MXPA00008010A - Composition for making temporary crowns and bridges - Google Patents

Abstract

The invention describes a dental composition, delivery system and method for making temporary crowns and bridges in which the composition comprises two free-radical polymerizable pastes, one a catalyst paste and the other a base paste, wherein the catalyst paste comprises at least one polymerizable monomer, at least one polymerization initiator which is a peroxide oxidizing agent, at least one first polymerization inhibitor and a filler, and wherein the base paste comprises at least one polymerizable monomer, at leat one polymerization accelerator, at least one second polymerization inhibitor, at least one non-polymerizable plasticizer and a filler. These catalyst and base pastes are stored in a dual cartridge from which they can be dispensed with a dispenser, preferably in a 1:1 volume ratio, and can be mixed in a static mixer to form a moldable polymerizing material, which is then applied to a prepared area of one or more teeth in a patient's mouth to form a crown or a bridge. The materials produced in this way have improved handling properties and exhibit a reduced oxygen inhibited layer on the surface of the cured material.

Description

COMPOSITION, DISTRIBUTION SYSTEM FOR THE SAME AND METHOD FOR MANUFACTURING TEMPORARY CROWNS AND BRIDGES Field of the Invention This invention relates to a dental material, a distribution system therefor and a method for manufacturing temporary crowns and bridges.

BACKGROUND OF THE INVENTION Materials for use in the manufacture of temporary and temporary crowns and bridges, are generally divided into two forms: powder / liquid and paste / paste; two mixing techniques: manual and self-mixing spatula; and two curing systems: self-curing and curing with light. Temporary crowns and bridges and temporary crowns and bridges are used in pending places of a permanent crown or bridge in a patient's mouth. Those useful for up to three months are often called crowns and temporary bridges, although those useful for up to a year are sometimes known as temporary crowns and bridges. The powdered / liquid form has been widely used in the past, particularly those containing monofunctional monomers.

Typically, the pulverized component comprises polymers such as poly (methyl methacrylate) mixed with dibenzoyl peroxide. The liquid component comprises plasticizers and monomers such as methyl methacrylate and / or butyl methacrylate. The paste / paste form, developed mainly in the last decade, is usually comprised of monofunctional monomers loaded with polymeric or glass charges. The technique of manual and mixed spatulation used in the past has the disadvantage that it introduces numerous air bubbles into the mixed pastes. Air bubbles trapped in the hardened material are harmful to physical resistance and lead to sites for bacterial colonies and discoloration. In addition, it is very difficult to measure the appropriate small amounts necessary to mix the components in a desired mixing ratio using this technique. In very recent years, the self-mixing technique has become the most preferred method for mixing the materials in the form of paste / paste. In this technique, the paste-like materials are stored individually in separate chambers of automixing cartridges. When they are going to be used, the pastes are mixed and dispersed automatically from their individual chambers and through a static mixer. A static mixer typically has a mixing chamber that encloses a stationary mixing member that causes the individual streams of paste in the chambers of the cartridge to combine, divide, recombine and mix. The components are extruded from their respective cartridges or cartridge chambers into the mixing chamber at the preferred ratios. The components are mixed as they pass through the mixing chamber and out through an outlet. The relationships are determined by the configurations of the cartridges from which the components are extruded to the mixer. The PROTEMP GARANT by ESPE Dental-Medizin GmbH, Seefeld / Oberbay. , Germany, TURBOTEMP by Danville Materials (San Ramón, California) and ULTRA TRIM by Bosworth Co. (Skokie, Illinois) are commercially available cartridges for polymerization mixing in a 1: 4 ratio of catalyst and base stocks, respectively . The LUXATEMP by DMG Hamburg, Germany and INTEGRITY by Dentsply / Caulk (Milfod, Delaware) are commercially available cartridges for mixing by polymerization in a 1:10 volume ratio of catalyst and base pastes, respectively. May et al., In U.S. Patent No. 5,376,691 describes two mixable pastes for producing temporary crowns and bridges in a volume ratio of between 1: 5 and 1:20. The '5,376,691 patent does not disclose the use of a polymerization inhibitor and contains a polymerizable monomer in the base paste only. Tateosian et al in US Patent No. 5, 554,665 describes a method and a disperser for producing a dental coating. Tateosian employs two pastes of similar viscosities which can be mixed in a volume ratio of 1: 1 to 1: 5, each paste contains a polymerizable monomer and a single polymerization inhibitor such as butylated hydroxytoluene. All of the disclosures of U.S. Patent Nos. 5,376,691 and 5,554,665 are incorporated, respectively, therefore, here by reference. Temporary crown and bridge materials of the prior art produced by mixing catalyst and base pastes of a cartridge, in a volume ratio different from 1: 1, such as between 1: 4 and 1:20, have disadvantages of use. Most dentists have a distribution system in a ratio of 1: 1 to disperse other dental materials, such as impression materials. Dispersing two pastes in a different ratio to 1: 1 requires a distribution system that is designed for that other desired predetermined unique relationship. Therefore, dentists have to buy an extra distribution system or change the piston that is used to push such pastes out of the cartridge after the dispersion of a printing material. The first case is not economical and creates the need for more storage space and more disinfection , since there are two systems instead of one. The second case is inconvenient in practice. It is also typical in the methods of the prior art to mix two liquids or two pastes with the same or similar viscosities in a static mixer. The catalyst paste, however, has rheological characteristics substantially different from those of the base paste. As a result, where the paste and the catalyst paste have the same viscosity, the catalyst paste initially moves through the mixer at a faster rate than the base paste, causing the unmixed catalyst paste to appear first at the outlet of the mixer. This causes a non-uniform and incomplete cure in portions of the dispersed mixture. Prior art materials, such as those described in U.S. Patent No. 5,554,665 produced by mixing two free radical polymerizable acrylic pastes, have a dispersed (dispersed) layer inhibited by oxygen (air), coarse, over the surface of the cured materials, a layer inhibited by oxygen is an uncured paste layer in which the polymerization is inhibited by the dissolved oxygen in the paste from the atmosphere. Such layers can not be completely avoided in free radical polymerizations. A layer inhibited by oxygen, thick, produces a very adhesive surface, which creates difficulty in handling and must be cleaned with alcohol. In addition, unreacted monomers in the layer inhibited by oxygen can be toxic and cause skin sensitivity. Ratcliffe et al in U.S. Patent No. 4,602,076 discloses the use of an organic peroxide in a photopolymerizable dental adhesive composition comprising a ketone photoinitiator that improves curing with visible light radiation at room temperature and in the presence of air. The 4,602,076 patent does not employ polymerization inhibitors.

Brief Description of the Invention The present invention provides a dental material for manufacturing temporary and temporary crowns and bridges, particularly temporary crowns and bridges, comprised of a catalytic paste and a base paste that can be mixed in a static mixer to form a moldable polymerizable material that exhibits improved handling properties and a layer inhibited by reduced oxygen on the surface of the cured material. Unless the context requires otherwise, both temporary and temporary crowns and bridges are referred to generically here as temporary crowns and bridges. In the dental material of the present invention, the catalyst paste is comprised of at least one polymerizable acrylic monomer, at least one polymerization initiator, at least one polymerization inhibitor and one charge. The base paste is comprised of at least one polymerizable acrylic monomer, at least one polymerization accelerator, at least one polymerization inhibitor, and one charge. Preferably, the catalyst paste and the paste are each comprised of at least one monofunctional acrylic polymerizable monomer, with at least one polymerizable acrylic monomer in the catalyst paste being different than the monomer of the base paste. Preferably also, at least one polymerization initiator is preferably an oxidizing agent and preferably a peroxide oxidizing agent and at least one polymerization accelerator is preferably a reducing agent. Additionally, at least one non-polymerizable plasticizer is preferably included in one of the pastes, particularly the base paste. Furthermore, in the preferred embodiments of the invention, at least two different polymerization inhibitors are present in the material. Preferably, one of the pastes, preferably the base paste, includes two different polymerization inhibitors. One type of polymerization inhibitor can be included in both pastes. Preferably, two different polymerization inhibitors are selected to respectively provide two different functions, one having an influence on the gel time, for example, to be placed in the range of one to two minutes from the time the pulps are mixed for the first time, and one that has influence on the hardening time, for example to place it in an interval of one to two minutes beyond the point at which it has gelled. Furthermore, in a preferred embodiment of the invention, a dental material for making temporary crowns and bridges comprised of a catalytic paste and a base paste in which the base paste contains a relatively large amount of a polymerization accelerator, for example, is provided. in the base paste, from approximately two to six times the amount normally considered as the maximum desirable amount. Preferably, the accelerator is accompanied by a proportional amount of polymerization inhibitor and a smaller amount of polymerization initiator in the catalyst paste. According to other aspects of the present invention, a dental material for manufacturing temporary crowns and bridges is provided comprising two free radical polymerizable pastes: a catalytic paste and a base paste, where the viscosity of the catalytic paste is greater than the viscosity of the base paste. Moreover, the two pastes are preferably stored separately in different chambers of a double cartridge where they can be dispersed with a manual disperser and mixed in a static mixer. In addition, the pastes of the preferred embodiment of the present invention are capable of being dispersed in about a volume ratio of 1: 1 and are provided in a double chamber cartridge that provides the dispersion in a volume ratio of about 1: 1. .

According to still another aspect of the present invention, there is provided a method for manufacturing temporary crowns and bridges comprising the steps of: 1) providing a free radical polymerization system, redox, having a catalytic paste and a base paste, wherein the catalyst paste comprises at least one polymerizable acrylic monomer, at least one polymerization initiator, at least one polymerization inhibitor and a filler, and wherein the base paste comprises at least one polymerizable acrylic monomer, at least one accelerator of the polymerization, at least one polymerization inhibitor, and one charge; and 2) mixing the catalyst and base pastes, preferably from a two-chamber cartridge through a static mixer to form a polymerizing material. The method preferably also includes the steps of 3) applying the polymerizing material directly to a previously made impression; and 4) molding the polymerizing material within a prepared area of one or more teeth in the mouth of a patient to form a crown or bridge. Preferably also, the catalyst paste comprises at least one polymerizable monomer, at least one polymerization initiator which is a peroxide oxidizing agent, at least one polymerization inhibitor and a filler, and the base paste comprises at least one polimepable monomer, at least one polymerization accelerator, at least one polymerization inhibitor, at least one non-polymerizable plasticizer and one filler. According to the present invention there is thus provided a dental material for making temporary crowns and bridges comprised of two radical polymerizable pastes which a) can be mixed in a volume ratio of 1: 1 in a static mixer, b) exhibits cuts short hardening coupled with prolonged gelation times due to the use of multiple inhibitors, c) does not sacrifice shelf stability and d) results in only a layer inhibited by minimal oxygen on the surface. These and other objects and advantages of the present invention will become more apparent from the accompanying description of the preferred embodiments of the invention and the examples.

Detailed Description In the present invention, the catalyst paste comprises at least one polymerizable acrylic monomer, at least one polymerization initiator, at least one polymerization inhibitor and one charge.

The polymerizable monomers useful in accordance with the principles of the present invention are functional (meth) acrylate monomers such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate. , tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,6-hexandiol di (meth) acrylate, trimethylol tri (meth) acrylate) propane, 2, 2-bis [4- (2-hydroxy-3-acryloioloxypropoxy) phenyl] propane, 2, 2-bis [1- (2-hydroxy-3-methacryloyloxypropoxy) phenyl] propane (popular name: Bis-GMA) ), 2,2-bis [4-acryloioloxy-ethoxy) phenyl] propane, 2,2-bis [4- (methacryloyloxy-ethoxy) phenyl] propane, urethane di (meth) acrylate, and the like. The term "(meth) acrylate" herein means methacrylate or acrylate.

Among the monomers listed above, 2,2-bis [4- (methacryloyloxy-ethoxy) phenyl] propane (popular name: ethoxylated bisphenol-A-dimethacrylate) is the preferred monomer for use in the catalyst paste. One or more polymerizable monomers can be used in the catalyst paste. The polymerization initiators can be chosen from known organic peroxides such as dibenzoyl peroxide, di-p-chlorobenzoyl peroxide, di-2-dichlorobenzoyl peroxide, tertiary butyl peroxybenzoate, methyl ethyl ketone peroxide, butyl peroxide diterciicrio, dicumil peroxide and eumeno hydroperoxide, and similicres. A preferred and preferred peroxide is dibenzoyl peroxide. A cycidicity of the dibenzoyl peroxide kgregicdic is preferably in the range of approximately 0.3 wt% to approximately 1.7 wt%. One or more initiators of polymerization may be used in the picictic cicticlítictc. The polymerization inhibitors used in the cyclical cycle include hydroxytoluene butyltene., hydroquinone, hydroquinone monomethyl ether, benzoquinonic, chloricnil, phenol and similiéres. A first preferred polymerization inhibitor used in the present invention is hydroxytoluene butyl, where the bis-enol-A-dimethyl-ethylic acid is used as the monomer. The inhibitor is used to remove small amounts of free radicals during picric icing, improving the likelihood of the picnic icicle. The effectiveness of the used tissue inhibitor will depend on costs such as the type of monomer used in lie picstic, the presence of other components, and the other components of other components present in the picstic. A technical expert can determine which Inhibitors will be useful in the picsticidal composition being used. A number of known inhibitors, their characteristics, and their compatibility with various monomeric systems are described in G. Odian, Principles of Polymerization p242-251 (1981), which is incorporated herein by reference. More than one inhibitor can be used in the catalytic paste. Payloads in the paste compositions of the present invention include organic and inorganic fillers. Organic fillers are particularly polymers or copolymers. The inorganic fillers are silicon dioxide and glasses. A preferred silicon dioxide is submicron amorphous fumed silica, preferably treated with a silane or polymer to improve hydrophobicity. The thixotropic characteristics of fumed silica greatly improve the thickness and adhesiveness of the paste and to allow easy extrusion through a static mixer. Glass fillers include borosilicate glass, barium glass, strontium glass, yttrium glass, zirconium glass, lanthanum glass and the like. A preferred glass filler is barium glass, which provides good radiopacity. Preferably, the glass filler has a particle size of at least 200 microns, more preferably in the range of about 0.1 to about 10 microns. In addition, the filler is preferably treated with a silane such as gamma-methacryloxy propyl trimethoxy silane (trademark A-174 manufactured by Union Carbide, Danbury, Connecticut) to improve the bond between the filler and the polymer matrix. Other silanes can also be substituted for this purpose. In the present invention, the base paste comprises at least one polymerizable monomer, at least one polymerization accelerator, at least one polymerization inhibitor, at least one non-polymerizable plasticizer and a filler. The polymerizable monomers listed for use in the catalyst paste may also be useful in the base paste as long as a different monomer is used in each paste. A preferred polymerizable monomer in the base paste is urethane dimethacrylate (UDMA). It is preferable to add a small amount of Bis-GMA as a second monomer to improve curing and thereby reduce the layer inhibited by oxygen and increase the flexural strength of the cured material. Polymerization accelerators should be used in combination with a peroxide to allow rapid polymerization of the monomer at room temperature. One skilled in the art will appreciate that tertiary amines are generally preferred for use in dental restorations, as described in the article by GM Brauer et al., In Day 58 of Dental Research 1994-2000 (1956), which it is incorporated here as a reference. One skilled in the art will also appreciate that known tertiary amines or freshly synthesized tertiary amines can be used. Typical tertiary amines include triethanolamine, N, N-3, 5-tetramethyl aniline, 4- (dimethylamino) -phenethyl alcohol, dimethyl aminobenzoic acid ester, dimethyl-p-toluidine, dihydroxyethyl-p-toluidine, and the like. A preferred amine accelerator for use in the present invention is dihydroxy ethyl-p-toluidine. An adequate amount of dihydroxyethyl-p-toluidine is in the range of 2% to 5% by weight. In a base composition in which less than 2% by weight of dihydroxyethyl-p-toluidine has been added and in a catalyst composition in which less than 0.3% by weight of dibenzoyl peroxide has been added, curing of the mixture does not It is satisfactory. In a base composition in which less than 2% by weight of dihydroxyethyl-p-toluidine has been added and in a catalytic composition in which 0.3% to 1.3% by weight of dibenzoyl peroxide has been added, the layer inhibited by the Oxygen on the surface of the cured material is too thick or too sticky. On the other hand, if the amount of dihydroxyethyl-p-toluidine exceeds 6% by weight of the base composition, the shelf life of the pulp decreases, and the cured material tends to be yellow in color. Suitable polymerization inhibitors in the base paste can be selected from the list described for the catalyst paste. Preferably, at least one inhibitor used in the catalyst paste or base is different from another inhibitor used in one of the pastes, preferably in the other paste.

In addition, at least one of the pastes preferably contains two different polymerization inhibitors to the messages. In the preferred embodiment of the invention, acceptable gel polymerization times, hardening times and shelf stability of the paste were observed when multiple inhibitors were used in either the catalyst paste or the base paste, and preferably in the paste base. Preferred inhibitors in the base paste are a combination of butylated hydroxytoluene and hydroxyquinone monomethyl ether. Both inhibitors act as a scavenger to trap free radicals and to prolong the gel time, hardening time and shelf stability of the pulp. l However, the hydroxyquinone monomethyl ether has a greater influence on the gel time and the butylated hydroxytoluene has a greater influence on the hardening time. As a result, the hydroxyquinone monomethyl ether prolongs the gelling time without unduly prolonging the hardening time, which would be the case with the butylated hydroxytoluene used only in larger amounts. The incorporation of different amounts of two different inhibitors will produce the desired gel time and hardening time. One skilled in the art will appreciate that the particular type (s) and amounts of inhibitors used in the system to produce the desired gelation times and hardening will depend on the particular types and amounts of monomers and other components present in the system. Preferably a non-polymerizable plasticizer is also included, and may be chosen from saturated or inert liquid organic compounds including alkyl phthalates, liquid paraffins and low molecular weight polyglycols. Examples are diethyl phthalate, dibutyl phthalate, poly (ethylene glycol) mineral oil - Mn 200-400, poly (propylene glycol) -Mn 400-4000 and the like, where Mn refers to the number average molecular weight. Preferred non-polymerizable plasticizers are dibutyl phthalate and / or poly (propylene glycol) -Mn 4000. One or more non-polymerizable plasticizers can also be added to the catalyst paste. The charge for the base paste can be selected from the same list of charges used in the catalyst paste or among other charges. A different charge may be used in the catalyst paste different from the base paste. A photoinitiator and promoter can be added to either the catalyst paste or the base paste to make the material curable clear. In this case, it is necessary that the paste compositions are stored in an opaque container, typically a black container. Camphorquinone is a typical photoinitiator used in dental materials. Other suitable photoinitiators and promoters are described in U.S. Patent No. 4,746,686, which is incorporated herein by reference. For aesthetic or other purposes, the paste compositions may include small amounts of additives such as pigments, opacifiers, fluorescers, ultraviolet stabilizers, antioxidants and the like provided they do not substantially affect curing.

In a general preferred embodiment according to the present invention, the catalyst paste and the base paste comprise the compositions in the following approximate ranges of weight proportions: CATALYTIC PASTE% IN WEIGHT Ethoxylated bisphenol-A-dimethacrylate 0-75 Bis-GMA 0-75 Urethane dimethacrylate 0-75 Triethylene glycol dimethacrylate 0-75 Poly (propylene glycol) -MN 4000 0-20 Dibenzoyl peroxide 0.3-1.7 Butylated hydroxytoluene 0-0.5 Hydroquinone monomethyl ether 0-0.1 Fuming silica 0-10 Barium glass, silanized 0-60 BASE PASTE% IN WEIGHT Bisphenol-A-dimethacrylate ethoxylate 0-75 BASE PASTE% IN WEIGHT Bis-GMA 0-75 Urethane dimethacrylate 0-75 Ethylene glycol dimethacrylate 0-75 Dibutyl phthalate 0-20 Dihydroxyethyl-p-toluidine 2-6 Canforquinone 0.2 Butylated hydroxytoluene 0-0.5 Hydroquinone monomethyl ether 0-0.1 Fuming silica 0-10 Barium glass, silanized 0-60 Additives 0-0.5 In a preferred embodiment of the present invention, both catalyst and base paste compositions are stored in a non-contact state, in separate chambers of a double cartridge described in U.S. Patent No. 5,554,665, which is incorporated herein by reference. A polymerizing material is produced by extruding the catalyst paste and the base paste through a static mixer attached to the double cartridge. Both of the catalytic paste and the base paste can be mixed in a volume ratio of between 1: 1 and 1: 2, between 1: 1 and 2: 1. Preferably, the catalyst paste and the base paste are mixed in a volume ratio of substantially 1: 1. The polymerization catalyst is activated when the catalytic and base pastes are mixed. The mixed paste begins to polymerize in less than 3 minutes from the start of mixing. The viscosity of the mixed paste increases gradually. Within less than 6 minutes from the start of mixing, the polymerizing paste hardens. Preferably, the catalyst paste and the base paste are mixed bubble-free and produce cured materials without bubbles with strong physical properties. Cured materials made in accordance with this embodiment of the present invention have a minimum thickness (less than 50 μm) of the layer inhibited by oxygen on the surface. In another preferred embodiment of the present invention, the viscosity of the catalyst paste according to the present invention is substantially higher than the viscosity of the base paste. Although the prior art methods typically mixed two liquids or two pastes with the same or similar viscosities in the static mixers *, the nature of the materials used in accordance with the present invention dictates that the catalyst paste is of a thicker consistency than the base paste for use in a 1: 1 dispersion system. The rheological characteristics of the catalyst paste are substantially different from those of the base paste. It was found that the mixture starts. it does not cure if the viscosities of the catalytic paste and the base paste are the same or similar because the catalyst paste tends to come out of an est mixer. faster than the base paste. A more satisfactory uniform mixing and curing can be obtained only when the catalyst paste is adjusted to be more thick than the base paste, so that the pulps are extruded thereto or at similar speeds. To increase the filler content, preferably the fumed silica content, in the catalytic paste gives: as a result a thicker paste, since some components of the filler such as fuming silica are highly sensitive to viscosity . The compositions of the present invention are advantageously used to make temporary crowns and bridges. Two polymerizable pastes, a catalytic paste and a base paste, are mixed from a double cartridge in a static mixer to form a polymerizing material which is then extruded directly onto a pre-made impression or a plastic matrix. Subsequently the impression or matrix, including the polymerizing material, is immediately applied to an area of one or more teeth prepared in the mouth of a patient. The polymerizing material is molded by pressing the plastic impression or matrix. Within a few minutes, the polymerizing material polymerizes and partially hardens. In a preferred embodiment, the plastic impression or matrix including the partially polymerized, molded material is removed from the patient's mouth before the polymerizing material hardens, and is further polymerized extraordinarily at room temperature to substantially complete the cure . In another embodiment of the invention, the partially polymerized material after molding is further cured by irradiating the molded material in a patient's mouth with light from a light curing apparatus. In another embodiment of the present invention, the partially polymerized material after molding is removed from the patient's mouth and further cured in a heat curing oven. Alternatively, the partially polymerized material after the mold is removed from the patient's mouth is further cured by irradiating the molded material in a light curing oven, which provides heat and light. The current invention overcomes the deficiencies of self-mixing systems for mixing catalyst paste and base paste in a volume ratio different from 1: 1, such as between 1: 4 and 1:20, and provides for the convenient use of dispersed pulps from a double cartridge in a static mixer to manufacture temporary crowns and bridges. The present invention employs multiple inhibitors in the paste compositions and overcomes the shortcomings of the self-curing systems allowing similar hardening times coupled with longer gelation times, while preserving their shelf stability. The system of this invention offers better handling properties, such as mixing, curing and layer inhibited by oxygen of minimum thickness (less than 50 μm) suitable on the surface of the cured materials.

EXAMPLE 1 The following example illustrates a preferred embodiment of the present invention.

TABLE 1 CATALYTIC PASTE IN WEIGHT Ethoxylated bisphenol-A-dimethacrylate 55.8i Dibenzoyl peroxide 1.0 Butylated hydroxytoluene 0.12 Fuming silica 5.0 Barium glass, silanized 38.0 BASE PASTE% IN WEIGHT Bis-GMA 5.0 Urethane dimethacrylate 41.42 Dibutyl phthalate 10.0 Dihydroxyethyl-p-toluidine 4.4 Butylated hydroxytoluene 0.06 Hydroquinone monomethyl ether 0.01 Fuming silica 3.0 Barium glass, silanized 36.0 Pigment 0.11 Both of the catalytic paste and the base paste were formed separately by mixing the ingredients in a planetary mixer. The catalytic paste had a consistency index of 2.9 cm and the base paste had a consistency index of 4.7 cm. The consistency index was determined by measuring the diameter of 1.0 grams of paste that had been placed between two flat and leveled glass plates and pressed under a weight of 108.0 grams for ten minutes. The catalyst paste and the base paste were stored in the separate chambers of a 50 ml double cartridge (CS050-01-09) manufactured by MixPac Systems, AG, Rotkreuz, Switzerland. The cartridge was then placed in a manual distributor manufactured by MixPac. A static mixer was attached to the cartridge. The catalytic and base pastes were extruded in a volume ratio of 1: 1 from the static mixer and applied directly to a pre-fabricated impression or matrix which was immediately placed on a prepared tooth. After approximately two minutes, 1 impression with the curing material was removed. The obtained crown was allowed to cure for approximately two additional minutes. After deburring and polishing, a temporary crown was formed.

EXAMPLE 2 The following example illustrates the comparison of gel time and hardening time for the base paste of Example 1 having two polymerization inhibitors and a base paste having a single polymerization inhibitor.

TABLE 2 BASE PASTE% IN WEIGHT Bis-GMA 5.0 Urethane dimethacrylate 41.43 Dibutyl phthalate 10.0 Dihydroxyethyl-p-toluidine 4.4 Butylated hydroxytoluene 0.06 Fuming silica 3.0 Barium glass, silanized 36.0 Pigment 0.11 The base paste with a single inhibitor was formed by mixing the ingredients of Table 2 in a planetary mixer. The catalyst paste was formed according to that described in Example 1. The catalyst paste and the paste were stored in the separate chambers of a 50 ml double cartridge manufactured by MixPac (CS 050-01-09). This cartridge was then placed in a manual distributor manufactured by MixPac. A static mixer was attached to the cartridge. The catalytic and base pastes were extruded in a 1: 1 volume ratio from the static mixer. The gelation times and hardening times are shown in Table 3 for the pastes of Examples 1 and 2, which contain two and a polymerization inhibitor in the base paste, respectively. The gelling time was measured as the time it takes for the initial mixing of the pastes for the material until there is no peak of the surface when tested with a manual pointed instrument. The hardening time was measured as the period of time during which the manual zone is able to penetrate the surface of the material.

TABLE 3 Samples Time of Gelification Time Hardening (Seconds) (Seconds) Material of Example 1 90 140 TABLE 3 (continued) Samples Time of Gelification Time Hardening (Seconds) (Seconds) Material of Example 2 40 90 The results of Table 3 show a significant difference in gel time between the base paste having a single polymerization inhibitor and that having two polymerization inhibitors. Although the hardening time is slightly longer in the material of Example 1, this is acceptable as long as a longer gel time is achieved. Preferably, the gelling time is in the range of about one to two minutes and the initial mixing of the pastes while the hardening time is approximately one to two times the gelling time from the initial mixing of the pastes.

EXAMPLE 3 The following example illustrates the similar viscosities (consistencies) of the catalytic and base pastes, which resulted in an unsatisfactory cure of the initial mixture. TABLE 4 CATALYTIC PASTE% IN WEIGHT Ethoxylated bisphenol-A-dimethacrylate 58.83 Dibenzoyl peroxide 1.0 Butylated hydroxytoluene 0.17 Fuming silica 3.0 Barium glass, silanized 37.0 BASE PASTE% IN WEIGHT Bis-GMA 5.0 Urethane dimethacrylate 41.08 Dibutyl phthalate 10.0 Dihydroxyethyl-p-toluidine 3.8 Hydroquinone monomethyl ether 0.01 Fuming silica 4.0 Barium glass, silanized 36.0 Pigment 0.11 Both of the catalytic paste and the base paste were formed separately by mixing the ingredients in a planetary mixer. The catalytic paste had a consistency index of 3.6 cm and the base paste had a consistency index of 3.9 cm. The viscosities of the catalytic and base pastes were very similar. The catalytic paste and the base paste were stored in the separate chambers of a 50 ml double cartridge made of MixPac (CS 050-01-09). This cartridge was then placed in a manual distributor manufactured by MixPac. A static mixer was attached to the cartridge. The catalyst and base pastes were extruded in a 1: 1 volume ratio of the static mixer, preferably at room temperature. In this system, the initial mixture of catalytic and base pastes mainly contains catalyst paste composition and consequently does not polymerize for a prolonged period of time. The catalyst paste of Example 1 had a consistency index substantially lower than that of the base paste due to the higher fumed silica content, and as a result, a satisfactory cure of the initial mixture was achieved.

EXAMPLE 4 The following example illustrates that the use of a higher level of dihydroxyethyl-p-toluidine of 4.4% by weight in Example 1 achieves a thinner oxygen-inhibited layer than the use of a lower level of hydroxyethyl-p-toluidine of this example.

TABLE 5 CATALYTIC PASTE% IN WEIGHT Ethoxylated Bisphenol-A-dimethacrylate 55. L Dibenzoyl peroxide 1.7 Butylated hydroxytoluene 0.12 Fuming silica 5.0 Barium glass, silanized 38.0 BASE PASTE% IN WEIGHT Bis-GMA 5.0 Urethane dimethacrylate 43.99 Dibutyl phthalate 10.0 Dihydroxyethyl-p-toluidine 0.9 BASE PASTE% IN WEIGHT Fuming silica 4.0 Barium glass, silanized 36.0 Pigment 0.11 Both of the catalytic paste and the base paste were formed separately by mixing the ingredients in a planetary mixer. The catalytic paste and the base paste were stored in the separate chambers of a 50 ml double cartridge manufactured by MixPac (CS 050-01-09). This cartridge was then placed in a manual distributor manufactured by MixPac. A static mixer was attached to the cartridge. The catalytic and base pastes were extruded in a 1: 1 volume ratio through the static mixer. The thickness of the layer inhibited by oxygen is shown in Table 6 for the legs of Examples 1 and 4, which contain different amounts of hydroxyethyl-p-toluidine in the base paste. The thickness of the layer inhibited by oxygen was determined by measuring the thickness of the uncured layer of paste, which had been placed between two microscope slides 0.15 mm apart under a microscope. The thickness of the layer inhibited by oxygen for the existing temporary crown materials is also presented in Table 6.

TABLE 6 Samples Ratio of the volume of the inhibited layer by mixing the catalyst and base oxygen (μm) Material of Example 1 1: 1 40 Material of Example 4 1: 1 50 Protemp Garant, ESPE 1: 4 40 Turbotemp, Danville 1: 4 53 Material Ultra Trim, Bosworth 1: 4 59 Luxatemp, DMG Hamburg 1:10 50 It can be seen that the material of Example 1 is only a 1: 1 ratio system that observes a layer inhibited by oxygen of 50 μm. The Protemp Garant also observes a layer inhibited by minimal oxygen, but employs a system with a ratio of 1: 4, and therefore, lacks the other benefits of the system with a ratio of 1: 1 of Example 1. From this Thus, adjusting the viscosity of the catalyst paste together with increasing the amount of accelerator in the base paste results in a layer inhibited by minimal oxygen in a system with a ratio of 1: 1.

EXAMPLE 5 The following example is a comparison with Example 1 illustrating the role of polymerization inhibitors in prolonging the shelf life of the catalyst paste and the base paste.

TABLE 7 CATALYTIC PASTE% IN WEIGHT Ethoxylated bisphenol-A-dimethacrylate 55.53 Dibenzoyl peroxide 1.3 Butylated hydroxytoluene 0.17 Fuming silica 5.0 Barium glass, silanized 38.0 BASE PASTE% IN WEIGHT Bis-GMA 5.0 Urethane dimethacrylate 42.89 Dibutyl phthalate 10.0 Dihydroxyethyl-p-toluidine 3.0 Fuming silica 3.0 Barium glass, silanized 36.0 Pigment 0.11 Both of the catalytic paste and the base paste were formed separately by mixing the respective ingredients of each in a planetary mixer. Catalytic paste and base paste were stored in separate chambers of a 50 ml double cartridge manufactured by MixPac (CS050-01-09). The shelf life test was performed by storing the full cartridges that had a stopper by closing one end at selected temperatures. At certain time intervals, the cartridge was removed from the oven and cooled to 23 ° C. The plug was removed from both cylinders, and a pointed probe (150 mm by 1 mm in diameter) was inserted into the paste to verify the polymerization. The shelf life at each temperature is the time from the initial formulation of the paste until just before the polymerization is first detected. Acceptable dental materials of this type generally have a shelf life at 42 ° C that exceeds 21 days. Table 8 shows the shelf life for the pastes of Examples 1 and 5. The results show that the shelf life at 42 ° C in the pulp with the highest level of dihydroxyethyl-p-toluidine (Example 1) was prolonged by incorporating inhibitors in both catalytic and base pastes. However, in the catalyst and base paste system of Example 5, which does not contain any inhibitor in the base stock, there was lower shelf stability of the base stock at 42 ° C. In addition, in the system of Example 5, with a larger amount of catalyst or initiator in the catalyst paste was necessary to compensate for the lack of accelerator in the base paste, even with a proportional increase in the inhibitor in the catalyst paste, shelf stability of the catalytic paste also decreased.

TABLE 8 Samples shelf life Life at 42 ° C shelf at 50 ° C Catalytic paste of Example 1 > 65 days 40 hours TABLE 8 (continued) Samples shelf life Life at 42 ° C shelf at 50 ° C Catalytic paste of Example 2 6 days 24 hours Base paste of Example 1 > 65 days 7 days Base paste of Example 2 20 days 1 day The description and the above methods demonstrate that the presence of a polymerizable monomer in both parts and a slightly high filler content in the catalyst paste allows a system with a ratio of 1: 1 with a satisfactory cure. In addition, the increase in accelerator content in the base paste decreases the thickness of the layer inhibited by oxygen. This can, however, cause instability in the mix. To maintain a high stability, a polymerization inhibitor is present in both pastes and two polymerization inhibitors are present in at least one of the pastes, preferably the base paste. This inhibition system also serves to increase the gel time of the mixture. Although the present invention has been illustrated by the description of embodiments thereof, and although the embodiments have been described in considerable detail, it is not intended to restrict the scope of the appended claims to such details by any means. In particular, certain materials may be replaced with materials now or later discovered that provide the functions set forth herein, and changes in the components may require changes corresponding to the quantities and proportions for the replacement components that are equivalent to those exposed for the components exposed. Additions and modifications will be readily apparent to those skilled in the art. For example, the viscosities of the pastes can be adjusted to work in a system to disperse in a ratio of 2 to 1 or 1 to 2. The invention in its broader aspects, therefore is not limited to the specific details, apparatus and representative methods and representative examples shown and described. Accordingly, modifications to such details can be made without departing from the scope and spirit of the applicant's general concept. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Claims (46)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. 1. A distribution system for distributing a material for manufacturing temporary crowns and bridges, the system is characterized in that it comprises: a cartridge having two material storage chambers, including a first chamber and a second chamber, the cartridge is configured for simultaneously ejecting material from each of the chambers in a predetermined volume relation towards a static mi a first chamber is prefilled with a catalytic paste including at least one polymerizable acrylic monomer, at least one polymerization initiator, a first polymerization inhibitor, and a filler; and the second chamber is prefilled with a base paste including at least one polymerizable acrylic monomer, at least one polymerization accelerator, a second polymerization inhibitor, a third polymerization inhibitor, a charge; and where a second polymerization inhibitor is different from the third polymerization inhibitor.
2. 2. The system according to claim 1, characterized in that the first and second polymerization inhibitors are the same.
3. 3. The system according to claim 1, characterized the catalytic paste includes a fourth polymerization inhibitor which is different from the first polymerization inhibitor.
4. 4. The system according to claim 1, characterized in that the catalytic paste further comprises at least one non-polymerizable plasticizer.
5. 5. The system according to claim 4, characterized in that the non-polymerizable plasticizer is selected from the group consisting of: dibutyl phthalate, polypropylene glycol-Mn 4000 and mixtures thereof.
6. 6. The system according to claim 1, characterized in one of the pastes further comprises at least one photoinitiator.
7. The system according to claim 6, characterized in that the photoinitiator camphorquinone.
8. The system according to claim 1, characterized in that the polymerizable acrylic monomer in the catalyst paste is one or more materials selected from the group consisting of: of: ethoxylated bisphenol-A-dimethacrylate and 2,2-bis [4- (2-hydroxy-3-methacryloyloxypropoxy) phenyl] propane.
9. The system according to claim 1, characterized in that the polymerization initiator is a peroxide oxidizing agent.
10. The system according to claim 9, characterized in that the peroxide oxidizing agent is dibenzoyl peroxide present at a concentration in the range of about 0.3% to about 1.7% by weight.
11. The system according to claim 1, characterized in that the first polymerization inhibitor is butylated hydroxytoluene.
12. The system according to claim 1, characterized in that the polymerizable acrylic monomer in the base paste is one or more materials selected from the group consisting of: urethane dimethacrylate, 2,2-bis [4- (2-hydroxy 3-methacryloyloxypropoxy) phenyl] propane and mixtures thereof.
13. 13. The system according to claim 1, characterized in that the accelerator of the polymerization is a tertiary amine.
14. 14. The system according to claim 13, characterized in that the accelerator of the polymerization is dihydroxyethyl-p-toluidine.
15. 15. The system according to claim 14, characterized in that the dihydroxyethyl-p-toluidine has a concentration in the range of about 2% to about 6% by weight.
16. 16. The system according to claim 1, characterized in that the second polymerization inhibitor is butylated hydroxytoluene.
17. 17. The system according to claim 16, characterized in that the third polymerization inhibitor is hydroquinone monomethyl ether.
18. 18. The system according to claim 1, characterized in that the non-polymerizable plasticizer is selected from the group consisting of: alkyl phthalates, liquid paraffins and low molecular weight polyglycols.
19. The system according to claim 18, characterized in that the base paste includes a non-polymerizable plasticizer selected from the group consisting of dibutyl phthalate, polypropylene glycol-Mn 4000 and mixtures thereof.
20. 20. The system according to claim 1, characterized the load is one or more materials selected from the group consisting of: fuming silica, barium glass, borosilicate glass, strontium glass, yttrium glass, zirconium glass and lanthanum glass .
21. 21. The system according to claim 1, characterized in that the catalyst paste has a viscosity greater than the viscosity of the base paste.
22. 22. The system according to claim 1, characterized the accelerator is present in an effective amount to obtain a layer inhibited by oxygen on the surface of the material after curing less than 50μm.
23. 23. The system according to claim 1, characterized in that: the viscosity of the catalytic paste is greater than the viscosity of the base paste; and the polymerization accelerator is present in an effective amount to achieve a layer inhibited by oxygen on the surface of the material after curing of less than 50μm.
24. 24. A distribution system for distributing material for making temporary crowns and bridges, the system is characterized in that it comprises: a cartridge having two material storage chambers, including a first chamber and a second chamber, the cartridge is configured to eject material simultaneously from each of the chambers in a predetermined volume ratio towards a static mixer first chamber is prefilled with a catalytic paste including at least one polymerizable acrylic monomer, at least one polymerization initiator, at least one inhibitor of the polymerization, and a charge; and the second chamber is prefilled with a base paste including at least one polymerizable acrylic monomer, at least one polymerization accelerator, at least one polymerization inhibitor, one charge; and wherein the catalyst paste has a viscosity greater than the viscosity of the base paste, so that the initial flow of the catalyst paste through the mixer corresponds to the initial flow of the base paste through the mixer according to a volume ratio default
25. 25. The system according to claim 24, characterized in that at least one polymerization inhibitor in the base paste includes an inhibitor that has a greater influence on the gel time than the hardening time and another that has a relatively greater influence on the hardening time than on the gel time.
26. 26. The system according to claim 24, characterized in that at least one polymerization inhibitor in the base paste includes two different polymerization inhibitors.
27. The system according to claim 24, characterized in that the cartridge is configured to eject material simultaneously from each of the chambers in a predetermined volume ratio of substantially 1 to 1.
28. 28. The system according to claim 24, characterized in that the chambers of the cartridge are each, respectively, prefilled with approximately equal volumes of the catalytic and base pastes.
29. The system according to claim 24, characterized in that the cartridge has a coupling configured to be connected to the inlet end in a static mixer, and each chamber has an outlet positioned to communicate with the inlet end of the mixer when the cartridge is coupled to it.
30. 30. The system according to claim 24, characterized in that at least one accelerator of the polymerization is present in an amount sufficient to achieve a layer inhibited by oxygen not greater than 50 microns when the material has cured.
31. The system according to claim 30, characterized in that at least one polymerization inhibitor in the base paste includes a polymerization inhibitor which, in combination with another polymerization inhibitor in the material, it prolongs the gelling time of the material from approximately one to two minutes from the mixing of the pastes.
32. 32. The system according to claim 24, characterized in that the amount of filler in the catalyst paste is sufficient to raise the viscosity thereof to more than the viscosity of the base paste.
33. The system according to claim 25, characterized in that the combination of the two polymerization inhibitors in the base paste is effective to provide a gel time of about one to about two minutes from the mixing of the pastes with a time of hardening from about one to about two minutes from the gelation of the material. 3 .
34. The system according to claim 24, characterized in that at least one polymerization inhibitor in the base paste produces a relatively long gel time and a relatively short curing time.
35. 35. The system according to claim 24, characterized in that the inhibitor in the catalytic paste and the inhibitor in the base paste reaches a hardening time of approximately one to two minutes from the mixing of the materials.
36. 36. The system according to claim 35, characterized in that the catalytic paste and the base paste each contain a single inhibitor.
37. 37. The system according to claim 36, characterized in that the inhibitor in the catalyst paste is the same as the inhibitor in the base paste.
38. 38. The system according to claim 37, characterized in that the inhibitor in the catalytic paste and the inhibitor in the base paste are both butylated hydroxytoluene.
39. 39. The system according to claim 1, characterized in that the accelerator of the polymerization is a reducing agent.
40. 40. The system according to claim 1, characterized in that the base paste further comprises at least one non-polymerizable plasticizer.
41. 41. The system according to claim 40, characterized in that the non-polymerizable plasticizer is selected from the group consisting of: dibutyl phthalate, polypropylene glycol-Mn 4000 and mixtures thereof.
42. 42. A distribution system for distributing material to manufacture temporary crowns and bridges, the system is characterized in that it comprises: a cartridge having two material storage chambers, including a first chamber and a second chamber, the cartridge is configured to eject material simultaneously from each of the chambers in a predetermined volume relation to a static mixer; the first chamber is prefilled with a catalytic paste including at least one polymerizable acrylic monomer, at least one polymerization initiator, at least one polymerization inhibitor, and one charge;, and the second chamber is pre-filled with a base paste which includes at least one polymerizable acrylic monomer, at least one polymerization accelerator, a polymerization inhibitor, a non-polymerizable plasticizer and a filler; and wherein the catalyst paste has a viscosity greater than the viscosity of the base paste, and the hardening time of the material is approximately one to two minutes from the mixing of the material.
43. 43. The system according to claim 42, characterized in that the inhibitor in the catalyst paste is the same as the inhibitor in the base paste.
44. 44. The system according to claim 42, characterized in that the inhibitor in the catalytic paste and the inhibitor in the base paste are both butylated hydroxytoluene.
45. 45. The system according to claim 42, characterized in that the accelerator is present in an amount effective to achieve a layer inhibited by oxygen on the surface of the material after curing of less than 50μm.
46. 46. The system according to claim 45, characterized in that the initiator is a peroxide oxidizing agent and the accelerator is a reductive agent.