Dentine Regeneration With Calcium Strontium Silicate: In Vitro Odontogenic Differentiation, Antimicrobial Activity, Immunomodulation and In Vivo Pulpotomy in Rat Molars

AIM: This study examined the in vitro and in vivo performance of calcium strontium silicate (CSR) as a novel biomaterial for vital pulp therapy (VPT), assessing its odontogenic differentiation, antibacterial activity, immunomodulation, inflammatory response and dentine regeneration potential compared to calcium silicate (CS) and Mineral Trioxide Aggregate (MTA). METHODOLOGY: CSR was synthesized via the sol-gel process. For the in vitro study, human dental pulp stem cells (HDPSCs) were assessed for viability, live/dead staining, trans-well migration assays and odontogenic gene expression (ALP, DSPP, DMP-1, RUNX2) using CCK-8, and RT-qPCR. Antibacterial activity against Streptococcus mutans and Lactobacillus acidophilus was assessed via colony- forming unit (CFU) counts. Immunomodulation was evaluated by RT-qPCR for inflammatory cytokines (IL-1β, TNF-α, IL-10). In the in vivo study, inflammatory responses were evaluated in Sprague-Dawley rats subjected to subcutaneous implantation for 7, 14 and 60 days, and pulpotomy procedures were performed on rat maxillary first molars and assessed after 30 and 60 days. The outcomes were analysed using micro-CT imaging and H&E staining. Statistical analyses included one-way ANOVA and non-parametric tests (p < 0.05). RESULTS: CSR significantly enhanced HDPSCs viability, migration and odontogenic gene expression compared to CS and MTA (p < 0.05). It exhibited superior antibacterial activity, with the lowest CFU counts (p < 0.05). CSR upregulated anti-inflammatory cytokine IL-10 and reduced pro-inflammatory cytokines. In vivo, CSR showed milder inflammation than CS and MTA at 7, 14 and 60 days (p < 0.05) and formed consistent calcified bridges in pulpotomy, with no pulp necrosis. CONCLUSIONS: CSR demonstrated superior biocompatibility, regenerative potential, and antibacterial properties making it a promising alternative to MTA for VPT, enhancing clinical outcomes.