LITHIUM SILICATE GLASS CERAMIC AND GLASS WITH ZrO2 CONTENT

Abstract

Lithium silicate glass ceramics and glasses are described which can advantageously be applied to zirconium oxide ceramics in particular by pressing-on in the viscous state and form a solid bond with these.

What is claimed is: 
     
         1 ) A method comprising:
 hot pressing i) a monolithic blank comprising lithium disilicate as the main crystalline phase, ii) a monolithic blank comprising lithium metasilicate as the main crystalline phase, or iii) or a monolithic blank with nuclei for lithium metasilicate and/or lithium disilicate formation, wherein a monolithic dental restoration is formed.   
     
     
         2 ) The method of  claim 1 , further comprising
 forming a monolithic blank with nuclei for lithium metasilicate and/or lithium disilicate formation; and   heating the monolithic blank with nuclei for lithium metasilicate and/or lithium disilicate formation to form the monolithic blank comprising lithium disilicate.   
     
     
         3 ) The method of  claim 2 , wherein the forming comprises:
 mixing oxide and/or carbonate precursors and, optionally, at least one coloring pigment;   heating the mixture of oxide and/or carbonate precursors to form a first glass melt;   contacting the first glass melt with water to form glass granules;   melting the glass granules to form a second glass melt;   forming a monolithic blank from the second glass melt; and   heating the monolithic blank to form a monolithic blank with nuclei for lithium metasilicate and/or lithium disilicate formation.   
     
     
         4 ) The method of  claim 1 , further comprising:
 prior to hot pressing, heating the monolithic blank with nuclei for lithium metasilicate and/or lithium disilicate formation at 650 to 750 ° C. at a heating rate of 15° C./minute to form a monolithic blank comprising lithium metasilicate as the main crystalline phase.   
     
     
         5 ) The method of  claim 4 , further comprising:
 heating the monolithic blank comprising lithium metasilicate as the main crystalline phase at 840 to 880° C. for 5 to 30 minutes to form a monolithic blank comprising lithium disilicate as the main crystalline phase.   
     
     
         6 ) The method of  claim 1 , wherein the hot pressing is carried out at a temperature of 900 to 950° C. 
     
     
         7 ) The method of  claim 1 , wherein the dental restoration is an inlay, onlay, crown, or abutment. 
     
     
         8 ) The method of  claim 1 , wherein the monolithic blank comprising lithium disilicate as the main crystalline phase comprises lithium disilicate glass ceramic with 55 to 71 weight percent SiO 2 , 9 to 17 weight percent Li 2 O, and at least 6.1 weight percent ZrO 2  based on a mass of the lithium disilicate glass ceramic. 
     
     
         9 ) The method of  claim 8 , wherein the lithium disilicate glass ceramic has a SiO 2 /Li 2 O molar ratio of 1.8 to 3. 
     
     
         10 ) The method of  claim 9 , wherein the lithium disilicate glass ceramic has a SiO 2 /Li 2 O molar ratio of 2.1 to 2.6. 
     
     
         11 ) The method of  claim 8 , wherein the lithium disilicate glass ceramic comprises 6.1 to 16 weight percent ZrO 2  based on the mass of the lithium disilicate glass ceramic. 
     
     
         12 ) The method of  claim 11 , wherein the lithium disilicate glass ceramic comprises 6.1 to 12 weight percent ZrO 2  based on the mass of the lithium disilicate glass ceramic. 
     
     
         13 ) The method of  claim 8 , wherein the lithium disilicate glass ceramic further comprises Y 2 O 3 , and wherein the lithium disilicate glass ceramic includes a combined amount of ZrO 2  and Y 2 O 3  of greater than 6.1 to 16 weight percent based on the mass of the lithium disilicate glass ceramic. 
     
     
         14 ) The method of  claim 13 , wherein the lithium disilicate glass ceramic includes a combined amount of ZrO 2  and Y 2 O 3  of greater than 6.1 to 12 weight percent based on the mass of the lithium disilicate glass ceramic. 
     
     
         15 ) The method of  claim 1 , wherein the lithium disilicate glass ceramic further comprises an oxide of pentavalent elements, wherein the oxide of the pentavalent elements is Bi 2 O 5 . 
     
     
         16 ) The method of  claim 1 , wherein the lithium disilicate glass ceramic further comprises an oxide of hexavalent elements selected from WO 3  or MoO 3 . 
     
     
         17 ) The method of  claim 1 , wherein no Na 2 O oxide is present in the lithium disilicate glass ceramic. 
     
     
         18 ) The method of  claim 1 , wherein the lithium disilicate glass ceramic further comprises at least 0.2 weight percent to less than 5.0 weight percent Al 2 O 3 . 
     
     
         19 ) The method of  claim 1 , wherein the lithium disilicate glass ceramic has a biaxial strength of from 200 to 500 MPa. 
     
     
         20 ) The method of  claim 1 , wherein the lithium disilicate glass ceramic includes lithium silicate crystals with a small-plate shaped crystal form.