CA2192353C - Low-fusing temperature porcelain - Google Patents
Low-fusing temperature porcelain Download PDFInfo
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- CA2192353C CA2192353C CA002192353A CA2192353A CA2192353C CA 2192353 C CA2192353 C CA 2192353C CA 002192353 A CA002192353 A CA 002192353A CA 2192353 A CA2192353 A CA 2192353A CA 2192353 C CA2192353 C CA 2192353C
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- porcelain
- low
- fusing temperature
- composition
- fusing
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Abstract
A low-fusing temperature porcelain composition for use in dental prostheses is disclosed having a fusing temperature of about 700 °C ~ 50 °°C and a coefficient of thermal expansion compatible witha substrate of metal or ceramic. The composition includes, in weight percent of the composition, SiO2 at 57-61, Al2O3 at 6.5-11.5, Na2O at 10-11, K2O at 8-16, Li2O at 1-3, CaO at 1.5-4, BaO at 1.5-2.5, CeO2 at 0.5-2, and Tb2O3 at 0.5-2.
Description
LOW-FUSING TEMPERATURE PORCELAIN
FTFT,n OF THE TNVRNTTON
The invention relates to porcelains used in dental prostheses. More particularly the--invention relates to a low-fusing temperature porcelain suitable for use in combination with metal or porcelain substrates.
A dental prosthesis often comprises a crown or bridge restbration in which a dental porcelain is fused to a supporting metal or ceramic substrate. Dental porcelains are generally a mixture of glass frit components or-natural feldspars or the like. There are a number of, key considerations in selecting frit components to form a porcelain that will be compatible with the selected substrate.
For example, the porcelain must have a coefficient of thermal expansion that is as close ~s possible to _ that of the substrate. Otherwise, a porcelain fused to ~~~2~5~
the substrate will tend to crack and separate from its supporting structure.
Another--key factor in selecting a porcelain component is its effect upon processing temperature of the porcelain; that is, the temperature that must be utilized in fusing the porcelain to the substrate.
Fusing temperatures of porcelain materials of the prior art have generally been on the order of 900°C-or higher.
Such elevatedtemperatures limit the composition of the substrate that may be used since some alloys or ceramic compositions will distort or otherwise suffer detrimental compositional changes under such processing conditions.
In selecting glass components and their amounts in the porcelain composition to achieve low-fusing temperatures and appropriate coefficients of thermal expansion, care also must be exercised to insure that the changes in composition do not otherwise adversely effect the qualities of the resulting fired porcelain with respect to its performance in a dental 219~3~~
environment. Such characteristics of concern are acid resistance, hardness, flexural strength and the like.
Thus, heretofore, it has remained the goal of researchers to- produce a porcelain glass frit a composition that has a low-fusing or processing temperature and a coefficient of thermal expansion such--that it can be used in combination with both metal and porcelain substrates in dental prostheses. Such a composition would have improved versatility for use in making, repairing or improving crowns, bridges, linings for dentures or as finish porcelains-and stains.
A low-fusing temperature porcelain composition for ' use in a dental prosthesis is provided. The porcelain composition comprises:
Frit Components Weight Percent Si02 57-61 A1Z03 6.5-11.5 Na20 10-I2 Kz0 8-16 LizO 1-3 Ca0 1.5-4 Ba0 1.S-2-.5 Ce02 0.5-2 ' TbzO; 0.5-2 The porcelain -of the invention has a fusing temperature of -about 700°C ~ 50°C-and a coefficient of thermal expansion compatible with a substrate of metal or ceramic. Preferably, the coefficient of thermal expansion is about 12-13 wm.K 1 [20 to 500°C).
The invention is a low-fusing temperature porcelain composition that is a mixture of oxides such that the -resulting frit has a fusing temperature of about 700°C + 50°C and -a coefficient of thermal expansion of 12-13 ~tm.R 1 [20 to 500°C] . The low fusing porcelain may be employed in dental crowns, bridges, restorations and dentures wherein- it is fused to a substrate or coping of metal or- conventional porcelains, such as Ceramco II~, and dental alloy copings, such as Ceramco- II~ Silver, both manufactured by Dentsply International Inc. of York, Pennsylvania.
The compositional range for the low-fusing temperature dental porcelains of the invention, having processing temperatures of less than about 705°C and a 219235:5 WO 96118373 ' PCTIC1S95/15626 coefficient of f.hermal expansion (CTE) of 12-13 ~m.K 1 [20 to 5.00°CI. is -a mixture of oxides having the following composition:
Table-1 Oxide Weight Percent SiOz 57-61 A1203 6.5-11.5 NaZO 10-12 K20 8-lfi Li20 1-3 Ca0 1.5-4 Ba0 1.5-2.5 Ce02 0.5-2 Tbz03 0.5-2 An optional ingredient is B203 at about 0-2°s by weight of the composition.
The _- following examples describe preferred compositions and characterize the resulting dental porcelain qualities.
Example 1 A single glass, frit, low temperature fusing porcelain is made by combining and --fusing oxides, and then forming a pulverized mixture,-as-is well known in WO 96118373 PCTfUS95/15626 the art, of the composition indicated in Table 1. The resulting porcelain has a firing temperature of 705°C
and a CTE of 12.5 Pm.K 1. Samples of the resulting mixture have the characteristics and properties shown in Table 2.
Table 2 Oxide Weight Percent Ex.l SiO~ 59 A1z03 7 Na20 10.5 K20 13 . 5 Li20 2 Ca0 2 Ba0 2 Ce02 1 Tb40y 1 Total 100 CTE ()xm.K
1 12.5 (30-500C) 705 Firing 1300 Temp.
(C) (F) Samples of the low-fusing glass of the invention are also characterized by their low chemical solubility. Chemical solubility was determined by ~19~~55 W0 96118373 PCTlUS95115626 boiling the porcelain samples in acetic acid for sixteen hours. The maximum allowable weight loss per ISO standards is 1. 0 ug/mm' . The measured weight loss of the glass frit of example 1 of the. invention is 0.26 ~g/mm'. The weight loss of a competitive low-fusing porcelain - in the marketplace (Durceram-LFC, manufactured by Degussa of Germany is 0.47 ~g/mm2.
Low-fusing porcelains of the invention are made in the same manner as Example 1, having the composition indicated in -'Table 3 below, and the desired characteristics within the scope ofthe invention.
21~~3~3 Table 3 Oxide Weight Percent Ex.2 Ex.3 Ex.4 Si02 59 59 57.7 AlzO~ 7 7 11.5 NazO 10 10 12 Li20 2 2 3 Ca0 2 2 3.8 Ba0 2 2 2 Bz03 - 2 -Ce02 1 1 1 Tb,O~ 1 1 1 Total 100 100 100 CTE (~tm.K'') (30-500C) 12.6 12.5 12.6 Firing Temp.
(C) 705 705 690 (F) - 1300 1300 1270 The examples ofthe invention when utilized in forming dentalprostheses are characterized by having an easier polishability due to the reduced hardness compared to conventional porcelains. The amounts of Ce02 and Tbz03 are adjusted to. provide desired fluorescence characteristics, ranging from bluish to white fluorescence.
Variations and modifications of the composition are within those skilled in the art, for example, to W 0 96118373 PC.TIUS95/15626 adjust the coefficient of thermal expansion to match the desired value of 12-13 ~tm.R 1, depending upon the substrate to which the porcelain will be applied.
v
FTFT,n OF THE TNVRNTTON
The invention relates to porcelains used in dental prostheses. More particularly the--invention relates to a low-fusing temperature porcelain suitable for use in combination with metal or porcelain substrates.
A dental prosthesis often comprises a crown or bridge restbration in which a dental porcelain is fused to a supporting metal or ceramic substrate. Dental porcelains are generally a mixture of glass frit components or-natural feldspars or the like. There are a number of, key considerations in selecting frit components to form a porcelain that will be compatible with the selected substrate.
For example, the porcelain must have a coefficient of thermal expansion that is as close ~s possible to _ that of the substrate. Otherwise, a porcelain fused to ~~~2~5~
the substrate will tend to crack and separate from its supporting structure.
Another--key factor in selecting a porcelain component is its effect upon processing temperature of the porcelain; that is, the temperature that must be utilized in fusing the porcelain to the substrate.
Fusing temperatures of porcelain materials of the prior art have generally been on the order of 900°C-or higher.
Such elevatedtemperatures limit the composition of the substrate that may be used since some alloys or ceramic compositions will distort or otherwise suffer detrimental compositional changes under such processing conditions.
In selecting glass components and their amounts in the porcelain composition to achieve low-fusing temperatures and appropriate coefficients of thermal expansion, care also must be exercised to insure that the changes in composition do not otherwise adversely effect the qualities of the resulting fired porcelain with respect to its performance in a dental 219~3~~
environment. Such characteristics of concern are acid resistance, hardness, flexural strength and the like.
Thus, heretofore, it has remained the goal of researchers to- produce a porcelain glass frit a composition that has a low-fusing or processing temperature and a coefficient of thermal expansion such--that it can be used in combination with both metal and porcelain substrates in dental prostheses. Such a composition would have improved versatility for use in making, repairing or improving crowns, bridges, linings for dentures or as finish porcelains-and stains.
A low-fusing temperature porcelain composition for ' use in a dental prosthesis is provided. The porcelain composition comprises:
Frit Components Weight Percent Si02 57-61 A1Z03 6.5-11.5 Na20 10-I2 Kz0 8-16 LizO 1-3 Ca0 1.5-4 Ba0 1.S-2-.5 Ce02 0.5-2 ' TbzO; 0.5-2 The porcelain -of the invention has a fusing temperature of -about 700°C ~ 50°C-and a coefficient of thermal expansion compatible with a substrate of metal or ceramic. Preferably, the coefficient of thermal expansion is about 12-13 wm.K 1 [20 to 500°C).
The invention is a low-fusing temperature porcelain composition that is a mixture of oxides such that the -resulting frit has a fusing temperature of about 700°C + 50°C and -a coefficient of thermal expansion of 12-13 ~tm.R 1 [20 to 500°C] . The low fusing porcelain may be employed in dental crowns, bridges, restorations and dentures wherein- it is fused to a substrate or coping of metal or- conventional porcelains, such as Ceramco II~, and dental alloy copings, such as Ceramco- II~ Silver, both manufactured by Dentsply International Inc. of York, Pennsylvania.
The compositional range for the low-fusing temperature dental porcelains of the invention, having processing temperatures of less than about 705°C and a 219235:5 WO 96118373 ' PCTIC1S95/15626 coefficient of f.hermal expansion (CTE) of 12-13 ~m.K 1 [20 to 5.00°CI. is -a mixture of oxides having the following composition:
Table-1 Oxide Weight Percent SiOz 57-61 A1203 6.5-11.5 NaZO 10-12 K20 8-lfi Li20 1-3 Ca0 1.5-4 Ba0 1.5-2.5 Ce02 0.5-2 Tbz03 0.5-2 An optional ingredient is B203 at about 0-2°s by weight of the composition.
The _- following examples describe preferred compositions and characterize the resulting dental porcelain qualities.
Example 1 A single glass, frit, low temperature fusing porcelain is made by combining and --fusing oxides, and then forming a pulverized mixture,-as-is well known in WO 96118373 PCTfUS95/15626 the art, of the composition indicated in Table 1. The resulting porcelain has a firing temperature of 705°C
and a CTE of 12.5 Pm.K 1. Samples of the resulting mixture have the characteristics and properties shown in Table 2.
Table 2 Oxide Weight Percent Ex.l SiO~ 59 A1z03 7 Na20 10.5 K20 13 . 5 Li20 2 Ca0 2 Ba0 2 Ce02 1 Tb40y 1 Total 100 CTE ()xm.K
1 12.5 (30-500C) 705 Firing 1300 Temp.
(C) (F) Samples of the low-fusing glass of the invention are also characterized by their low chemical solubility. Chemical solubility was determined by ~19~~55 W0 96118373 PCTlUS95115626 boiling the porcelain samples in acetic acid for sixteen hours. The maximum allowable weight loss per ISO standards is 1. 0 ug/mm' . The measured weight loss of the glass frit of example 1 of the. invention is 0.26 ~g/mm'. The weight loss of a competitive low-fusing porcelain - in the marketplace (Durceram-LFC, manufactured by Degussa of Germany is 0.47 ~g/mm2.
Low-fusing porcelains of the invention are made in the same manner as Example 1, having the composition indicated in -'Table 3 below, and the desired characteristics within the scope ofthe invention.
21~~3~3 Table 3 Oxide Weight Percent Ex.2 Ex.3 Ex.4 Si02 59 59 57.7 AlzO~ 7 7 11.5 NazO 10 10 12 Li20 2 2 3 Ca0 2 2 3.8 Ba0 2 2 2 Bz03 - 2 -Ce02 1 1 1 Tb,O~ 1 1 1 Total 100 100 100 CTE (~tm.K'') (30-500C) 12.6 12.5 12.6 Firing Temp.
(C) 705 705 690 (F) - 1300 1300 1270 The examples ofthe invention when utilized in forming dentalprostheses are characterized by having an easier polishability due to the reduced hardness compared to conventional porcelains. The amounts of Ce02 and Tbz03 are adjusted to. provide desired fluorescence characteristics, ranging from bluish to white fluorescence.
Variations and modifications of the composition are within those skilled in the art, for example, to W 0 96118373 PC.TIUS95/15626 adjust the coefficient of thermal expansion to match the desired value of 12-13 ~tm.R 1, depending upon the substrate to which the porcelain will be applied.
v
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A low-fusing temperature porcelain composition for use in a dental prosthesis, consisting essentially of, in weight percent of the porcelain composition:
said porcelain having a fusing temperature of about 700°C ~
50°C and a coefficient of thermal expansion compatible with a substrate of metal or ceramic suitable for a dental prothestic.
said porcelain having a fusing temperature of about 700°C ~
50°C and a coefficient of thermal expansion compatible with a substrate of metal or ceramic suitable for a dental prothestic.
2. The porcelain of claim 1, having a coefficient of thermal expansion of about 12-13 µm. K -1 measured at 20° to 500°C.
3.~The porcelain of claim 1, further comprising up to about 2 weight percent by weight of B2O3.
4.~A low-fusing temperature porcelain composition for use in a dental prosthesis, comprising:
a glass frit, having a processing temperature of about 705°C and a coefficient of thermal expansion of about 12-13 µm.K -1 measured at 20° to 500°C and, in weight percent (~ 0.5) of the composition:
a glass frit, having a processing temperature of about 705°C and a coefficient of thermal expansion of about 12-13 µm.K -1 measured at 20° to 500°C and, in weight percent (~ 0.5) of the composition:
5.~A dental prosthesis, comprising the low-fusing temperature porcelain of claim 4, fused to a ceramic substrate.
6. A dental prosthesis, comprising the low-fusing temperature porcelain of claim 1, fused to a substrate of metal or ceramic.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/354,385 | 1994-12-12 | ||
| US08/354,385 US5552350A (en) | 1994-12-12 | 1994-12-12 | Low-fusing temperature porcelain |
| PCT/US1995/015626 WO1996018373A1 (en) | 1994-12-12 | 1995-12-01 | Low-fusing temperature porcelain |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2192353A1 CA2192353A1 (en) | 1996-06-20 |
| CA2192353C true CA2192353C (en) | 2005-11-08 |
Family
ID=35539256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002192353A Expired - Lifetime CA2192353C (en) | 1994-12-12 | 1995-12-01 | Low-fusing temperature porcelain |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2192353C (en) |
-
1995
- 1995-12-01 CA CA002192353A patent/CA2192353C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2192353A1 (en) | 1996-06-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20151201 |
|
| MKEX | Expiry |
Effective date: 20151201 |