Exploring the Multifunctional Potential of Bioactive Glass-Ionomer Cements

Conventional bioactive glasses enhance mineralization in glass-ionomer cements (GICs), but their high sodium content adversely affects mechanical performance, limiting clinical utility. To address the limitations of bioactive glass, this study explores a novel sodium-free, fluoride- and magnesium-enriched bioactive glass (J-BAG) in GICs. The mechanical performance, ion release, antibacterial efficacy against multispecies cariogenic biofilms, and mineralization capacity were investigated. The J-BAG (38.3SiO₂-6P₂O₅-43.9CaO-6.8CaF₂-5MgO) and two experimental ionomer glasses were synthesized using the melt-quench technique. A new ionomer glass, LG99Sr-Mg-Zn, with molar composition (4.5SiO₂-3Al₂O₃-1.5P₂O₅-3SrF₂-0.5SrO-1MgO-0.5ZnO), was developed from a previously established LG99Sr (4.5SiO₂-3Al₂O₃-1.5P₂O₅-3SrF₂-2SrO), with Fuji IX (GC Corporation, Tokyo, Japan) serving as the reference material. Incorporating J-BAG at 5 and 10 weight% into the experimental Mg-Zn and reference GICs resulted in significant improvements in compressive and flexural strength as well as microhardness, compared with unmodified GICs, with further gains noted postmaturation. However, mechanical properties declined at 15% loading, especially with finer J-BAG particles. Therefore, the 5% J-BAG-loaded LG99Sr-Mg-Zn (LG5) and 10% J-BAG-loaded Fuji IX (F10) formulations were selected for further testing. LG5 and F10 exhibited significantly enhanced fluoride release, along with elevated magnesium and zinc release from LG5. Antibacterial assays revealed biofilm inhibition and reduced live biomass (P < 0.05) compared with controls. Mineralization studies confirmed that higher J-BAG concentrations and longer immersion in media led to greater mineral deposition. In addition, LG5 and F10 facilitated mineral deposition on demineralized dentine surfaces and partially occluded dentinal tubules. In conclusion, the incorporation of J-BAG at 5% in Mg-Zn-fortified GIC and 10% in Fuji IX simultaneously enhanced mechanical properties, ion release, mineralization, and antibacterial performance. This multifunctionality supports the therapeutic and restorative roles of GICs in clinical dentistry. It offers a promising solution for atraumatic restorative treatments and long-term tooth rehabilitation in patients at high risk of caries.