The present invention relates to a photocurable dental composition comprising a specific polymerization initiator system containing the combination of a photoinitiator compound and a coinitiator compound being a sulfinate compound or a sulfonate compound. The present invention also relates to the use of this polymerization initiator system in a photocurable dental composition.

It is an object of the present invention to provide a monomer which can provide a cured product having both high toughness and rigidity. The present invention is a (meth)acrylate (D) which is a reaction product of a thiol compound (A) having two or more mercapto groups; an iso(thio)cyanate compound (B) having two or more iso(thio)cyanato groups; and a hydroxy (meth)acrylate compound (C) having one or more polymerizable groups.

It is an object of the present invention to provide a monomer which can provide a cured product having both high toughness and rigidity. The present invention is a (meth)acrylate (D) which is a reaction product of a thiol compound (A) having two or more mercapto groups; an iso(thio)cyanate compound (B) having two or more iso(thio)cyanato groups; and a hydroxy (meth)acrylate compound (C) having one or more polymerizable groups.

A light-curable dental impression material comprising (a) a polymerizable polysiloxane resin composition comprising compounds of formula (I)
E-(L.sup.1-Z).sub.n-L.sup.2-E   (I)
(b) a particulate filler; and
(c) a photoinitiator.

A light-curable dental impression material comprising (a) a polymerizable polysiloxane resin composition comprising compounds of formula (I)
E-(L.sup.1-Z).sub.n-L.sup.2-E   (I)
(b) a particulate filler; and
(c) a photoinitiator.

A light-curable dental impression material comprising (a) a polymerizable polysiloxane resin composition comprising compounds of formula (I)
E-(L.sup.1-Z).sub.n-L.sup.2-E   (I)
(b) a particulate filler; and
(c) a photoinitiator.

The invention provides alight-curable dental material comprising a polymerizable compound having at least one ethylenically unsaturated bond and a hexaaryl bisimidazole as a photopolymerisation initiator.

The invention provides alight-curable dental material comprising a polymerizable compound having at least one ethylenically unsaturated bond and a hexaaryl bisimidazole as a photopolymerisation initiator.

The invention provides alight-curable dental material comprising a polymerizable compound having at least one ethylenically unsaturated bond and a hexaaryl bisimidazole as a photopolymerisation initiator.

The present invention relates to a photocurable dental composition comprising a specific polymerization initiator system containing the combination of a photoinitiator compound and a coinitiator compound being a sulfinate compound or a sulfonate compound. The present invention also relates to the use of this polymerization initiator system in a photocurable dental composition.