Abstract

Background Vital pulp therapy (VPT) is recognized as a minimally invasive alternative to root canal treatment for teeth with initial and mild to moderate pulpitis. However, effective inflammation control remains a key challenge, as existing pulp capping materials exhibit limited anti-inflammatory efficacy. This study aimed to develop an injectable, photocurable pulp capping material with dual anti-inflammatory and pro-odontogenic functions to improve VPT outcomes for inflamed pulp. Methods The Sal B/GelMA composite hydrogel was synthesized and characterized for physicochemical properties, drug release profile, and biodegradation. Its cytocompatibility was assessed using CCK-8 assay, live/dead staining, and cytoskeletal (F-actin) observation. The migration of human dental pulp stem cells (hDPSCs) was evaluated via a wound healing assay. In vitro, hDPSCs were cultured with lipopolysaccharide (LPS) to mimic an inflammatory environment. The anti-inflammatory effect of Sal B/GelMA hydrogel was evaluated by measuring the mRNA levels of IL-1β, IL-6, and TNF-ɑ. Odontogenic differentiation was assessed by alkaline phosphatase (ALP) activity, alizarin red S staining, and the expression of Runx2, OCN, DMP1, and DSPP. A rat pulpitis model was established for in vivo evaluation. The hydrogel’s ability to alleviate inflammation and stimulate reparative dentin formation was evaluated using micro-CT, hematoxylin and eosin (H&E) staining, Masson’s trichrome staining, and immunohistochemistry. Results The hydrogel exhibited a porous microstructure, excellent cytocompatibility, biodegradability, and sustained Sal B release kinetics. In LPS-induced hDPSCs, it significantly suppressed pro-inflammatory cytokine expression while concurrently enhancing odontogenic differentiation, as evidenced by upregulated gene expression, increased ALP activity, and enhanced mineralization. In vivo, the Sal B/GelMA hydrogel exhibited favorable biocompatibility with no signs of obvious tissue necrosis a