Dental composition based on silicone crosslinkable by cation process

A dental composition comprising:

• (1) crosslinkable or polymerizable silicone monomers which are a mixture of compounds of the formula:
• (i)
• wherein a=0, 1 or 2;
• (ii)
• wherein a=0;
• and
• (iii)
• wherein a=0 and b=1;
• said crosslinkable or polymerizable monomers being the only crosslinkable or polymerizable monomers in the composition,
• (2) at least one dental filler present in a proportion of at least 10% by weight relative to the total weight of the composition, and
• (3) an effective quantity of at least one organometallic complex borate photoinitiator having a residual light absorption of between 200 and 500 nm, the photoinitiator having a cationic and a borate anionic entity, said cationic entity being of formula (II):
• (L1L2L3M)+q,
• wherein:
• M represents a group 4 to 10 metal,
• L1 represents 1 ligand bound to the metal M by π by electrons, said ligand being η3-alkyl, η5-cyclopendadienyl, η7-cycloheptratrienyl and optionally substituted η6-benzene having from 2 to 4 condensed rings, each ring being capable of contributing to the valency layer of the metal M by 3 to 8 π electrons;
• L2 represents a ligand bound to the metal M by π electrons, said ligand being n7-cycloheptratrienyl or n6-benzene and the compounds having from 2 to 4 condensed rings, each ring being capable of contributing to the valency layer of the metal M by 6 or 7 π electrons;
• L3 represents from 0 to 3 ligands, which are identical or different, linked to the metal M by σ electrons, said ligand(s) being CO or NO2+;
• the total electron charge q of the complex to which L1, L2 and L3 contribute and the ionic charge of the metal M being positive and equal to 1 or 2;
• and
• said anionic borate being of formula (Ill):
• [BXaRb]−
• wherein:
• a and b are integers ranging, for a, from 0 to 3 and, for b, from 1 to 4 with a+b=4, the symbols X represent:
• a halogen atom with a=0 to 3, or
• an OH functional group with a=0 to 2,
• the symbols R are identical or different and represent:
• a phenyl radical substituted with at least one electron-attracting group or with at least 2 halogen atoms, this being when the cationic entity is an onium of an element of groups 15 to 17,
• a phenyl radical substituted with at least one element or one electron-attracting group, this being when the cationic entity is an organometallic complex of an element of groups 4 to 10, or
• an aryl radical containing at least two aromatic nuclei, optionally substituted with at least one electron-attracting group or element, regardless of the cationic entity.