# US 9,434,639 B2 · Lithium silicate materials

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- Number: US 9,434,639 B2
- Document ID: US9434639B2
- Status: Granted
- Kind: B2
- Application number: 14/567,173
- Filed: 2014-12-11
- Published: 2015-04-02
- Granted: 2016-09-06
- Earliest claimed: 2005-02-08
- Assignees: Ivoclar Vivadent AG
- Applicants: Ivoclar Vivadent AG
- Inventors: Elke Signer-Apel; Wolfram Höland; Marcel Schweiger; Christian Ritzberger; Harald Bürke; Volker Rheinberger
- Web page: https://patentgrep.com/patent/US9434639B2

## CPC

- C03C 10/0027: {containing SiO2, Al2O3, Li2O as main constituents}
- A61C 5/70: Tooth crowns; Making thereof
- A61C 5/77: Methods or devices for making crowns
- A61C 8/0001: {Impression means for implants, e.g. impression coping}
- A61C 8/0012: {characterised by the material or composition, e.g. ceramics, surface layer, metal alloy (use of specific materials A61K6/00)}
- A61C 8/0048: {Connecting the upper structure to the implant, e.g. bridging bars (A61C8/0028 takes precedence)}
- A61C 13/0004: {Computer-assisted sizing or machining of dental prostheses}
- A61C 13/0006: {Production methods}
- A61C 13/0022: {Blanks or green, unfinished dental restoration parts}
- A61C 13/082: {Cosmetic aspects, e.g. inlays; Determination of the colour (A61C19/10 takes precedence)}
- A61C 13/083: Porcelain or ceramic teeth {(A61C13/081 takes precedence; preparations A61K6/80)}
- A61K 6/78: Pigments
- A61K 6/804: comprising manganese oxide
- A61K 6/807: comprising magnesium oxide
- A61K 6/818: comprising zirconium oxide
- A61K 6/833: Glass-ceramic composites
- C01B 33/32: Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence)
- C03B 32/02: Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)}
- C03C 3/097: containing phosphorus, niobium or tantalum
- C03C 4/0021: {for dental use}
- C03C 10/0045: {containing SiO2, Al2O3 and MgO as main constituents}
- C03C 10/0054: {containing PbO, SnO2, B2O3}
- Y10T 83/04: Processes
- Y10T 409/303752: Process
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.

## Claims

### Claim 1

A lithium silicate glass ceramic for dental restorations which comprises a main crystalline phase comprising lithium metasilicate, wherein the lithium metasilicate crystals comprise lamellar or platelet crystals, and wherein the molar ratio of SiO2 to Li2O is at least 2.2:1.

### Claim 2 (depends on 1)

The lithium silicate glass ceramic of claim 1, wherein the lithium metasilicate forms more than 50 and up to 80 vol. % of the lithium silicate glass ceramic.

### Claim 3 (depends on 1)

The lithium silicate glass ceramic of claim 1, wherein the glass ceramic is in form of a blank or a dental restoration.

### Claim 4 (depends on 3)

The lithium silicate glass ceramic of claim 3, wherein the blank is shaped into a dental restoration by machining or pressing.

### Claim 5 (depends on 4)

The lithium silicate glass ceramic of claim 4, wherein machining comprises grinding, trimming or milling.

### Claim 6 (depends on 4)

The lithium silicate glass ceramic of claim 4, wherein the dental restoration is an inlay, an onlay, a bridge, an abutment, a facing, a veneer, a facet, a crown, a partial crown, a framework or a coping.

### Claim 7 (depends on 1)

The lithium silicate glass ceramic of claim 1, comprising SiO2, Li2O and a nucleating agent.

### Claim 8

A lithium silicate glass ceramic material formed by:
a) heating a starting glass material which is essentially free of ZnO and comprises SiO2, LiO2, K2O, Al2O3, nucleating agent, and optionally Me(II)O, wherein Me(II)O is CaO, BaO, MgO, SrO or combinations thereon, in a first temperature range for a period of time such that nuclei suitable to form lithium metasilicate crystals are formed; and
b) heating the material from a) in a second temperature range, which is higher than the first temperature range for a period of time to produce lithium silicate glass ceramic which has lithium metasilicate as the main crystalline phase, and wherein the crystals are of lamellar or platelet form.

### Claim 9 (depends on 8)

The lithium silicate glass ceramic of claim 8, wherein the material formed after step b) is convertible to a lithium silicate glass ceramic having disilicate as the main crystalline phase by heating to a third temperature which is higher than the second temperature.