The evaluation of anti-osteoclastic activity of the novel calcium hydroxide biodegradable nanoparticles as an intracanal medicament.

INTRODUCTION: The aim of this study was to evaluate the anti-osteoclastic activity of calcium hydroxide-loaded poly(lactic-co-glycolic acid) nanoparticles (Ca(OH)2 -loaded PLGA NPs) in comparison to calcium hydroxide nanoparticles (Ca(OH)2 NPs).

METHODS: RAW 264.7 cell lines (third-fifth passage) were cultured and incubated with soluble receptor activator of nuclear factor-κB ligand (RANKL) in triplicates. Subsequently, Ca(OH)2 -loaded PLGA NPs and Ca(OH)2 NPs were added for 7 days to evaluate their effects on RANKL-induced osteoclast differentiation of RAW 264.7 cells by tartrate-resistant acid phosphatase (TRAP) activity. Additionally, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was conducted to confirm the cytotoxicity of treatments to cells.

RESULTS: TRAP staining showed a significant reduction in osteoclast number when treated with Ca(OH)2 -loaded PLGA NPs than Ca(OH)2 NPs (p<0.01). In comparison to the control, the number of osteoclasts significantly reduced upon treatment with Ca(OH)2 -loaded PLGA NPs (p<0.05) but no significant difference in Ca(OH)2 NPs. Furthermore, osteoclast morphology in both treatment groups exhibited smaller sizes than the control group. Neither Ca(OH)2 -loaded PLGA NPs nor Ca(OH)2 NPs demonstrated cytotoxic effects on RAW264.7 cells.

CONCLUSIONS: Both Ca(OH)2 NPs with and without PLGA have the ability to inhibit osteoclast differentiation. However, Ca(OH)2 -loaded PLGA NPs exhibit greater potential than Ca(OH)2 NPs, making them a promising intracanal medicament for cases of root resorption.