Radical polymerization inhibitors for light-curable dental materials

A light-curable surface coating, light-curable ink, or light-curable adhesive material comprising a polymerizable compound having at least one ethylenically unsaturated bond and a 1,3-dipolar compound as a polymerization inhibitor, wherein the 1,3-dipolar compound is selected from a group consisting of:

• (a) a nitrone of the following formula (VIII):
• wherein
• R6, R7 and R8 are independently or a substituted or unsubstituted aryl group, arylalkyl group, alkyl group, alkenyl group, alkynyl group, cycloalkyl group or cycloalkylalkyl group;
• or R7 and R8 form a 5-membered, 6-membered or 7-membered nitrogen-containing ring together with atoms to which they are attached to,
• (b) an azide of the following formula (IV):
• wherein R1 of formula (IV) is a substituted or unsubstituted aryl group, arylalkyl group, alkyl group, alkenyl group, alkynyl group, cycloalkyl group or cycloalkylalkyl group,
• (c) a diazo compound of the following formula (V):
• wherein R1 and R2 of formula (V) are independently hydrogen;
• or a substituted or unsubstituted aryl group, arylalkyl group, alkyl group, alkenyl group, alkynyl group, cycloalkyl group, cycloalkylalkyl group or benzoyl group, or
• (d) a nitrilylide of the following formula (VI):
• wherein R1, R2 and R3 of formula VI are independently hydrogen;
• or a substituted or unsubstituted aryl group, arylalkyl group, alkyl group, alkenyl group, alkynyl group, cycloalkyl group or cycloalkylalkyl group, preferably one of R1, R2, and R3 is not hydrogen.