Nowadays, distribution and microorganism resistance against antimicrobial compounds have caused crucial food safety problems. Hence, nanotechnology and zeolite are recognized as new approaches to manage this problem due to their inherent antimicrobial activity. Different studies have confirmed antimicrobial effects of Nano particles (NPs) (metal and metal oxide) and zeolite, by using various techniques to determine antimicrobial mechanism. This review includes an overview of research with the results of studies about antimicrobial mechanisms of nanoparticles and zeolite. Many researches have shown that type, particle size and shape of NPs and zeolite are important factors showing antimicrobial effectiveness. The use of NPs and zeolite as antimicrobial components especially in food technology and medical application can be considered as prominent strategies to overcome pathogenic microorganisms. Nevertheless, further studies are required to minimize the possible toxicity of NPs in order to apply suitable alternatives for disinfectants and antibacterial agents in food applications.

Introduction. Chitosan is a natural biopolymer that attracted enormous attention in biomedical fields. The main components of regenerative endodontic procedures (REPs), as well as tissue engineering, are scaffolds, stem cells, and growth factors. As one of the basic factors in the REPs is maintaining vascularization, this study was aimed at developing basic fibroblast growth factor‐ (bFGF‐) loaded scaffolds and investigating their effects on the angiogenic induction in human dental pulp stem cells (hDPSCs). Methods. Poly (ε‐caprolactone) (PCL)/chitosan‐ (CS‐) based highly porous scaffold (PCL/CS) was prepared and evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. The adhesion and survival potency of seeded cells were assessed by SEM and MTT assays, respectively. The amount of angiogenic markers was investigated in gene and protein levels by real‐time PCR and western blotting assays, respectively. Results. Based on our findings, the SEM and FTIR tests confirmed the appropriate structure of synthesized scaffolds. Besides, the adhesion and survival rate of cells and the levels of VEGFR‐2, Tie2, and Angiopoietin‐1 genes were increased significantly in the PCL/CS/bFGF group. Also, the western blotting results showed the upregulation of these markers at protein levels, which were considerably higher at the PCL/CS/bFGF group (P < 0.05). Conclusions. On a more general note, this study demonstrates that the bFGF‐loaded PCL/CS scaffolds have the potential to promote angiogenesis of hDPSCs, which could provide vitality of dentin‐pulp complex as the initial required factor for regenerative endodontic procedures.

Aim. The objectives of this study were to develop a new bioactive composite resin containing silver/zinc oxide (Ag/ZnO) nanoparticles and investigate the effects on mechanical, cytotoxic, biocompatibility, and antimicrobial properties. Materials and Methods. Disc-shaped specimens were prepared from composite with and without nanoparticles in separate culture media containing Streptococcus mutans, Lactobacillus, and Candida albicans. Bracket bonding evaluation was performed on composite without nanoparticles (O), composite containing ZnO (Z) nanoparticles, composite containing ZnO nanoparticles and silver ions (A&Z), and composite containing Ag/ZnO nanoparticles (AZ) synthesized using optical precipitation. Results. Composite resin with nanoparticles (AZ, A&Z, and Z) showed significant antimicrobial properties ( < 0.05). The mean shear bond strength of A&Z composite resin (13.61 ± 0.73 MPa) was significantly less than that of conventional composite resin (19.03 ± 4.12 MPa) ( < 0.05). In addition, the mean shear bond strength of AZ composite resin (20.49 ± 1.03 MPa) was significantly higher than that of Z (16.35 ± 1.03 MPa) and A&Z composite resins. Conclusions. Incorporation of ZnO nanoparticles and their compounds into orthodontic composite resins induced antibacterial properties against oral pathogens, and of all these nanoparticles, the AZ group exhibited the best antimicrobial activity and highest shear bond strength.

White spot lesions (WSLs) are one of the adverse effects of fixed orthodontic treatments. They are the primary sign of caries, which means inhibiting this process by antibacterial agents will reverse the procedure. The current study tested the surface modification of nickel‐titanium (NiTi) wires with ZnO nanoparticles (NPs), as antimicrobial agents. As the morphology of NPs is one of the most critical factors for their properties, the antibacterial properties of different morphologies of ZnO nanostructures coated on the NiTi wire were investigated. For the preparation of ZnO nanostructures, five coating methods, including chemical vapor deposition (CVD), chemical precipitation method, polymer composite coating, sol‐gel synthesis, and electrospinning process, were used. The antibacterial activity of NPs was assessed against Streptococcus mutans by the colony counting method. The obtained results showed that all the samples had antibacterial effects. The antibacterial properties of ZnO NPs were significantly improved when the specific surface area of particles increased, by the ZnO nanocrystals prepared via the CVD coating method.

Polymethyl methacrylate (PMMA) is widely used to manufacture removable orthodontic appliances. However, since the porous structure, cold‐curing acrylic resins are susceptible to bacterial adhesion and colonization. The aim of this study was to investigate the antibacterial and mechanical properties of a cold‐curing PMMA resin containing ZnO and TiO₂ nanoparticles supported on the 4A zeolite. ZnO and TiO₂ nanoparticles supported on the 4A zeolite were synthesized. Nanoparticles were added in three compositions as ZnO/4A, TiO₂/4A, and ZnO/TiO₂/4A at 2wt% and 4wt% concentrations to cold‐curing acrylic resin powder (SR Triplex® Cold Ivoclar Vivadent AG, FL‐9494 Schaan/Liechtenstein). X‐ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE‐SEM), energy dispersive X‐ray (EDX), transmission electron microscopy (TEM), and dynamic light scattering (DLS) were performed to investigate the nanocomposite characteristics. A direct test method was used to assess the antibacterial properties against Streptococcus mutans, Klebsiella pneumoniae, and Escherichia coli. The surface roughness of acrylic samples was measured with a profilometer. Flexural strength was evaluated by a three‐point bending test, and one‐way ANOVA and Tukey’s post hoc tests were used for statistical evaluation of the data. A p value of less than 0.05 was considered statistically significant. XRD confirmed the accurate crystalline structure of synthesized nanoparticles; FE‐SEM images showed nanoparticle dispersion within polymerized acryl. The addition of 2 and 4 wt% of ZnO/4A, TiO₂/4A, and ZnO/TiO₂/4A caused colony reduction in all types of tested microorganisms more than 99% and 100%, respectively. The mean flexural strengths of acrylic specimens containing 2wt% and 4wt% of synthesized nanoparticles were significantly lower than those of the resin without nanoparticles. Fabricated samples showed favorable antibacterial properties but decreased flexural strength.