US Patent 6899948 Dental materials with nano-sized silica particles

A dental material comprising a hardenable resin and silica particles dispersed within the hardenable resin, wherein the silica particles have an average diameter of less than about 200 nm and are present in an amount greater than about 40 wt % of the weight of the dental material. The dental material may further comprise a heavy metal oxide. The dental material can be used as dental adhesives, artificial crowns, anterior or posterior fillings, casting materials, cavity liners, cements, coating compositions, mill blanks, orthodontic devices, restoratives, prostheses, and sealants.