GB1267448A - Polymerizable dental restorative compositions - Google Patents

Abstract

1,267,448. Polymerizable dental materials. MINNESOTA MINING & MFG. CO. 14 March, 1969 [15 March, 1968; 12 July, 1968], No. 13681/69. Heading C3P. Mouldable dental restorative compositions having a moisture absorption, after hardening and exposure to moisture, of less than 2% 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 including a polymerizable polyacrylate or polymethacrylate ester of at least one polyol having primary hydroxyl groups and the poly- (meth) acrylate being substantially free from active hydrogen atoms and devoid of peroxides. The compositions preferably include 72-78% by weight of the filler and 28-22% by weight of the binder. The binder optionally includes an accelerator for free radical polymerization; preferred accelerators are dimethyl-p-toluidine and N,N - bis - (hydroxyalkyl) - 3,5 - xylidines having 2-4 carbon atoms in the alkyl groups. Suitable fillers include silicon dioxide (quartz), lithium, aluminium silicates and hydroxyapatite; the filler may be conventionally treated to promote adhesion by the binder, e.g. with a vinyl silane treatment. The polymerizable ester used is preferably a polymethacrylate of the formula in which M is a methacryloyl group, D is a C 2 -C 5 alkylene group, a group of the formula -CH 2 -Y-CH 2 - (where Y is cycloalkylene) or 3-oxapentylene, n is 1 or 2 and X is the acyl residue of a mono- or bi-nuclear aromatic dicarboxylic acid of 8-19 carbon atoms or an unsaturated dibasic aliphatic acid of up to 5 carbon atoms. Also useful are bis- and tris- (methacryloxymethyl) derivatives of diphenyl ether. To effect polymerization of the compositions an initiator such as benzoyl peroxide is added immediately before polymerization.