U.S. patent application number 09/344089 was filed with the patent office on 2001-11-01 for prefabricated components for dental appliances.
This patent application is currently assigned to ANN M. KNAB. Invention is credited to KARMAKER, AJIT, PRASAD, ARUN, SCHULMAN, MARTIN L..
Application Number | 20010036617 09/344089 |
Document ID | / |
Family ID | 46256527 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010036617 |
Kind Code |
A1 |
KARMAKER, AJIT ; et
al. |
November 1, 2001 |
PREFABRICATED COMPONENTS FOR DENTAL APPLIANCES
Abstract
Ready-to-use preshaped, prefabricated cured structural
components are prepared in a variety of shapes and sizes to be used
in the fabrication of dental appliances. Preferably the structural
components are fabricated of a fiber-reinforced composite material
or a particulate-filled composite material comprising fibers or
particulate filler impregnated with a polymeric matrix. The
polymeric matrix is partially or fully cured to the point of
sufficient hardness to provide a ready-to-use structural component
for use in the fabrication of dental appliances such as orthodontic
retainers, bridges, space maintainers, tooth replacement
appliances, splints, crowns, partial crowns, dentures, posts,
teeth, jackets, inlays, onlays, facings, veneers, facets, implants,
abutments, cylinders, and connectors.
Inventors: |
KARMAKER, AJIT;
(WALLINGFORD, CT) ; SCHULMAN, MARTIN L.; (ORANGE,
CT) ; PRASAD, ARUN; (CHESHIRE, CT) |
Correspondence
Address: |
ANN M KNAB
JENERIC/PENTRON INCORPORATED
53 NORTH PLAINS INDUSTRIAL ROAD
WALLINGFORD
CT
06492
|
Assignee: |
ANN M. KNAB
|
Family ID: |
46256527 |
Appl. No.: |
09/344089 |
Filed: |
June 25, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09344089 |
Jun 25, 1999 |
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09190806 |
Nov 12, 1998 |
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6186790 |
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09190806 |
Nov 12, 1998 |
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09059492 |
Apr 13, 1998 |
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Current U.S.
Class: |
433/173 ;
433/172 |
Current CPC
Class: |
A61C 13/0003 20130101;
A61C 13/0022 20130101; A61C 5/30 20170201 |
Class at
Publication: |
433/173 ;
433/172 |
International
Class: |
A61C 008/00 |
Claims
What is claimed is:
1. A material for use in the fabrication of a dental appliance
system comprising: a prefabricated preshaped block of
particulate-filled composite material comprising a polymeric matrix
and a particulate component wherein the block is shaped and cured
to a hardness for use in the dental appliance system.
2. The material of claim 1 wherein the block is modified by
machining, cutting or carving.
3. The material of claim 1 wherein the block is machined using a
CAD CAM machine.
4. The material of claim 1 wherein the shape of the block is
selected from the group consisting of a square, rectangle,
triangle, rhomboid, ovoid, and cylinder.
5. The material of claim 1 wherein the block is either straight or
curved.
6. The material of claim 1 wherein the block has undergone partial
polymerization.
7. The material of claim 1 wherein the block has undergone full
polymerization.
8. The component of claim 1 wherein the dental appliance system is
selected from the group consisting of single crowns, inlays and
onlays.
9. The component of claim 1 further including a coating
thereon.
10. The component of claim 1 wherein the blocks further include one
or more layers of composite material.
11. A component for use in a dental appliance system comprising: a
prefabricated preshaped cured particulate-filled composite material
comprising a polymeric matrix and a particulate filler wherein the
particulate-filled composite material is shaped in the form of a
block.
12. The component of claim 11 wherein the block is modified by
machining, cutting or carving.
13. The component of claim 11 wherein the shape of the component is
selected from the group consisting of a square, rectangle,
triangle, rhomboid, ovoid, and cylinder.
14. The component of claim 11 wherein the particulate-filled
composite material has undergone partial polymerization.
15. The component of claim 11 wherein the particulate-filled
composite material has undergone full polymerization.
16. The component of claim 11 wherein the dental appliance system
is selected from the group consisting of single crowns, inlays and
onlays.
17. The component of claim 11 further including a veneer
thereon.
18. The component of claim 17 wherein the veneer is fabricated of
composite material.
19. The component of claim 17 wherein the blocks are either
straight or curved.
20. A kit for the fabrication of a dental appliance comprising: one
or more prefabricated preshaped cured blocks of particulate-filled
composite material comprising a polymeric matrix and a particulate
filler wherein the block is shaped and cured to a hardness for use
in a dental appliance system.
21. The kit of claim 20 wherein the blocks are designed for use
with CAD CAM systems.
22. The kit of claim 20 wherein the blocks are of a variety of
different shades.
23. The kit of claim 20 further comprising composite material,
fiber-reinforced composite material and filler material.
24. A dental restoration comprising: a prefabricated preshaped
cured particulate-filled composite material comprising a polymeric
matrix and particulate filler wherein the particulate-filled
composite material is shaped in the form of a block.
25. The dental restoration of claim 24 wherein the block is
modified prior to incorporation into the dental restoration.
26. A blank for the manufacture of a dental restoration comprising:
a prefabricated preshaped cured particulate-filled composite
material comprising a polymeric matrix and a particulate filler
component wherein the particulate-filled composite material is
shaped and cured for use in a CAD/CAM system.
27. A ready-to-use component for use in a CAD/CAM system
comprising: a prefabricated preshaped cured particulate-filled
composite material comprising a polymeric matrix and a particulate
filler component wherein the particulate-filled composite material
is shaped and cured for use in a CAD/CAM system.
28. A dental restoration which comprises the component of claim
1.
29. A dental restoration manufactured from the blank of claim
26.
30. A method of making a dental restoration comprising: putting a
block of a prefabricated preshaped cured particulate-filled
composite material comprising a polymeric matrix and a particulate
filler wherein the block of particulate-filled composite material
is shaped and cured to a hardness for use in the dental appliance
system onto a milling device and machining the block to a desired
shape.
31. The method of claim 30 further comprising adding one or more
layers of composite material to the machined block and curing the
one or more layers of composite material.
32. A method of making a dental restoration comprising: fabricating
a particulate-filled composite material into the shape of a block;
curing the shaped block to provide a prefabricated, cured block;
machining the block to provide the dental restoration.
33. The method of claim 32 further comprising modifying the dental
restoration.
34. The method of claim 33 wherein the modifying comprises one or
more of grinding, cutting, abrading, etching, silanating, and
veneering.
35. The method of claim 33 wherein the modifying comprises bonding
the dental restoration to a fiber-reinforced composite
material.
36. The method of claim 33 wherein the modifying comprises bonding
a one or more layers of dental composite materials thereto.
37. A method of making a dental restoration comprising: fabricating
a particulate-filled composite material into the shape of a block;
curing the shaped block to provide a prefabricated, cured block;
milling the block under the control of a CAD/CAM system to provide
a dental restoration.
38. A method of making a dental restoration comprising: fabricating
a particulate-filled composite material into the shape of a block;
curing the shaped block to provide a prefabricated, cured block;
modifying the cured block by cutting, grinding or machining the
structural component to the desired shape.
39. The material of claim 1 wherein the polymeric matrix is present
in an amount ranging from about 20 to about 30% by weight and the
particulate filler is present in an amount from about 65 to about
85% by weight of the particulate-filled composite.
40. The material of claim 39 wherein the polymeric matrix comprises
a dental resin material comprising: (a) from about 10 to about 30
weight percent of a methacrylate oligomer; (b) from about 65 to
about 90 weight percent of an ethoxylated bisphenol A
dimethacrylate having the
formulaCH.sub.2.dbd.C(CH.sub.3)CO.sub.2(C.sub.2H.sub.4O).sub.xC.sub.6H.su-
b.4C(CH.sub.3).sub.2C.sub.6H.sub.4(OC.sub.2H.sub.4).sub.yO.sub.2CC(CH.sub.-
3).dbd.CH.sub.2wherein x+y is an integer from 1 to 20; and (c) from
about 0 to about 40 weight percent of a diluent monomer for
decreasing the viscosity of the dental resin composition, wherein
each of the components (a), (b), and (c) is a different monomer and
such that the specific amounts with the ranges yield a 100% by
weight polymerization system.
41. The material of claim 1 wherein the particulate filler
comprises one or more fillers selected from silica, silicate glass,
quartz, barium silicate, strontium silicate, barium borosilicate,
barium sulfate, barium molybdate, barium methacrylate, barium
yttrium alkoxy (Ba.sub.2Y(OR).sub.x), strontium borosilicate,
borosilicate, lithium silicate, amorphous silica, ammoniated or
deammoniated calcium phosphate,alumina, zirconia, tin oxide,
tantalum oxide, niobium oxide and titania.
42. The material of claim 1 wherein the particulate filler
comprises a mixture of from about 5 to about 20% by weight of
borosilicate glass and from about 80 to about 95% by weight of
barium borosilicate.
43. The material of claim 42 wherein the particulate filler has an
average particle size of from about 0.5 to about 5 microns.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part application of application
Ser. No. 09/190,806 filed Nov. 12, 1998 entitled PREFABRICATED
COMPONENTS FOR DENTAL APPLIANCES which is a continuation-in-part of
application Ser. No. 09/059,492 filed Apr. 13, 1998 entitled
PREFABRICATED COMPONENTS FOR DENTAL APPLIANCES and further claims
priority to application Ser. No. 08/998,849 filed Dec. 29, 1997
entitled DENTAL RESIN MATERIALS.
TECHNICAL FIELD
[0002] The present invention relates generally to dental appliances
and restorations and more particularly to prefabricated components
for use in dental appliances and restorations and methods of
manufacture thereof
BACKGROUND OF THE INVENTION
[0003] Dental appliances and restorations such as bridges, crowns,
dentures and the like may be used to restore a missing tooth and
retain natural teeth in position and prevent migration subsequent
to orthodontic treatment. Structural components used in these
appliances often include wires, bars, posts, shells, beams, clasps
and other shapes. The shape of the structural components may vary
depending upon the requirements of the appliance.
[0004] The manufacture of frameworks for bridges using current
techniques can be time consuming and labor intensive. Some
techniques may involve taking uncured fiber-reinforced composite
material and forming uncured strips of the fiber-reinforced
composite material into a bridge framework upon a dental cast. The
procedure can be an involved and complex process depending upon the
final shape desired. Moreover, dental technicians and practitioners
may use less than the optimum amount of fiber for reinforcement
when preparing the dental framework in order to reduce the cost
which may lead to low strength and therefore potential fracture of
the final product. Furthermore, the complexity of the dental
appliance may require a certain dexterity to achieve optimal
properties that may not be achievable by some technicians and
practitioners.
[0005] Other types of materials such as metals, alloys and ceramics
have been used with great success in the manufacture of dental
restorations and have exhibited flexural strengths as high as 300
MPa and above. Unfortunately, the aesthetic appearance is sometimes
less than pleasing due to the unfavorable light transmission
properties of these materials.
[0006] There remains a need to simplify the process of fabricating
dental appliances to reduce time and labor involved in the
preparation process and to provide appliances having optimum
properties. It is desirable to reduce the risk of contamination
during the fabrication of dental appliances. It is desirable to
maintain strength of dental appliances without sacrificing
aesthetic and light transmitting properties.
SUMMARY OF THE INVENTION
[0007] These and other objects and advantages are accomplished by
the present invention wherein preshaped, prefabricated cured
components are prepared in a variety of shapes and sizes to be used
in the fabrication of dental appliances. Preferably the components
are fabricated of a fiber-reinforced composite material comprising
fibers impregnated with a polymeric matrix. After impregnation of a
fibrous material with a polymeric matrix, the resultant
fiber-reinforced composite material is shaped and is partially or
fully cured to the point of sufficient hardness to provide a
component for use in the fabrication of dental appliances including
but not limited to orthodontic retainers, bridges, space
maintainers, tooth replacement appliances, dentures, crowns, posts,
jackets, inlays, onlays, facings, veneers, facets, implants,
abutments and splints.
[0008] In one embodiment of the present invention, the components
are in the shape of a structure for immediate use in the
fabrication of a dental appliance. The structural components are
formed into any known shapes useful in the fabrication of a dental
appliance or restoration. Preferably, the structural components are
in the shape of bars or pontics. The pontics have interproximal
extensions and may be single unit or multiple unit useful in the
fabrication of frameworks for bridges. The structural components
may be "ready-to-use" for immediate use in the fabrication of a
dental appliance or restoration or may be further modified, for
example by cutting, carving or grinding prior to using in the
fabrication of a dental appliance or restoration.
[0009] In another embodiment of the present invention, the
components are formed into pieces or blocks of fiber-reinforced
composite material. The blocks of material are useful in making a
variety of shapes and sizes and may be modified by a variety of
methods including but not limited to machining, carving, cutting,
grinding, etching and abrading.
[0010] The bars, pontics and blocks may be of any cross-sectional
configuration effective to provide strength and stiffness to the
finished dental appliance.
[0011] In yet another embodiment herein, blocks of particulate
filled composite material are formed and may be provided in a
variety of shapes and sizes. The particulate filled composite
blocks may be modified by a variety of methods including but not
limited to machining, carving, cutting, grinding, etching and
abrading. The blocks may be of any cross-sectional configuration
effective to design or model dental materials and restorations
therefrom.
[0012] In the method of the present invention, the components are
made after the impregnation of the fibers with a polymeric matrix.
After impregnation of the fibers, the resultant composite material
is formed into, for example, a long bar and cured or polymerized to
a hardness whereby the bar may be cut and/or machined without
deforming the structural integrity of the bar. The bar is
preferably cut into short segments and is ready for use in the
fabrication of dental appliances. The bars may be used as is or may
be further modified by cutting, grinding, machining, and the like
to provide a specifically shaped or customized component. The
component may further be veneered with particulate-filled composite
to develop clinically acceptable anatomy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Features of the present invention are disclosed in the
accompanying drawings, wherein similar reference characters denote
similar elements throughout the several views, and wherein:
[0014] FIG. 1 is a perspective view of bars of different shapes
that may be formed in accordance with the present invention;
[0015] FIG. 2 is a front elevational view of a multi-unit pontic
formed in accordance with the present invention;
[0016] FIG. 3 is a top plan view of a multi-unit pontic formed in
accordance with the present invention;
[0017] FIG. 4 is a top plan view of a series of molds used to
fabricate single unit pontics in accordance with the present
invention;
[0018] FIG. 5 is a front elevational view of a single unit pontic
formed using a mold in FIG. 4; and
[0019] FIG. 6 is a side elevational view of a mold used to
fabricate long bars in accordance with the present invention.
[0020] FIG. 7 is a perspective view of a cylindrical block formed
in accordance with the present invention;
[0021] FIG. 8 is a perspective view of a tooth machined out of the
block shown in FIG. 7;
[0022] FIG. 9 is a perspective view of a rectangular block formed
in accordance with the present invention;
[0023] FIG. 10 is a perspective view of a bridge machined out of
the block shown in FIG. 9;
[0024] FIG. 11 is a perspective view of a square block formed in
accordance with the present invention;
[0025] FIG. 12 is a perspective view of a cylinder machined out of
the block shown in FIG. 11;
[0026] FIG. 13 is a perspective view of a partial implant system
formed from structural components of the present invention;
[0027] FIG. 14 is a perspective view of a curved rectangular block
formed in accordance with the present invention; and
[0028] FIG. 15 is a perspective view of an implant superstructure
machined out of the block shown in FIG. 14.
DETAILED DESCRIPTION
[0029] The prefabricated components in accordance with the present
invention are preferably formed from a fiber-reinforced composite
material comprising a polymeric matrix and reinforcing fibers
within the matrix. The fibers are embedded in the matrix manually
or mechanically by a variety of techniques including, but not
limited to matched die processes, autoclave molding, resin
injection molding (RIM), sheet, dough and bulk molding, press
molding, injection molding, reaction injection molding, resin
transfer molding (RTM), compression molding, open molding,
extrusion, pultrusion and filament winding. U.S. Pat. Nos.
4,717,341 and 4,894,012 to Goldberg et al. show methods of
impregnation and are hereby incorporated by reference. Preferably
the fiber-reinforced polymeric matrix is formed using the
pultrusion or filament winding technique.
[0030] Alternatively, the prefabricated components are formed from
a particulate-filled composite material comprising a polymeric
matrix and particulate filler within the matrix. Preferably, the
prefabricated components of particulate filled composite material
are formed into blocks of material of a variety of shapes and sizes
which can thereafter be modified by a variety of methods including
but not limited to machining, carving, cutting, grinding, etching
and abrading. Preferably, the blocks of material are useful in CAD
CAMming processes and equipment in the fabrication of dental
restorations.
[0031] The polymeric matrix element of the fiber-reinforced and
particulate-filled composites is selected from those known in the
art of dental materials, including but not being limited to
polyamides, polyesters, polyolefins, polyimides, polyarylates,
polyurethanes, vinyl esters or epoxy-based materials. Other
polymeric matrices include styrenes, styrene acrylonitriles, ABS
polymers, polysulfones, polyacetals, polycarbonates, polyphenylene
sulfides, and the like.
[0032] Preferred polymeric materials include those based on acrylic
and methacrylic monomers, for example those disclosed in U.S. Pat.
Nos. 3,066,112, 3,179,623, and 3,194,784 to Bowen; U.S. Pat. Nos.
3,751,399 and 3,926,906 to Lee et al.; commonly assigned U.S. Pat.
Nos. 5,276,068 and 5,444,104 to Waknine; and commonly assigned U.S.
Pat. No. 5,684,103 to Jia et al., the pertinent portions of all
which are herein incorporated by reference. An especially preferred
methacrylate monomer is the condensation product of bisphenol A and
glycidyl methacrylate, 2,2'-bis[4-(3-methacryloxy-2-hydroxy
propoxy)-phenyl]-propane (hereinafter abbreviated "BIS-GMA").
Polyurethane dimethacrylates (hereinafter abbreviated "PUDMA"),
triethylene glycol dimethacrylate (hereinafter abbreviated
"TEGDMA"), polyethylene glycol dimethacrylate (hereinafter
abbreviated "PEGDMA"), polycarbonate dimethacrylate (hereinafter
abbreviated "PCDMA") and ethoxylated bisphenol A dimethacrylate
(hereinafter abbreviated "EBPADMA") are also commonly-used
principal polymers suitable for use in the present invention.
[0033] The polymer matrix typically includes polymerization
initiators, polymerization accelerators, ultraviolet light
absorbers, anti-oxidants, and other additives well known in the
art. The polymer matrices may be visible light curable,
self-curing, dual curing, and vacuum, heat, and pressure curable
compositions as well as any combination thereof The visible light
curable compositions include the usual polymerization initiators,
polymerization accelerators, ultraviolet absorbers, fluorescent
whitening agents, and the like. Preferred light curing initiators
include camphorquinone (CQ) and trimethyl benzoyl phosphine oxide
(TPO). The heat curable compositions, which are generally filled
compositions, include, in addition to the monomeric components, a
heat cure initiator such as benzoyl peroxide,
1,1'-azobis(cyclohexanecarbo-nit- rile), or other free radical
initiators. The preferred fiber-reinforced polymeric matrix is a
curable matrix, wherein light cure effects partial cure of the
matrix, and final curing is by heat under controlled
atmosphere.
[0034] The preferred particulate-filled polymeric matrix is a heat
curable polymeric matrix comprising one or more heat initiators
mentioned above. Preferably the polymeric matrix of the
particulate-filled composite comprises a resinous dental
composition as set forth in commonly owned, copending application
Ser. No. 08/998,849 filed Dec. 29, 1997 which is hereby
incorporated by reference which is derived from the reaction of an
ethoxylated bisphenol A dimethacrylate and a co-monomer, preferably
a polycarbonate dimethacrylate condensation product described in
U.S. Pat. Nos. 5,276,068 and 5,444,104 to Waknine and more
preferably a dimethacrylate oligomer. The resinous dental
composition can additionally include a third, diluent monomer to
increase the surface wettability of the resinous matrix. The
ethoxylated bisphenol A dimethacrylate in accordance with the
present invention has the following structure:
CH.sub.2.dbd.C(CH.sub.3)CO.sub.2(C.sub.2H.sub.4O).sub.xC.sub.6H.sub.4C(CH.-
sub.3).sub.2C.sub.6H.sub.4(OC.sub.2H.sub.4).sub.yO.sub.2CC(CH.sub.3).dbd.C-
H.sub.2
[0035] wherein x+y is an integer from 1 to 20, and preferably an
integer from 2 to 7. Such material is available from Sartomer.RTM.
under the trade name SR348 or SR480, or from Esschem.
[0036] The preferred polycarbonate dimethacrylate condensation
product co-monomer results from the condensation, under carefully
controlled conditions, of two parts by weight of a
hydroxyalkylmethacrylate of the formula
H.sub.2C.dbd.C(CH.sub.3)C(O)O--A--OH, in which A is a
C.sub.1-C.sub.6 alkylene, with 1 part by weight of a
bis(chloroformate) of the formula ClC(O)--(OR).sub.n--OC(O)Cl, in
which R is a C.sub.2-C.sub.5 having at least two carbon atoms in
its principal chain, and n is an integer in the range from 1 to
4.
[0037] Preferably, the ethoxylated bisphenol A dimethacrylate is
used in an amount in the range from about 65 to about 90 percent by
weight of the total resin composition which forms the polymeric
matrix. More preferably, the ethoxylated bisphenol A dimethacrylate
is used in an amount in the range from about 70 to about 80 percent
by weight of the total resin composition. Typically, the
dimethacrylate oligomer, preferably a polycarbonate dimethacrylate,
is incorporated into the resinous composition in an amount from
about 10 to about 30 weight percent of the total resin composition.
Optionally, a diluent is present in an amount from about 0 to about
40 weight percent of the total resin composition.
[0038] When no diluent component is employed, the preferred range
for the ethoxylated bisphenol A dimethacrylates is from about 65 to
about 90 weight percent, and most preferably about 70 weight
percent of the total resin composition, and the preferred range for
the dimethacrylate oligomer is from about 10 to about 30 weight
percent, and most preferably about 30 weight percent of the total
resin composition which forms the polymeric matrix.
[0039] The fiber-reinforced polymeric matrix may further comprise
at least one filler known in the art and used in dental restorative
materials, the amount of such filler being determined by the
specific use of the fiber-reinforced composite. Generally, no or
relatively little additional filler is present in the polymeric
matrix, i.e., up to thirty percent by weight of the composite.
Suitable fillers are those capable of being covalently bonded to
the polymeric matrix itself or to a coupling agent that is
covalently bonded to both. Examples of suitable filling materials
include but are not limited to those known in the art such as
silica, silicate glass, quartz, barium silicate, strontium
silicate, barium borosilicate, strontium borosilicate,
borosilicate, lithium silicate, amorphous silica, ammoniated or
deammoniated calcium phosphate and alumina, zirconia, tin oxide,
and titania. Particularly suitable fillers for dental filling-type
materials prepared in accordance with this invention are those
having a particle size ranging from about 0.1-5.0 microns with a
silicate colloid of 0.001 to about 0.07 microns and may be prepared
by a series of milling steps comprising wet milling in an aqueous
medium, surface etch milling and dry or wet silanation. Some of the
aforementioned inorganic filling materials are disclosed in
commonly-assigned U.S. Pat. Nos. 4,544,359 and 4,547,531 to
Waknine, the pertinent portions of which are incorporated herein by
reference.
[0040] The particulate-filled polymeric matrix comprises at least
one filler known in the art and used in dental restorative
materials, the amount of such filler being determined by the
specific use of the particulate-filled composite. Generally, from
about 65 to about 85% by weight of a filler is present in the
particulate-filled composite and preferably, about 75 to about 83%
by weight of the composite is filler in combination with about 17
to about 35% by weight and preferably about 20 to about 30% by
weight and more preferably about 20 to about 26% by weight of the
composite is unfilled heat curable dental resin material which
makes up the polymeric matrix. Suitable fillers are those capable
of being covalently bonded to the polymeric matrix itself or to a
coupling agent that is covalently bonded to both. Examples of
suitable filling materials include but are not limited to those
known in the art such as silica, silicate glass, quartz, barium
silicate, barium sulfate, barium molybdate, barium methacrylate,
barium yttrium alkoxy (Ba.sub.2Y(OR).sub.x), strontium silicate,
barium borosilicate, strontium borosilicate, borosilicate, lithium
silicate, amorphous silica, ammoniated or deammoniated calcium
phosphate, alumina, zirconia, tin oxide, tantalum oxide, niobium
oxide, and titania. Particularly suitable fillers for dental
filling-type materials prepared in accordance with this invention
are those having a particle size ranging from about 0.1-5.0 microns
with a silicate colloid of 0.001 to about 0.07 microns and may be
prepared by a series of milling steps comprising wet milling in an
aqueous medium, surface etch milling and dry or wet silanation.
Some of the aforementioned inorganic filling materials are
disclosed in commonly-assigned U.S. Pat. Nos. 4,544,359 and
4,547,531 to Waknine, the pertinent portions of which are
incorporated herein by reference.
[0041] Preferably, the particulate-filled composite comprises an
inorganic filler having an average particle size diameter of about
0.5 to about 5 microns homogeneously dispersed in an organic
polymerizable monomeric matrix comprising ethoxylated
dimethacrylate which is set forth in commonly owned, copending
application Ser. No. 08/998,849 filed Dec. 29, 1997 which is hereby
incorporated by reference. In addition, a relatively small amount
of fumed silica is also predispersed within the monomeric matrix.
The inorganic filler primarily comprises an X-ray opaque alkali
metal or alkaline earth metal silicate such as lithium alumina
silicate, barium silicate, strontium silicate, barium borosilicate,
strontium silicate, barium borosilicate, strontium borosilicate,
borosilicate, as well as the aforementioned materials. For purposes
of illustration, and as the preferred silicate species, barium
borosilicate will hereinafter be employed as being typical of the
alkali metal or alkaline earth metal silicates which can be
suitable employed in the present invention. The barium borosilicate
exhibits an index of refraction close to that of the organic
monomeric matrix in which it is dispersed. The filler can
additionally contain a relatively small amount of borosilicate
glass which imparts greater compressive strength to the resulting
composite and enhances the translucency thereof thereby enabling
better blending of the restorative material with the adjacent
teeth. In addition, the presence of the borosilicate glass helps
narrow the gap in the mismatch of refractive indices between the
barium borosilicate inorganic fiber phase and the organic monomeric
matrix.
[0042] Details of the preparation of the inorganic filler, which
comprises a mixture of from about 5 to about 20% by weight of
borosilicate glass and form about 80 to about 95% by weight barium
borosilicate, and has an average particle size diameter of from
about 0.5 to about 5 microns, can be found in the aforementioned
U.S. Pat. Nos. 4,544,539 and 4,547,531.
[0043] The reinforcing fiber element of the fiber-reinforced
composite preferably comprises glass, carbon, graphite, polyaramid,
or other fibers known in the art, such as polyesters, polyamides,
and other natural and synthetic materials compatible with the
polymeric matrix. Some of the aforementioned fibrous materials are
disclosed in commonly assigned copending U.S. Pat. Application Ser.
Nos. 08/907,177, 09/059,492, 60/055,590, 08/951,414 and U.S. Pat.
Nos. 4,717,341 and 4,894,012 all which are incorporated herein by
reference. The fibers may further be treated, for example,
chemically or mechanically etched and/or silanized, to enhance the
bond between the fibers and the polymeric matrix. The fibers
preferably take the form of long, continuous filaments, although
the filaments may be as short as 0.1 to 4 millimeters. Shorter
fibers of uniform or random length might also be employed.
Preferably, the fibers are at least partially aligned and oriented
along the longitudinal dimensions of the wire. However, depending
on the end use of the composite material, the fibers may also be
otherwise oriented, including being normal or perpendicular to that
dimension. The fibrous element may optionally take the form of a
fabric. Fabric may be of the woven or non-woven type and is
preferably preimpregnated with a polymeric material as set forth
above. Examples of suitable woven fabric materials include but are
not limited to those known in the art such as E glass and S glass
fabrics and reinforcement fabrics sold by NFGS Inc. of New
Hampshire under the style numbers 6522 and 7581. One preferred
non-woven fabric material is available under the name Glass Tissue
(20103A) from Technical Fibre Products Ltd. of Slate Hill, N.Y. The
fibrous component may be present in the fiber reinforced composite
material in the range from about 20% to about 85%, and more
preferably between about 30% to about 65% by weight.
[0044] Fabric may also be combined with the fiber-reinforced
composite material to produce a high strength appliance. Fabric may
be of the woven or non-woven type as discussed above and is
preferably preimpregnated with a polymeric material. Suitable
polymeric materials are those listed above as polymeric matrix
materials. In accordance with one embodiment of the present
invention, the fiber-reinforced polymeric composite material is
preformed into structural components to provide ready-to-use units
for use in the fabrication of dental appliances. The structural
components are formed into any known shape(s) useful in the
fabrication of a dental appliance or restoration. Preferably, the
structural components are in the shape of bars or pontics. The
pontics have interproximal extensions and may be single unit or
multiple unit useful in the fabrication of frameworks for bridges.
The bars and pontics may be straight or curved depending on the end
use. The structural components may be "ready-to-use" for immediate
use in the fabrication of a dental appliance or restoration or may
be further modified, for example by cutting, carving or grinding
prior to using in the fabrication of a dental appliance or
restoration.
[0045] FIG. 1 shows various shapes of bars formed in accordance
with the present invention. FIGS. 1A through 1D depict bars of
square 10, circular 12, rectangular 14 and triangular 16
cross-section, respectively. Structural components in the form of
bars are typically used in the manufacture of dental bridges or
posts. If posts are desired, the cross-sectional dimension of the
post must be narrow enough to fit within the root canal.
[0046] More complicated shapes of preformed structural components
may be formed from the structural bars either manually or
mechanically by carving, cutting, grinding, machining or using
other similar means. The complicated shapes may include pontics of
varying lengths and shapes as noted above and as shown in FIGS. 2,
3 and 5, but are not limited to the specific shapes shown.
Alternatively, the complicated shapes may be formed by pressing
composite material into molds and fully or partially curing into a
hardness sufficient to withstand cutting, carving or machining. In
a preferred embodiment, preformed structural bars are placed within
a series of molds and composite material is filled into the
cavities surrounding the bars to form a single unit pontic 50 as
shown in FIG. 5.
[0047] FIG. 2 shows a multiple unit pontic 20 that may be used in
the preparation of an anterior bridge. FIG. 3 displays a multiple
unit pontic 30 that could be used in the preparation of a
bridge.
[0048] FIG. 4 depicts a series of molds 40 having cavities 42
therein connected to laterally extending thin sections 44. FIG. 6
shows a single mold 60 have a longitudinally extending cavity 62
used to fabricate a long bar that may be cut into smaller sections
after it has cured. In accordance with one process of the present
invention, one or more layers of filled composite material may be
poured into cavities 42. Preferred composite materials are
available from JENERIC/PENTRON Inc., Wallingford, Conn., under the
trademarks FLOW-IT and LUTE-IT. One or more layers of
pre-impregnated woven or nonwoven fabric may be placed on the
composite layer(s). Alternately, the fabric may be first placed in
the cavities 42 and composite material may be deposited thereover.
After the composite and/or fabric is provided in cavities 42,
preformed structural bars 10 may be placed within mold 40 as shown.
More composite material may be used to fill any voids in cavities
42. The material is cured to form a structural component in the
shape of a single unit pontic 50 having a central pontic section 52
and laterally extending arms 52. Preferably, the molded component
is cured to a sufficient hardness whereby it may be machined or
carved to a desired final shape by the technician or dentist during
fabrication of the dental appliance. The molded component may be
partially cured at the time of fabrication and the curing can be
completed at the time of fabrication of the dental appliance or the
molded component may be fully cured at the time of manufacture
thereof. Mold 60 may be used in a similar fashion to molds 40 to
prepare a long bar that may cut into smaller sections after it has
cured.
[0049] In accordance with the invention herein, the composites are
formed into pieces or blocks of fiber-reinforced or
particulate-filled composite material. Commercially available
Fiberkor.RTM. composite available from Jeneric/Pentron Inc.,
Wallingford, Conn. may be used to fabricate the fiber-reinforced
composite blocks and commercially available Sculpture.RTM.
composite from Jeneric/Pentron Inc., Wallingford, Conn. may be used
to fabricate the particulate filled composite blocks. The blocks of
material may be of a variety of shapes and sizes and may be
modified by a variety of methods including but not limited to
machining, carving, cutting, grinding, abrading or etching.
[0050] FIGS. 7, 9 and 11 depict blocks formed in accordance with
the present invention. FIG. 7 shows a cylindrical block, FIG. 9
shows a rectangular block and FIG. 11 shows a square block. FIG. 8
depicts a tooth which has been machined from the block shown in
FIG. 7. FIG. 10 shows a bridge machined from the block in FIG. 9.
FIG. 12 shows a cylinder for use is an implant machined from the
block in FIG. 11.
[0051] The cylinder shown in FIG. 12 can be used in combination
with prefabricated bars of the present invention or may be used
with uncured fiber-reinforced composite material such as
Fiberkor.RTM. available from Jeneric/Pentron Inc., Wallingford,
Conn. An implant may be manufactured with one or all of its
components fabricated from the structural components of the present
invention including but not limited to the abutments, cylinders and
framework. The resulting implant components provide good shock
absorbency. Preferably the implant components are machined out of
blocks fabricated in accordance with the present invention. The
machined blocks may include retentive designs on the eternal
service for proper linkage to create multi-unit bridges or to
reinforce bonding to the overlay composite materials. The implant
superstructure may additionally include pontic components for
proper support of the overlay material. FIG. 13 shows a partial
implant system wherein cylinders 130 and bars 132 are disposed
therebetween to form the superstructure. Cylinders 130 are
preferably machined from blocks made in accordance with the present
invention. Bars 132 are likewise manufactured in accordance with
the present invention.
[0052] FIGS. 14 shows a curved rectangular block formed in
accordance with the present invention. FIG. 15 shows an implant
superstructure 150 which has been machined from the block shown in
FIG. 14. Superstructure 150 comprises cylinders 152 interconnected
with pontic sections 154.
[0053] In accordance with the method of the present invention, the
components may be manufactured on line as part of the fiber
impregnation process or may be molded into shapes after the
impregnation process. In a preferred embodiment of the invention,
components in the form of, for example, bars or blocks may be
manufactured following the process of fiber impregnation with a
matrix material. The bars or blocks are preferably formed under
pressure and undergo either full or partial polymerization to
impart specific properties for specific applications. Long,
continuous bars or blocks may be molded and cured to a hardness
sufficient to withstand cutting, carving or machining and
subsequently cut into the desired lengths at the time of
manufacture or at some point thereafter. The cross-section of the
structural components may be square, rectangular, triangular,
rhomboidal, ovoidal, tapered, cylindrical, or of any other
cross-sectional configuration effective to provide strength and
stiffness to the finished dental appliance. The dimensions may be
of varying lengths, widths and heights and the shades thereof may
be of any shade suitable for dental materials. Coloring agents
known in the art may be added to the polymeric matrix material
prior to curing.
[0054] The components may be used as frameworks or understructures
for crowns, bridges, implant abutment cylinders, implant
superstructures and the like. The framework/understructure can be
made from the structural components in a variety of ways. The
method of fabrication may be manual or automated. In the manual
method, a technician can select a component of, for example,
rectangular shape. The technician cuts the block to proper
dimension and size and carves out the desired anatomical features
using standard laboratory tools.
[0055] To perform the procedure by automated or mechanical means,
an apparatus such as a CAD/CAMming machine is used to automatically
shape the structural component into the form or contour desired.
The component is preferably in the form of a block (also known as a
blank) for CAD/CAMming purposes. The technicians and/or
practitioners collect three dimensional data regarding the final
desired shape of the dental appliance or restoration and machine or
mill the block or blank to achieve the final desired shape. The
data may be collected from actual teeth, implants, etc. or from
models or prefabricated frameworks (of wax, duralay, etc.) prepared
on teeth or stone models or from an impression taken of the tooth
or teeth to be corrected by using a scanning device such as the
Pro-Scan.TM. device available from IntraTech in Irving, Tex. The
data may be used as is or may be modified using computer software.
Based on the data, the blank is machined via CAM to a
three-dimensional dental appliance or material. The CAD/CAM process
may be performed at one location or the CAD data may be transferred
via modem or electronic transmission to another location where
computer assisted machining or milling is performed. The machined
part may be further modified or treated with for example, a surface
treatment such as abrasion, etching, or silanation, or with a
special bonding agent. Additionally, the machined part can be
joined with other preimpregnated fiber-reinforced materials prior
to being overlaid with a coating or veneer. The veneer may be a
particulate-filled composite material such as commercially
available Sculpture.RTM. material available from Jeneric/Pentron
Inc., Wallingford, Conn. and is preferably applied to the machined
or manually carved part to provide the final anatomy. The finished
appliance or restoration can either be bonded or mechanically
anchored. Bonding is the preferred fastening means.
[0056] The prefabricated, preshaped cured components of the present
invention can substantially eliminate operator induced errors,
greatly save time and enhance overall properties and longevity of
final restorations. For implant restorations, replacement of the
rigid (high modulus) metal components with a lower modulus material
of the fiber-reinforced composite structural components, improves
shock absorption.
[0057] As will be appreciated, the present invention provides
preshaped, prefabricated cured components having optimum strength.
The components may be ready-to-use structural components,
structural components which may or may not be further modified
prior to use, or components which must be further modified prior to
use. The components are provided of varying shapes and sizes
offering many options to the technician or practitioner in the
fabrication of dental appliances. Due to the many different shapes,
sizes and contours of teeth, a kit may be provided including
ready-to-use structural components in the shape of pontics and bars
of varying configurations and sizes to offer the technician and
practitioner options with which to construct dental appliances.
Accordingly, custom made dental appliances can be easily fabricated
using the ready-to-use structural components. The ready-to-use
components may be further modified prior to fabrication of a dental
appliance or restoration. Kits may also be provided with component
blocks of varying shapes, sizes and colors offering many options to
the technician and practitioner.
[0058] While various descriptions of the present invention are
described above, it should be understood that the various features
can be used singly or in any combination thereof Therefore, this
invention is not to be limited to only the specifically preferred
embodiments depicted herein.
[0059] Further, it should be understood that variations and
modifications within the spirit and scope of the invention may
occur to those skilled in the art to which the invention pertains.
Accordingly, all expedient modifications readily attainable by one
versed in the art from the disclosure set forth herein that are
within the scope and spirit of the present invention are to be
included as further embodiments of the present invention. The scope
of the present invention is accordingly defined as set forth in the
appended claims.
* * * * *