Lithium silicate glass ceramic for fabrication of dental appliances

• US 20100083706A1
• Filed: 12/03/2009
• Published: 04/08/2010
• Est. Priority Date: 04/11/2008
• Status: Abandoned Application

• Current Assignee: James R Glidewell Dental Ceramics Incorporated
• Original Assignee: James R Glidewell Dental Ceramics Incorporated
• Inventors: Castillo, Rodolfo
• Application Number:
  US12/592,825
• Publication Number:
  US 20100083706A1
• Time in Patent Office: Days
• US Class Current: 65/66
• CPC Class Codes: A61K 6/836 Glass
• CPC Class Codes: A61L 27/105 containing Al2O3
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: C03C 4/0021 for dental use

Abstract

The present invention relates to preparing an improved lithium silicate glass ceramic for the manufacture of blocks for dental appliance fabrication using a CAD/CAM process and hot pressing system. The lithium silicate material has a chemical composition that is different from those reported in the prior art with 1 to 10% of germanium dioxide in final composition. The softening points are close to the crystallization final temperature of 830° C. indicating that the samples will support the temperature process without shape deformation.

Claims

1. A lithium silicate ceramic glass made from a composition mixture comprising:

up to about 59% wt SiO2;

up to about 20% wt Li₂O

up to about 10% wt GeO₂;

and selected amounts %wt of at least Al₂O₃, K₂O, B₂O₃, CaO, F, MgO,CeO₂ and P₂O₅.

2. The lithium silicate ceramic glass recited in claim 1 wherein said composition mixture also comprises one or more of the following components:

ZrO₂, TiO₂, Er₂O₃, V₂O₅, MnO₂, Tb₄O₇, Ta₂O₅, Sm₂O₃, Pr₂O₃, Y₂O₃, Nb₃O₅, SnO, and Eu₂O₃.

6. The lithium silicate glass ceramic recited in claim 1 comprising a molar ratio of (SiO₂+GeO₂)/Li₂O between 1.7 and 2.5.

3. A lithium silicate ceramic glass made from a composition mixture comprising:

about 58.2% wt SiO₂;

about 16.0% wt Li₂O;

about 4.5% wt K₂O; and

about 4.5% wt of Al₂O₃; and

about 8.4% wt GeO₂.

4. The lithium silicate ceramic glass recited in claim 3 wherein said composition mixture also comprises at least 2.5% wt of each of the following components:

P₂O₅, ZrO₂, CeO₂, Pr₂O₃, Y₂O₃, and Sm₂O₃.

5. The lithium silicate ceramic glass recited in claim 4 further comprising one or more of the following additional components:

TiO₂, SnO, Eu₂O₃, Er₂O₃, Nb₂O₃ and V₂O₅.

7. A method of fabricating dental restorations of lithium silicate glass;

the method comprising the steps of;

(a) blending a mix of precursors;

(b) ball milling the mix to homogenize components of the mix;

(c) melting the resulting mix of step (b) for about 1 to 5 hours at a temperature of 1400 to 1500°

C.;

(d) pouring the melt of step (c) into graphite molds to form shaped blanks and cooling such blanks to room temperature;

(e) heating the blanks of step (d) at a temperature of 630°

to 650°

C. for 10 to 40 min;

(f) milling the blanks of step (e) into dental restorations; and

(g) heating the restoration of step (f) at temperature of 350°

to 830°

C.

9. The method of claim 7 wherein one of said precursors in step (a) is germanium oxide.

8. A method of fabricating dental restorations of lithium silicate glass;

the method comprising the steps of;

(a) blending a mix of precursors;

(b) ball milling the mix to homogenize components of the mix;

(c) melting the resulting mix of step (b) for about 1 to 5 hours at a temperature of 1400 to 1500°

C.;

(d) pouring the melt of step (c) into graphite molds to form shaped blanks and cooling such blanks to room temperature;

(e) heating the blanks of step (d) at a temperature of 630°

to 650°

C. for 10 to 40 min;

(f) hot pressing the blanks of step (e) into dental restorations at a temperature of 800°

to 870°

C.

10. The method of claim 8 wherein one of said precursors in step (a) is germanium oxide.