Nanotechnology-Based Dental Materials: Applications in Preventive and Restorative Dentistry

Abstract

Nanotechnology, the design and use of materials with at least one dimension between 1 and 100 nanometres, has led to a new generation of dental materials. At the nanoscale, materials have a very large surface area relative to their volume and may show different physical, chemical and biological properties from their bulk forms. In preventive dentistry, nanohydroxyapatite toothpastes have shown remineralising and anticaries effects comparable to fluoride in several trials, and amorphous calcium phosphate nanoparticles, casein phosphopeptide–amorphous calcium phosphate and nano-sized bioactive glass support remineralisation of early enamel lesions and reduce dentine hypersensitivity. Silver nanoparticles, including nano silver fluoride, have antibacterial and caries-arresting activity. In restorative dentistry, nanofilled and nanohybrid resin composites combine high strength with good polish retention; nanofillers improve glass-ionomer cements and adhesives; quaternary ammonium, silver and calcium phosphate nanoparticles are being incorporated into composites and adhesives to make them antibacterial and remineralising; and nanostructured zirconia and implant surfaces are being developed. Other applications include nanoparticle-based endodontic irrigants and sealers, drug delivery and periodontal regeneration scaffolds. Despite these advances, much of the evidence comes from laboratory studies, and long-term clinical trials are limited. The potential toxicity of nanoparticles to oral tissues, patients and dental staff, and their environmental impact, require further study and appropriate regulation. This review summarises the principles, current applications, evidence base, safety concerns and future directions of nanotechnology-based materials in preventive and restorative dentistry.