Dental composition based on silicone crosslinkable by cation process

A dental composition comprising:

• (1) at least one crosslinkable and/or polymerizable silicone oligomer or polymer which is liquid at room temperature or which is heat-meltable at a temperature of less than 100° C., and which comprises:
• at least one unit of formula (FS):
• 42
• in which:
• a=0, 1 or 2,
• R0, identical or different, represents an alkyl, cycloalkyl, aryl, vinyl, hydrogeno or alkoxy radical, preferably a C1-C6 lower alkyl,
• Z, identical or different, is an organic substituent comprising at least one reactive epoxy, and/or alkenyl ether and/or oxetane and/or dioxolane and/or carbonate functional group,
• and at least two silicon atoms,
• (2) at least one aromatic hydrocarbon photosensitizer with one or more aromatic nuclei which are substituted or not, having a residual light absorption of between 200 and 500 nm,
• (3) at least one dental filler present in a proportion of at least 10% by weight relative to the total weight of the composition,
• (4) and an effective quantity of at least one borate-type photoinitiator, chosen from those of formula:
• Δ in which the cationic entity of the borate is selected from:
• the onium salts of formula (I):
• [(R1)n-A-(R2)m]+ (I)
• in which formula:
• A represents an element of groups 15 to 17 such as for example:
• I, S, Se, P or N,
• R1 represents a carbocyclic or heterocyclic C6-C20 aryl radical, it being possible for said heterocyclic radical to contain, as heteroelements, nitrogen or sulfur,
• R2 represents R1 or a linear or branched C1-C30 alkyl or alkenyl radical;
• said radicals R1 and R2 being optionally substituted with a C1-C25 alkoxy, C1-C25 alkyl, nitro, chloro, bromo, cyano, carboxyl, ester or mercapto group,
• n is an integer ranging from 1 to v+1, v being the valency of the element A,
• m is an integer ranging from 0 to v−1 with n+m=v+1,
• the organometallic salts of formula (III):
• (L1L2L3M)+q
• in which formula:
• M represents a group 4 to 10 metal, in particular iron, manganese, chromium or cobalt,
• L1 represents 1 ligand bound to the metal M by π by electrons, which ligand is chosen from the ligands η3-alkyl, η5-cyclopendadienyl and η7-cycloheptratrienyl and the η6-aromatic compounds chosen from the optionally substituted η6-benzene ligands 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 3 to 8 π electrons;
• L2 represents a ligand bound to the metal M by π electrons, which ligand is chosen from the ligands η7-cycloheptratrienyl and the η6-aromatic compounds chosen from the optionally substituted ligands η6-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, which ligand(s) is (are) chosen from CO and 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;
• Δ the anionic borate entity of which has the formula [BXaRb]− in which:
• 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 (chlorine, fluorine) with a=0 to 3,
• * 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 such as for example OCF3, CF3, NO2, CN, and/or with at least 2 halogen atoms (fluorine most particularly), 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, in particular a halogen atom (fluorine most particularly), CF3, OCF3, N2, CN, this being when the cationic entity is an organometallic complex of an element of groups 4 to 10,
• an aryl radical containing.at least two aromatic nuclei such as for example biphenyl, naphthyl, optionally substituted with at least one electron-attracting group or element, in particular a halogen atom, including fluorine in particular, OCF3, CF3, NO2, CN, regardless of the cationic entity.