| 摘要 |
<p>Silicic acid pellets are used, which have an average particle size from. 5 to 50 //c m, enclosing primary silicic acid particles, having an average size comprised between 1 and 100 nm, as an excipient of dental mass material based on polymerizable unsaturated ethylenic monomers. The reinforced excipient is substantially colourless and lends itself to mixing in large quantity with polymerizable monomer masses, particularly with the mono- and di-, respectively polyfunctional esters of acrylic and methacrylic acid; it provides a plastic, shapable and deformable paste. If necessary, the silicic acid pellets are used with microfine silicic acid, non-granulated, having an average particle size from 1 to 100 nm. The shapes obtained after hardening of polymerizable masses with the excipients exhibit a higher pressure resistance, a low thermal expansion, a high colour stability and a low hygroscopy and lend themselves to fine polishing. The excipients obtained are generally appropriate for preparations for tooth filling and care as well as for the preparation of artificial teeth.</p> |
