Abstract
BACKGROUND/PURPOSE: Regenerative pulp therapy's efficacy is constrained by root canal disinfectants' effects on residual dental pulp stem cells. This study investigates sodium hypochlorite's influence on dental pulp stem cells (DPSCs) viability, mitochondrial function, and osteogenic differentiation, providing cellular and molecular foundations for optimizing clinical protocols. MATERIALS AND METHODS: Human deciduous teeth-derived DPSCs were treated with sodium hypochlorite (0.5%-5%) for 1 min. Cell viability, cytoskeletal integrity, and mitochondrial morphology were assessed via CCK-8, immunofluorescence, and MitoTracker labeling. Osteogenic potential was evaluated through ALP activity, mineralized nodule quantification, and osteogenic marker expression. A juvenile rat model validated findings through immunohistochemistry and molecular analysis of periapical tissues. RESULTS: Sodium hypochlorite exhibited concentration-dependent effects. At ≤1%, DPSCs maintained >80% viability with intact cytoskeleton, while ≥3% significantly inhibited proliferation and induced mitochondrial autophagy. Low concentration (0.5%) minimally affected osteogenic differentiation markers, while higher concentrations progressively suppressed osteogenic potential. In vivo experiments corroborated these findings. CONCLUSION: Low-concentration sodium hypochlorite (≤0.5 %) preserves DPSC viability, mitochondrial function, and differentiation capacity, whereas higher concentrations impair cellular functions through autophagy induction. These findings support using lower concentrations in regenerative endodontics to maintain stem cell potential while ensuring adequate disinfection.