, the tested silver-based dental alloys released only small amounts of silver and exhibited no relevant cytotoxic or inflammatory effects under in vitro conditions. These findings support their continued evaluation within biocompatibility frameworks.
