Radiopaque cationically polymerizable compositions comprising a radiopacifying filler, and method for polymerizing same
Polymerizable compositions that include: (a) a cationically active functional group; (b) an initiation system capable of initiating cationic polymerization of the cationically active functional group; and (c) a filler composition that includes various radiopacifying fillers in an amount sufficient to render the polymerizable composition radiopaque. Components (a), (b), and (c) are selected such that the polymerizable composition polymerizes to form a polymerized composition having a Barcol hardness, measured using a GYZJ-935 meter, of at least 10 within 30 minutes following initiation of the cationically active functional group at a reaction temperature of 25° C.
1. Non vitreous microparticles prepared by a sol-gel method in which an aqueous or organic dispersion or sol of amorphous silicon oxide is mixed with an aqueous or organic dispersion, sol, or solution of a radiopacifying metal oxide, or precursor organic or inorganic compound,
said microparticles being substantially free of crystalline microregions or inhomogeneities detectable via powder x-ray diffraction.
2. Non vitreous microparticles prepared by a sol-gel method in which an aqueous or organic dispersion or sol of amorphous silicon oxide is mixed with an aqueous or organic dispersion, sol, or solution of a radiopacifying metal oxide, or precursor organic or inorganic compound,
said microparticles comprising:
(i) a plurality of amorphous microregions comprising oxygen and silicon,
(ii) a plurality of semicrystalline radiopacifying, metal oxide microregions, and
(iii) no greater than 40% by weight of B 2 O 3 or P 2 O 5 ,
said plurality of amorphous microregions being substantially uniformly interspersed with said plurality of semicrystalline microregions,
said microparticles being substantially free of crystalline microregions or inhomogeneities having diameters greater than 0.4 micrometers.
3. Non vitreous microparticles according to claim 2 comprising 20–40% by weight zirconium oxide, 0.01–20% by weight boron oxide, and 1–90% by weight silicon oxide.
4. The microparticles of claim 1 further comprising 0.01–80% by weight of B 2 O 3 .
5. The microparticles of claim 1 further comprising 0.01–40% by weight of P 2 O 5 .
6. The microparticles of claim 1 , wherein the microparticles are surface-treated with silane.
7. The microparticles of claim 1 , wherein the radiopacifying metal oxide is selected from the group consisting of oxides of yttrium, strontium, barium, zirconium, hafnium, niobium, tantalum, tungsten, molybdenum, tin, zinc, and lanthanide, and combinations thereof.
8. The microparticles of claim 1 further comprising 0.1 to 55% by weight aluminum oxide.
9. The microparticles of claim 1 further comprising a fluoride.
10. The microparticles of claim 1 further comprising a metal hexafluorophosphate.
11. The microparticles of claim 1 , wherein the microparticles are fluorescent.
12. The microparticles of claim 1 , wherein the microparticles are surface-treated with silane.
13. The microparticles of claim 2 , wherein the radiopacifying metal oxide is selected from the group consisting of oxides of yttrium, strontium, barium, zirconium, hafnium, niobium, tantalum, tungsten, molybdenum, tin, zinc, and lanthanide, and combinations thereof.
14. The microparticles of claim 2 further comprising 0.1 to 55% by weight aluminum oxide.
15. The microparticles of claim 2 further comprising a fluoride.
16. The microparticles of claim 2 further comprising a metal hexafluorophosphate.
17. The microparticles of claim 2 , wherein the microparticles are fluorescent.