Combined metal nanoparticles (MNPs) can exhibit more beneficial effects than those of single MNPs. However, the combination may cause unexpected cytotoxicity due to differences in the metals' properties. This study investigated the cytotoxic effects of single and mixed exposures to antibacterial metal nanoparticles (MNPs), including silver (AgNPs), zinc oxide (ZnONPs), and platinum nanoparticles (PtNPs) of two different sizes, on cultured cells subjected to hydrogen peroxide-induced oxidative stress.

AgNP cytotoxicity decreased when mixed with PtNPs. However, ZnONP-PtNP combination showed no improvement in cell viability compared to ZnONPs alone. Regarding lipid peroxidation, Pt30NPs reduced lipid peroxidation, while Pt5NPs tended to enhance it.

These findings underscore the importance of optimizing MNP size and type when integrating multifunctional nanoparticles with antioxidant and antibacterial properties into dental materials.

Numerous dental products containing calcium hydroxide as their main component, which exhibits strong alkalinity and is expected to exert antibacterial and tissue-regenerative effects, are widely used in clinical practice. In root canal treatment and cavity lining, many commercial products contain not only calcium hydroxide, but also other chemical substances, resulting in diverse compositions and distinct biological characteristics. Therefore, we selected nine representative products currently available on the domestic market and compared their cytotoxicity using two-dimensional (2D) culture and three-dimensional (3D) collagen-based culture system. In the 2D cytotoxicity assay, cell viability measured by the MTT method revealed marked differences among products, whereas the differences observed using the LDH assay were less pronounced. The cytotoxicity of oil-based paste products was higher with the 3D culture method than with the 2D method, likely due to differences in solubility in the culture medium. In addition, products containing zinc oxide–eugenol exhibited slightly higher cytotoxicity. Marked variations in biological properties were noted among products containing calcium hydroxide, indicating the need for users to understand the specific characteristics of each product and ensure their safe application.

The purpose of this study is to evaluate the efficacy of a solution containing antibiotics and antifungal agents added to bicarbonate Ringer's solution (ABRS) warmed to 37°C as a temporary storage solution for rinsing during dental procedures and for tooth replantation.Human-derived osteoblasts, periodontal ligament fibroblasts, and oral mucosal epithelial cells were stored in ABRS or physiological saline at 4°C and 37°C for 60 minutes, and mitochondrial activity and morphological changes were observed. Furthermore, tooth replantation experiments were conducted using beagle dogs, and the results were observed histopathologically. All cell types preserved by ABRS exhibited high mitochondrial activity, which was particularly pronounced when warmed to 37°C. Histopathological examination revealed that teeth stored in ABRS showed less root resorption and no inflammatory findings compared to teeth stored in saline.

In dental procedures previously using saline or water, the use of ABRS warmed to 37°C was shown to improve the survival rate of cells constituting periodontal tissue and to be an effective preservation solution for suppressing root resorption in replanted teeth.