The in vitro assessment of resin coating materials containing calcium phosphate, bioactive glass, and polylysine for glass ionomer cement restorations

Objective: Glass ionomer cements (GICs) require protective surface coatings to enhance their clinical performance. This study developed novel protective resin coatings for GICs containing monocalcium phosphate monohydrate (MCPM), bioactive glass nanoparticles (BAGs), and poly-L-lysine (PLS) and evaluated their physical, mechanical, and biological properties when applied to GICs.

Materials and methods: Experimental resin coating materials were formulated with 5–10 wt% of MCPM, BAGs, and PLS. The degree of monomer conversion was measured usingAttenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) (n = 6). GICs coated with the experimental materials were evaluated for biaxial flexural strength and modulus after 24 h water immersion using a universal testing machine (n = 8). Vickers surface microhardness up to 4 weeks of water immersion was also determined (n = 5). Fluoride and elemental release in water were analyzed using a fluoride-specific electrode and inductively coupled plasma optical emission spectrometry (n = 3). Cell viability was assessed using an MTT assay with mouse fibrosarcoma (n = 3). A commercial resin coating (EQUIA Forte Coat, EQ) served as control. Data were analyzed using one-way ANOVA and Tukey HSD test.

Results: While EQ showed higher monomer conversion (87%) compared to experimental materials (72–74%) (p < 0.05), GICs coated with experimental materials demonstrated comparable strength to EQ-coated GICs. The experimental coatings exhibited similar F, Al, Na, and Si releases to EQ-coated GICs, with enhanced P release. All experimental coatings exhibited comparable cell viability (>70%) to the commercial material.

Conclusion: The novel GIC protective coatings containing MCPM, BAGs, and PLS demonstrated acceptable in vitro performance comparable to commercial materials while potentially offering enhanced remineralization through increased elemental release.