Fabrication of pH-Responsive Zn2+-Releasing Glass Particles for Smart Antibacterial Restoratives

Abstract

The on-demand release of antibacterial components due to pH variations caused by acidogenic/cariogenic bacteria is a possible design for smart antibacterial restorative materials. This study aimed to fabricate pH-responsive Zn2+-releasing glass particles and evaluate their solubilities, ion-releasing characteristics, and antibacterial properties in vitro. Three kinds of silicate-based glass particles containing different molar ratios of Zn (PG-1: 25.3; PG-2: 34.6; PG-3: 42.7 mol%) were fabricated. Each particle was immersed in a pH-adjusted medium, and the solubility and concentration of the released ions were determined. To evaluate the antibacterial effect, Streptococcus mutans was cultured in the pH-adjusted medium in the presence of each particle, and the bacterial number was counted. The solubility and concentration of Zn2+ released in the medium increased with a decrease in medium pH. PG-3 with a greater content of Zn demonstrated higher concentrations of released Zn2+ compared with PG-1 and PG-2. PG-2 exhibited bactericidal effects at pH 5.1, whereas PG-3 demonstrated bactericidal effects at pH values of 5.1 and 6.1, indicating that PG-3 was effective at inhibiting S. mutans even under slightly acidic conditions. The glass particle with 42.7 mol% Zn may be useful for developing smart antibacterial restoratives that contribute to the prevention of diseases such as caries on root surfaces with lower acid resistance.

Limited utility of salivary mineral content in prediction of fragility fractures among postmenopausal women

“…Median values obtained in the present study proved to be quite similar in both subgroups (6.8-6.85) and matched normal values. 36,37 Slightly lower pH values were found in study participants with fractures, but the difference was not significant. Our results were similar to those observed by Pereira et al, who compared postmenopausal women with low bone mineral density (BMD) to controls without bone loss and found a pH proportion of 7.1-7.2.…”

Smart Dental Materials Intelligently Responding to Oral pH to Combat Caries: A Literature Review

“…In addition, the composition of BGs could be modified to achieve specific biological effects, such as the release of particular ions. The pH-responsive Zn 2+ -releasing glass particles could release more Zn 2+ when pH decreases ( Figure 5 d) and inhibit the growth of S. mutans in a slightly acidic environment ( Figure 5 e), so that it could be used to prevent root caries with low acid resistance [ 49 ].…”

Metal-doped silicate and phosphate glasses for antibacterial dental biomaterials

“…Deng et al. [ 69 ] recently fabricated acidity-responsive silicate glasses containing high Zn concentrations (33–38 mol%; Figure 1 ). These glasses are modifications of the BioUnion filler that increase the Zn content and remove the Ca incorporated in the BioUnion filler.…”