GB1328854A - Low water absorption dental restorative - Google Patents

Abstract

1328854 Polymerizable dental materials MINNESOTA MINING & MFG CO 2 Nov 1970 [3 Nov 1969] 52071/70 Addition to 1267448 Heading C3P Mouldable dental restorative compositions having a moisture absorption, after hardening and exposure to moisture, of less than 1% by weight, comprise an inorganic particulate filler and a liquid binder capable of being polymerized in the presence of a free radical initiator, the binder comprising a monomeric polyacrylate or polymethacryate ester of an etherified diphenol which has been etherified at each phenolic hydroxyl group by a molecule of a diol or triol, the diphenol group comprising at least two aromatic nuclei joined directly through a single carbon-carbon bond or through a divalent linking group, and the polyester being substantially free from active hydrogen atoms and devoid of peroxides. A polymerization accelerator is preferably also included, e.g. an N,N-bis- (hydroxyalkyl) - p - toluidine or -3,5 - xylidene wherein the alkyl group has 2 to 6 carbon atoms. Suitable fillers include lithium aluminium silicates, hydroxy apatite, silica or siliceous materials, alumina or aluminoferrous materials, and glasses such as borosilicate glasses; the filler may be modified to promote adhesion by the binder, e.g. by a conventional vinyl silane treatment. Small amounts of pigment may be included in the filler for visual colour or fluorescent effect. The polymerizable ester is preferably one of the formula in which M is a methacryloyl or acryloyl group, D is C 2 -C 6 alkylene, X is the nucleus of a diphenol having at least two aromatic nuclei joined as described above and having from 12-24 carbon atoms, T is the nucleus of a triprimary triol and n is an integer. The compositions can be stored in two-component kit form with the ingredients of the composition being apportioned between the two components. In examples an adduct of glycidyl methacrylate and phenyl salicylate is used as a comonomer for the binder, and benzoyl peroxide is used as polymerization initiator.