The purpose of root canal filling is to form an appropriate seal between the dentin wall and the root canal filling material and provide good antibacterial properties to combat drug-resistant microorganisms. Therefore, root canal filling must provide a seal and adhere to the root dentin, acting as a barrier to seal any remaining bacteria and prevent infection or reinfection of the root canal system.
Bacterial leakage is one of the main reasons for root canal treatment failure. Root canal sealant contraction by 1% has been shown to provide an opening for bacterial entry at the interface between the sealant and the tooth gel or dentin. The function of the sealing agent is to adhere or bond the core filling material into the root canal and fill any secondary or lateral root canal. The sealing of the root canal should be achieved by connecting the sealant to the dentin and solid filler material, ideally with dimensional stability.
Effective root canal treatment requires removal or reduction of bacteria in the root canal, completely enclose the root canal, and allow the filling material to be highly fitted with the cleaned root canal area and dentin wall, and if feasible to penetrate the dentin tubules.
AH Plus (Dentsply, De Trey GmbH, Konstanz, Germany) is an epoxy resin-based blocking agent. Due to its outstanding physical and chemical and biological properties, it is one of the most commonly used and recommended root canal blocking agents in clinical practice. Other sealants, such as bioceramic-based sealants, are also becoming increasingly popular for their unique properties and can be regarded as alternatives.
In addition, most root canal sealants significantly lose their antibacterial properties after solidification. Compared with anaerobic bacteria, Gram-positive facultative bacteria have stronger resistance to antibacterial drugs used in root canal treatment. Enterococcus faecalis (E. faecalis) is the most common bacteria that leads to persistent or secondary infections, and persistent infection is the main cause of failure of root canal treatment.
Even with flushing plans, intra-root canal medications and other types of equipment, microorganisms can reproduce in complex root canal designs. Therefore, blocking agents containing antibacterial active ingredients can better function by in closer contact with bacteria remaining in the root canal system.
Nanotechnology is one of the most promising new application areas in the world today. The most famous nano product is nanosilver. Due to its strong antibacterial activity, silver nanoparticles have been used as intra-root canal drugs and root canal disinfectants in many studies.
In recent years, a large number of studies around the world have shown that silver nanoparticles (Ag NPs) have the strongest antibacterial effect compared to other antibacterial nanomaterials. Gold nanoparticles have recently become the focus of many researches due to their optical properties and their applications in biomedical science.
Loading drugs or flushing fluids in the root canal with nanoparticles is challenging or impossible because nanoparticles must be synthesized and characterized to verify that they have the appropriate size, shape and type before they can be loaded into the material. This utilization is limited because of the need for complex equipment and the need to continuously modify the selected concentration using mathematical formulas.
A disinfectant specially designed for dentistry has been introduced recently. Product description and detailed specifications are provided by the manufacturer. Nano Care Plus Silver Gold® (Nano Care) by Dental Nanotechnology contains silver nanoparticles and trace gold, which is produced in Katowice, Poland. Manufacturers claim that Nano Care’s pharmacological combination has a lasting antibacterial effect.
It prevents bacteria from recolonizing within the root canal system and acts as an additional cleaner for organic waste. Since silver and gold nanoparticles have a variety of sizes, shapes and surface energy, they are guaranteed to have antibacterial properties to a variety of bacteria. The most common type of nanoparticle in Nano Care solutions is AgNP, accounting for 99% of the total particles and an average size of 29.07 nanometers.
Gold nanoparticles (AuNP) account for 1% of the remaining, suspended in 70% isopropanol with an average particle size of 136.7 nm/nm. It consists of many circular, disc-shaped and spherical nanoparticles with particle sizes of 48 nanometers. Since there is only one interaction point, the spherical structure of the nanoparticles reduces the possibility of agglomeration.
Furthermore, metal nanoparticles are dispersed in liquid carriers (eg isopropanol), which also has the additional advantage of reducing the agglomeration of nanoparticles by dissolving in liquid carriers (eg methanol and isopropanol).
Studies have shown that bond strength and sealant permeability may be affected by the type of sealant used and the pretreatment of the root canal wall. According to the literature review, no studies have been made on the effect of NanoCare as a component of root canal dentin pretreatment or blocking agent.
NanoCare’s main purpose is to act as a disinfectant and nanoparticle-based solution to enhance antibacterial effects. The research question is “Can it enhance/reduce bond strength?” To determine whether using these nanobiomaterials as root canal dentin pretreatment or loading into sealants can be a practical method to improve the bonding of sealants, this study investigated whether bonding gold and silver together (especially a single compound) can lead to synergistic effects between their respective properties. The null hypothesis tested no significant differences between the test groups.
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