Bonding compositions to the hard tissue of human body

A bonding composition consisting essentially of

• (A) from 30 to 99.8% by weight of at least one polymerizable monomer selected from the monomer group consisting of acrylate esters, methacrylate esters, acrylamide derivatives and methacrylamide derivatives, wherein all the members of said monomer group contain a carboxyl, epoxy, amino or hydroxyl group in the molecule,
• (B) from 70 to 0.2% by weight of at least one member selected from the group consisting of
• (B-I) alkoxy-containing titanium compounds having the formula ##STR50## wherein R.sub.6 is a C.sub.1-20 aliphatic hydrocarbon having up to two substituents selected from the group consisting of hydroxyl, C.sub.1-3 alkoxy and di(hydroxyalkyl)amino in which the alkyl has 2 or 3 carbon atoms, R.sub.7, R.sub.8 and R.sub.9, which are the same or different, have the same meaning as R.sub.6 and additionally include a group of the formula ##STR51## wherein R.sub.10 is ##STR52## or C.sub.1-20 saturated aliphatic hydrocarbon containing up to two substituents selected from the group consisting of hydroxyl, C.sub.1-3 alkoxy and acyl having the formula ##STR53## wherein R.sub.21 is alkyl having 1 to 3 carbon atoms, and (B-II) silane compounds containing at least three alkoxy groups in the molecule,
• a catalyst for the polymerization of the composition and an activator for the formation of free radicals by reaction with the catalyst.