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.

1 . A process for preparing dental restorations comprising shaping of a lithium silicate glass ceramic by
 (i) pressing or   (ii) machining   to the dental restoration,   wherein the glass ceramic comprises at least 6.1 wt.-% ZrO 2 ,   wherein the glass ceramic comprises lithium disilicate crystals.   
     
     
         2 . The process according to  claim 1 , wherein the glass ceramic comprises more than 10 vol.-% of lithium disilicate crystals. 
     
     
         3 . The process according to  claim 1 , wherein the glass ceramic comprises more than 20 vol.-% of lithium disilicate crystals. 
     
     
         4 . The process according to  claim 1 , wherein the glass ceramic comprises more than 30 vol.-% of lithium disilicate crystals. 
     
     
         5 . The process according to  claim 1 , wherein the dental restorations are selected from inlays, onlays, crowns, veneers, facings or abutments. 
     
     
         6 . The process according to  claim 1 , wherein the pressing is conducted at a temperature in the range of from 700 to 1200° C. 
     
     
         7 . The process according to  claim 1 , wherein the pressing is conducted at a pressure in the range of from 2 to 10 bar. 
     
     
         8 . The process according to  claim 1 , wherein the machining is carried out in a CAD/CAM process. 
     
     
         9 . The process according to  claim 1 , wherein after the shaping the glass ceramic is heat treated to convert lithium metasilicate glass ceramic to lithium disilicate glass ceramic. 
     
     
         10 . The process according to  claim 1 , wherein the glass ceramic comprises at least 10.0 wt.-% ZrO 2 . 
     
     
         11 . The process according to  claim 1 , wherein the glass ceramic comprises 55.0 to 71.0 wt.-% SiO 2 . 
     
     
         12 . The process according to  claim 1 , wherein the glass ceramic comprises 9.0 to 17.0 wt.-% Li 2 O. 
     
     
         13 . The process according to  claim 1 , wherein the glass ceramic comprises 0.5 to 12.0 wt.-% nucleating agent, and wherein the nucleating agent is selected from P 2 O 5 , TiO 2 , Nb 2 O 5  and/or metals. 
     
     
         14 . The process according to  claim 1 , wherein the glass ceramic comprises further alkali metal oxide in an amount of 1.0 to 7.0 wt.-%, and wherein the further alkali metal oxide is selected from K 2 O, Cs 2 O and/or Rb 2 O. 
     
     
         15 . The process according to  claim 1 , wherein the glass ceramic comprises up to 5.0 wt.-% alkaline earth metal oxide, and wherein the alkaline earth metal oxide is selected from CaO, BaO, MgO and/or SrO. 
     
     
         16 . The process according to  claim 1 , wherein the glass ceramic comprises 0.2 to 10.0 wt.-% oxide of trivalent elements, and wherein the oxide of trivalent elements is selected from Al 2 O 3 , Y 2 O 3 , La 2 O 3 , and/or Bi 2 O 3 . 
     
     
         17 . The process according to  claim 1 , wherein the glass ceramic comprises at least one further oxide of tetravalent elements, at least one further oxide of pentavalent elements, and/or at least one oxide of hexavalent elements. 
     
     
         18 . The process according to  claim 1 , wherein the glass ceramic comprises at least one of the following components: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   Component  
                   wt.-% 
                 
                     
                     
                 
                     
                   SiO 2   
                   55.0 to 71.0 
                 
                     
                   Li 2 O 
                    9.0 to 17.0 
                 
                     
                   K 2 O 
                    1.0 to 5.0, 
                 
                     
                   Al 2 O 3   
                    0.5 to 5.0, 
                 
                     
                   P 2 O 5   
                    0.5 to 12.0, 
                 
                     
                   ZrO 2   
                    6.1 to 20.0. 
                 
                     
                     
                 
             
                
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         19 . The process according to  claim 1 , wherein a blank of the glass ceramic is shaped to the dental restoration. 
     
     
         20 . Process of using lithium silicate glass ceramic for preparing dental restorations, wherein the glass ceramic is shaped by pressing or machining to the dental restoration, and wherein the glass ceramic comprises at least 6.1 wt.-% ZrO 2 . 
     
     
         21 . Process of using lithium silicate glass ceramic according to  claim 20 , wherein the dental restorations are selected from inlays, onlays, crowns, veneers, facings and abutments.