Low-temperature flow-synthesis-assisted urethane-grafted zinc oxide-based dental composites: physical, mechanical, and antibacterial responses

Abstract

A novel way was adopted to graft zinc oxide (ZnO) with urethane-modified dimethacrylate (UDMA) in order to utilize them as reinforcing agents in resin-based dental composites. Experimental novel composites were synthesized having UDMA-grafted and nongrafted ZnO, at a concentration of 0 wt.%, 5 wt.%, and 10 wt.%. The same concentrations of ZnO were also incorporated in Filtek Z250 XT (3 M ESPE, USA). The antibacterial behavior was evaluated against Streptococcus mutans by direct-contact test at one, three, and seven days of incubation. The compressive strength and Vickers microhardness were tested as per ISO 9917 and ISO/CD6507-1, respectively. For abrasive wear resistance, mass loss and roughness average after tooth-brushing cycles of 24,000 at custom-made tooth-brushing simulator were evaluated using noncontact profilometer. Data analysis was carried out using post hoc Tucky’s test and nonparametric Kruskal–Wallis test. Direct contact test revealed that the antibacterial potential of novel and commercial composites was increased with an increase in the concentration of grafted ZnO as compared with nongrafted, whereby the potential was the highest at day seven. There was a significant decrease in compressive strength and Vickers hardness of commercial composites on addition of grafted ZnO while there was no significant difference in the strength of experimental novel composite. The abrasive wear of commercial and experimental composites was within clinical limits. Low-temperature flow-synthesis method was successfully employed to synthesize grafted and nongrafted ZnO. The UDMA-grafted ZnO can be incorporated into dental composites without decreasing their strength and these composites can be used to combat secondary caries.

Biological and Physicochemical Characterization of Self-Adhesive Protective Coating Dental Restorative Material after Incorporation of Antibacterial Nanoparticles

“…The addition of zinc oxide and titanium dioxide nanoparticles in dental restorative materials improves not only antibacterial qualities but also physical and mechanical properties such as microhardness, compressive strength, and flexural strength [ 19 , 31 ]. In the present study, zinc oxide and titanium dioxide nanoparticles were separately incorporated in different concentrations, whereby the hypothesis is accepted that antibacterial performance was improved after adding these nanoparticles.…”

“…ZnO nanoparticles internalized by bacteria can cause cell damage and growth inhibition through electrostatic interactions [ 18 ]. Moreover, ZnO has been incorporated into a variety of dental restorative materials to enhance the mechanical and biological properties [ 19 , 20 ]. Increasing the concentration of ZnO nanoparticles in restorative materials results in augmented antimicrobial activity; however, at higher concentrations of the nanoparticles, the depth of light cure of the resin is reduced [ 21 ].…”

Structural, Physical, and Mechanical Analysis of ZnO and TiO2 Nanoparticle-Reinforced Self-Adhesive Coating Restorative Material

“…TiO 2 nanoparticle-reinforced dental resins showed significant antimicrobial effects and resulted in the prevention of recurrent caries and enamel demineralization [36]. However, the inhibition of biofilm formation within the oral cavity through nanoparticles possessing antimicrobial effects has been incorporated into polymeric materials as a function of their biocidal effect [39].…”

Bioactive Dental Resin Composites with MgO Nanoparticles

“…22,23 For example, incorporating a small amount of silver nanoparticles (AgNPs) or zinc oxide nanoparticles (ZnONPs) into dental composites can significantly inhibit or kill multiple microorganisms (e.g., Streptococcus mutans, Lactobacillus, Candida albicans, etc.). 11,24,25 However, these nanoparticles may cause discoloration 26 and/or have a degree of cytotoxicity, genotoxicity, and potential risk of excessive heavy metal accumulation. 27 −30 In comparison to other metallic nanoparticles, magnesium oxide nanoparticles (MgONPs) is a potential alternative for its multiple advantages of a broad-spectrum antibacterial effect, simple preparation, low cost, stable color, and low toxicity.…”

“…These nanosized particles exhibit unique performances, such as high antibacterial efficacy, less acquired resistance, appealing mechanical, and optical properties, due to their high surface-to-volume ratio and diverse particle morphology. , For example, incorporating a small amount of silver nanoparticles (AgNPs) or zinc oxide nanoparticles (ZnONPs) into dental composites can significantly inhibit or kill multiple microorganisms (e.g., Streptococcus mutans, Lactobacillus , Candida albicans, etc. ). ,, However, these nanoparticles may cause discoloration and/or have a degree of cytotoxicity, genotoxicity, and potential risk of excessive heavy metal accumulation. − …”