Application of dental nanomaterials: potential toxicity to the central nervous system

Abstract

Nanomaterials are defined as materials with one or more external dimensions with a size of 1–100 nm. Such materials possess typical nanostructure-dependent properties (eg, chemical, biological, optical, mechanical, and magnetic), which may differ greatly from the properties of their bulk counterparts. In recent years, nanomaterials have been widely used in the production of dental materials, particularly in light polymerization composite resins and bonding systems, coating materials for dental implants, bioceramics, endodontic sealers, and mouthwashes. However, the dental applications of nanomaterials yield not only a significant improvement in clinical treatments but also growing concerns regarding their biosecurity. The brain is well protected by the blood–brain barrier (BBB), which separates the blood from the cerebral parenchyma. However, in recent years, many studies have found that nanoparticles (NPs), including nanocarriers, can transport through the BBB and locate in the central nervous system (CNS). Because the CNS may be a potential target organ of the nanomaterials, it is essential to determine the neurotoxic effects of NPs. In this review, possible dental nanomaterials and their pathways into the CNS are discussed, as well as related neurotoxicity effects underlying the in vitro and in vivo studies. Finally, we analyze the limitations of the current testing methods on the toxicological effects of nanomaterials. This review contributes to a better understanding of the nano-related risks to the CNS as well as the further development of safety assessment systems.

<p>Nanoparticles And Human Saliva: A Step Towards Drug Delivery Systems For Dental And Craniofacial Biomaterials</p>

“…This study investigates issues related to the antibacterial activities of zinc oxide and silver nanoparticles against the bacteria responsible for odontogenic infections in the area of the head and neck, as well as their behaviour in the saliva. The release of H 2 O 2 is a possible mechanism for the antibacterial activity of ZnO NPs,69 whereas the antibacterial activity of Ag NPs is based on cell lysis through the inhibition of DNA replication, expression of ribosomal and cellular proteins and interference with the electron transport chain 70…”

“…Moreover, they showed that zinc oxide NPs were significantly more effective against S. mutans than nanosilver. According to another study, Salem et al,70 zinc oxide nanoparticles inhibit adenylyl cyclase activity leading to the decade of the second messenger in the process of biofilm formation. In this study, biofilm formation was not evaluated, but the zinc oxide nanoparticles used as the sole antibacterial agent were significantly inferior to hydrosilver, which confirmed other observations that Zn NPs exhibited a relatively low antibacterial capacity 72,73.…”

Titanium Dioxide, but Not Zinc Oxide, Nanoparticles Cause Severe Transcriptomic Alterations in T98G Human Glioblastoma Cells

“…For example, TiO 2 nanoparticles (TiO 2 -NPs) and ZnO nanoparticles (ZnO-NPs) are used in 43 and 25 different categories of cosmetics, respectively [ 5 ]. Biomedical applications in imaging diagnostics, such as drug carriers or dental composite resins, together with applications in food industry packaging or as taste carriers or sensors [ 2 , 6 , 7 ], are matters of serious concern about human exposure. Moreover, the Organization for Economic Cooperation and Development (OECD) has included TiO 2 -NPs and ZnO-NPs among those NMs whose safety should be addressed as a priority [ 8 ].…”

<p>Local Cellular Responses to Metallic and Ceramic Nanoparticles from Orthopedic Joint Arthroplasty Implants</p>

“…However, when mechanical stress overwhelms components’ protective capacity, corrosive substances such as metallic particles, inorganic metallic salts as well as free metal ions are released. 43 These products, mostly released from metal-on-metal (MOM) and metal-on-polyethylene (MOP) bearings, can accumulate in the surrounding tissues, or even disseminate to distant lymph nodes and organs, 44 – 46 causing adverse local and/or systemic risk.…”