MULTI SECTIONAL DENTAL ZIRCONIA MILLING BLOCK, PROCESS OF PRODUCTION AND USE THEREOF

• US 20150282905A1
• Filed: 10/02/2013
• Published: 10/08/2015
• Est. Priority Date: 10/17/2012
• Status: Active Grant

• Current Assignee: Solventum Intellectual Properties Company (Solventum Corp.)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Jahns, Michael, Hauptmann, Holger
• Granted Patent: US 10,028,809 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61C 13/0006 Production methods
• CPC Class Codes: A61C 13/082 Cosmetic aspects, e.g. inlays; Determination of the colour A61C19/10 takes precedence
• CPC Class Codes: A61K 6/818 comprising zirconium oxide
• CPC Class Codes: A61K 6/82 comprising hafnium oxide
• CPC Class Codes: A61K 6/822 comprising rare earth metal oxides
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 25/02 Oxides
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C04B 2111/00836 for medical or dental applications
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3239 Vanadium oxides, vanadates or oxide forming salts thereof, e.g. magnesium vanadate
• CPC Class Codes: C04B 2235/3241 : Chromium oxides, chromates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3256 : Molybdenum oxides, molybdates or oxide forming salts thereof, e.g. cadmium molybdate
• CPC Class Codes: C04B 2235/3262 : Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO
• CPC Class Codes: C04B 2235/3272 : Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• CPC Class Codes: C04B 2235/3275 : Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
• CPC Class Codes: C04B 2235/3418 : Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• CPC Class Codes: C04B 2235/449 : Organic acids, e.g. EDTA, citrate, acetate, oxalate
• CPC Class Codes: C04B 2235/5409 : expressed by specific surface values
• CPC Class Codes: C04B 2235/5454 : nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/6023 : Gel casting
• CPC Class Codes: C04B 2235/61 : Mechanical properties, e.g. fracture toughness, hardness, Young's modulus or strength
• CPC Class Codes: C04B 2235/612 : Machining
• CPC Class Codes: C04B 2235/72 : Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/762 : Cubic symmetry, e.g. beta-SiC
• CPC Class Codes: C04B 2235/765 : Tetragonal symmetry
• CPC Class Codes: C04B 2235/77 : Density
• CPC Class Codes: C04B 2235/945 : Products containing grooves, cuts, recesses or protusions
• CPC Class Codes: C04B 2235/95 : Products characterised by their size, e.g. microceramics
• CPC Class Codes: C04B 2235/96 : Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 2235/9646 : Optical properties
• CPC Class Codes: C04B 2235/9653 : Translucent or transparent ceramics other than alumina
• CPC Class Codes: C04B 2237/348 : Zirconia, hafnia, zirconates or hafnates
• CPC Class Codes: C04B 2237/582 : by joining layers or articles of the same composition but having different additives
• CPC Class Codes: C04B 2237/84 : Joining of a first substrate with a second substrate at least partially inside the first substrate, where the bonding area is at the inside of the first substrate, e.g. one tube inside another tube
• CPC Class Codes: C04B 35/486 : Fine ceramics
• CPC Class Codes: C04B 35/624 : Sol-gel processing
• CPC Class Codes: C04B 35/6263 : characterised by their solids loadings, i.e. the percentage of solids
• CPC Class Codes: C04B 35/6269 : Curing of mixtures
• CPC Class Codes: C04B 35/632 : Organic additives
• CPC Class Codes: C04B 35/63424 : Polyacrylates; Polymethacrylates
• CPC Class Codes: C04B 35/63488 : Polyethers, e.g. alkylphenol polyglycolether, polyethylene glycol [PEG], polyethylene oxide [PEO]
• CPC Class Codes: C04B 38/0054 : the pores being microsized or nanosized
• CPC Class Codes: Y10T 428/24997 : Of metal-containing material

Abstract

The invention relates to a porous dental milling block comprising at least two geometrically defined Material Sections A and B, Material Section A comprising a tetragonal zirconia crystal phase in an amount A-T in % and a cubic zirconia crystal phase in an amount A-C in %, Material Section B comprising cubic zirconia crystal phase in an amount B-T in % and cubic zirconia crystal phase in an amount B-C in %, wherein (amount of tetragonal phase A-T in %)/(amount of cubic phase content A-C in %)>1 and (amount of tetragonal phase content B-T in %)/(amount of cubic phase content B-C in %)<1. The invention also relates to a process of production of the porous dental milling block and its use for producing a dental article.

Claims

1. A porous dental milling block comprising at least two geometrically defined Material Sections A and B,

Material Section A comprising a tetragonal zirconia crystal phase in an amount A-T in wt.-% and a cubic zirconia crystal phase in an amount A-C in wt.-%,

Material Section B comprising a cubic zirconia crystal phase in an amount B-T in wt.-% and a cubic zirconia crystal phase in an amount B-C in wt.-%,

wherein

(amount of tetragonal phase A-T in wt.-%)/(amount of cubic phase content A-C in wt.-%)>

1

and

(amount of tetragonal phase content B-T in wt.-%)/(amount of cubic phase content B-C in wt.-%)<

1

the material of Material Sections A and B showing a N2 adsorption and/or desorption behaviour of isotherm IV according to IUPAC classification,

2. The porous dental milling block of claim 1, the material of Material Sections A and B being characterized by the following property:

the sintering temperature being in a range of 1200 to 1400°

C.

3. The porous dental milling block of claim 1 being characterized by at least one of the following features:

the ratio of the tetragonal phase content A-T in % to the cubic phase content A-C in % in Section A being in a range from about 1.2 to about 50,

the ratio of the tetragonal phase content A-T in % to the cubic phase content A-C in % in Section B being in a range from about 0.02 to about 0.8.

4. The porous dental milling block of claim 1 being characterized by at least one of the following features as regards Material Section A before sintering to final density:

showing a N2 adsorption and desorption behaviour with a hysteresis loop of type H1 according to IUPAC classification;

showing a N2 adsorption and desorption behaviour with a hysteresis loop in a p/p0 range of 0.70 to 0.95;

average connected pore diameter;

from about 10 to about 100 nm or from about 10 to about 80 nm or from about 10 to about 50 nm;

average grain size of crystalline zirconia;

less than about 100 nm;

BET surface;

from about 10 to about 200 m2/g;

Biaxial flexural strength;

from about 10 to about 40 or from about 15 to about 30 MPa;

x, y, z dimension;

at least about 5 mm or at least about 10 or at least about 20 mm;

Vickers hardness;

from about 25 (HV 0.5) to about 150 (HV

     1);

having an isotropic sintering behaviour;

density;

2.2 to 3.3 g/cm3;

sintering temperature;

from about 1200 to about 1400°

C.;

having an ZrO2 content;

from about 85 to about 98 mol %;

having a HfO2 content;

from about 0 to about 3 mol %;

having an Y2O3 content;

from about 1 to about 15 mol %;

having an Al2O3 content;

from about 0 to about 1 mol %.

5. The porous dental milling block of claim 1 being characterized by at least one of the following features as regards Material Section B before sintering to final density:

showing a hysteresis loop when analyzed with regard to its adsorption and desorption behaviour to nitrogen;

showing a N2 adsorption and desorption behaviour with a hysteresis loop of type H1 according to IUPAC classification;

showing a N2 adsorption and desorption behaviour with a hysteresis loop in a p/p0 range of 0.70 to 0.95;

average connected pore diameter;

from about 10 to about 100 nm or from about 10 to about 80 nm or from about 10 to about 50 nm;

average grain size of crystalline zirconia;

less than about 100 nm;

BET surface;

from about 10 to about 200 m2/g;

Biaxial flexural strength;

from about 10 to about 40 or from about 15 to about 30 MPa;

x, y, z dimension;

at least about 5 mm or at least about 10 or at least about 20 mm;

Vickers hardness;

from about 25 (HV 0.5) to about 150 (HV

     1);

having an isotropic sintering behaviour;

density;

2.2 to 3.3 g/cm3;

sintering temperature;

from about 1200 to about 1400°

C.;

having an ZrO2 content;

from about 85 to about 98 mol %;

having a HfO2 content;

from about 0 to about 3 mol %;

having an Y2O3 content;

from about 1 to about 15 mol %;

having an Al2O3 content;

from about 0 to about 1 mol %.

6. The porous dental milling block according to claim 1, Material Section A and Material Section B having the shape of layers or blocks, being arranged in a core-shell structure, or having tooth-like shapes or a combination thereof.

7. The porous dental milling block according to claim 1 not comprising oxides selected from TiO2, SiO2 or mixtures thereof in an amount above 2 mol % with respect to the weight of the porous dental milling block.

8. The porous dental milling block according to claim 1 comprising means for attaching it to a machining device, the means for attaching being selected from grooves, notches, recesses, stamps and holding devices like frames, stumps and combinations thereof.

9. A process of producing a porous dental milling block having at least two material sections differing by their content of cubic phase and tetragonal phase as described in claim 1, the process comprising the steps of

a. casting a sol (I) containing zirconia crystallites into a mould (I), the zirconia crystallites having a crystal phase composition (1),

b. transferring the sol (I) to a gel body (I),

c. optionally transferring the gel body (I) to a mould (II),

d. casting a sol (II) containing zirconia crystallites so that it gets into contact with gel body (I), the zirconia crystallites having a crystal phase composition (2),

e. transferring sol (II) into a gel body (II),

f. optionally repeating steps (d) and (e) thereby casting additional sol(s) into either mould (II) or another mould to which the gel bodies of either step (d) or obtained after conducting step (e) have been transferred,

g. removing solvent contained in the gel bodies to obtain an aerogel,

h. heat-treating the aerogel to obtain a porous zirconia article.

10. A process of producing a porous dental milling block especially according to claim 1 having at least two material sections differing by their content of cubic phase and tetragonal phase, the process comprising the steps of

providing a Mixture A of a Sol S1-T and a Sol S2-C,

Sol S1-T comprising tetragonal zirconia crystallites,

Sol S2-C comprising cubic zirconia crystallites,

the amount of tetragonal zirconia crystallites in Sol S1-T (in wt.-% with respect to the whole Mixture A) being greater than the amount of cubic zirconia crystallites in Sol S2-C (in wt.-% with respect to the whole Mixture A),

the mixture further comprising a polymerizable system containing polymerizable component(s) and initiator component(s),

providing a Mixture B of a Sol S2-T and a Sol S2-C,

Sol S2-T comprising tetragonal zirconia crystallites,

Sol S2-C comprising cubic zirconia crystallites,

the amount of tetragonal zirconia crystallites in Sol S2-T (in wt.-% with respect to the whole Mixture B) being smaller than the amount of cubic zirconia crystallites in Sol S2-C (in wt.-% with respect to the whole Mixture B),

the mixture further comprising a polymerizable system containing polymerizable component(s) and initiator component(s),

conducting one of the following steps:

optionally curing Mixture A to obtain a dental milling block precursor A,

optionally curing Mixture B to obtain a dental milling block precursor B,

bringing into contact

if present, Mixture A with Mixture B or

if present, dental milling block precursor A with Mixture B or

if present dental milling block precursor B with Mixture A to obtain System AB,

curing System AB to obtain a dental milling block precursor AB,

if present, removing remaining solvent,

heating the dental milling block precursor AB to a temperature where the components of the polymerizable system or polymerized system pyrolyse.

11. A process of producing a porous dental milling block especially according to claim 1 having at least two material sections differing by their content of cubic phase and tetragonal phase, the process comprising the steps of

providing a Sol S1-T comprising tetragonal zirconia crystallites,

providing a Sol S1-C comprising cubic zirconia crystallites,

the amount of tetragonal zirconia crystallites in Sol S1-T (in wt.-% with respect to the sum of crystallites in Sol S1-T and Sol S1 -C) being greater than the amount of cubic zirconia crystallites in Sol S1-C (in wt.-% with respect to the sum of crystallites in Sol S1-T and Sol S1-C),

mixing Sol S1-T and Sol S1-C to obtain a Mixture A,

adding a polymerizable system containing polymerizable component(s) and initiator component(s) to Mixture A,

casting the mixture into a mould,

optionally curing the mixture to obtain a dental milling block precursor A,

providing a Sol S2-T comprising tetragonal zirconia crystallites having a tetragonal phase content,

providing a Sol S2-C comprising cubic zirconia crystallites having a cubic phase content, the amount of tetragonal zirconia in Sol S2-T (in wt.-% with respect to the sum of crystallites in Sol S2-T and Sol S2-C) being smaller than the amount of cubic zirconia in Sol S2-C (in wt.-% with respect to the sum of crystallites in Sol S2-T and Sol S2-C),

mixing Sol S2-T and Sol S2-C to obtain a Mixture B,

adding a polymerizable system to Mixture B,

bringing the dental milling block precusor A in contact with Mixture B to obtain System AB,

drying System AB to obtain a dental milling block precursor AB,

if present, removing remaining solvent,

heating the dental milling block precursor AB to a temperature where the components of the polymerisable system or polymerized system pyrolyse.

12. A process of producing a porous dental milling block especially according to claim 1 having at least two material sections differing by their content of cubic phase and tetragonal phase, the process comprising the steps of

providing a Sol A,

Sol A comprising tetragonal zirconia crystallites in an amount A-T in wt.-% and cubic zirconia crystallites in an amount A-C in wt.-%,

the amount of tetragonal zirconia crystallites in Sol A being greater than the amount of cubic zirconia crystallites in Sol A,

Sol A further comprising a polymerizable system containing polymerizable component(s) and initiator component(s),

providing a Sol B,

Sol B comprising tetragonal zirconia crystallites in an amount B-T in wt.-% and cubic zirconia crystallites in an amount B-C in wt.-%,

the amount of tetragonal zirconia crystallites in Sol B being smaller than the amount of cubic zirconia crystallites in Sol B,

Sol B further comprising a polymerizable system containing polymerizable component(s) and initiator component(s),

conducting one of the following steps:

optionally curing Sol A to obtain a dental milling block precursor A,

optionally curing Sol B to obtain a dental milling block precursor B,

bringing into contact

if present, Sol A with Sol B or

if present, dental milling block precursor A with Sol B or

if present, dental milling block precursor B with Sol A to obtain System AB,

curing System AB to obtain a dental milling block precursor AB,

if present, removing remaining solvent,

heating the dental milling block precursor AB to a temperature where the components of the polymerizable system or polymerized system pyrolyse.

13. A process of producing a dental ceramic article comprising the step of machining the porous dental milling block as described in claim 1 or the dental milling block obtainable by the process described in claim 9 and optionally sintering the dental ceramic article.

14. The dental ceramic article obtainable according to the process described in claim 13, the dental article being characterized by the following features after sintering:

Comprising two Material Sections A and B,

Material Section A being less translucent than Material Section B,

Density;

at least about 98.5% of theoretical density;

Biaxial flexural strength;

from about 450 MPa to about 2200 MPa;

Contrast ratio reflectance value of Material Section A;

from about 40 to about 90%;

Contrast ratio reflectance value of Material Section B;

from about 5 to about 40%.

15. A kit of parts comprising at least one porous dental milling block as described in claim 1 or obtainable according to a process as described in claim 9, a treatment solution and optionally application equipment.