Storage stable glass ionomer composition and use thereof

1. A kit of parts for preparing a glass ionomer composition for dental use, the kit comprising a Paste A and a Paste B,

Paste A comprising:

water,

acid-reactive inorganic filler A,

non acid-reactive filler B1,

sugar alcohol with 6 hydroxyl moieties,

Paste B comprising:

water,

polyacid,

non acid-reactive filler B2,

the ratio of sugar alcohol to water in Paste A being in a range of 1:10 to 1:3 in parts by weight,

the sugar alcohol being present in an amount of not more than 2 wt. % with respect to a whole composition obtained when mixing Paste A and Paste B and

the water being present in an amount of not more than 15 wt. % with respect to the whole composition,

wherein a hardened composition obtained by mixing Paste A and Paste B and letting the mixture harden is characterized by the following parameters alone or in combination:

flexural strength: above 20 MPa determined according to EN-ISO 9917-2:2010 with the proviso that for covering the composition a glass slab is used instead of a foil;

compressive strength: above 100 MPa determined according to EN-ISO 9917-1:2007 with the proviso that for covering the composition a glass slab is used instead of a foil.

2. The kit of parts according to claim 1 , the sugar alcohol being selected from mannitol, sorbitol, and mixtures thereof.

3. The kit of parts according to claim 1 , the ratio of sugar alcohol in parts by weight to acid-reactive inorganic filler A in parts by weight in Paste A being from 1:10 to 1:100.

4. The kit of parts according to claim 1 , Paste A and Paste B being provided in a ratio of 2:1 to 1:2 with respect to volume.

5. The kit of parts according to claim 1 being characterized as follows:

Paste A comprising:

water in an amount of 5 to 20 wt. %,

acid-reactive inorganic filler A in an amount of 40 to 90 wt. %,

non acid-reactive filler B1 in an amount of 1 to 20 wt. %,

sugar alcohol in an amount of 0.5 to 2.0 wt. %,

wt. % with respect to the weight of Paste A,

Paste B comprising:

water in an amount of 9 to 20 wt. %,

polyacid in an amount of 10 to 70 wt. %,

non-acid reactive filler B2 in an amount of 5 to 70 wt. %,

wt. % with respect to the weight of Paste B.

6. The kit of parts according to claim 1 ,

the non acid-reactive filler B1 being selected from powders and powder dispersions, the particles of which have a mean particle size in the range of 10 nm to 500 nm,

the non acid-reactive filler B2 being selected from powders, the particles of which have a mean particle size in the range of 1 to 10 μm.

7. The kit of parts according to claim 1 , either Paste A or Paste B or Paste A and Paste B comprising in addition the following components alone or in combination:

preservative agent(s);

coloring agent(s);

chelating agent(s);

solvent(s).

8. The kit of parts according to claim 1 ,

Paste A being characterized by the following parameters alone or in combination:

viscosity: 100 to 50,000 Pa*s at 28° C., measured at a shear rate of 1 s −1 ;

pH value: 5 to 10;

Paste B being characterized by the following parameters alone or in combination:

viscosity: 100 to 50,000 Pa*s at 28° C., measured at a shear rate of 1 s −1 ;

pH value: 1 to 4.

9. The kit of parts according to claim 1 being characterized as follows:

Paste A comprising:

water in an amount of 6 to 20 wt. %,

the acid-reactive inorganic filler A

in an amount of 50 to 90 wt. %,

the acid-reactive inorganic filler A having a mean particle size in the range of 1 to 15 μm and

being selected from metal oxides, metal hydroxides, hydroxyapatite, fluoroaluminosilicate glasses and mixtures thereof,

the non acid-reactive filler B1,

in an amount of 5 to 15 wt. %

being selected from silica particles having a mean particle size in the range of 10 to 500 nm

the sugar alcohol

in an amount of 0.5 to 2.0 wt. % and

being sorbitol,

wt. % with respect to the weight of Paste A,

Paste B comprising:

water in an amount of 10 to 20 wt. %,

the polyacid in an amount of 10 to 70 wt. %,

a chelating agent in an amount of 0.1 to 12 wt. %,

the non acid-reactive filler B2

in an amount of 5 to 70 wt. %,

being selected from quartz, silica, alumina, titania, zirconia and mixtures thereof,

wt. % with respect to the weight of Paste B.

10. The kit of parts according to claim 1 , neither Paste A nor Paste B comprising at least one or more or all of the following components:

polymerizable component(s) in an amount above 1 wt. %;

initiator component(s) suitable to cure polymerizable component(s) in an amount above 1 wt. %;

2-hydroxyethyl cellulose, sodium alginate, or sodium carboxymethyl cellulose in an amount above 0.5 wt. %;

wt. % with respect to the weight of the respective Paste A or Paste B.

11. A process of producing a glass ionomer composition, the process comprising the step of mixing Paste A and Paste B of the kit of parts described in claim 1 .

12. A hardened glass ionomer composition for dental use, the hardened composition being obtainable or as obtained by mixing Paste A and Paste B of the kit of parts described in claim 1 and letting the mixture harden,

the hardened glass ionomer composition being characterized by the following parameters in combination:

flexural strength: above 20 MPa determined according to EN-ISO 9917-2:2010 with the proviso that for covering the composition a glass slab is used instead of a foil;

compressive strength: above 100 MPa determined according to EN-ISO 9917-1:2007 with the proviso that for covering the composition a glass slab is used instead of a foil.

13. The hardened glass ionomer composition as described in claim 12 , or the kit or parts as described in claim 1 for use as or for preparing a dental cement, dental filling material, dental core build up material or dental root channel filling material.

14. The kit of parts according to claim 1 wherein the acid-reactive filler A is selected from aluminosilicate glasses and fluoroaluminosilicate glasses.

15. The kit of part according to claim 1 , wherein the Paste B contains a complexing agent characterized by the following features alone or in combination:

solubility: soluble in water (at least 50 g/l water at 23° C.);

molecular weight: from 50 to 500 g/mol, or from 75 to 300 g/mol.

16. The kit of parts according to claim 15 , wherein the Paste B contains a complexing agent selected from the group consisting of tartaric acid, citric acid, ethylene diamine tetra acetic acid (EDTA), salicylic acid, mellitic acid, dihydroxy tartaric acid, nitrilotriacetic acid (NTA), 2,4 and 2,6 dihydroxybenzoic acid, phosphono carboxylic acids, phosphono succinic acid and mixtures thereof.