U.S. patent application number 11/906244 was filed with the patent office on 2011-04-07 for methods for making provisional and long-term dental crowns and bridges.
Invention is credited to Andrew M. Lichkus, Benjamin Jiemin Sun, Andrew Mathias Young.
Application Number | 20110081627 11/906244 |
Document ID | / |
Family ID | 38917393 |
Filed Date | 2011-04-07 |
United States Patent
Application |
20110081627 |
Kind Code |
A1 |
Sun; Benjamin Jiemin ; et
al. |
April 7, 2011 |
Methods for making provisional and long-term dental crowns and
bridges
Abstract
The invention provides methods of making provisional and
long-term dental restorations, particularly dental veneers, crowns
and bridges. In one embodiment, the restoration can be fabricated
indirectly by a dental laboratory. In another version, a dental
practitioner can make the restoration chairside for a patient in a
dental office. A polymerizable dental composite material, which is
dimensionally shape-stable in its uncured state, is used to make
the restoration. A substructure such as a metal coping can be used
to support the polymerizable material. The material includes a
polymerizable acrylic compound, polymerization initiator system
capable of being activated by light or heat, and preferably a
filler material. The resulting dental restoration has good
aesthetics, mechanical strength, and margins and contacts.
Inventors: |
Sun; Benjamin Jiemin; (York,
PA) ; Young; Andrew Mathias; (Dallastown, PA)
; Lichkus; Andrew M.; (York, PA) |
Family ID: |
38917393 |
Appl. No.: |
11/906244 |
Filed: |
October 1, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60848117 |
Sep 29, 2006 |
|
|
|
Current U.S.
Class: |
433/199.1 ;
433/223 |
Current CPC
Class: |
A61C 19/003 20130101;
A61C 13/0003 20130101; A61C 13/20 20130101; A61C 5/77 20170201;
Y10T 29/49567 20150115 |
Class at
Publication: |
433/199.1 ;
433/223 |
International
Class: |
A61C 5/10 20060101
A61C005/10; A61C 13/003 20060101 A61C013/003 |
Claims
1. A method of forming a dental restoration, comprising the steps
of: dispensing a heated polymerizable material into a matrix;
positioning the matrix over an area of a pre-formed dental model
that will receive the restoration and allowing the polymerizable
material to cool so as to form a dimensionally shape-stable,
uncured restoration; removing the matrix while maintaining the
uncured restoration seated on the model; irradiating the
polymerizable material with light so that it fully cures and forms
a hardened restoration; and removing the cured restoration from the
model.
2. The method of claim 1, wherein the polymerizable material
comprises: polymerizable acrylic compound; and polymerization
initiation system, capable of being activated by light or heat, for
polymerizing the material.
3. The method of claim 2, wherein the polymerizable acrylic
compound of the material is a semi-crystalline material.
4. The method of claim 2, wherein the polymerization initiation
system of the material comprises a photoactive agent.
5. The method of claim 2, wherein the polymerizable material
further comprises particulate filler.
6. The method of claim 5, wherein the filler material is selected
from the group of inorganic and organic materials and mixtures
thereof.
7. A method of making a dental restoration having a supporting
substructure on a dental model of a patient's dental anatomy,
comprising the steps of: placing a supporting substructure over a
targeted area on the dental model that will receive the
restoration; dispensing a heated polymerizable material into a
matrix; positioning the matrix over the supporting substructure and
allowing the polymerizable material to cool so as to form a
dimensionally shape-stable uncured restoration; removing the matrix
from the model while maintaining the uncured restoration seated on
the model; irradiating the polymerizable material with light so
that it fully cures and forms a hardened restoration; and removing
the cured restoration from the model.
8. The method of claim 7, wherein the substructure is a metallic
material.
9. The method of claim 8, wherein a metal primer coating is applied
to the substructure prior to placing the substructure on the
model;
10. The method of claim 9, wherein an opaque coating is applied
over the metal primer coating and the coated substructure is
light-cured prior to placing the substructure on the model.
11. The method of claim 7, wherein the substructure is a ceramic
material.
12. The method of claim 11, wherein the ceramic material is
zirconia.
13. The method of claim 7, wherein the substructure is a
fiber-reinforced composite.
14. The method of claim 7, wherein the polymerizable material
comprises: polymerizable acrylic compound; and polymerization
initiation system, capable of being activated by light or heat, for
polymerizing the material.
15. The method of claim 14, wherein the polymerizable material
further comprises particulate filler.
16. A method of forming a dental restoration, comprising the steps
of: dispensing a heated polymerizable material into a hardened
dental impression of a patient; positioning the impression
containing the polymerizable material in the mouth of a patient so
the composite material is molded over a targeted area that will
receive the restoration and allowing the material to cool so as to
form a dimensionally shape-stable, uncured restoration; removing
the impression containing the polymerizable material from the
mouth; and irradiating the restoration with light so that it fully
cures and forms a hardened restoration.
17. The method of claim 16, wherein the uncured restoration is
maintained within the impression material prior to being irradiated
with light.
18. The method of claim 16, wherein the uncured restoration is
removed from the impression material prior to being irradiated with
the light.
19. The method of claim 16, wherein the uncured restoration is
placed back inside of the mouth after it has been removed from the
impression material and prior to being irradiated with light so
that the patient can bite down and the fit of the restoration can
be checked.
20. The method of claim 16, wherein the polymerizable material
comprises: polymerizable acrylic compound; and polymerization
initiation system, capable of being activated by light or heat, for
polymerizing the material.
21. The method of claim 20, wherein the polymerizable material
further comprises particulate filler.
22. The method of claim 16, wherein the uncured restoration is
irradiated with light while it is positioned inside of the mouth so
that it partially cures.
23. A method of forming a dental restoration, comprising the steps
of: dispensing a heated polymerizable material into a hardened
dental impression of a patient; placing the impression containing
the polymerizable material in the mouth of a patient so that the
material is molded over a targeted area that will receive the
restoration and allowing the material to cool so as to form a
dimensionally shape-stable, uncured restoration; removing the
impression from the mouth while leaving the shape-stable, uncured
restoration over the targeted area inside of the mouth so that the
restoration can be fitted; and removing the restoration from the
mouth and irradiating it with light so that it fully cures and
forms a hardened restoration.
24. The method of claim 23, wherein the patient bites down prior to
removing the uncured restoration from the mouth so that the fit of
the restoration can be checked.
25. The method of claim 23, wherein the uncured restoration is
irradiated with light while it is positioned inside of the mouth so
that it partially cures.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application 60/848,117 having a filing date of Sep. 29,
2006, the entire contents of which are hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to methods for
making provisional and long-term dental crowns, bridges, inlays,
onlays, veneers, implants, and other dental restorations. A
polymerizable composite resin having good dimensional
shape-stability is used to make the dental restoration. A
substructure such as a metal coping, ceramic substructure, or
fiber-reinforced polymeric substructure can be used to support the
polymerizable material. In one method, the restoration can be
fabricated indirectly by a dental laboratory and sent to a dentist
for placing in the mouth of a patient. In another version, the
dentist can make the restoration in the dental office directly. The
restoration can be made while the patient is sitting in the dental
chair.
[0004] 2. Brief Description of the Related Art
[0005] Dental restorations, such as crowns and bridges, are used to
restore or replace lost tooth structure, teeth, or oral tissue.
Provisional (or temporary) restorations are intended to be used for
a relatively short time. For example, a dentist will often use a
provisional crown, until a permanent crown is ready to be placed in
the mouth of a patient. Following one conventional procedure, the
dentist makes the provisional crown for the patient at the dental
office and a dental laboratory makes the permanent crown. The
dentist mounts the provisional crown to protect the tooth while the
permanent crown is being made. Later, the dentist removes the
provisional crown and replaces it with the permanent crown.
[0006] The provisional crown typically is made from a polymeric
material such as an acrylic. In one method used to prepare a
provisional crown, a polymerizable material is placed in a
pre-formed impression or matrix which then is inserted into the
patient's mouth. The polymerizable material is molded over the
prepared tooth structure by pressing the impression thereon. Then,
the impression containing the molded material, which may only be
partially-cured at this point, is removed from the patient's mouth.
The molded material is fully cured by a self (chemical)-curing,
light-curing, or heat-curing mechanism, which may occur outside of
the mouth, to form the ultimate provisional crown. Finally, the
dental practitioner places the provisional crown over the prepared
tooth and bonds the crown to the tooth using temporary dental
cement. The provisional crown helps maintain the health and
function of the tooth while a dental laboratory manufactures the
permanent crown. At a subsequent office visit, the dentist removes
the provisional crown and checks the color, occlusion, and fit of
the permanent crown. If satisfactory, the dentist affixes the
permanent crown to the tooth using permanent dental cement.
[0007] Dental compositions containing polymerizable resins and
filler particles often are used to prepare the provisional crowns,
bridges, and other restorations. Such dental compositions can be
self (chemically)-curable, light-curable, or dual-curable. The
dental compositions are cured and hardened by different chemical
mechanisms to form a strong and durable material. In one example, a
dentist uses a self-curing composition, which is prepared from two
paste components. One component used to make the composition is a
base paste and the other component is a catalyst paste. The base
paste typically contains polymerizable monomers such as
methacrylate or acrylate monomers; a free-radical polymerization
accelerator such as a tertiary amine; and fillers such as silica,
glasses, or alumina. Meanwhile, the catalyst paste typically
includes a polymerizable monomer, a free-radical polymerization
initiator such as dibenzoyl peroxide, and fillers. To prepare the
composition, the amine-containing base and peroxide-containing
catalyst pastes are combined and mixed together. As the pastes are
mixed together, the catalyst system (amine and peroxide) react with
each other and initiate polymerization and hardening of the
composition. The polymerization process involves a reaction between
the reducing agent (amine) and oxidizing agent (peroxide). This
mechanism is commonly referred to as a redox mechanism.
[0008] Compositions that can be used to make temporary crown and
bridges are described generally in the patent literature. For
example, Tateosian et al., U.S. Pat. No. 5,554,665 discloses a
dental composition that is formed by the static mixing of two
complementary pastes. A catalyst paste includes a polymerizable
methacrylate, a peroxide, and a stabilizer such as butylated
hydroxytoluene. The stabilizer is effective at preventing
polymerization for at least 180 days at 23.degree. C. A
complementary accelerator and radiation-cure initiator paste
includes a polymerizable methacrylate and a reducing agent for the
peroxide such as dihydroxyethyl-p-toluidine. According to the '665
patent, the paste compositions preferably have substantially the
same viscosity and are mixed in a volume ratio between 1:1 and
1:5.
[0009] Xie, U.S. Pat. No. 5,977,199 discloses a delivery system for
delivering dental cement material for making temporary crowns and
bridges. A catalyst paste and base paste are dispensed from a dual
cartridge and mixed in a static mixer to form a polymerizing
material. The catalyst paste comprises at least one polymerizable
monomer, polymerization initiator, polymerization inhibitor, and
filler. The base paste comprises at least one polymerizable
monomer, at least one polymerization accelerator, polymerization
inhibitor, and filler. According to the '199 patent, the viscosity
of the catalyst paste must be substantially greater than the
viscosity of the base paste in order for the mixture to cure
effectively.
[0010] Methods for making permanent crown, bridges, and other
restorations having a metal coping or other supporting substructure
are also known in the art. The metal copings are often covered with
polymer-based materials. The metal copings support the
polymer-based veneering layer and provide the required structural
strength and toughness for the restoration to survive the long term
forces of mastication. Polymer-based materials typically consist of
polymerizable resins and filler particles. Such dental compositions
can be self (chemically)-curable, light-curable, or dual-curable.
The dental compositions are cured and hardened by different
chemical mechanisms to form a strong and durable material. For
example, Delahaye, U.S. Pat. No. 5,697,785 discloses a dental
prosthesis containing a metal support with at least one
reconstruction mass (polymeric binder containing inorganic filler
dispersed therein) having sufficient bending strength and hardness
is fixed to the metal support. One shortcoming with such
conventional dental prosthetics is that the polymeric material,
which is fixed to the metal support, can have shape instability
while it is uncured. The material can change shape or slump
somewhat while it is in an uncured condition.
[0011] Conventional provisional (temporary) dental restorations are
used by patients for a relatively short period of time. As
discussed above, the provisional crown is used by the patient while
a permanent crown is made. Today, provisional crowns and bridges
typically are used by a patient for a period of about three to six
months. In general, such provisional restorations are effective,
but there is a need in the dental field for restorations that can
be used for longer periods.
[0012] The present invention provides methods for making such
dental restorations. A dental practitioner can use the resulting
dental restoration as a provisional expecting that it will remain
in the patient's mouth for a time period of about 1 to about 12
months. On the other hand, if the dental practitioner wishes to use
the dental restoration as a long-term product, expecting that it
will remain in the patient's mouth for a period of time longer than
about 12 months, he or she can do so. The dental restorations of
this invention can be used as either provisional or long-term
dental products because of their advantageous properties.
Particularly, the restorations are strong and durable and do not
break or fracture easily. Because of their mechanical strength, the
restorations can withstand hard occlusion forces. In addition, the
restorations have pleasing aesthetics matching the shade of natural
teeth. Moreover, the restorations have good margins and
interproximal contacts, providing the patient with comfort while
promoting dental health. The restoration covers and supports the
tooth structure sufficiently so that it protects the tooth's pulpal
portion.
[0013] One object of the present invention is to provide a method
that a dental laboratory can use to make dental crowns, bridges,
inlays, onlays, veneers, implants, and other dental restorations
having good mechanical strength, aesthetics, and occlusal fit. The
restorations can be made with a supporting substructure such as a
metal coping.
[0014] Another object of this invention is to provide a method that
a dental practitioner can use to design and fabricate the crown,
bridge, or other dental restoration "chairside." This would help
make the crown manufacturing and fitting process less
time-consuming and costly. The dentist may be able to mount the
crown on the patient's tooth in a single office visit.
[0015] These and other objects, features, and advantages of this
invention are evident from the following description and
illustrated embodiments.
SUMMARY OF THE INVENTION
[0016] This invention provides methods for making provisional and
long-term dental crowns, bridges, inlays, onlays, veneers,
implants, and other dental restorations. In one version, a dental
laboratory can make the restoration. This method involves
dispensing a heated polymerizable material into a matrix and
positioning the matrix over an area of a pre-formed dental model
that will receive the restoration. The material may comprise
polymerizable acrylic compound, polymerization system capable of
being activated by light or heat for polymerizing the composition,
and filler material. A substructure such as a metal coping, ceramic
substructure, or fiber-reinforced polymeric substructure can be
used to support the polymerizable material.
[0017] The material, which is preferably a composite material
containing filler particulate, is allowed to set and cool and form
a dimensionally shape-stable uncured restoration on the dental
model. The matrix is then removed, while the composite material, in
the shape of the restoration, remains seated on the model. Light is
used to irradiate the composite material so that it cures and forms
a hardened restoration directly on the model. Finally, the
restoration is removed, finished, and polished. A visible
light-curing sealant can be applied to provide a stain-resistant
and glossy surface finish to the restoration if desired. The
restoration is now ready to be mounted on a patient's tooth.
[0018] In another embodiment, a dental practitioner can make the
dental restoration in the dental office. The restoration can be
made while the patient is sitting in the dental chair. This method
involves dispensing a heated polymerizable composite material into
a hardened dental impression. The same composite material as
described above can be used in this method. The practitioner
positions the impression containing the composite material in the
mouth of a patient so the material is molded over the targeted area
that will receive the restoration. The material is allowed to cool
and form a dimensionally shape-stable, uncured restoration. The
impression containing the composite material is removed from the
mouth. Then, the restoration is irradiated with light so that it
cures and hardens. The restoration can be maintained within the
impression material while it is being light-cured. Alternatively,
the restoration can be removed from the impression material before
it is light-cured.
[0019] Another chairside method involves removing the impression
from the mouth, while leaving the shape-stable, uncured restoration
over the targeted area inside of the mouth so that the restoration
can be fitted. Then, the restoration is removed from the mouth and
irradiated with light so that it cures and hardens. If desired, the
uncured restoration can be irradiated with light while it is
positioned in the mouth so that it partially cures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The present invention relates to methods of making dental
crowns, bridges, inlays, onlays, veneers, implants, and other
dental restorations using a polymerizable material having good
dimensional stability. In one embodiment, the restoration can be
fabricated indirectly by a dental laboratory and sent to a dentist
for placing in the mouth of a patient. In another version, the
dentist can make the restoration at a patient chair in the dental
office.
[0021] The polymerizable material used in accordance with this
invention comprises a polymerizable acrylic compound and
polymerization initiation system, capable of being activated by
light or heat for polymerizing the composition. Preferably, the
polymerizable material is a composite material containing filler
particulate. By the term, "composite material" as used herein, it
is meant that the material contains at least a portion of
particulate filler. The polymerizable material and restorations
prepared from such materials have certain properties as defined
below.
[0022] The polymerizable dental materials of the invention
preferably include from about 0.1 to about 100 percent by weight of
a crystalline resin and from about 0 to 100 percent by weight of an
amorphous component. When heated, the polymerizable dental
materials soften and are more flowable and have less crystallinity.
The polymerizable materials can rapidly solidify. Rapid
solidification provides the materials with a combination of
flowable and dimensional stability properties, depending upon
temperature prior to polymerization. Furthermore, in a preferred
embodiment, the polymerizable materials can partially recrystallize
rapidly. This ability to rapidly recrystallize helps densify the
polymeric products and provides the products with flowable and
dimensional stability properties, depending upon temperature prior
to polymerization. The polymerizable materials have several
different characteristics, particularly that of: (i) flowable
dental composites at elevated temperatures; ii) of packable
composites at lower temperatures as the material cools down; and
iii) of wax-like dental composites at room temperature and body
temperature. The polymerizable material includes a portion of
crystals that melts during polymerization. It is believed that this
crystalline portion includes crystals of oligomer and/or crystals
of monomer. The volume of liquid formed by melting the crystals is
greater than the volume of crystals. This expansion reduces the
shrinkage of the polymerizable dental material caused by
polymerization.
[0023] "Crystallinity" as used herein refers to regularity and
order within a material resulting in a heat of fusion of at least
1.0 J/g at and below 50.degree. C. "Heat of Fusion" as used herein
refers to enthalpy of fusion as determined by ASTM 793-95. Percent
crystallinity is determined by measuring the heat of fusion using
differential scanning calorimetry according to ASTM test method E
793-95.
[0024] "High strength dental polymeric material" as used herein
means a material having flexural modulus of at least 200,000 psi
and flexural strength of at least 5,000 psi. More preferably, the
material has flexural modulus of at least 300,000 psi and flexural
strength of at least 8,000 psi. Most preferably, the material has
flexural modulus of at least 400,000 psi and flexural strength of
at least 12,000 psi. The flexural strength and flexural modulus
properties are measured according to ASTM D790 (1997).
[0025] "Wax-like" as used herein refers to material which is
flowable (fluid) at and above 40.degree. C., and becomes
dimensionally stable (solidifies, that is, becomes non-fluid) at
least at and below 23.degree. C., within 5 minutes. Thus, wax-like
material is flowable when it is at a temperature of 40.degree. C.
and greater, and becomes dimensionally stable when it is at a
temperature of 23.degree. C. and lower. Flowable wax-like material
having a temperature from 100.degree. C. to 40.degree. C., becomes
dimensionally stable within 5 minutes upon cooling by exposing it
to ambient temperature between 37.degree. C. and 0.degree. C.
Flowable wax-like composite paste having a temperature from
100.degree. C. to 40.degree. C., becomes dimensionally stable
within (in order of increasing preference) 4, 2, 1 or 0.5 minutes
upon cooling by exposing it to ambient temperature between
23.degree. C. and 0.degree. C.
[0026] "Dimensional stability" as used herein refers to material
which is shape-stable as determined by testing methods according to
ADA (American Dental Association) consistency test specification
19, Paragraph 4.3.4 (23.degree. C.), JAVA Vol. 94, April, 1977,
pages 734-737.
Polymerizable Material
Polymerizable Acrylic Compounds
[0027] Polymerizable acrylic compounds that can be used in the
composition of this invention, include, but are not limited to,
mono-, di- or poly-acrylates and methacrylates such as methyl
acrylate, methyl methacrylate, ethyl acrylate, isopropyl
methacrylate, n-hexyl acrylate, stearyl acrylate, allyl acrylate,
glycerol diacrylate, glycerol triacrylate, ethyleneglycol
diacrylate, diethyleneglycol diacrylate, triethyleneglycol
dimethacrylate, tetraethylene glycol di(meth)acrylate,
1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate,
trimethylolpropane tri(meth)acrylate, 1,2,4-butanetriol
trimethacrylate, 1,4-cyclohexanediol diacrylate,
1,4-cyclohexanediol dimethacrylate, 1,6-hexanediol
di(meth)acrylate, pentaerythritol triacrylate, pentaerythritol
tetraacrylate, pentaerythritol tetramethacrylate, sorbitol
hexacrylate,
2,2-bis[4-(2-hydroxy-3-acryloyloxypropoxy)phenyl]propane;
2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane
(Bis-GMA); modified Bis-GMA (the reaction product of Bis-GMA and
1,6 diisocyanatohexane);
2,2-bis[4-(acryloyloxy-ethoxy)phenyl]propane;
2,2-bis[4-(methacryloyloxy-ethoxy)phenyl]propane (or ethoxylated
bisphenol A-dimethacrylate) (EBPADMA); urethane di(meth)acrylate
(UDMA), diurethane dimethacrylate (DUDMA), polyurethane
dimethacrylate (PUDMA); 4,13-dioxo-3,14
dioxa-5,12-diazahexadecane-1,16-diol diacrylate; 4,13-dioxo-3,14
dioxa-5,12-diazahexadecane-1,16-diol dimethacrylate; the reaction
product of trimethyl 1,6-diisocyanatohexane and bisphenol A
propoxylate and 2-hydroxyethyl methacrylate (TBDMA); the reaction
product of 1,6 diisocyanatohexane and 2-hydroxyethyl methacrylate
modified with water (HDIDMA); the reaction product of 1,6
diisocyanatohexane and 2-hydroxyethyl acrylate modified with water
(HDIDA); alkoxylated pentacrythritol tetraacrylate; polycarbonate
dimethacrylate (PCDMA); the bis-acrylates and bis-methacrylates of
polyethylene glycols; and copolymerizable mixtures of acrylated
monomers and acrylated oligomers.
[0028] In addition to the foregoing polymerizable acrylic
compounds, the composition may contain acidic monomers such as
dipentaerythritol pentacrylate phosphoric acid ester (PENTA);
bis[2-(methacryloxyloxy)-ethyl]phosphate; and vinyl compounds such
as styrene, diallyl phthalate, divinyl succinate, divinyl adipate
and divinylphthalate. Diluent polymerizable monomers also may be
added to the composition. For example, hydroxy alkyl methacrylates,
ethylene glycol methacrylates, and diol methacrylates such as
tri(ethylene glycol) dimethacrylate (TEGDMA) may be added to reduce
viscosity and make the composition more suitable for application. A
polymerizable acrylic compound can be used alone in the composition
or mixtures of the compounds can be used. Mixtures of polymerizable
monomers and oligomers, as described in the Examples below, are
particularly preferred.
Polymerization System
[0029] A polymerization system can be used in the composition of
this invention, which initiates polymerization (hardening) of the
composition by a light-curable or heat-curable reaction. In one
embodiment, a photoactive agent such as, for example, benzophenone,
benzoin and their derivatives, or alpha-diketones and their
derivatives is added to the composition in order to make it
light-curable. A preferred photopolymerization initiator is
camphorquinone (CQ). Photopolymerization can be initiated by
irradiating the composition with blue, visible light preferably
having a wavelength in the range of about 380 to about 500 nm. A
standard dental blue light-curing unit can be used to irradiate the
composition. The camphorquinone (CQ) compounds have a light
absorbency maximum of between about 400 to about 500 nm and
generate free radicals for polymerization when irradiated with
light having a wavelength in this range. Photoinitiators selected
from the class of acylphosphine oxides can also be used. These
compounds include, for example, monoacyl phosphine oxide
derivatives, bisacyl phosphine oxide derivatives, and triacyl
phosphine oxide derivatives. For example,
2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO) can be used
as the photopolymerization initiator. In one embodiment, a material
referred to as "ALF" comprising camphorquinone (CQ); butylated
hydroxytoluene (BHT); N,N-dimethylaminoneopentyl acrylate, and
methacrylic acid can be used in the composition.
[0030] In another embodiment, heat-activated polymerization
initiators, such as peroxides, can be added to make the composition
heat-curable. The peroxides generate free radicals to initiate
polymerization and hardening of the composition at elevated
temperature. Peroxides such as dibenzoyl peroxide (BPO),
di-p-chlorobenzoyl peroxide, di-2,4-dichlorobenzoyl peroxide,
tertiary butyl peroxybenzoate, methyl ethyl ketone peroxide,
ditertiary butyl peroxide, dicumyl peroxide and cumene
hydroperoxide, and the like can be used.
[0031] In addition to the photoactive and heat activated agents,
the composition may include a polymerization inhibitor such as, for
example, butylated hydroxytoluene (BHT); hydroquinone; hydroquinone
monomethyl ether; benzoquinone; chloranil; phenol; butyl
hydroxyanaline (BHT); tertiary butyl hydroquinone (TBHQ);
tocopherol (Vitamin E); and the like. Preferably, butylated
hydroxytoluene (BHT) is used as the polymerization inhibitor. The
polymerization inhibitors act as scavengers to trap free radicals
in the composition and to extend the composition's shelf life.
Fillers
[0032] Conventional filler materials, including reactive and
non-reactive fillers, may be added to the composition. Reactive
fillers include metal oxides and hydroxides, metal salts, and
glasses that are acid-reactive. Such fillers are commonly used in
dental ionomer cements. Examples of metal oxides include, but are
not limited to, barium oxide, calcium oxide, magnesium oxide, and
zinc oxide can be used. Examples of metal salts include, but are
not limited to, aluminum acetate, aluminum chloride, calcium
chloride, magnesium chloride, zinc chloride, aluminum nitrate,
barium nitrate, calcium nitrate, magnesium nitrate, and strontium
nitrate. Suitable glasses include, but are not limited to, borate
glasses, phosphate glasses, and fluoroaluminate glasses. The
glasses may or may not have fluoride-releasing properties. The
benefits of using fluoride-releasing glasses are well known. Such
materials are capable of releasing fluoride into the oral cavity
over the long term. Fluoride generally provides added protection
against acid attack that can cause tooth decay. Although, such
fluoride-releasing glasses are generally not used in temporary
dental restorations, since such restorations are intended for
short-term use only. Organic particles such as poly(methyl
methacrylate), poly(methyl/ethyl methacrylate), crosslinked
polyacrylates, polyurethanes, polyethylene, polypropylene,
polycarbonates and polyepoxides, and the like also can be used as
fillers.
[0033] A wide variety of non-acid reactive filler materials
including nano-particles also can be added to the composition.
Inorganic fillers, which can be naturally-occurring or synthetic,
can be added. Such materials include, but are not limited to,
silica, titanium dioxide, iron oxides, silicon nitrides, glasses
such as calcium, lead, lithium, cerium, tin, zirconium, strontium,
barium, and aluminum-based glasses, borosilicate glasses, strontium
borosilicate, barium silicate, lithium silicate, lithium alumina
silicate, kaolin, quartz, and talc. Preferably, the silica is in
the form of silanized fumed silica. A preferred glass filler is
silanized barium boron aluminosilicate.
[0034] The average particle size of the particles comprising the
filler material is normally in the range of about 0.1 to about 10
microns and more preferably in the range of about 0.1 to about 5
microns. If a fumed silica filler material is used, the silica
particles are preferably nanometer-sized. Other nano-sized
particles can be used in the compositions. The silica particles and
nano-particles preferably have an average diameter of less than 200
nm. The filler particles can be surface-treated with a silane
compound or other coupling agent to improve bonding between the
particles and resin matrix. Suitable silane compounds include, but
are not limited to, gamma-methacryloxypropyltrimethoxysilane,
gamma-mercaptopropyltriethoxysilane,
gamma-aminopropyltrimethoxysilane, and combinations thereof.
[0035] In one preferred embodiment, the composition comprises about
5 to about 15 wt. % TBDMA; about 3 to about 10 wt. % HDIDMA; about
1.5 to about 5 wt. % HDIDA; about 5 to about 10 wt. % UDMA; about 5
to about 10 wt. % EBPADMA; about 0 to about 0.5 wt. % TPO; about
0.1 to about 1.0 wt. % ALF and about 50 to about 80 wt. % filler
material (silicon dioxide/glass). In another embodiment, the
composition is substantially free of the ALF activator.
[0036] In yet another preferred embodiment, the composition
comprises about 0 to about 10 wt. % TBDMA; about 3 to about 15 wt %
modified Bis-GMA, about 2 to about 10 wt. % HDIDMA; about 0 to
about 5 wt. % HDIDA; about 0 to about 10 wt. % UDMA; about 0 to
about 10 wt. % EBPADMA; about 0 to about 0.5 wt. % TPO; about 0.1
to about 1.0 wt. % ALF and about 50 to about 80 wt. % filler
material (silicon dioxide/glass). These compositions were
formulated to match the Refractive Index (RI) of the fillers used
so as to obtain optimum translucency in the cured compositions. The
matched RI of the components enabled the fabrication of translucent
enamel layers and provided superior esthetics.
[0037] TBDMA is added to the composition in the form of semi-solid
high molecular weight oligomers. The addition of TBDMA provides the
composite with good toughness and strength, good handling
properties and adjusts the Refractive Index (RI) of the composite
material to provide the desired translucency. HDIDMA and HDIDA are
added as solid, semi-crystalline monomers. The H.sub.2O modified
HDIDMA and HDIDA also provides a reduced crystallization time.
Modified Bis-GMA, UDMA and EBPADMA are added as liquids in order to
adjust filler load and softness at uncured stage and increase the
flowability of the composite material. They also can further adjust
the RI of the cured composite material, while assisting in
decreasing the cure time. Lucirin-TPO and ALF are photoinitiators
that initiate the polymerization of the monomers and oligomers and
provide a relatively short cure time. Pigments are used to adjust
the shade of the composite. The filler materials provide the
composition with beneficial handling and mechanical properties.
[0038] As described further below, the composite material used in
the method of this invention is dimensionally stable when it is in
its uncured state. The composite material, with its
semi-crystalline components as described above, forms a hard,
non-sticky surface layer upon being crystallized. The
semi-crystalline components are partially recrystallizable and help
the material to rapidly solidify. When polymerized, the
crystallized phase melts effectively resulting in volume expansion,
which offsets polymerization shrinkage somewhat. The resulting
polymeric material has low shrinkage and stress.
[0039] The above-described composition can be used to fabricate
dental crowns, bridges, inlays, onlays, veneers, implants, and
other dental restorations. Although the method of this invention is
described primarily below as a method for making a dental crown, it
should be understood that the method can be used to make any
desired dental restoration.
Methods
Indirect Dental Laboratory Method
[0040] In one method for making the dental crown, which can be
referred to as an indirect dental laboratory method, the dentist
first takes an initial impression of the patient's entire dental
anatomy including the tooth that will receive the crown using
conventional impression-forming techniques.
[0041] The impression material is normally prepared from two paste
components. At least one of the paste components contain an
elastomeric material such as vinyl terminated polysiloxanes capable
of undergoing addition polymerization. Once the pastes are mixed
together, they start to harden and form a rubbery material. The
dentist dispenses the impression material into a bite tray and
inserts the tray into a patient's mouth. The patient bites down on
the impression material in the tray. Then, the tray is removed from
the mouth and the impression material is allowed to cure and
harden. A negative impression of the teeth, including the
unprepared tooth that will receive the crown, and surrounding gum
tissue is formed.
[0042] In some cases, the dentist will prepare the tooth that will
receive the crown during this office visit. The dentist performs
"crown prep" work on the tooth by filing and grinding it to a
"core" or "stump." A high-speed or low-speed handpiece equipped
with a diamond bur is used to grind the tooth. The dentist then
takes an impression of the prepared tooth following the same
techniques as described above. Following this procedure means that
two hardened impressions are formed, a first impression of the
patient's full dental anatomy including the unprepared tooth and a
second impression containing the crown-prepped tooth that will
eventually receive the crown. At this point, a conventional
provisional crown can be mounted over the prepared tooth structure
to protect it while the permanent crown is being made.
[0043] The hardened impressions are sent to a dental laboratory
that will fabricate the crown. The dental technician, at the
laboratory, prepares a cast (or model) by pouring dental plaster or
stone into the first hardened impression. This results in a
finished plaster model having a shaped surface closely matching the
patient's complete dental anatomy. In other cases, the dentist will
prepare the finished plaster models and send them directly to the
laboratory.
[0044] Next, the laboratory technician prepares a matrix using a
putty made from silicone or other moldable material. The matrix
putty has good handling properties. The technician can mold and
shape the matrix over the area of the model requiring the
crown.
[0045] To make the matrix, the technician may need to fill in
edentulous areas on the dental model with a denture tooth, shape
and contour the tooth anatomy using wax or resin, and make other
modifications to the model. The model teeth should be clean and
free of any foreign debris. Then the matrix putty is molded over
the shaped teeth. The matrix should be molded over the teeth so
that it extends beyond the margins of the teeth. Particularly, it
should extend at least 2 mm beyond the tooth margins.
[0046] The technician presses the matrix putty on the surface of
the teeth to form the impression. The matrix putty is allowed to
harden. Then, the hardened matrix is removed from the model. The
resulting impression in the hardened matrix is an accurate negative
likeness of the patient's tooth anatomy. Now, the crown is ready to
be fabricated using the composite material of this invention.
[0047] It can be difficult to apply the composite material to the
dental model if there are jagged edges or irregular formations
present on the model. Thus, the dental model should first be
prepared eliminate any unnecessary protrusions. The crown portion
of the teeth of the model can be reduced using a bur or other sharp
instrument. Typically, the crown portion is reduced by a depth of
approximately 1.0 mm. Also, adjacent teeth on the model may be
inadvertently fused together, and the interproximal contacts of the
fused teeth should be removed using a saw instrument. Once the
model has been adequately reduced and prepared, a thin coating of a
separating agent (for example, oxygen barrier coating available
from Dentsply) is applied to the surface of the model.
[0048] As discussed above, if the dentist has prepared the tooth
for receiving the crown in the office visit and taken an impression
of the prepared tooth, a second dental model of the patient's
dental anatomy including the crown-prepped tooth is fabricated. The
dental laboratory may make this model, or the dentist may make this
model at his/her office and send it to the laboratory. In such
cases, the oxygen barrier coating or other separating agent is
applied to the surface of this model.
[0049] Next, the dental practitioner or laboratory technician
dispenses layers of the dental composite material of this invention
into the hardened matrix putty. The composite material is heated to
a temperature generally above 40.degree. C. and preferably to a
temperature in the range of about 50.degree. C. to about
100.degree. C. If the temperature is too low, the material will not
flow sufficiently. On the other hand, if the temperature is too
high, the material will take a substantially long time to cool. The
practitioner places layers of the composite material into the
matrix beginning with the enamel layer. The heated enamel layer is
carefully smoothed out using a spatula, preferably a heated
spatula, or other applicator. Then, the practitioner applies more
composite material to the matrix to form the dentin layer. Care
should be taken that the correct amount of composite material is
placed into the matrix. If a sufficient amount of composite
material is not introduced, gaps will form in the resulting crown,
and there will be occlusion problems. On the other hand, if too
much composite material is introduced, the occlusion of the crown
may be too high. This can occur even though the highly flowable
nature of the heated composite material allows excess material to
squeeze out easily. The shade of the composite material is
carefully selected so that it matches the color of the patient's
natural teeth.
[0050] Once the hardened matrix has been filled sufficiently with
the composite material, it is placed over the area of the dental
model that includes the tooth to receive the crown. If only one
model of the teeth containing the unprepared tooth has been made
and prepared, as described above, then the composite material is
applied to this model. In cases where two dental models have been
made, a first model containing the unprepared tooth and a second
model containing the crown-prepped tooth, then the composite
material is applied to the second model.
[0051] Once seated, the composite material is allowed to set for
approximately one to three minutes to form a shape-stable, uncured
provisional crown. The hardened matrix is then removed from the
model leaving the composite material in the shape of a dental crown
seated on the model. Although the composite material is uncured at
this point, it is dimensionally stable, and it remains
substantially fixed in place. The composite material has wax-like
characteristics, good viscosity, and handling properties. The
material does not slump or substantially change shape. Contoured
and molded to form a crown on the targeted area of the dental
model, the composite material does not expand or shrink
substantially from that site. By contrast, conventional materials
may have poor viscosity and handling characteristics. Such
materials may be too thin so that they lose their shape or too
thick so that they are difficult to mold.
[0052] If necessary, additional composite material can be added to
touch-up the provisional crown as it is seated on the model. Any
excess composite material on the model should be removed. A knife
or other sharp instrument can be used to scrape off the excess
material. Then, optional, a thin layer of a visible light curing
(VLC) sealer is applied to the surface of the provisional crown.
Now, the model, which is seated with the composite material in a
crown shape, is placed in a light-curing oven and irradiated with
curing light and heated in accordance with a pre-determined curing
cycle. The curing time will depend upon many different factors
including the light-curing oven used. In general, the materials of
this invention completely set and harden in the range of about one
(1) to about fifteen (15) minutes.
[0053] After the cured dental crown and supporting model are
removed from the oven, the assembly is cooled. Then, the crown is
removed from the model using fingers, a crown remover, or other
suitable instrument. The crown is finished and polished using
conventional techniques. The crown can be polished using buffing
wheels. Aluminum oxide can be used to steam clean the interior
surface of provisional crown for subsequent effective bonding to
reline or cement material at dentist's office. If needed, the
provisional crown also can be mechanically polished using buffing
wheels and abrasives. Lastly, if the practitioner or technician
wishes, a VLC sealant which provides a stain-resistant and glossy
surface finish may be applied to the surface of the crown and the
crown may be cured again in a light-curing oven.
[0054] The dental laboratory sends the finished crown back to the
dentist. Once the dentist receives the crown, he or she can prepare
the tooth that will receive the crown, if this has not already been
done, by filing the tooth structure to a core or stump as described
above. Then, the finished crown is affixed to the prepared tooth in
the mouth of the patient using a suitable reline material and
dental cement. Conventional dental cements, as are known in the
dental field, may be used in this step. In cases where a temporary
crown has been mounted over the tooth structure, it is first
removed and then the crown of this invention is affixed to the
tooth using dental cement.
[0055] In another embodiment, a substructure such as, for example,
a metal coping can be used in the construction of the crown,
bridge, or other restoration. The underlying substructure helps
support the composite material used to make the restoration. Thus,
the polymerizable composite material forms the visible portion of
the crown and is bonded to the underlying substructure. Additional
mechanical retention may be introduced to improve and maintain the
integrity of bonding between substructure and the polymerizable
composite material.
[0056] The strength and toughness of the crown is enhanced by using
a metal coping or other supporting substructure. Cast metals,
alloys, ceramo-metal materials, high strength ceramics, and
fiber-reinforced composites can be used as copings or substructures
for the restorations. The high strength ceramics include, but are
not limited to, alumina, zirconia, mullitc, titanium oxide,
magnesium oxide, SIALON and their mixtures. Metals and alloys and
their mixtures, such as Nobel alloys, palladium-based alloys,
cobalt-based alloys, nickel-based alloys, pure titanium and alloys,
gold-based metal-ceramic alloys, nickel chromium alloys, and the
like can be used as copings or substructures. Possible reinforced
fibers include glass, carbon, graphite, polyaramid, high density
polyethylene, alumina, and mixtures thereof, as well as other
fibers known in the art.
[0057] There are several known methods used for fabricating
substructures. For example, metal copings are commonly used and
these copings can be made by a "lost wax" technique. Here, the
dentist takes an impression of the prepared tooth, and a dental
model (as described above) is prepared from the impression. A wax
coping is then manually built-up on the model. After the wax coping
has been finished, it is removed from the model and invested in a
material that forms a mold (investment), which is heated so as to
burn out the wax and leave a cavity. This cavity or die can be used
to cast the metal coping. Any suitable metal or metal alloy such as
gold alloy or nickel chromium alloy can be used to make the metal
coping. After hardening, the mold is removed from the metal
casting.
[0058] Another example is to use computer-aided design (CAD) and
computer-aided manufacturing (CAM) technology systems to collect
information and design and manufacture the copings. One such system
for making esthetic metal-free crowns and bridges using zirconia as
the substructure is available from Dentsply under the tradename,
CERCON. In this system, a wax pattern (coping and pontic) with a
minimum thickness of 0.4 mm is made. The system scans the wax
pattern and mills a zirconia bridge coping from pre-sintered
zirconia blanks. The coping is then sintered in a heat furnace for
6 to 8 hours. After the coping is placed back on the prepared
surface of the dental model, primer and opaque coatings are applied
to the coping surface.
[0059] The following method can be used for fabricating a single
crown with metal substructure in accordance with this invention.
First, impressions (or digital scans) are made of the areas in the
patient's mouth that will receive the crown. The impressions (or
digital scans) are taken prior to and after the tooth is prepared.
Then, a dental model made from the second impression (or digital
scan) is used to prepare the coping. A metal coping is prepared
using conventional techniques as described above. A metal primer is
applied to the surface of the metal coping, and an opaque coating
is applied over the primer and cured. The finished metal coping is
placed over the area of the preformed dental model intended to
receive the restoration.
[0060] Then, the dental practitioner or laboratory technician
dispenses layers of the composite polymerizable material into a
hardened impression material or matrix in a manner as described
above. For example, first an enamel layer of the composite material
having the desired shade can be warmed and dispensed into the
hardened impression. The enamel layer is spread around evenly and
smoothed out, using a spatula or other instrument, to form a
translucent incisal layer on the occlusal surface. Secondly, a more
pigmented dentin layer can be applied. Once the hardened impression
has been filled with the appropriate layers of composite material,
it is immediately seated onto the prepared metal coping. After a
few minutes, the hardened impression is removed, thereby exposing
the uncured crown material supported by the metal coping. The
uncured crown structure can be trimmed, shaped, sculpted, occluded,
patched-up, and stained, thus providing a structure that is nearly
finished prior to curing. A thin layer of sealer can be applied to
the crown surface and the structure can be cured in a light-curing
unit to form a final crown. This crown can be finally cemented over
the patient's prepped tooth.
[0061] It is understood that any suitable substructure can be used
to make the crown, bridge, or other restoration in accordance with
this invention in addition to those mentioned above. Ceramic
(metal-free) substructures such as CERCON systems and
fiber-reinforced copings can be used in addition to metal
copings.
[0062] The shape-stable polymerizable materials of this invention
enable multi-chromatic veneers, crowns, bridges, implants, and
other restorations to be fabricated with superb esthetics on
various substructures.
Dental Practitioner's Chairside Method
[0063] Following this method, a dental practitioner first takes an
impression of the patient's teeth including the unprepared tooth
that will receive the crown. The dentist takes this impression
using the same techniques as described above. A plastic tray filled
with polyvinyl siloxane (PVS), alginate, or other suitable
impression material is used. The dentist presses the tray
containing the silicone material on the surface of the teeth to
form the impression. After the impression has been formed in the
silicone material, the dentist removes the tray from the mouth. The
impression is allowed to harden. The resulting hardened impression
is an accurate negative likeness of the patient's tooth
anatomy.
[0064] Then, the dentist places multiple layers of the
above-described composite material into the hardened impression
beginning with the enamel layer. The composite material is heated
and carefully placed into desired incisal areas of the impression
to form the enamel layer. Next, the dentin layer is injected into
the impression. As discussed above, it is important that the
correct amount of composite material be placed into the impression.
The shade of the composite material is also carefully selected and
customized so that it matches the color of the patient's natural
teeth. Alternatively, the dentist may wish to inject only a single
layer of the shaded composite material into the hardened
impression.
[0065] After filling the impression with the composite material, it
is inserted into the patient's mouth. It is positioned in the mouth
in such a way that the composite material is molded and shaped over
the previously prepared tooth that will receive the restoration. As
the impression is fitted in the mouth, excess composite material is
allowed to escape around the margins and adjacent teeth.
[0066] Alternatively, the dentist can prepare a model and work
outside of the mouth. In this case, the dentist takes an impression
of the prepared tooth using conventional impression material. A
model including a core or stump tooth structure is then made by
pouring or injecting a low viscosity and suitably rigid die
material, such as die silicone, plaster, dental stone, or the like
into the hardened impression. Then, the impression which contains
the composite material as described above can be fitted over the
dental model and a crown can be prepared. Following this method,
the dentist can work extraorally to prepare the crown.
[0067] Turning back to the chairside method described above, the
composite material is allowed to cool and form a dimensionally
stable, uncured crown structure within the impression inside of the
mouth. The impression containing the composite material is then
removed from the mouth. If needed, the dentist trims excess
composite material away from the margins and adjacent teeth. Next,
the uncured, shaped crown structure is placed back inside of the
mouth so that the crown is positioned over the prepared tooth
structure. The patient can bite down on the crown so that margins,
contacts, and occlusion can be checked by the practitioner and
adjusted accordingly. The fitted crown is then removed from the
mouth.
[0068] Next, the crown is irradiated with light so that it cures
and forms a fully hardened crown product. A standard handheld
dental curing light or light-curing oven may be used to fully cure
the crown structure. Suitable light-curing ovens are available from
Dentsply including, for example, the Eclipse.RTM. processing unit,
Enterra.TM. visible light-curing (VLC) unit, and Triad.RTM. 2000
VLC unit. Suitable handheld light units include halogen, plasma arc
(PAC), and light-emitting diode (LED) dental curing lights. These
include, for example, those sold under the brand names: QHL75.RTM.
Lite (Dentsply); Spectrum.RTM. 800 curing unit (Dentsply); Sapphire
(DenMat); SmartLite iQ2.TM. (Dentsply); Elipar.RTM. (3M Espe); and
L.E. Demetron II.TM. (Kerr).
[0069] The crown can be finished with burs and polished using
customary finishing techniques as needed. In addition, a VLC
sealant, which provides a stain-resistant and glossy surface finish
may be applied to the crown.
[0070] The finished crown is now ready to be permanently affixed to
the tooth. Conventional permanent cements, as known in the dental
field, may be used in this step.
[0071] In a second embodiment of this method, the composite
material cools and forms a stable, uncured crown structure inside
of the mouth. But, in the next step, only the impression is removed
from the mouth. The shape-stable uncured crown structure remains in
the mouth. The dentist can then trim excess composite material away
from the margins of the crown and adjacent teeth. As the patient
bites down upon the crown, the margins, contacts, and bite
occlusion can be checked by the practitioner and adjusted
accordingly. Next, the shaped crown structure is partially cured in
the mouth using a handheld dental curing light as described above.
The partially cured crown is then removed from the mouth. It may be
finished with a bur as needed. In addition, a sealant, which
provides a stain-resistant and glossy surface finish, may be
applied to the crown. A dental curing light or light-curing oven
may be used to fully cure the crown structure.
[0072] A third version of this method is similar to the method
described above, except there is no partial curing step. The
composite material is completely cured outside of the mouth.
Particularly, this method involves first cooling the composite
material to form a stable, uncured crown structure within the
mouth. In the next step, only the impression material is removed
from the mouth. This leaves the uncured crown structure in place.
The practitioner can check the crown fit and make any needed
adjustments. Then, the shaped crown structure is removed and fully
cured by exposing it to light radiation outside of the mouth using
dental curing lights or ovens.
[0073] Following a fourth method, the dentist also can work outside
of the mouth. In this method, the impression containing the
composite material is first placed over a dental model. The
impression is then removed from the model, but the composite
material remains. This leaves an uncured, shape stable crown
structure positioned on the model. The crown structure can be
partially light-cured on the model if the dentist wishes to perform
this step. Then, the partially-cured crown can be removed and
finished with burs and polished to its final desired shape. After
applying a sealant to the crown's surface, it is ready to be fully
cured and hardened.
[0074] In yet another embodiment, the uncured, shaped crown
structure is removed from the impression material and only the
crown, by itself, is placed back inside of the mouth. The crown is
mounted over the prepared tooth structure and margins, contacts,
and occlusion are checked. The crown is then removed from the
mouth. As described above, the crown can be finished and a sealant
can be applied to its surface before the crown is placed in a
light-curing oven and fully cured.
[0075] One advantage of composite material of this invention is
that it can be shaped and molded to form stable crown structures
that can be partially light-cured inside of the mouth. This
partial-curing step normally occurs after the margins, contacts,
and occlusion have been checked and adjusted accordingly. The
above-mentioned dental curing lights may be used to partially cure
the material. Then, the partially-cured crown is removed from the
mouth and finished with burs and polishers to its final desired
shape. After applying a sealant to the crown's surface, it is ready
to be fully cured and hardened. The crown may be placed in a
standard light-curing oven, as mentioned above, and fully cured via
light irradiation.
[0076] The veneers, crowns, bridges, implants, and other
restorations produced by the methods of this invention have superb
esthetics, durability, and other desirable properties. The uncured,
shape-stable restorations prepared according to the methods have
advantages over conventional materials with respect to occlusal
adjustment, comfort, fitting. The uncured, shape-stable
restorations can be adjusted and modified by melting, carving,
molding, pressing, and other techniques. Restorations having ideal
occlusal surfaces that provide a comfortable bite for the patient
can be made per this invention.
[0077] Preferably, the restorations produced by this invention are
high strength dental polymeric materials having a flexural modulus
of at least 500,000 psi and a flexural strength of at least 5,000
psi. More preferably, the high strength dental polymeric materials
have a flexural modulus of at least 1,000,000 psi and a flexural
strength of at least 10,000 psi.
[0078] The dental restorations produced by this invention have
excellent properties and can be used as provisional or long-term
restorations. A dental practitioner can use the dental restoration
as a provisional expecting that it will remain in the patient's
mouth for a time period of about 1 to about 12 months. Moreover, if
there is a need, the dental practitioner can use the restoration
long-term, expecting that it will remain in the patient's mouth for
a period of time longer than about 12 months. The properties and
other features of the restorations are such that they can be used
for either short-term or long-term periods. The restorations have
high mechanical strength, pleasing aesthetics, a hard and smooth
surface finish, and good margins and contacts making them ideal
products for protecting the dental health of a patient. This
invention meets the needs of dental profession for quick, easy, and
accurate ways to fabricate provisional and long-term veneers,
crowns, bridges, and other restorations.
[0079] The present invention is further illustrated by the
following examples, but these examples should not be construed as
limiting the scope of the invention.
EXAMPLES
Example 1
Preparation of Oligomer
[0080] A reactor was charged with 1176 grams of
trimethyl-1,6-diisocyanatohexane (5.59 mol) and 1064 grams of
bisphenol A propoxylate (3.09 mol) under dry nitrogen flow and
heated to about 65.degree. C. under positive nitrogen pressure. To
this reaction mixture, 10 drops of catalyst dibutyltin dilaurate
were added. The temperature of the reaction mixture was maintained
between 65.degree. C. and 140.degree. C. for about 70 minutes and
followed by additional 10 drops of catalyst dibutyltin dilaurate. A
viscous paste-like isocyanate end-capped intermediate product was
formed and stirred for 100 minutes. To this intermediate product,
662 grams (5.09 mol) of 2-hydroxyethyl methacrylate and 7.0 grams
of BHT as an inhibitor were added over a period of 70 minutes while
the reaction temperature was maintained between 68.degree. C. and
90.degree. C. After about five hours stirring under 70.degree. C.,
the heat was turned off, and oligomer was collected from the
reactor as semi-translucent flexible solid and stored in a dry
atmosphere.
Example 2
Preparation of Monomer
[0081] A reaction flask was charged with 700 grams of
1,6-diisocyanatohexane and heated to about 70.degree. C. under a
positive nitrogen pressure. To this reactor were added 1027 grams
of 2-hydroxyethyl methacrylate, 0.75 gram of catalyst dibutyltin
dilaurate and 4.5 grams of butylated hydroxy toluene (BHT). The
addition was slow and under dry nitrogen flow over a period of two
hours. The temperature of the reaction mixture was maintained
between 70.degree. C. and 90.degree. C. for another two hours and
followed by the addition of 8.5 grams of purified water. One hour
later, the reaction product was discharged as clear liquid into
plastic containers and cooled to form a white solid and stored in a
dry atmosphere.
Example 3
Preparation of Monomer
[0082] A reaction flask was charged with 168 grams of
1,6-diisocyanatohexane and heated to about 70.degree. C. under a
positive nitrogen pressure. To this reactor were added 228 grams of
2-hydroxyethyl acrylate, 0.12 gram of catalyst dibutyltin dilaurate
and 0.86 grams of butylated hydroxy toluene (BHT). The addition was
slow and under dry nitrogen flow over a period of two hours. The
temperature of the reaction mixture was maintained between
70.degree. C. and 85.degree. C. for another three hours and
followed by the addition of 0.9 grams of purified water. One hour
later, the reaction product was discharged as clear liquid into
plastic containers and cooled to form a white solid and stored in a
dry atmosphere.
Examples 4A-4D
Preparation of Polymerizable Composite Materials
[0083] In the following Examples 4A-4D, different polymerizable
composite materials were prepared as described further below.
TABLE-US-00001 TABLE 1 Formulations of Composite Resins Example 4A
Example 4B Example 4C Example 4D Components (wt %) (wt %) (wt %)
(wt %) Oligomer of Example 1 8.072 8.033 8.072 8.033 Monomer of
Example 2 5.24 5.24 5.24 5.24 Monomer of Example 3 3.50 3.50 3.50
3.50 (HEMA-UDMA) Branched aliphatic 5.83 5.83 5.83 5.83 urethane
dimethacrylate (7,7,9- trimethyl-4,13-dioxo-3,14 dioxa-5,12-
diazahexadecane-1,16-diol dimethacrylate) Ethoxylated bisphenol A
6.99 6.99 6.99 6.99 dimethacrylate* (Lucirin TPO) 0.10 0.10
2,4,6-Trimethylbenzoyldiphenyl phosphine oxide Methacrylic acid
0.085 0.085 0.06 0.06 Butylated hydroxytoluene 0.004 0.004 0.003
0.003 N,N-dimethylaminoneopentyl acrylate 0.163 0.163 0.117 0.117
gamma-methacryloxypropyl 0.050 0.050 0.036 0.036 trimethoxy silane
(Camphorquinone) 0.048 0.048 0.034 0.034 bicyclo[2,2,1]
heptane-2,3-dione-1,1,7- trimethyl-(IS) Amorphous Silica (silaned)
0.50 0.50 Barium fluoro alumino borosilicate 69.50 70.00 69.50
70.00 glass*** Titanium Dioxide** 0.017 0.050 0.017 0.050 Yellow
Iron Oxide 7055 0.005 0.005 Cromophtal Red-BRN 0.0003 0.0003
2-napthalenecarboxamide, N,N'-(2- chloro-1,4-phenylene)
bis{4-{(2,5- dichlorophenyl) azo}-3-hydroxy-} Black Iron Oxide 7053
0.001 0.001 Lumilux Blue LZ fluorescing agent 0.001 0.001 0.001
0.001 (dihydroxy terepthalate acid ester) Total % 100 100 100 100
*SR348 - purchased from Sartomer Company, Inc. **Titanium Dioxide
is one of three different types of TiO.sub.2: Titanox 328, 3328,
325 ***Particles have one or more different average particle sizes
and are selected from average particles sizes range from 0.1
micrometer to 10 micrometers.
Example 5
[0084] Table 2 shows the components of the compositions of Examples
5A through 5D. The compositions of Examples 5A through 5D were
prepared by mixing and degassing the components shown in Table 2 at
85.degree. C. to 95.degree. C.
TABLE-US-00002 TABLE 2 Formulations of Composite Resins Example 5A
Example 5B Example 5C Example 5D Components (wt %) (wt %) (wt %)
(wt %) Oligomer of Example 1 4.619 4.0926 1.149 1.129 Monomer of
Example 2 4.20 5.25 4.00 4.54 Monomer of Example 3 1.45 2.50 1.80
3.03 (HEMA-UDMA) Branched aliphatic 5.45 5.00 5.00 5.05 urethane
dimethacrylate (7,7,9- trimethyl-4,13-dioxo-3,14 dioxa-5,12-
diazahexadecane-1,16-diol dimethacrylate) Modified Bis-GMA 5.75
7.20 11.9 Ethoxylated bisphenol A 6.00 5.0 6.00 dimethacrylate*
(Lucirin TPO) 0.02 0.02 0.10 2,4,6-Trimethylbenzoyldiphenyl
phosphine oxide Methacrylic acid 0.067 0.076 0.076 0.058 Butylated
hydroxytoluene 0.003 0.004 0.004 0.003 N,N-dimethylaminoneopentyl
acrylate 0.132 0.152 0.152 0.115 gamma-methacryloxypropyl 0.040
0.054 0.054 0.041 trimethoxy silane (Camphorquinone) 0.038 0.044
0.044 0.033 bicyclo[2,2,1] heptane-2,3-dione-1,1,7- trimethyl-(IS)
Amorphous Silica (silaned) 2.00 0.50 0.50 0.50 Barium fluoro
alumino borosilicate 76.00 71.50 74.00 73.50 glass*** Titanium
Dioxide** 0.051 Yellow Iron Oxide 7055 0.005 Cromophtal Red-BRN
0.0001 2-napthalenecarboxamide, N,N'-(2- chloro-1,4-phenylene)
bis{4-{(2,5- dichlorophenyl) azo}-3-hydroxy-} Black Iron Oxide 7053
Lumilux Blue LZ fluorescing agent 0.001 0.0013 0.001 0.001
(dihydroxy terepthalate acid ester) Total % 100 100 100 100 *SR348
- purchased from Sartomer Company, Inc. **Titanium Dioxide is one
of three different types of TiO2: Titanox 328, 3328, 325
***Particles have one or more different average particle sizes and
are selected from average particles sizes range from 0.1 micrometer
to 10 micrometers.
TABLE-US-00003 TABLE 3 Mechanical Properties of Compositions in
Examples Compared to Commercial Materials Flexural Flexural Stress
Modulus Wear Resistance - Compositions (MPa) (GPa) Volume Loss
(mm.sup.3) 4A 164 11.0 0.032 4B 171 10.8 0.033 4C 171 11.3 0.029 4D
158 9.9 0.029 5A 160 12.5 0.0121 5B 166 10.0 0.0133 5C 153 10.0
0.0060 5D 162 9.8 0.0145 SINFONY enamel E2 (3M) 105 4.6 0.081
SINFONY dentin A2 (3M) 109 4.6 0.115 GRADIA enamel E2 (GC) 101 6.1
0.060
[0085] Volume loss (cubic mm at 400,000 cycles), was used as a
measure of the wear resistance of the polymerized compositions. A
three body cyclic abrasion wear machine (Leinfelder method in
vitro/University of Alabama) was used to determine volume loss.
Samples were cured in an Enterra.TM. (sold by Dentsply
International) curing unit for 5 or 6 minutes.
[0086] Flexural Strength and Flexural Modulus of the polymerized
compositions were measured by using three-point bend test on
Instron bending unit according to ISO 10477. Samples were cured in
an Enterra.TM. curing unit for 5 minutes.
Example 6
Laboratory Fabricated Crown Requiring Reline to Mount
[0087] A silicone matrix putty was molded and shaped over a
targeted tooth and area on a dental model requiring a crown. The
putty was molded over the targeted tooth so that it extended about
2 mm beyond the tooth's margins. The matrix putty was allowed to
harden. Then, the hardened putty was removed from the model. After
the dental model was adequately reduced, a thin coat of model
separator (oxygen barrier coating available from Dentsply
International) was applied to the prepared areas.
[0088] Then, a small amount of heated enamel resin (prepared in
above Example 4A) was applied into the incisal area of the hardened
matrix putty. A hot spatula was used to spread out the resin and
remove any excess material from the matrix. Then, a sufficient
amount of the dentin resin (prepared in above Example 4B) was
extruded from a heated syringe to fill the matrix. Thus, the matrix
was filled with a composite resin material. Immediately thereafter,
the filled matrix was placed over the prepared dental model and
excess material was allowed to escape around the margins. Once
seated, the composite material was allowed to set for approximately
one (1) to three (3) minutes to form the shape-stable crown. The
matrix was then removed from the model leaving the resulting crown
in place. After the matrix was removed, excess composite material
around the margins and adjacent teeth on the model was carefully
removed. At this point, the crown can be easily shaped, contoured,
occluded and adjusted as needed since it is shape-stable and in an
uncured state.
[0089] The model with the mounted crown was then placed inside of a
light-curing oven and irradiated with curing light and heated in
accordance with a pre-determined curing cycle. The crown was then
removed from the model and shaped and contoured as needed. Finally,
a thin layer of a visible light curing sealer was applied to the
surface of the crown and the crown was cured for about two minutes.
The finished crown was relined and cemented on a crown-prepped
tooth in a patient's mouth.
Example 7
Laboratory Fabricated Crown Mounted Using Dental Cement
[0090] In this example, two dental models were made, a first model
containing the unprepared tooth and a second model containing the
crown-prepped tooth.
[0091] A silicone matrix putty was molded and shaped over the
targeted area of the first dental model. The putty was molded over
the targeted tooth so that it extended about 2 mm beyond the
tooth's margins. The matrix putty was allowed to harden. Then, the
hardened putty was removed from the model. A thin layer of oxygen
barrier coating was applied to the second dental model.
[0092] Then, a small amount of heated enamel resin (prepared in
above Example 4C) was applied into the incisal area of the hardened
matrix putty. A hot spatula was used to spread out the resin and
remove any excess material from the matrix. Then, a sufficient
amount of the dentin resin (prepared in above Example 4D) was
extruded from a heated syringe to fill the matrix. Thus, the matrix
was filled with a composite resin material. Immediately thereafter,
the filled matrix was placed over the second dental model
(containing the crown-prepped tooth) and excess material was
allowed to escape around the margins. Once seated, the composite
material was allowed to set for approximately one (1) to three (3)
minutes to form the shape-stable crown. The matrix was then removed
from the model leaving the resulting crown in place. After the
matrix was removed, excess composite material around the margins
and adjacent teeth was carefully removed. The resulting crown can
be easily shaped, contoured, occluded and adjusted as needed since
it is shape-stable and in an uncured state.
[0093] A thin layer of a visible light curing sealer was applied to
the surface of the crown. The model with the mounted crown was then
placed inside of a light-curing oven and irradiated with curing
light and heated in accordance with a pre-determined curing cycle.
The resulting crown was finished and polished as needed. Then, the
crown was cemented on a crown-prepped tooth in a patient's
mouth.
Example 8
Laboratory Fabricated Bridge Requiring Reline
[0094] A silicone matrix putty was molded and shaped over the area
of a dental model requiring a dental bridge. The matrix putty was
allowed to harden. Then, the hardened putty was removed from the
model. After the dental model was adequately reduced, a thin layer
of oxygen barrier coating was applied to the prepared areas of the
model.
[0095] Then, a small amount of heated enamel resin (prepared in
above Example 4C) was applied into the incisal area of the hardened
matrix putty. A hot spatula was used to spread out the resin and
remove any excess material from the matrix. Then, a sufficient
amount of the dentin resin (prepared in above Example 4D) was
extruded from a heated syringe to fill the matrix. Thus, the matrix
was filled with a composite resin material. Immediately thereafter,
the filled matrix was placed over the dental model and excess
material was allowed to escape around the margins. Once seated, the
composite material was allowed to set for approximately two (2) to
five (5) minutes to form the shape-stable bridge. The matrix was
then removed from the model leaving the resulting bridge. After the
matrix was removed, excess composite material around the margins
and adjacent teeth was carefully removed. The resulting bridge can
be easily shaped, contoured, occluded and adjusted as needed.
[0096] The model with the mounted bridge was then placed inside of
a light-curing oven and irradiated with curing light and heated in
accordance with a pre-determined curing cycle (including a flip
cure as needed). The bridge was then removed from the model and
shaped and contoured as needed. Finally, a thin layer of a visible
light curing sealer was applied to the surface of the bridge and
the bridge was cured for about two minutes. The finished bridge was
relined and cemented on the prepared teeth in a patient's
mouth.
Example 9
Laboratory Fabricated Bridge Mounted Using Dental Cement
[0097] In this example, two dental models were made, a first model
containing the unprepared tooth and a second model containing the
bridge-prepped teeth.
[0098] A silicone matrix putty was molded and shaped over the
targeted area of the first dental model. The matrix putty was
allowed to harden. Then, the hardened putty was removed from the
model. A thin layer of oxygen barrier coating was applied to the
second dental model.
[0099] Then, a small amount of heated enamel resin (prepared in
above Example 5C) was applied into the incisal area of the hardened
matrix putty. A spatula was used to spread out the resin and remove
any excess material from the matrix. Then, a sufficient amount of
the dentin resin (prepared in above Example 5B) was extruded from a
heated syringe to fill the matrix. Thus, the matrix was filled with
a composite resin material. Immediately, the filled matrix was
placed over the second dental model (containing the bridge-prepped
teeth) and excess material was allowed to escape around the
margins. Once seated, the composite material was allowed to set for
approximately two (2) to five (5) minutes to form the shape-stable
bridge. The matrix was then removed from the model leaving the
resulting bridge. After the matrix was removed, excess composite
material around the margins and adjacent teeth was carefully
removed. The resulting bridge can be easily shaped, contoured,
occluded and adjusted as needed. Then, a thin layer of visible
light curing sealer was applied to the surface of the bridge. The
model was placed in a light-curing oven and irradiated with curing
light and heated in accordance with a pre-determined curing cycle
(including a flip cure as needed). The resulting bridge was
finished and polished as needed. The bridge was then cemented on
the prepared teeth in the patient's mouth.
Example 10
Chairside Crown Mounted Using Dental Cement
[0100] A quadrant impression of the area for receiving a crown in a
patient's mouth was taken prior to preparation of the tooth. The
margin areas of the impression were trimmed to within 2 mm of the
tooth margin areas to allow easy escape of excess material. The
tooth for receiving the crown was prepared and lightly lubricated
with Vaseline or a similar separating medium (including
light-curable separating medium). A small amount of the heated
enamel resin of Example 4A was applied into the incisal area of the
impression. A hot spatula was used to spread out the resin and
remove any excess in the impression. A desired amount of the dentin
resin of Example 4B was extruded from a heated compule or syringe
to fill the impression. The impression was placed immediately onto
the prepared tooth and excess material was allowed to escape around
the margins. After the impression was removed, excess material
around the margins and adjacent teeth was carefully removed. The
crown can be bitten, shaped, contoured, occluded and adjusted as
needed. Then, the crown was removed from the prepared tooth. Die
silicone was injected into the cavity of the crown to form a die.
After a sealer was applied, the crown was cured in an Enterra.TM.
light-curing unit (available from Dentsply International) for 6
minutes. The crown was finished and polished. It was then cemented
on a crown-prepped tooth in the patient's mouth.
Example 11
Chairside Crown Mounted Using Dental Cement
[0101] A quadrant impression of the area for receiving a crown in a
patient's mouth was taken prior to the preparation of the tooth.
The margin areas of the impression were trimmed to within 2 mm of
the tooth margin areas to allow easy escape of excess material. The
tooth for receiving crown was prepared and lightly lubricated with
Vaseline. A small amount of the enamel resin of Example 4C was
applied into the incisal area of the impression. A spatula was used
to spread out the resin and remove any excess in the impression. A
desired amount of the dentin resin of Example 4D was extruded from
a heated compule or syringe to fill the impression. The impression
was immediately placed onto the prepared tooth and excess material
was allowed to escape around the margins. After the impression was
removed, excess material around the margins and adjacent was
carefully removed. The crown was removed from the prepared tooth.
After a sealer was applied, the crown was cured in a Triad.RTM.
light-curing unit (Dentsply) for 10 minutes. The crown was finished
and polished. It was then cemented on a crown-prepped tooth in the
patient's mouth.
Example 12
Chairside Crown Made Using a Partial Light-Curing Process
[0102] A quadrant impression of the area for receiving a crown in a
patient's mouth was taken prior to the preparation of a tooth. The
margin areas of the impression were trimmed to within 2 mm of the
tooth margin areas to allow easy escape of excess material. The
tooth for receiving crown was prepared and lightly lubricated with
Vaseline. A small amount of the enamel resin of Example 5C was
applied into the incisal area of the impression. A spatula was used
to spread out the resin and remove any excess in the impression. A
desired amount of the dentin resin of Example 5B was extruded from
a heated compule or syringe to fill the impression. Immediately,
the impression was placed onto the prepared tooth and excess
material was allowed to escape around the margins. The impression
was removed and the shape-stable crown remained in place. Then, the
crown was partially cured with a handheld light for 5 seconds. A
QHL75 curing light (Dentsply) was used. (Alternatively, other
suitable dental curing lights also may be used.) The crown was then
removed from the mouth and the margins were finished to desired
shape. After a sealer was applied, the crown was fully cured in an
Enterra.TM. light-curing unit (Denstply) for 5 minutes. The crown
was then cemented on the crown-prepped tooth in the patient's
mouth.
Example 13
Chairside 3 Unit Bridge Mounted Using Dental Cement
[0103] A quadrant impression of the area for receiving a dental
bridge in a patient's mouth was taken prior to the preparation and
extraction of teeth. The margin areas of the impression were
trimmed to within 2 mm of the tooth margin areas to allow easy
escape of excess material. Teeth were extracted and the teeth for
receiving the bridge were dry prepared and lightly lubricated with
Vaseline. A small amount of the enamel resin of Example 5D was
applied into the incisal areas of the impression. A spatula was
used to spread out the resin and remove any excess in the
impression. A desired amount of the dentin resin of Example 4D was
extruded from a heated syringe to fill the impression. Immediately,
the impression was placed onto the prepared teeth and tooth
extracted area and excess material was allowed to escape around the
margins. After the impression was removed, the excess material
around the margins and adjacent teeth was carefully removed. The
resulting bridge can be bitten, shaped, contoured, occluded and
adjusted as needed. The bridge was removed and die silicone was
injected into the cavities of the crowns and under the pontic to
form a supporting model. After a sealer was applied, the bridge was
cured in an Enterra.TM. light unit (Dentsply) for 6 minutes and
flip cured for an additional 1.5 minutes. The bridge was finished
and polished. It was then cemented on the prepared teeth in the
patient's mouth.
Example 14
Chairside 3 Unit Bridge Made Using a Partial Light-Curing
Process
[0104] A quadrant impression of the area for receiving a dental
bridge in a patient's mouth was taken prior to the preparation and
extraction of teeth. The margin areas of the impression were
trimmed to within 2 mm of the tooth margin areas to allow the easy
escape of excess material. Teeth were extracted and the teeth for
receiving the bridge were prepared and lightly lubricated with
Vaseline. A small amount of the enamel resin of Example 5C was
applied into the incisal areas of the impression. A spatula was
used to spread out the resin and remove any excess in the
impression. A desired amount of the dentin resin of Example 5B was
extruded from a heated syringe to fill the impression. Then, the
impression was immediately placed onto the prepared teeth and tooth
extracted area and excess material was allowed to escape around the
margins. After the impression was removed, excess material around
the margins and adjacent teeth carefully removed. The resulting
bridge can be bitten, shaped, contoured, occluded and adjusted as
needed. The bridge was partially cured with a handheld light for 15
seconds. (QHL75 curing light from Dentsply) The bridge was removed
from the prepared teeth and the margins were finished to desired
shapes. Die silicone was injected into the cavities of the crowns
and under the pontic to form a supporting model (Optionally, the
partially cured bridge might can be cured in a light-curing unit
without using die silicone). After a sealer was applied, the bridge
was cured in an Enterra.TM. light-curing unit (Dentsply) for 5
minutes and flip cured for an additional 1.5 minutes. The bridge
was finished and locally polished. It was then cemented on the
prepared teeth in the patient's mouth.
Example 15
Crown Having Metal Substructure
[0105] A matrix (impression) was prepared on a tooth model, which
was made from the impression of the patient's dental anatomy prior
to preparation of the tooth intended to receive the crown. The
margin areas of the impression were trimmed to within 2 mm of the
tooth margins on the model to allow for easy escape of excess
material. Then, a dental model made from an impression of the
prepped tooth was used for preparation of the coping. A metal
coping was prepared according to conventional techniques. The metal
surface of the coping was sandblasted and steam cleaned. After
metal primer was applied on the surface of the coping, an opaque
coating was applied and cured for 5 minutes in Enterra.TM.
light-curing unit (Dentsply). Then, a second layer of opaque
coating was applied as needed to completely mask the metal surface,
and this coating also was cured. The finished metal coping was
placed on the model.
[0106] Next, a small amount of the enamel resin of Example 4C was
applied into the incisal area of the impression. A hot spatula was
used to spread out the resin. Then, a small amount of dentin resin
of Example 4D was extruded from a heated syringe to fill the
impression. Immediately, the impression was placed onto the
prepared model and excess material was allowed to escape around the
margins. The impression was then removed and excess material around
the margins and adjacent teeth was carefully removed. The resulting
crown structure was shaped and adjusted as needed. A sealer coating
was then applied, and the crown was cured in an Enterra.TM.
light-curing unit (Dentsply) for 5 minutes. The crown was finished
and locally polished as needed. It was then sent to a dentist and
cemented in a patient's mouth.
Example 16
Bridge Having Metal Substructure
[0107] A short-span dental bridge having a metal substructure was
prepared in the same manner as the crown in Example 15.
Example 17
Crown Having Zirconia Substructure
[0108] A matrix (impression) was prepared on a tooth model, which
was made from the impression of the patient's dental anatomy mouth
prior to preparation of the tooth intended to receive the crown.
The margin areas of the impression were trimmed to within 2 mm of
the tooth margins on the model to allow for easy escape of excess
material. A zirconia substructure was prepared according to the
Cercon system (Dentsply). The surface of the zirconia substructure
was steam cleaned. After primer was applied on the surface of the
substructure, an opaque coating was applied and cured for 5 minutes
in an Enterra.TM. light-curing unit (Dentsply). Then, a second
layer of opaque coating was applied as needed to completely mask
the zirconia surface, and this coating also was cured. The finished
zirconia substructure was placed on the model.
[0109] Next, a small amount of the enamel resin of Example 5C was
applied into the incisal area of the impression. A spatula was used
to spread out the resin. Then, a small amount of dentin resin of
Example 5B was extruded from a heated syringe to fill the
impression. Immediately, the impression was placed onto the
prepared model and excess material was allowed to escape around the
margins. The impression was then removed and excess material around
the margins and adjacent teeth was carefully removed. The resulting
crown structure was shaped and adjusted as needed. A sealer coating
was then applied, and the crown was cured in an Eclipse.RTM.
light-curing unit (Dentsply) for 3 minutes. The crown was finished
and locally polished as needed. It was then sent to a dentist and
cemented in a patient's mouth.
Example 18
Bridge Having Zirconia Substructure
[0110] A short-span dental bridge having a zirconia substructure
was prepared in the same manner as the crown in Example 17.
Example 19
Crown Having Fiber-Reinforced Substructure
[0111] A Matrix was prepared on a tooth model, which was made from
the impression of the area for receiving a crown in a patient's
mouth prior to preparation of the tooth. The margin areas of the
impression were trimmed to within 2 mm of the margin areas to allow
the easy escape of excess material. A fiber-reinforced coping was
prepared and cured according to prior arts. The finished
fiber-reinforced substructure was placed on the model.
[0112] A small amount of the enamel resin of Example 4A was applied
into the incisal area of the Matrix. A hot spatula was used to
spread out the resin and remove any excess in the Matrix. Desired
amount of Dentin resin of Example 4B was extruded from a heated
syringe to fill the Matrix and immediately placed the Matrix onto
above model and excess material was allowed to escape around the
margins. After the impression was removed, excess material around
margins and adjacent was carefully removed. The crown formed can be
shaped, contoured, occluded and adjusted as needed. After sealer
was applied, it was cured in an Enterra.TM. light unit (sold by
Dentsply International Inc.) for 6 minutes. It was finished and
locally polished as needed. It was then sent to dentist and
cemented in patient's mouth.
Example 20
Bridge Having Fiber-Reinforced Substructure
[0113] A short-span dental bridge having a fiber-reinforced
substructure was prepared in the same manner as the crown in
Example 19.
[0114] Workers skilled in the art will appreciate that various
modifications can be made to the embodiments and description herein
without departing from the spirit and scope of the present
invention. It is intended that all such modifications be covered by
the appended claims.
* * * * *