Size-Dependent Bioactivity of Silver Nanoparticles and Calcium Hydroxide Mixtures Against hDPSCs: An In Vitro Study

TL;DR

This study shows that 10 nm silver nanoparticle mixtures and calcium hydroxide are most effective for promoting dental stem cell health and mineralization.

Contribution

The study introduces size-dependent effects of silver nanoparticle mixtures on human dental pulp stem cells.

Findings

10 nm mixtures and calcium hydroxide showed highest cell viability and lowest ROS release.

10 nm mixtures and calcium hydroxide increased anti-inflammatory cytokines and mineralization.

2 nm and 5 nm mixtures reduced cell viability and caused morphological distortion.

Abstract

This study aimed to assess the biocompatibility and bioactivity of three different silver nanoparticles (AgNPs) and calcium hydroxide [Ca(OH)2] mixtures against human dental pulp stem cells (hDPSCs). hDPSCs were treated with one of the following medicaments: 2 nm mixture, 5 nm mixture, 10 nm mixture, Ca(OH)2 alone, and triple antibiotic paste (TAP). Cell viability was evaluated using the Cell Counting Kit-8 and LIVE/DEAD Viability/Cytotoxicity Kit. Reactive oxygen species (ROS) were quantified using the 2′,7′-dichlorofluorescein diacetate redox probe. Transforming growth factor (TGF)-β1, interleukin (IL)-1β, tumor necrosis factor (TNF)-α>, and alkaline phosphatase (ALP) were quantified using enzyme-linked immunosorbent assays. Mineralization was assessed using Alizarin Red S staining. Data were compared across groups using the Kruskal–Wallis test and within groups using the Wilcoxon signed-rank test (p < 0.05). Ca(OH)2 alone and the 10 nm mixture demonstrated the highest cell viability and lowest ROS release (p < 0.05), while the 2 nm and 5 nm mixtures resulted in decreased viability and significant morphological distortion of the cells. Ca(OH)2 alone and the 10 nm mixture comparably demonstrated the highest production of anti-inflammatory cytokine TGF-β1 (p < 0.05), the lowest production of proinflammatory cytokines IL-1β and TNF-α (p < 0.05), and the highest ALP release and mineralization (p < 0.05). Within the limitations of this in vitro study, Ca(OH)2 alone and the 10 nm mixture improved hDPSCs’ viability, proliferation, differentiation, and mineralization. Both illustrated a significantly higher anti-inflammatory response by the residing stem cell population.

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