Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including a second component containing structurally defined...
Reexamination Certificate
1994-07-25
2002-06-11
Yamnitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including a second component containing structurally defined...
C428S328000, C428S212000, C428S304400, C428S307300, C428S457000, C428S613000, C433S223000, C433S228100, C419S002000, C029S896100, C075S955000
Reexamination Certificate
active
06403212
ABSTRACT:
BACKGROUND OF THE INVENTION
In crown and bridge prosthodontics, metal copings are conventionally used to provide the essential structural strength and rigidity necessary for a dental restoration to resist the forces of mastication. In a ceramic-to-metal dental restoration, the metal coping forms the understructure, over which is applied a fired-on coating of porcelain or acrylic. A coating of porcelain is used over the coping for aesthetics and to simulate natural teeth. To the dental patient, color and the overall appearance of the dental restoration are critical factors in the satisfaction of the restoration. Accordingly, the color of the metal coping is important and should enhance the aesthetics of the restoration. For a ceramic-to-metal dental restoration, the metal coping should enhance the porcelain by providing a background color contrast.
In a co-pending application of Applicants entitled Moldable Dental Material and Method, Ser. No. 887,245, filed May 19, 1992, now U.S. Pat. No. 5,234,343, a dental material composition is taught which can be readily shaped or molded into any desired shape for repairing and/or forming a dental restoration, without waxing and casting. The composition of the material and method of application is taught in Applicants′ U.S. Pat. Nos. 4,742,861 and 4,990,394, the disclosure of which is herein incorporated by reference. In general, the dental material is composed of high- and low-fusing temperature metal particles combined in a matrix with a volatile binder for forming a dental restoration directly on a refractory die or model of the tooth or teeth to be restored. The material is shaped on the die into a desired configuration and heat-treated at a temperature to melt, or substantially melt, the low-fusing temperature metal particles and to volatize the binder, resulting in a porous, sponge-like structure having the shape it was given prior to heat treatment. A low-melting temperature filler material, preferably of gold, is then melted into the sponge-like structure to form a solid metal coping, with a configuration identical to the configuration of the shaped material on the refractory die before heat treatment and without experiencing distortion and/or shrinkage.
The solidified metal should possess a desirable color, which is reproducible with high accuracy, for use in forming a dental restoration. Heretofore, the process was temperature sensitive and even minor variations in the temperature during the heat-treatment procedures would permit some oxidation of the metals to occur, which could deleteriously affect its color, and even more seriously, could inhibit the flow of filler material into the porous sponge, which would affect the size of the solidified sponge. In fact, even the type of furnace used or its condition was able to affect the ability to accurately control the temperature during the heat-treatment procedures. Although sophisticated furnace temperature control equipment is commercially available, the implementation of such equipment is costly and would be unacceptable to the dental practitioner. The sensitivity to temperature variation also limited the process to the fabrication within the furnace of one restoration at a time.
SUMMARY OF THE INVENTION
A dental material composition has been discovered which can be molded with little effort to form a dental coping, dental crown, or filling. The composition preferably containing wax forms a material which may be worked on a refractory die, dies made of other materials or in the mouth. The procedure for forming a metal coping, repairing a dental restoration or filling a tooth can be readily practiced either at the dental laboratory or by the dentist in the dental office.
The moldable dental composition of the present invention comprises: high-fusing temperature metal particles having an irregular nonspherical geometry and a thin cross-sectional average thickness, a volatile binder preferably comprising wax, and finely divided carbonaceous particles in a concentration above at least 0.005 wt. % of the dental material. The composition may also contain low-fusing metal particles having a melting temperature below a preselected heat-treatment temperature sufficient to melt the binder and the low-fusing metal particles, but not the high-fusing metal particles.
The moldable dental material of the present invention comprises:
high-fusing temperature metal particles having an irregular, nonspherical geometry and a thin cross-sectional average thickness;
a volatile binder in a concentration of at least twenty percent (20%) by volume; and
finely divided carbonaceous particles, in a concentration above at least 0.005 wt.% of the dental composition.
REFERENCES:
patent: 4997699 (1991-03-01), Shoher et al.
patent: 5272184 (1993-12-01), Shoher et al.
patent: 5332622 (1994-07-01), Shoher et al.
Shoher Itzhak
Whiteman Aharon Eliyahu
LandOfFree
Moldable dental material composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Moldable dental material composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Moldable dental material composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2943381