Silver-Doped Bioactive Glass/Chitosan Hydrogel with Potential Application in Dental Pulp Repair

The major indications of a successful inflamed-pulp-capping procedure are the formation of a dense calcified dentin barrier and the preservation of healthy pulp tissue concomitant with elimination of inflammation. Our aim is to evaluate the effects of an injectable silver-doped bioactive glass/chitosan hydrogel (Ag-BG/CS), as a pulp-capping material, and explore the molecular mechanisms of Ag-BG/CS in regards to its bioactive and anti-inflammatory properties. First, the structure and component of the material were analyzed by scanning electron microscopy. Then, the downstream molecular mechanisms and anti-inflammatory effects were characterized by quantitative polymerase chain reaction (qPCR) and Western blot. Finally, a preclinical model of rat pulpitis was used to explore the potential of Ag-BG/CS in controlling pulp inflammation in vivo. The results showed that Ag-BG/CS induced stronger reparative dentin formation and enhanced preservation of vital pulp tissue when compared to the mineral trioxide aggregate (MTA) which is the currently used clinical standard. Ag-BG/CS also significantly increased the phosphorylation of p38 and ERK1/2(p42/44) of dental pulp cells, indicating that Ag-BG/CS enhanced pulpal repair through the mitogen-activated protein kinase (MAPK) pathway. This novel material may represent a superior solution for dental pulp-capping clinical scenarios with specific advantages for cases of early diffuse pulpitis in immature permanent teeth.