Fluoride Releasing/Recharging Ability of Bulk-Fill and Resin Modified Glass Ionomer Cements After the Application of Different Surface Coating Agents: An In -Vitro Study

Objective: Evaluate the effect of nano-filled coating on fluoride release/recharging ability of Equia forte Fil and Fuji II LC glass ionomer cements in comparison to commonly used surface coatings; universal adhesive and petroleum jelly. Methodology: 24 disc-shaped samples for each group were prepared with glass hybrid (Group I) and resin- modified glass ionomer cement (Group II). Each group was divided into four subgroups; 1: Control, 2: Equia Forte Coat, 3: Single bond Universal and 4: Petroleum jelly. Fluoride ions released was measured at different time intervals using fluoride-specific ion-electrode. After 63 days, samples were immersed in sodium-fluoride gel and fluoride recharge capability was evaluated. Results: Application of coats on glass hybrid resulted in significant decrease in fluoride ions release at all tested time intervals, in comparison to control group (p<0.0001). The least ions release was recorded in nano-filled coat and universal adhesive. For RMGIC, delay in burst release was observed after coating, with the least fluoride release recorded in nano-filled coated subgroup. All groups showed the ability to recharge with NaF gel and re-release again. Conclusions: 1. Application of coatings has dramatic reducing effect on fluoride ions release/recharging ability. 2. Nano-filled coating and universal adhesive have a hindering influence on fluoride ions release more than petroleum jelly. 3. The effect of nano-filled coating is more evident on glass hybrid than on resin- modified glass ionomer cement. 4. Application of coatings on glass hybrid and RMGIC delayed the burst release but maintained the fluoride release ability of GICs at constant level.