Formulation and characterization of a novel fluoride-releasing dental composite

Objectives The aims of this study were to formulate a novel fluoride-releasing dental composite and to evaluate its mechanical properties, fluoride release and recharge capabilities, water sorption and solubility. Methods A fluoride-releasing dimethacrylate monomer containing a ternary zirconium fluoride chelate was synthesized. Three experimental fluoride-releasing composites were fabricated with different monomer formulas (wt.%)—(1) Control A: 40 BisGMA/40 TEDMA/20 UEDMA; (2) Experimental: 20 F-releasing monomer/20 BisGMA/40 TEDMA/20 UEDMA; (3) Control B: the same formula as Control A except that it contained 10 wt.% (of total monomer) tetrabutylammonium fluoride (TBAF), which had a fluoride content equivalent to Experimental. All three materials had the same filler content: 55 wt.% silanized fluoroaluminosilicate particles (0.8 μm) and 10 wt.% silanized fumed silica (14 nm). All materials contained 0.17 wt.% camphorquinone (CQ) as a photoinitiator and 0.69 wt.% ethyl-4-dimethylaminobenzoate (4EDMAB) as an accelerator. The materials were tested for fluoride release (for 184 days), fluoride recharge, compressive and flexure strength, water sorption and solubility. The data were analyzed using ANOVA and Tukey-HSD tests, and Kruskal–Wallis test. Results The experimental composite had significantly higher fluoride release and fluoride recharge capabilities than both Control composites. It had significantly better physical and mechanical properties than Control B. Significance The combined use of the fluoride-releasing dimethacrylate monomer and fluoride-releasing filler can provide sustained high fluoride release and recharge as well as acceptable mechanical and physical properties. Simply adding organic fluoride salt in the monomer yields composites with poor mechanical and physical properties.