The Fabrication of CaF₂-Containing Bioactive Glass Polymer-Infiltrated Ceramic-Network Restorative Material

Objectives: This study aimed to fabricate a novel CaF₂-containing bioactive glass polymer infiltrated ceramic network material with improved mechanical properties and fluoride releases recharge ability and to compare the mechanical properties and fluoride release and recharge ability to the commercially available materials.

Materials and Methods: A CaF₂-containing bioactive glass (CaF₂-BG) was synthesized using sol-gel method and mixed with low fusing glass ceramic to fabricate disc specimens via slip casting. Subsequently, the discs were sintered and underwent polymer infiltration process to create CaF₂-BG polymer-infiltrated ceramic network (CaF₂-BG PICN) material. For ion release and recharge testing, commercially available fluoride-releasing materials, including resin-modified glass ionomer (Fuji II LC), bioactive composite (Activa Bioactive), compomer (Dyract) and giomer (Beautifil-II) were used for comparison. Disc-shaped specimens (n=3, 10 mm diameter, and 2 mm thickness) were fabricated and subjected to fluoride release and recharge tests. Daily fluoride release was measured every 24 hours for 20 days, both pre-recharge and post-recharge, using a fluoride ion-selective electrode. Additionally, mechanical properties of all mentioned materials, as well as resin nanoceramic block (Lava Ultimate) and RIPC block (Vita Enamic), were evaluated for biaxial flexural strength and Vickers hardness according to ISO standards (n=10, 10 mm diameter, and 2 mm thickness). Scanning electron microscopy (SEM) was employed to assess the microstructure of each material while energy-dispersive X-ray spectroscopy was used for material composition analysis. The results were statistically analyzed using ANOVA followed by post hoc Tukey’s test.

Results: In this study, we invented a novel CaF₂-BG PICN material. Notably, the CaF₂-BG PICN material exhibited favorable fluoride release over the entire test duration compared to Fuji II LC and outperforming the other fluoride-releasing materials tested. Regarding mechanical properties, Lava Ultimate demonstrated the highest biaxial flexural strength, while Vita Enamic exhibited the highest Vickers hardness. Impressively, the CaF₂-BG PICN material displayed good overall mechanical properties. Additionally, scanning electron microscopy (SEM) revealed an interconnecting network structure in the CaF₂-BG PICN material, similar to that observed in Vita Enamic.

Conclusions: The CaF₂-BG PICN material was successfully fabricated and demonstrated the ability for fluoride release and recharge, along with optimal biaxial flexural strength and hardness when compared to commercially available materials. Notably, the CaF₂-BG PICN material exhibited favorable fluoride release and recharge throughout the testing period, comparing to commercially available fluoride-releasing materials.