The development of resin-coating materials for enhancing elemental release of coated glass ionomer cements

This study aimed to develop resin coatings containing monocalcium phosphate monohydrate (MCPM), Sr/F-doped bioactive glass (Sr/F-BAGs), and pre-reacted glass ionomer fillers (SPG) that enhance ion release without detrimentally affecting the mechanical properties of GIC. The objective of this study was to evaluate the degree of monomer conversion (DC), biaxial flexural strength, surface microhardness, and ion release of the GICs coated with experimental coating materials compared to a commercial product (EQUIA Coat, EC). Four experimental resin coating materials containing 10-20 wt% of MCPM with Sr/F-BAGs and 5-10 wt% SPG were prepared. The DC of the coating material was determined using ATR-FTIR. The flexural strength and surface microhardness of the coated GICs were assessed. Fluoride and elemental (Ca,P,Sr,Si,Al) release were measured using fluoride-specific electrodes and ICP-OES. The DC of the experimental coating material (60-69 %) was higher than that of EC (55 %). The strength of GICs coated with experimental materials (35-40 MPa) was comparable to EC (37 MPa). However, their surface microhardness (13-24 VHN) was lower than EC (44 VHN). The experimental coating materials reduced fluoride release by ∼43 %, similar to EC (∼40 %). However, experimental coating materials promoted higher P and Sr release than EC. In conclusion, GICs coated with the experimental resin coating containing ion-releasing additives exhibited mechanical properties similar to those of the commercial product. The new coating materials promoted a higher level of ion release for GICs. These properties could potentially enhance remineralizing actions for the coated GICs.