Penetration and Adaptation of the Highly Viscous Zinc-Reinforced Glass Ionomer Cement on Contaminated Fissures: An In Vitro Study with SEM Analysis

Novel pit and fissure sealant with nano-CaF2 and antibacterial monomer: Fluoride recharge, microleakage, sealing ability and cytotoxicity

Conventional resin-based sealants release minimal fluoride ions (F) and lack antibacterial activity. The objectives of this study were to: (1) develop a novel bioactive sealant containing calcium fluoride nanoparticles (nCaF2) and antibacterial dimethylaminohexadecyl methacrylate (DMAHDM), and (2) investigate mechanical performance, F recharge and re-release, microleakage, sealing ability and cytotoxicity. Helioseal F served as commercial control. The initial F release from sealant containing 20% nCaF2 was 25-fold that of Helioseal F. After ion exhaustion and recharge, the F re-release from bioactive sealant did not decrease with increasing number of recharge and re-release cycles. Elastic modulus of new bioactive sealant was 44% higher than Helioseal F. The new sealant had excellent sealing, minimal microleakage, and good cytocompatibility. Hence, the nanostructured sealant had substantial and sustained F release and antibacterial activity, good sealing ability and biocompatibility. The novel bioactive nCaF2 sealant is promising to provide long-term F ions for caries prevention.

Effect of the Addition of Varying Concentrations of Silver Nanoparticles on the Fluoride Uptake and Recharge of Glass Ionomer Cement

This study aimed to compare the amount of fluoride uptake and the recharge and release characteristics of conventional glass ionomer cement (GIC) without any additives in comparison to conventional glass ionomer cement supplemented with silver nanoparticles (AgNPs) at two concentrations: 0.1% and 0.2% (w/w). A total of 60 specimens were used in this in vitro study. The sample was divided into six groups—including three groups without fluoride charge: Group 1 (conventional GIC), Group 2 (GIC with 0.1% silver nanoparticles), and Group 3 (GIC with 0.2% silver nanoparticles; and three groups with fluoride charge: Group 4 (conventional GIC with fluoride); Group 5 (GIC with 0.1% silver nanoparticles with fluoride); Group 6 (GIC with 0.2% silver nanoparticles with fluoride), where Group 1 is considered the control group and the other five groups are used as the test groups. The amount of fluoride released was measured on days 1, 2, 7, 15, and 30. The comparisons were made between the groups with and without fluoride and among all the groups. A significant difference in the amount of fluoride released was observed between the groups, with the highest amount occurring in Group 1, followed by Group 2; the lowest amount of fluoride released was observed in Group 3 (p < 0.05). The groups with fluoride recharge (Groups 4, 5, and 6) exhibited a higher amount of fluoride release than the groups with no recharge (Groups 1, 2, and 3); however, Group 1 has more fluoride release compared to all other groups on days 1, 2, 7, 15, and 30 (p < 0.05). The amount of released fluoride decreased from day 1 to day 30 in all of the groups in the study. Despite the antimicrobial and anticariogenic benefits of adding silver nanoparticles to GIC, it seems that fluoride release characteristics are significantly affected by the addition of this material. This may force the clinician to a compromise between the antimicrobial benefit of silver nanoparticles and the remineralizing advantage of fluoride.