Dental Cement Composition, Kit of Parts and Use Thereof

1 . A dental cement composition comprising

a resin matrix comprising

a (meth)acrylate component comprising

at least two (meth)acrylate moieties,

a polyol spacer group between the at least two (meth)acrylate moieties, the polyols spacer group having a molecular weight Mw of at least 3,000 g/mol,

an acidic polymerizable component, preferably an acidic (meth)acrylate component,

a non-acidic polymerizable component having a molecular weight Mw below 1,000 g/mol, preferably a non-acidic (meth)acrylate component,

filler,

an initiator system,

optionally additives.

2 . The dental cement composition according to claim 1 , the (meth)acrylate component having either of the following structures:

MA-S2-L-S1-L-S2-MA  (I)

MA-S2-L-(S1-U-S1) x -L-S2-MA  (II)

MA-S2-U-(S1-U-S1) x -U-S2-MA  (III)

with

MA being an acrylate or methacrylate moiety,

L being a urethane, an ester or an ether link,

U being a urethane moiety,

S1 being a polyol moiety, preferably a polyether polyol, having a molecular weight Mw of at least 3,000 g/mol,

S2 being a spacer group connecting a (meth)acrylate moiety and a urethane, an ester or ether moiety,

x being 1 to 2.

3 . The dental cement composition according to claim 2 ,

the spacer groups S2 comprising an C 2-6 alkyl chain;

the spacer group S1 comprising a polyol chain having the formula

—[(CH 2 ) n —(CHR′)—O] k —[(CH 2 ) m —(CHR″)—O] l —(CH 2 ) m —(CHR″)—

with

n=1 to 6, preferably 1 to 4, in particular 1, n being able to vary within the chain,

m=1 to 6, preferably 1 to 4, in particular 3, m being able to vary within the chain,

k, l=2 to 500, preferably 4 to 250, in particular 10 to 200,

R′, R″=H, methyl, ethyl, preferably R′=R″=H.

4 . The dental cement composition according to claim 1 , the (meth)acrylate component being a urethane (meth)acrylate component comprising at least two (meth)acrylate moieties, and not more than 4 or not more than 2 urethane moieties.

5 . The dental cement composition according to claim 1 , characterized by the following features alone or in combination:

the ratio of (meth)acrylate component to acidic polymerizable component being in a range of 2:1 to 20:1 with respect to wt. %;

the ratio of (meth)acrylate component to non-acidic polymerizable component being in a range of 1:1 to 20:1 with respect to wt. %;

the ratio of acidic polymerizable component to non-acidic polymerizable component being in a range of 1:10 to 5:1 with respect to wt. %.

6 . The dental cement composition according to claim 1 , the initiator system comprising a redox initiator system, a photo-initiator, or a combination of both.

7 . The dental cement composition according to claim 1 , the filler comprising non-acid reactive fillers.

8 . The dental cement composition according to claim 1 comprising

the (meth)acrylate component in an amount of 30 to 80 wt. %,

the acidic polymerizable component in an amount of 5 to 40 wt. %,

the non-acidic polymerizable component in an amount of 2 to 30 wt. %,

the filler in an amount of 5 to 55 wt. %,

the initiator system in an amount of 1 to 10 wt. %,

additives in an amount of 0 to 20 wt. %,

wt. % with respect to the weight of the whole composition.

9 . The dental cement composition according to claim 1 not comprising the following components alone or in combination:

(meth)acrylate functionalized fillers in an amount of more than 5 wt. %;

softener in an amount of more than 5 wt. %;

polyhydric alcohol in an amount of more than 5 wt. %,

eugenol in an amount of more than 0.1 wt. %;

wt. % with respect to the dental cement composition.

10 . The dental cement composition according to claim 1 , the (meth)acrylate component being obtainable by reacting a polyol component having a molecular weight Mw of at least 3,000 g/mol with either a (meth)acrylate component having an isocyanate moiety, or a (meth)acrylic acid component, preferably an acid anhydride or acid chloride.

11 . The dental cement composition according to claim 1 being characterized by the following features alone or in combination before hardening:

viscosity: 10 to 70 Pa*s at 28° C. and a shear rate of 10 s −1 ;

pH value: 5 to 1.

12 . The dental cement composition according to claim 1 being characterized by the following features alone or in combination after hardening:

elongation at break: 20 to 50%;

tensile strength: 4 to 10 MPa;

shear bond strength to polymerized (meth)acrylate material: 8 to 30 MPa;

shear bond strength to dentin: 0.1 to 3 MPa.

13 . The dental cement composition according to claim 1 being provided as a kit of parts comprising a base part and a catalyst part,

the base part comprising,

a portion of the (meth)acrylate component,

the acidic polymerizable component,

a portion of the non-acidic polymerizable component,

a part of the initiator system, preferably an oxidizing component,

a portion or part of the filler

the catalyst part comprising,

a portion of the (meth)acrylate component,

a portion of the non-acidic polymerizable component,

a part of the initiator system, preferably a reducing component,

a portion or part of the filler

wherein the other components of the dental cement composition are present either in the base part or the catalyst part or the base part and the catalyst part.

14 . A dental cement composition for use in a process of temporarily restoring a dental situation in a mouth of a patient, the process comprising the steps of

providing a dental restoration and the dental cement composition as described in claim 1

fixing the dental restoration with the aid of the dental cement composition to the dental situation to be restored,

removing the dental restoration from the dental situation.

15 . A kit of parts comprising the dental cement composition as described in claim 1 and a dental crown or a curable dental composition for producing a temporary dental restoration being different from the dental cement composition.