The Use of Nanoparticles to Control Oral Biofilm Formation

Nanoparticles are normally considered to be of a size no greater than 100 nm, and the exploitation of their unique attributes to combat infection has increased markedly over the past decade. The potential of nanoparticles to control the formation of biofilms within the oral cavity, as a function of their biocidal, anti-adhesive, and delivery capabilities, is now coming under close scrutiny. Possible uses as constituents of prosthetic device coatings, as topically applied agents, and within dental materials are being explored. The latest insights into the application of nanoparticles in the control of oral infections, including their use in photodynamic therapy, will be discussed in this review. In particular, the use of nanoparticulate silver, copper, zinc, silicon, and their oxides will be considered in relation to their effects on bacterial populations. The recent interest in the applications of nanoparticulate polymers and calcium phosphates will also be assessed. Particular attention will be paid to the toxicity issues surrounding the potential impact of nanoparticles on oral and other tissues. </jats:p

Nano Metallic-Oxides as Antimicrobials for Implant Coatings

The use of metallic nanoparticles in the field of orthopaedics as antimicrobial components of coatings is receiving particular attention. An innovative approach has been developed whereby various metal/metal oxide nanoparticles are used to prevent infection occurring on the surface of prostheses. In this study nano metallic oxides (zinc oxide - ZnO and tungsten oxide - WO3) were used. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of each nanoparticulate were determined against four species of bacteria (Staphylococcus aureus, Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa). Subsequently the nanoparticles were prepared in a suspension of ethanol and sprayed onto the surface of glass using electrohydrodynamic deposition. Quantitative assessments as regards the antimicrobial properties of these coated samples were carried out. Comparisons of the antibacterial properties demonstrated that 2500 µg/ml or above of the oxides were required to kill the species of bacteria tested. WO3 was the most effective oxide tested in suspension using growth inhibition tests. However, coated samples demonstrated that ZnO was more bactericidal than WO3 under these conditions.</jats:p