Acidity-induced release of zinc ion from BioUnion^TM filler and its inhibitory effects against <i>Streptococcus mutans </i>

Abstract

BioUnion filler incorporated into restorative/coating materials is a new bio-functional glass powder. The most unique function of BioUnion filler is its ability to release Zn 2+ in acidic environments. In this study, the ion release profile of BioUnion filler under acidic conditions and its antibacterial effects against Streptococcus mutans were evaluated. The concentrations of Zn 2+ released from BioUnion fillers into acetic acids were greater than those released into water. S. mutans inhibition by BioUnion fillers was greater with sucrose than without sucrose, reflecting a decrease in suspension pH in response to the addition of sucrose. Exposure to acids increased Zn 2+ release from BioUnion fillers, and the fillers after repeated exposure to acids demonstrated inhibitory effects against S. mutans. These findings suggest that BioUnion filler accelerated the release of Zn 2+ under acidic conditions, which induced bactericidal/inhibitory effects against S. mutans.

Cutting-edge filler technologies to release bio-active components for restorative and preventive dentistry

“…Zn 2+ is known to exhibit antibacterial effects against oral bacteria 37,46) . The MIC/MBC values of zinc against S. mutans were reported to be lower than those of fluoride 6) . Interestingly, Liu et al 6) reported that BioUnion fillers demonstrated accelerated release of Zn 2+ under acidic conditions and exerted strong bactericidal or inhibitory effects against oral bacteria.…”

“…Therefore, other antibacterial nanoparticles have been used as fillers for resinous materials. Zinc oxide powders, incorporated as opaque reinforcing fillers in resin composites 36) , display antimicrobial properties by blocking the synthesis of bacterial cell walls 6,37) . Zinc acts directly by altering cell proteins via processes such as transmembrane proton translocation, or indirectly by inhibiting protease-induced bacterial adhesion [37][38][39] .…”

“…It was shown that resin composites incorporating these fillers acted as a single source of both calcium (Ca 2+ ) and fluoride (F − ) ions in aqueous solutions, and that the composites could be readily recharged with F − . However, because the effective concentration of Ca 2+ and F − ions against microorganisms is so high, the antimicrobial effects of a local increase in pH due to calcium ions from bioglass 45S5 or 65S or the release of fluoride ions from fluoridecontaining glass fillers are limited 6) . As a result, additional components are needed to more effectively demonstrate antibacterial effects against oral microorganisms.…”

“…Incorporation of filler particles that release active components is a potential method to create bio-active materials. Many approaches are available to develop fillers with the ability to release active agents, and intensive studies have been conducted on ion-releasing inorganic fillers 1,[3][4][5][6] . Considering the diverse functions exhibited by various kinds of ions, several restorative or coating materials incorporating glass fillers with multiple ion-releasing effects have been commercialized and are in clinical use 1,6) .…”

“…Many approaches are available to develop fillers with the ability to release active agents, and intensive studies have been conducted on ion-releasing inorganic fillers 1,[3][4][5][6] . Considering the diverse functions exhibited by various kinds of ions, several restorative or coating materials incorporating glass fillers with multiple ion-releasing effects have been commercialized and are in clinical use 1,6) . Another technology of interest is a new filler made of non-biodegradable polymer particles 2) , which work as a reservoir to release not only chemicals but also proteins, and can be incorporated into restorative/prosthetic materials.…”