Objectives
Fluoride-based cariostatic agents are commonly used in dental products and are generally considered safe. However, ongoing discussions about potential adverse effects are driving research into alternative agents, such as lanthanide salts. This study aims to evaluate the cytotoxic effects of different cariostatic agents, including fluoride compounds (NaF, Na2PO3F, NH4F) and lanthanide salts (Ce(NO3)3, CeCl3, Sm(NO3)3, SmCl3).
Materials and methods
Mouse fibroblasts (L-929) were cultured in Eagle’s Minimum Essential Medium supplemented with 5% fetal bovine serum and 1% penicillin-streptomycin. Cell viability was assessed via MTT assay after 24 h of exposure to test compounds at concentrations of 0.0128, 0.064, 0.32, 1.6, 8, 40, 200 and 1000 mM, and lactate dehydrogenase (LDH) release was quantified to assess membrane integrity. The accumulation of reactive oxygen species (ROS) was determined after 24 h. Data were analyzed by non-parametric methods at a significance level of α = 0.05 (Mann-Whitney U and Kruskal-Wallis tests).
Results
Cell viability decreased significantly for NaCl and NaNO3 at 200 mM, and for NaF, NH4F, Ce(NO3)3, CeCl3, Sm(NO3)3 and SmCl3 at 1.6 mM, falling below 70% of control (P ≤ 0.0178). Similarly, LDH assays indicated a significant incline in cytotoxicity at a concentration of 200 mM for NaCl, NaNO3 and Na2PO3F, and at 8 mM for NaF, NH4F and all lanthanide compounds (P ≤ 0.0016). ROS quantification showed that NaF, NH4F, CeCl3, Sm(NO3)3 and SmCl3 induced oxidative stress at 1.6 mM with statistical significance (P ≤ 0.0065).
Conclusions
Fluoride and lanthanide compounds exhibited similar in vitro biocompatibility, comparable to that of table salt.
Clinical relevance
Both fluoride- and lanthanide-based cariostatic agents appear to pose a low biological risk to surrounding oral tissues when used at appropriate doses in dental products.