US20080085493A1

US20080085493A1 - Methods for making provisional and long-term dental crowns and bridges

Info

Publication number: US20080085493A1
Application number: US11/805,672
Authority: US
Inventors: Benjamin Sun; Andrew Young; Andrew Lichkus
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-09-29
Filing date: 2007-05-24
Publication date: 2008-04-10
Also published as: JP2010504826A; WO2008042375A1; US20110081627A1; CA2664786C; US9119692B2; CA2664786A1; JP2013078629A; JP2010504827A; US8636928B2; CA2664785C; US20140103557A1; EP2066259A1; EP2073750B1; JP5553604B2; US20110104641A1; JP5794972B2; EP2066259B1; WO2008042376A1; EP2073750A1; CA2664785A1

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. The material includes a polymerizable acrylic compound, polymerization initiator system capable of being activated by light or heat, and a filler material. The resulting dental restoration has good aesthetics, mechanical strength, and margins and contacts.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

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

1. Field of the Invention
The present invention relates generally to methods for making provisional and long-term dental crowns, bridges, inlays, onlays, veneers, and other dental restorations. A polymerizable composite resin having good dimensional shape-stability is used to make the dental restoration. 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 at the side of the dental chair where the patient is seated.
2. Brief Description of the Related Art
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.
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 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 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 the 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.
Dental compositions containing polymerizable resins and filler particles often are used to prepare 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. Typically, the respective pastes are stored separately in side-by-side auto-mix cartridges. When a dentist is ready to prepare the composition, the pastes are extruded through a dispensing tip attached to the cartridges. The dispensing tip normally contains a static mixing element. 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.
Compositions that can be used to make temporary crown and bridges are described generally in the patent literature. For example, May et al., U.S. Pat. No. 5,376,691 discloses dental cement for making temporary crowns and bridges. The dental cement is prepared from a first paste comprising a difunctional acrylate such as urethane diacrylate, an activator such as a tertiary amine, and radiopaque filler such as barium and/or strontium glasses. The second paste includes no substance having active double bonds, a catalyst such as dibenzoyl peroxide, a silicon dioxide material, and a softener that cannot be polymerized along with the other components but is sufficiently insoluble in the mouth. The softeners can be selected from such compounds as liquid paraffins, long-chain glycols, and inert alkylphthalates.
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° 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.
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.
Conventional temporary dental restorations, such as provisional crowns and bridges, 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.
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 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.
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, and other dental restorations having good mechanical strength, aesthetics, and occlusal fit.
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.
These and other objects, features, and advantages of this invention are evident from the following description and illustrated embodiments.

SUMMARY OF THE INVENTION

This invention provides methods for making provisional and long-term dental crowns, bridges, inlays, onlays, veneers, and other dental restorations. In one version, a dental laboratory can make the restoration. This method involves dispensing a heated polymerizable composite material into a matrix and positioning the matrix over an area of a pre-formed dental model that will receive the restoration. The composite material may comprise polymerizable acrylic compound, polymerization system capable of being activated by light or heat for polymerizing the composition, and filler material.
The composite material 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.
In another embodiment, a dental practitioner can make the dental restoration at the patient's chair in the dental office. 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 that 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.
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

The present invention relates to methods of making dental crowns, bridges, inlays, onlays, veneers, and other dental restorations using polymerizable dental composite 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 the chair of the dental patient in the dental office.
The polymerizable dental composite material used in accordance with this invention comprises a polymerizable acrylic compound; a polymerization initiation system, capable of being activated by light or heat for polymerizing the composition; and a filler material. The material can be prepared using the following components.
Dental Composite Material
Polymerizable Acrylic Compounds
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); 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.
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.
Polymerization System
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.
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.
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
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.
A wide variety of non-acid reactive filler materials 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.
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. The silica 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.
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.
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 reflective index of the composite material to provide the desired translucency. HDIDMA and HDIDA are added as solid, semi-crystalline monomers. The H₂O modified HDIDMA and HDIDA also provides a reduced crystallization time. UDMA and EBPADMA are added as liquids in order to impart flowability to the composite material at elevated temperatures, while assisting in decreasing the cure time, Lucrin-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 added to the composition to provide the composition with beneficial mechanical properties.
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 material has low shrinkage and stress.
The above-described composition can be used to fabricate dental crowns, bridges, inlays, onlays, veneers, 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
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 techniques.
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.
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 containing 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.
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.
Next, the laboratory technician prepares a matrix using a matrix 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.
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.
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.
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.
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 to prepare it.
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° C. and preferably to a temperature in the range of about 50° C. to about 100° 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.
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, 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.
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.
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, 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.
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 provisional crown. 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.
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 a dental cement.
Dental Practitioner's Chairside Method
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 that is 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.
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.
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.
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.
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.
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® processing unit, Enterra® visible light-curing (VLC) unit, and Triad® 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® Lite (Dentsply); Spectrum® 800 curing unit (Dentsply); Sapphire (DenMat); SmartLite iQ2™ (Dentsply); Elipar® (3M Espe); and L.E. Demetron II™ (Kerr).
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.
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.
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 on the crown, the margins, contacts, and 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.
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.
Following a fourth method also allows the dentist a chance to work outside of the mouth. First, the impression containing the composite material is 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.
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.
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.
The dental restorations produced by each of the methods of 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.
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

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° 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° C. and 140° 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° C. and 90° C. After about five hours stirring under 70° 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

A reaction flask was charged with 700 grams of 1,6-diisocyanatohexane and heated to about 70° 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° C. and 90° 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

A reaction flask was charged with 168 grams of 1,6-diisocyanatohexane and heated to about 70° 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° C. and 85° 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

In the following Examples 4A-4D, different polymerizable composite materials were prepared as described further below.

TABLE 1


Formulations of Composite Resins

	Example	Example	Example	Example
Components	4A (wt %)	4B (wt %)	4C (wt %)	4D (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)	5.83	5.83	5.83	5.83
Branched aliphatic
urethane dimethacry-
late (7,7,9-trimethyl-
4,13-dioxo-3,14
dioxa-5,12-diazahexa-
decane-1,16-diol
dimethacrylate)
Ethoxylated bisphenol	6.99	6.99	6.99	6.99
A dimethacrylate*
(Lucirin TPO)			0.10	0.10
2,4,6-Trimethyl-
benzoyldiphenyl
phosphine oxide
Methacrylic acid	0.085	0.085	0.06	0.06
Butylated	0.004	0.004	0.003	0.003
hydroxytoluene
N,N-dimethylamino-	0.163	0.163	0.117	0.117
neopentyl acrylate
gamma-methacryloxy-	0.050	0.050	0.036	0.036
propyl 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	0.50		0.50
(silaned)
Barium fluoro	69.50	70.00	69.50	70.00
alumino boro-
silicate glass***
Titanium Dioxide**	0.017	0.050	0.017	0.050
Yellow Iron Oxide		0.005		0.005
7055
Cromophtal Red-BRN		0.0003		0.0003
2-napthalenecarbox-
amide, N,N′-(2-chloro-
1,4-phenylene) bis{4-
{(2,5-dichlorophenyl)
azo}-3-hydroxy-}
Black Iron Oxide		0.001		0.001
7053
Lumilux Blue LZ	0.001	0.001	0.001	0.001
fluorescing agent (di-
hydroxy 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.

Example 5

Laboratory Fabricated Crown Requiring Reline to Mount

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.
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 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.
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 6

Laboratory Fabricated Crown Mounted Using Dental Cement

In this example, two dental models were made, a first model containing the unprepared tooth and a second model containing the crown-prepped tooth. 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.
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 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.
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 7

Laboratory Fabricated Bridge Requiring Reline

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.
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 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.
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. 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 8

Laboratory Fabricated Bridge Mounted Using Dental Cement

In this example, two dental models were made, a first model containing the unprepared tooth and a second model containing the bridge-prepped teeth.
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.
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, 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 provisional or long term 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. The resulting bridge was finished and polished as needed. The bridge was then cemented on the prepared teeth in the patient's mouth.

Example 9

Chairside Crown Mounted Using Dental Cement

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 dry 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 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 Eclipse® light-curing unit (available from Dentsply International) for 10 minutes. The crown was finished and polished. It was then cemented on a crown-prepped tooth in the patient's mouth.

Example 10

Chairside Crown Mounted Using Dental Cement

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 dry 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 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 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 an Eclipse® 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 11

Chairside Crown Made Using a Partial Light-Curing Process

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 dry prepared and lightly lubricated with Vaseline. A small amount of the 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. Immediately, the impression was placed onto the prepared tooth and excess material was allowed to escape around the margins. The impression was removed. Then, the crown was partially cured with a handheld light for 20 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 Eclipse® light-curing unit (Denstply) for 10 minutes. The crown was then cemented on the crown-prepped tooth in the patient's mouth.

Example 12

Chairside 3 Unit Bridge Mounted Using Dental Cement

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 4C 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 and Eclipse® light unit (Dentsply) for 10 minutes. The bridge was finished and polished. It was then cemented on the prepared teeth in the patient's mouth.

Example 13

Chairside 3 Unit Bridge Made Using a Partial Light-Curing Process

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 dry prepared and lightly lubricated with Vaseline. A small amount of the enamel resin of Example 4A was applied into the incisal areas 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 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 60 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 Eclipse® light-curing unit (Dentsply) for 10 minutes. The bridge was finished and locally polished. It was then cemented on the prepared teeth in the patient's mouth.
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.

Claims

1. A method of forming a dental restoration, comprising the steps of:

dispensing a heated polymerizable composite material into a matrix;

positioning the matrix over an area of a pre-formed dental model that will receive the restoration and allowing the composite material to set on the model;

allowing the composite material to cool and form a dimensionally shape-stable, uncured restoration on the model;

removing the matrix from the model;

irradiating the composite material with light so that it cures and forms a hardened restoration on the model; and

removing the restoration from the model.

2. The method of claim 1, wherein the composite material comprises:

polymerizable acrylic compound;

polymerization initiation system capable of being activated by light or heat, for polymerizing the composition; and

filler material.

3. The method of claim 2, wherein the polymerizable acrylic compound of the composition is a semi-crystalline material.

4. The method of claim 2, wherein the polymerization initiation system of the composition comprises a photoactive agent.

5. The method of claim 4, wherein the polymerization initiation system of the composition comprises camphorquinone.

6. The method of claim 4, wherein the polymerization initiation system of the composition comprises 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

7. The method of claim 2, wherein the composition further comprises a filler material selected from the group of inorganic and organic materials and mixtures thereof.

8. A method of forming a dental restoration, comprising the steps of:

dispensing a heated polymerizable composite material into a hardened dental impression of a patient;

positioning the impression containing the composite material in the mouth of a patient so that the composite material is molded over a targeted area that will receive the restoration;

allowing the material to cool and form a dimensionally shape-stable, uncured restoration;

removing the impression containing the composite material from the mouth;

irradiating the restoration with light so that it cures and forms a hardened restoration.

9. The method of claim 8, wherein the restoration is maintained within the impression material prior to being irradiated with light.

10. The method of claim 8, wherein the restoration is removed from the impression material prior to being irradiated with the light.

11. The method of claim 10, wherein the restoration is placed back inside of the mouth after it has been removed from the impression material and prior to irradiation with light so that the patient can bite down upon the restoration and the fit of the restoration can be checked.

12. A method of forming a dental restoration, comprising the steps of:

placing the impression containing the composite material in the mouth of a patient so that the composite material is molded over a targeted area that will receive the 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;

removing the restoration from the mouth and irradiating it with light so that it cures and forms a hardened restoration.

13. The method of claim 12, wherein the patient bites down upon the restoration prior to removing the restoration from the mouth so that the fit of the restoration can be checked.

14. The method of claim 8 or 12, wherein the uncured restoration is irradiated with light while it is positioned inside of the mouth so that it partially cures.

15. The method of claim 8 or 12, wherein the composite material comprises:

polymerizable acrylic compound;

filler material.

16. The method of claim 15, wherein the polymerizable acrylic compound of the composition is a semi-crystalline material.

17. The method of claim 15, wherein the polymerization initiation system of the composition comprises a photoactive agent.

18. The method of claim 17, wherein the polymerization initiation system of the composition comprises camphorquinone.

19. The method of claim 17, wherein the polymerization initiation system of the composition comprises 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

20. The method of claim 15, wherein the composition further comprises a filler material selected from the group of inorganic and organic materials and mixtures thereof.