Dental resin materials, method of manufacture, and uses thereof
View Patent ↗A filler for a dental resin composition is disclosed, comprising silica particles derived from a nanoparticulate silica sol, the filler material having at least one crystalline phase. The filler material provides improved wear resistance and other properties.
1. A filler made in accordance with a method comprising:
drying a sol comprising individual amorphous silica nanoparticles having diameters of about 1 to about 50 nanometers, wherein the individual amorphous silica nanoparticles are in the form of chains having lengths of about 5 to about 400 nanometers, at a temperature and for a time effective to remove liquid therefrom; and
heating the dried silica sol to a temperature at about or above about 800° C. and for a time effective to form at least one crystalline phase therein.
2. The filler of claim 1 wherein the heated dried silica sol has at least one crystalline phase that retains nanostructured character.
3. The filler of claim 1 , wherein the chains have lengths of about 5 to about 300 nanometers.
4. The filler of claim 1 , wherein the silica nanoparticles have diameters of about 1 to about 30 nanometers.
5. The filler of claim 1 , wherein the silica nanoparticles have diameters of about 1 to about 20 nanometers.
6. The filler of claim 1 , wherein the method further comprises surface treating the heated dried silica sol with a silane.
7. The filler of claim 6 , wherein the silane comprises gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, gamma-aminopropyltriethoxysilane, or mixtures thereof.
8. The filler of claim 7 , further comprising a microparticulate glass filler, a ceramic filler, or a mixture thereof.
9. The filler of claim 1 , further comprising an opacifying oxide.
10. The filler of claim 1 , wherein an X-ray diffraction pattern of material formed after the drying shows a dominant amorphous curve and no crystalline peaks, and an X-ray diffraction pattern of material formed after the heating exhibits crystalline peaks.
11. The filler of claim 1 , wherein the sol that is dried comprises amorphous elongated silica nanoparticles in an aqueous solution.
12. The filler of claim 1 , wherein, prior to said drying and heating, the sol comprising silica nanoparticles is mixed with a microparticulate filler.
13. The filler of claim 1 , wherein, prior to said drying and heating, the sol comprising the silica nanoparticles is mixed with a microparticulate filler and an opacifying oxide or calcinable precursor thereof.
14. A composition comprising the filler of claim 1 in admixture with a resin material to form a dental composite.