CA2126541C - Method and dispenser for making dental products - Google Patents

Abstract

A method of forming dental products, such as dentures, denture relines, dental crowns, dental bridges and dental restorative materials, temporary crown, temporary bridge, provisional crown or provisional bridge, from two polymerizable paste compositions each having a complimentary component of a free radical catalyst system and a polymerizable acrylic compound. One of these paste compositions includes an oxidizing agent and a stabilizer and the other includes a reducing agent as components of a redox catalyst system for free radical polymerization. These paste compositions are mixed in a static mixer to form a polymerizing paste composition, which is then shaped into a dental prosthesis. A
handheld mixing dispenser useful in carrying out this method, includes a static mixing conduit, and two containers enclosing the polymerizable paste compositions. The static mixing conduit encloses a static mixing member. The containers are adapted to be connected in fluid flow communication with the static mixing conduit. In the paste composition which includes the reducing agent a photoinitiator may be preferably included. Each container is sufficiently oxygen permeable to maintain inhibition of polymerization of the polymerizable paste composition therein for at least 12 months at 23°C.

Description

2~.2~1~~
PATENT
Case 7 712 METHOD AND DISPENSER FOR MAKING DENTAL PRODUCTS
The invention relates to packaging, storing, mixing and applying paste compositions useful in forming prosthetic products.
The invention provides free radical polymerizable acrylic paste compositions enclosed in an air permeable container connected to a static mixing channel, which are useful to form dental products such as dental appliances and dental prostheses, for example dentures, denture refines, dental crowns, dental bridges and dental restorative materials.
8irger in U.S. Patent 3,435,012 discloses anaerobic sealant composition containing monoacrylate esters. Bernd et al in U.S.
Patent 3,861,870 discloses adhesives or sealing agents which harden on exclusion of oxygen. Matsuda et al in U.S. Patent 3,899,382 discloses anaerobic bonding agent. Heiss in U.S. Patent 4,129,611 discloses thermoplastic polyurethanes of mixtures of hard and soft thermoplastic polymers. Kohmura et al in U.S. Patent 4,267,133 discloses manufacture of denture base. 8unyan in U.S.
Patent 4,331,580 discloses flowable anaerobic sealant composition.
V~/erber in U.S. Patent 4,431,787 discloses anaerobic adhesi~aes.
Ratcliffe et al in U.S. Patent 4,602,076 discloses photopolymerizable compositions. Blackwell et al in U.S. Patent 4,657,941 discloses biologically compatible adhesive containing a phosphorus adhesion promoter and a sulfiniv accelerator. Ibsen et al in U.S. Patent 4,674,980 discloses dental composite and 2126a~:~
porcelain repair. Engelbrecht in U.S. Patent 4,771,112 discloses compounds that consist of aldehyde, epoxide isocyanate, or halotriazine groups of polymerizable groups, and of a higher-moiecular backbone, mixtures that contain them, and the use thereof. Engelbrecht et al in U.S. Patent 4,806,381 discloses polymerizable compounds containing acid and acid derivatives, mixtures containing the same, and use thereof. Eilackwell et al in U.S. Patent 4,816,495 discloses biologically compatible adhesive visibPe light curable compositions. iCashihara et al in U.S. Patent 4,84.2,936 discloses composite basic resin particles, its preparation and resinous composition for coating use containing the same.
Engelbrecht in U.S. Patent 4,872,936 discloses polymerizable cement mixtures. Mori et al in U.S. Patent 4,880,857 discloses carbon black-graft polymer, method for production thereof, and use thereof. Mori et al in U.S. patent 4,940,749 discloses carbon black-graft polymer method far production thereof, and use thereof. Mori et al in U. S. patent 4,994,520 discloses carbon black-graft polymer, method for production thereof, and use thereof. Antonucci et al in U.S. Patent 5,037,473 discloses denture liners. Omura in U.S.
Patent 5,091,441 discloses dental composition. 8lackwell in U.S.
Patent 5,218,070 discloses dental/medica! compositions and use.
Ying in Canadian Patent 1,259,149 discloses dental restorative composition containing rnonofunctional monomer. Howard et al in Canadian Patent 1,102,039 discloses radiation curable coating compositions containing unsaturated addition - polymerizable urethane resin. Suling et a! in Canadian Patent 1,145,880 discloses moulded dental pigments. Denver et al in Canadian Patent ~~.2~:~~:~_ 1,148,294 discloses dental compositions Ikeda et al in Canadian Patent 1,149,538 discloses curable resin compositions. Ratcliffe et al in Canadian Patent 1,189,995 discloses polymerizable dental composition containing a mixture of fine particle size and large particle size fillers. I=ellmann et al in Canadian Patent 1,200,046 discloses permanent dental restorative material. Michl et al in Canadian Patent 1,209,298 discloses photopolymerizabie composition especially for dental purposes. Dbsen et al discloses in Canadian Patent 1,243,796 dental composite and porcelain repair.
ibsen et al in Canadian Patent 1,244,177 discloses methacrylate functional resin dental composite and porcelain repair compositions.
Schaefer in Canadian patent 1,244,581 discloses priming material for plastic dental members. Randklev in Canadian Patent 1,245,437 discloses radiopaque low visual opacity dents! composites containing non-vitreous microparticles. Waknine in Canadian patent 1,262,791 discloses two component iPaste-Paste) self curing dental restorative material. 0kada et a! in Canadian Patent Application 2,002,017 discloses dental restorative material. Held et al in Canadian Patent Application 2,009,471 discloses hybrid plastic filling material. Mitra et a! in Canadian Patent Application 2,032,T73 discloses dental compositions, a method of making shaped dental articles via photoiniferter polymerization of the dental compositions, and shaped dental articles produced thereby. Holmes in Canadian Patent Application 2,033,405 discloses dental material containing anti-slump additive. Rheinberger in Canadian Patent Application 2,051,333 discloses polymerizable dental material.
Tateosian et al in European Patent Application 0 334 256 A2 - 2~~~'~~:~
discloses dental appliance preparation and material therefor.
Muramoto et al in European Patent Application 0 1.85 439 A3 discloses composite resin particles, its preparation and resinous composition for coating use containing the same. Kuboto et al in U.K. Patent Application GB 2,189,793A discloses Polymerizable compositions fr~r dental restoration. Heynold et al in PCT/DE87/00135 discloses polymerizable mass for production of non-hardening moulded elements, particular of dental prostheses.
Luxatemp - Automix discloses a cartridge for polymerization. DMG
HAMBURG discloses paste containing cannulas. Dentsply and Caulk each discloses impression material in a cartridge system having a static mixer.
'typically prior art dentures are produced by combination of polymerizable methacrylate monomers and a polymeric organic filler such as polymethylmethacrylate and its copolymers, which may be superficially soluble in the monomer. These combinations of monomers and polymers are pasty dough-like and polymerize in a mold using peroxides and heat and/or a reducing agent to catalyze the polymerization. Prior art dentures are also commonly produced from paste-like combinations of polymerizable methacrylate monomers, oiigomers or prepcilymers and organic and inorganic fillers. They may be shaped free-form on a model or polymerized in a mold. A disadvantage of prior art photopolyrnerizable dental composites is their relatively low degree of conversion to polymer.
Air entrapment during spatulation and mixing is detrimental to strength and provides sites for bacteria! colonies, stain and plaque to form. Air dissolved in a free radical polymerizable composition is ~~2~~~.~_ necessary for premature polymerization inhibitors such as butylated hydroxytolune (BHT) to function to stabilize the material.
it is an object of the invention to provide a means to prepare redox and photoredox polymerized dental prosthesis especiatly dentures, denture relines, dental crowns, dental bridges and dental restorative ma tarials which are readily formed in a dental laboratory or office.
It is an object of the invention to provide a dispensing system for mixing two paste compositions to produce substantially porosity free dentures and denture relines, dental crowns, dental bridges and dental restorative materials.
It is an object of the invention to provide substantially color stable and porosity-free redox and photoredox polymerized dentures, denture relines, dental crowns, dental bridges and dental restorative materials.
It is an object of the invention to provide a device for forming a dental product including two oxygen permeable containers enclosing polymerizable paste compositions, one of which includes a peroxide and at least one polymerizable acrylic compound.
It is an object of the invention to form a dental product by static mixing of two complimentary pastes one of which includes a peroxide and an acrylic polymerizable compound and the other includes a reducing agent for the peroxide and a polymerizable acrylic compound and then forming and curing the dental product.
As used herein "shelf life" at a specified temperature refers to the time for degradation as discussed in Accelerated ~egradation Testing by G. Fagain, H. Sheehan and Fi. O.Kennedy, American 2~.~~~~~"~
9iotechnoloc~~r Laboratory, 1/olume 9, #9, pages 31-32, 43etober 1991.
As used herein "solvent'' refers to compounds in which free radical polymerizable acrylic compounds dissolve, such as t-butyl alcohol, but which are not free radical poiymerizable acrylic compounds.
As used herein "radiation" refers to electromagnetic radiation including visible and ultraviolet light, microwave and/or infrared electromagnetic radiation.
As used herein "acrylic'' includes compounds of substituted acrylic moieties such as methacryi, cyanoacryl and fluoroacryl-moieties.
As used herein ''dental products" includes dental appliances and dental prostheses.
As used herein ''dental appliances°' means dente! products for use in the mouth including orthodontic devices for example devices for movement of teeth.
As used herein "temporary crown" refer to crowns which effectively resist discoloration, detachment and/or breakage for about three weeks.
As used herein ''temporary bridge" refer to bridges which effectively resist discoloration, detachment and/or breakage for about three weeks.
As used herein ''provisional crown°' refer to crowns which effectively resist discoloration, detachment and/or breakage for about one year.

_.
~s used herein "provisional bridge" refer to bridges which resist discoloration, detachment andlor breakage for about one year.
Brief Description of the Dra~orings Figure 1 is a schematic top view of a static mixing article of manufacture in accordance with the invention.
Figure 2 is a photographic enlargement (3.4 times actual size) of a portion of the prior art Bosworth product shown in Figure 7.
Figure 3 is a photographic enlargement (3.4 times actual size) of a portion of the prior art Extoral product shown in Figure 7.
Figure 4 is a photographic enlargement (3.4 times actual size) of a portion of the prior art Astron product shown in Figure ?.
Figure 5 is a photographic enlargement (3.4 times actual size) of a portion of the static mixed (S.NI.) product of the invention shown in Figure 7.
Figure 6 is a black and white photographic enlargement of a portion of a product formed by hand spatutation (H.S.) of the composition used in the invention shown in Figure 7.
Figure 7 is a photograph (0.B5 times actual size) of: the static mixed denture refine product of the invention made as described in Example 9 (upper left); of the hand spatulated denture reline product of the invention made as described in Example 7 (upper right); of a prior denture reline product sold by Astron (lower left);
of a prior denture reline product sold by Extoral (lower middle) and of a prior denture reline product sold by Bosworth (lower right).
a 21~~~~::~
summary of the Invention A method of farming dental products, such as dentures, denture relines, dental crowns, dental bridges and dental restorative materials, temporary craven, temporary bridge, provisional crown or provisional bridge, from two polymerizable paste compositions each having a complimentary component of a free radical catalyst system and a polymerizable acrylic compound. One of 'these paste compositions includes an oxidizing agent and a stabilizer and the ether includes a reducing agent as components of a redox catalyst system far free radical polymerization. These paste compositions are mixed in a static mixer to form a polymerizing paste composition, which is then shaped into a dente! prosthesis. A
handheld mixing dispenser useful tn carrying out this method, includes a static mixing conduit, and two containers enclosing the polymerizabte paste compositions. The static mixing conduit encloses a static mixing member. The containers are adapted to be connected in fluid flaw communication with the static mixing conduit. In the paste composition which includes the reducing agent a photoinitiator may be preferably included. Each container is sufficiently oxygen permeable to maintain inhibition of polymerization of the polymerizabte paste composition therein far at least 12 months at 23°C.
~etailed ~escriptian of the Invention The invention is now described with mare particular reference to Figure 1 which shows a dispenser article 1O in accordance with the invention having housing 11 which supports an oxygen 2~~~~~_~.
permeable cylindrical container 12 enclosing catalyst containing polymerizable paste composition 13, and oxygen permeable cylindrical container 14. enclosing accelerator containing polymerizable paste composition 15. Preferably the containers are cylindrical and have a wail thickness of from about C.1 to about 2 mm. Containers 12 and 14 are connected to mixing channel 16 which encloses a static mixing member 17 having a series of baffles turned at angles that cause the two streams from conduits 13 and 20 to divide and recombine and mix. Mixing channel 16 is in fluid flow communication with containers 12 and 14 through conduits 18 and 20 respectively. Mixing channel 16 is connected to housing 11 by interlocking flanges 22 and 24. Containers 12 and 14 are filled with polymerizabie paste compositions 13 and 15 respectively without including of air by entrapment. Preferably compositions 13 and 15 are extruded at a predetermined rate into static mixing channel 1 f> where they are combined essentially without inclusion of air by entrapment to farm a polymerizing composition which is readily modeled and/or molded. Additional mixing, such as on a slab or in a bowl, is not required.
In use the operator presses actuator 26 which forces rods 2~
and 3t~, which support plungers 32 and 34, into containers 12 and 14. Plungers 32 and 34 press against disc shaped end uvalls 36 and 38 respectively. End walls 36 and 33 press upon polymerizable compositions 13 and 15 forcing them through conduits 1$ and 20 into mixing channel 16. Polymerizable paste compositions 13 and 15 each contain a component of a polymerization catalyst system which upon mixing provides a free radical generating catalyst 21~6~~~
system. Polymerizable accelerator paste composition 15 includes a reducing agent and in a preferred embodiment a radiation activated initiator, and at least one polymerizable compound. 'The catalyst paste composition 13 includes an oxidizer and at least one polyrnerizabie compound. Polymerizable paste compositions 13 and 15 are extruded simultaneously through a static mixing channel 16.
The palymerizable compositions 13 and 15 are mixed by static mixing member 1 ? and fiorm a polymerizing composition which is readily molded to a dental prosthesis. In a preferred embodiment, fiurther polymerization ofi the melded composition may be then accomplished by application of external energy such as light, microwaves, heat, and/or by additional redox polymerization.
Preferably the polymerizable paste compositions 13 and 15 each contain at least 10% filler, have a viscosity of at least 5000 centipoise (cps) and are substantially solvent free i.e., have less than 1 percent by weight solvent, mare preferably 9ess than 0.5 percent by weight solvent and most prefierabfy do net include a solvent. Palymerizabie paste compositions 13 and/or 15 prefierably includes a fiiller and polymerizable (meth)acryiate compound.
In a preferred embodiment ofi the invention a dispenser device includes two connected syringe tubes each having a plunger. The plungers are connected for simultaneous actuation by the operator to discharge the pastes simultaneously through a third discharge tube containing a static mixing element to fiorm a polymerizing paste having dissolved air in a concentration which is insufificient to result in visible voids in the polymerized product fiormed by the polymerizing paste composition.

In a preferred embodiment compositions of the invention are used to reline dentures. Polymerizable pastes are statically mixed to form a polymerizing reline paste composition which is extruded directly onto a denture which is being relined to better fit the changed soft tissue contours of the mouth of the patient since the denture was originally produced, or to otherwise improve the fit of the denture to the patients mouth. Air is not entrapped within the statically mixed polymerizing reline paste composition as it would be if the polymerizable pastes had been mixed by stirring or spatulation. The polymerizing reline paste composition is adapted (shapedl to areas to be impressed. The polymerizing reline paste composition is readily modeled with a gloved finger or suitable tool.
An impression of the mouth is made in the polymerizing reline paste composition after it is mixed but before it is no longer impressionable, which defines the work time. The polymerization catalyst is activated during the mixing. The polymerizing reline paste composition preferably has a work time of less than about 5 minutes. Within minutes the extruded polymerizing composition is partially polymerized and hardened. The exotherm of the polymerizing composition is lower than it would be if substantially all of the monomer had been r~nore rapidly converted to polymer.
The temperature of the exotherm of polymerizing composition is easily tolerated without discomfort to the patient. In a preferred embodiment the reline composition is further polymerized extraora!!y using a dental light curing oven which provides heat and light. In a preferred embodiment of the invention a mouth molded partially polymerized reline composition adhered to a denture is placed after 1 '9 2~.~~i~~
impressing into a T411AD~ 2000 light curing oven (sold by Dentsply International Inca for from 1 to 20 minutes to additionally polymerize the reline composition. Alternatively, a partially converted reline composition adhered to a denture is invested in plaster or other media to retain its shape and heated to thermally more completely convert and cure reline composition. In another embodiment of the invention partially polymerized reline composition and the denture adhered to it are removed from the patient's mouth and further cured under vacuum, pressure in air, water, nitrogen or other inert Liquid and/or gas filled container at elevated temperature to substantially complete cure, convert and polymerize the composition. One advantage of this method of packaging, mixing and conversion to cured article is that, because concentrations of amine or other potential color forming reducing agents are low, the potential for unwanted color formation during or after polymerization in minimized.
In another preferred embodiment of the invention the polymerizing paste composition is extruded directly into a preformed mold cavity. The mold is preferably formed by the lost "wax"' or other mold making process. The polymerizing paste is extruded under pressure and polymerized within the mold at ambient temperatures or with the application of heat or light to accelerate polymerization to form a dental prosthesis, such as a denture or crown and bridge element.
In another preferred embodiment of the invention a polymerizing paste composition is extruded from 'the static mixer into a tray and applied directly onto the patients tissue and modeled 1z to form a custom tray. Alternatively a polymerizing paste is extruded on a model of a patient's tissues to form an impression tray, or a dental prosthesis. In another embodiment a polymerizing paste is extruded directly onto the teeth and a bite registration impressed therein, or it is used to repair a prosthesis which is fixed in the patients rreouth. These methods are convenient for deposition of the polymerizing composition at the site of use and provide dental products which are lower in porosity and therefor more stain resistant than if mixed by hand spatulation. In all these applications the product which results is rigid, with a modulus of elasticity greater than about 100,000 psi.
Preferred monomers, oligomers and prepolymers for use in accordance with the invention include polyester and polyether methacryiates, urethane methacryiate, and polyglycol methacrylate(s). Polymerizable methacrylates are waxy, syrupy or mobile liquids. In a preferred embodiment each polymerizable paste composition includes a methacrylate monomer, oligomer, or prepolymer such as Uvithane y83, 893 or 892 (soil by iVlorton International? or ~Craynor CN 961-, 962, 964, 966, 971 or 9~3 (sold by 6artomer) dVlhoromer 6661-0 (sold by Rohm Tech.) and an organic filler and an inorganic filler.
Polymerizable acrylic compounds useful in accordance with the invention include compounds within the scope of general formula (I):

~~.26~~~~.
0 R~
i1 I
(R ) ~ - 0 - C - C = CI-~ (1) n wherein R is an acrylic-free organic moiety, R1 is hydrogen, halogen, alkyl, substituted alkyl or cyano radical and n is an integer from 1 to 6 and m is an integer from 1 to 1000.
R is a hydrocarbyl spacer unit such as alkyl or aromatic or polyether, polyurethane, polyester, glycol, poiygiycol including forms thereof substituted with carboxyl, phosphoric and other acid moieties and salts thereof.
Examples of unsaturated acrylic compounds containing phosphorus and phosphonic acid esters which may be used as polymerizable acrylic compounds useful in accordance with the invention include, but are not limited to, monomers containing phosphoric acid groups such as hydroxyethyl methacrylate monophosphate, 2,2'-bis(alpha-methacryloxy-beta-hydroxypropoxyphenyi)propane diphosphonate (BIB-Gh/IA
diphosphonate), BIB-GiVIA methacryloxyethyl phosphate, glyceryl dimethacrylate rnonofluorophosphate, and glyceryl dimethacrylate phosphate. Preferred compounds are those polyethyfenicaily unsaturated monophosphates of the formula (III):
14.

2:~~6~;~~~

1 Ii CI-'~ - C - CO - 0 R - O - P - OH /11i) n i OH
OP

CHZ - C - CO - O R - P - OH (IIIA) n i OH
and salts thereof, in which R is an organic radical having a valency of n + 1;
and R may be interrupted by one or more oxygen atoms and may be substituted or unsubstituted, and may comprise an aliphatic radical, or a cycloaliphatic radical, or an aryl radical; R1 is as defined above and n is an integer of at beast 1.
Polymerizabie acrylic compounds useful to provide poiymerizable pasts compositions in accordance with the invention include monofunctional monomers and multifunctional oligomers andlor monomers having di- or polyfunctional moieties which are capable of addition polymerization. In general, preferred reactive functionalities which serve as active sites for this polymerization are acrylic. BVlonofunctionai monomers include cyclohexyl methacrylate, benzyl methacrylate, methacrylate, t-butyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and 2-ethylhexyl methacryla~te.
Suitable multifunctional monomers and oligomers may be selected from numerous families of poiyfunctional vinyl and/or addition polymerizable monomers such as acrylic and lower alkyl acrylic acid 2~~~~~:~
diesters, acrylic and lower alkyl acrylic acid esters fiormed from alcohols, which alcohols have a different reactive fiunctional group, such as carboxyl and hydroxyl groups, urethane diacrylates and dimethacrylates, polyvinylic compounds, divinyl aromatic compounds, and others as will be apparent to those skilled in the art.
Preferred, multifunctional monomers and oligemers useful as polymerizable acrylic compounds in polymerizable paste compositions of the invention include esters of unsaturated acids, e.g., acrylic, methacrylic, ethacrylic, propacrylic, butacrylic, malefic, fumaric, citraconic, mesaconic, itaconic, malonic, or aconitic, acids.
ether unsaturated acids will be readily apparent to those skilled in the art. These acids are preferably reacted with either saturated or unsaturated polyhydroxylic alcohols to form esters which are effective multifunctional monomers and eiigomers useful in the formulation of the compositions of the invention. In general, these alcohols have one or more hydroxytic functionality and have from ~
to about 30 carbon atoms. Thus, useful alcohols include allyl, methaliyl, crotyl, vinyl, butenyl, isobutenyl, and similar unsaturated alcohols as well as polyols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, glycerol, 1,3,3-trimethylpl-propane, pentaerythritol, dihydroxyphenol, and alkyiidene bisphenols such as bisphenol-A, 1,1-bis (4-hydroxyphenyl) rnethane, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl sulfione, dihydroxydiphenyl ether, dihydroxydiphenyl sulfoxide, resorcinol, hydroquinone, etc.

212~~~:~.
Preferred multifunctional monomers and otigomers useful as polymerizable acrylic compounds in polymerizabte paste compositions of the invention include the esters of a monomeric unsaturated acids with an unsaturated mono-hydroxylic alcohol such as allyl acryiate, altyl methacrylate, dimethallyi fumarate, ill-allyl acrylamide, crotyl acrytate, allyl crotonate, allyi cinnamate and diallyt maleate. Other preferred species are the di-, tri-, and higher esters of polyhydroxytic alcohots such as ethylene glycol diacrylate (dimethacrylate and C2-C~ homologs), trimethylolpropane trimethacrylate, and the dimethacrylate ester of bisphenol-A as welt as other acrylate and alkyl acrylate esters. Furthermore, mixtures of multifunctional monomers and/or oligomers are useful in the practice of the invention.
Polymerizabte acrylic compounds such as bis-GMA and the urethane dimethacrytate formed from the reaction of hydroxyethyl acrylate, hydroxypropyl acrylate, and their methacrylate homoiogs with 2,2,4-trimethylhexyl-1,6-diisocyanate (hereinafter referred to as "urethane dimethacrytate" or '°diacrytate°") are especially useful, as are ethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate trimethylolpropane trimethacrytate and the dimethacrytate ester of bisphenol-A and urethane adducts thereof. The corresponding acrylates are similarly useful as is diallyl maleate.
In a preferred aspect of the invention, polymerizable acrylic compounds useful in accordance with the invention are vinyl urethane ar urethane-(meth)acrylate monomer or prepolymer materials characterized by the structural formula (11):
a~

~:~~6~~
R~ O H H O R~
i II I I II i CH2 = C-C-O-RZ-O-C-N-R3 N-C-O-R~ O-C-C = CHZ (I3) O O
wherein each R1 independently, is R1 is hydrogen, halogen, alkyl, substituted alkyl or cyano radical R2 and R4, independently, are aikylene, substituted alkylene, cycloalkylene, substituted cycloaklylene, arylene or substituted arylene; and, R3 is alkylene, substituted alkylene, cycloalkylene, arylene, substituted arylene, heterocyclic, substituted heterocyclic, the reaction product ofi an organic diisocyanate or an isocyanate terminated prepolymer and a compound having hydroxyl fiunctionality, or the reaction product of a polyol or a hydroxyl terminated prepolymer and a compound having isocyanto functionality.
Preferred rubber modifiiers for use in polymerizable compositions in accordance with the invention include acrylic rubber modifier /Paraloid 1C1VI 33~ manufiactured by Rohm and Haas) and methacrylated butadiene-styrene rubber tlVletablen C~2~ produced by Elfi Atochem).
A prefierred stabilizer is butylated hydroxytoluene.
Rreferred fillers usefiul in the paste compositions of the invention include organic tillers. such as particulate polymer, and inorganic filler such as glass, ceramic, or glass ceramic. Prefierably the filler has a particle size of less 'than about 2~O~m, more prefierably less than about 1 ~Op.m and most preferably less 'than about 3ap~m. prganic fillers include natural and synthetic polymers and copolymers which prefierably are fiormed by atomization techniques, emulsion polymerization, bulk polymerization or 1~

2~.~6~i~~
suspension polymerization . The fiillers may be comminuted by ball milling, sharing or by atomization. Inorganic fillers are produced by fusion or sol gel techniques and may be comminuted by ball milling, attritor milling atomization, attention milling or precipitation.
Preferred inorganic fillers include silica, quartz, borosilicates, silicious fillers, inorganic glasses, such as barium aluminum silicate, lithium aluminum silicate, strontium, lanthanum, and tantalum aluminosilicate glasses. A preferred inorganic filler is microfine amorphous silicone dioxide particulate. Silanated inorganic fillers are considered for purposes of this invention to be inorganic fillers and are also preferred. Silanated means that some of the silanol groups have been substituted or reacted with, 'for example, dimethyidiclorosilane to form a hydrophobic filler.
Preferably the polymerizable compositions mixed in accordance with the invention have substantially the same viscosity.
Preferably the polymerizable compositions are mixed in a volume ratio between 1:1 and 1:5. iVlore prefierably the polymerizable compositions are mixed in a volume ratio between 1:1 and 1:3.
Itllost preferably the polymerizable compositions are mixed in a 1:1 volume ratio. Preferably each container has an oxygen permeability coefificient at least about 0.4 x '10-lOcm2lsec (cm Hg). Preferably each polymerizable paste composition in each container has a shelfi life of at least 180 days. Preferred microwave activated catalyst systems include benzopinacole or tertiary butyl perisononanoate.
Prefierably dental products made in accordance with the invention have a specific gravity at least 0.5% greater 'than a corresponding product fiormed by hand spatulation of said polymerizable paste 2~.~6~!~~
compositions, and forming and curing the spatulated paste composition.
Prior Art: Astron Example 1 Powder and liquid are mixed in a ratio of ~.5 cm3/ml in accordance with the instructions of the manufacturer of Astron LC
reline: Astron Dental Corp. Wheeling, 1L to form a paste which is placed in a mold and covered by a polyethylene film and allowed to stand for 5 minutes and then light cured 'for 5 minutes in an Astron XL (sold by Astron Dental Corp.) light curing unit t~ form a disk. A
3.4 times actual size photographic enlargement of the disk is shown in Figure 4. These powder and liquid compositions are described by Smith et ai in the International Journal of Prosthodontics Volume 4 Number 1951 pages 445-448. The powder includes poly(ethyl methacrylate), peak mw 245,488, and '! .0% benzoyl peroxide. The liquid includes: n-butyl methacrylate, ethoxylated bis phenol A
dimethacrylate, dimethyl-pare-toluidine and camphorquinone.
Prior Art: Extoral Example 2 Powder and liquid are mixed in a ratio of 2.0 cm3/ml in accordance with the instructions of the manufacturer of Extoral reline material: Pro-Den Systems Portland, Ore. to form a paste which is placed in a mold and covered by a polyethylene film and allowed to stand for 5 minutes and then light cured for 5 minutes in a Star Cure 360 (sold by Star Dental) light curing unit to form a 2I26~~~
disk. A 3.4 times actual size photographic enlargement of the disk is shown in Figure 3.
These powder and liquid compositions are described by Smith et al in the International Journal of Prosthodontics Volume 4 Number 1991 pages 445-448. The powder includes: poly(ethyl methacrylatel/poly(methyl methacrylatel copolymer (9/1,, peak mw 381.987; 0.9% benzoyl peroxide. The liquid includes: 67.1 ethoxylated bisphenol A dimethacrylate 30.1 % cyclohexyl methacrylate, 0.14% camphorquinone. The cured material includes 2.83% inorganic filter, (see Baryon et al, Dent IVlater 8:27-277, July 1992 pages 274-277 at page 276.
Prior Art: Bosworth Example 3 Powder and liquid are mixed in a ratio of 1.9 cm3/ml in accordance with the instructions of the manufacturer Bosworth Reline material: Flarry J. Bosworth Skokie, IL to form a paste which is placed in a mold and covered by a polyethylene film and allowed to stand for 5 minutes and then light cured for 5 minutes in an Pro Lite 3 (sold by Pro Den Corporation) light curing unit to form a disk.
A 3.4 times actual size photographic enlargement of the disk is shown in Figure 6. These powder and liquid compositions are described by Smith et al. The powder includes poly(ethyl methacrylate>, peak mw 300,312; and 0.9% benzoyl peroxide. The liquid includes 13.9% n-butyl methacrylate; 74.1 % ethoxylated bisphenol A dimethacrylate; dimethyl-para-toluidine and 0.16%
camphorquinone.

~~~~~4~.
Iratalyst Paste Example 4 A catalyst paste is formed by mixing in a planetary mixer 4210 g 7,7,9-trimethyl-~,13-dioxo-3,14.-dioxa-5,12-dioldimethacryl-ate, 0.7 g 3-methacryioxy-propyltrimethoxysilane, 3.5 g butylated hydroxytoluene, 70 g benzoyl peroxide, and 2715 g powder blend.
The powder blend is formed by mixing 3270 g fumed silica inorganic filler, 32920.7 g poly(methyl methacrylate-co-ethylene glycol dimethacrylate-co-ethyl methacrylate-styrene) (49.2:0.9;34.0:16.0) and 10 g pigment. This paste cornposition is stored in a chamber of a polypropylene cartridge tube having a wall thickness of 1 mm in a dual cartridge used in a hand activated dispenser made by iVlixPac.
CAT/.~L~f~'Z' ~A9TE
Percent by Weight 7,7,9-Trimethyl-4,13-dioxo-3,14-dioxa-5,12-dioidimethacrylate 60.15 3-lVlethacryioxypropyltrimethoxysilane 0.01 Butylated hydroxytoluene 0.05 Benzoyl Peroxide 1.00 Fumed silica inorganic fiiller 3.50 Poly (methyl methacrylate-co-ethylene glycol dimethacrylate-co- 35.26 ethyl methacrylatestyrene) 09.2:038:34.0:16.0) Pigment 0.03 100.00 ~1~6~.~~
Accelerator and radiation cure initiator~aste Example 5 An accelerator and radiation cure initiator paste is formed by mixing in a planetary mixer 216.58 7,7,9-trimethyi-4,13-dioxo-3,14-dioxa-5,12-dioldimethacrylate, 0.0368 3-methacryloxypropyitrimeth-oxysitane, O.CSg butylated hydroxytoiuene, 0.658 camphorquinone 1.088 ~2-hydroxy-4-methoxyphenyi) benzophenone, 0.98 dihydroxy-ethyl-p-toluidine and 140.758 of powder blend formed as described in Example 4, in a planetary mixer. This paste composition is stored in the other chamber of the polypropylene cartridge of the dispenser used in Example 4. it has the composition shown in Table 1.
Accelerator and radiation cure initiator paste Example 6 An accelerator and radiation cure initiator paste is formed by mixing in a planetary mixer 215.58 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,1 ~-dioldimethacrytate, 0.036 g 3-methacryloxypropyltri-methoxysilane, 0.05 g butyiated hydroxytoluene, 0.55 camphor-quinone 1.08 g (2-hydroxy-4-methoxyphenyl) benzophenone, '! .8 g dihydroxyethyl-p-toluidine and 140.75 g of powder blend formed as described in Example 4. This paste composition is stored in a chamber of a polypropylene cartridge tube of a dispenser prepared as described in Example 4. It has the composition shown in Table 1.

212~~~~
Table 1 Accelerator and radiation cure initiator paste compositions Example 5 Example 6 Percent by Percent by Weight Weight 7,7,9-Trimethyi-4,13-dioxo-3,14-dioxa-5,12-dioidimethacrylate60.33 60.io 3-P~Aethacryloxypropyltrimethoxysilane0.01 0.01 butylated hydroxytoluene 0.01 0.01 Camphorquinone 0.18 0.18 Dihydroxyethyl-p-toluidine 0.25 0.50 Fumed Silica 3.5n 3.53 Poly (methyl methacrylate-co-ethylene35.68 35.66 giycol dimeth-acrylate-co-ethyl methacrylate-styrene)(49.2:038:3~d.0:1 6.0) Pigment 0.01 static Mixed Redr~x and Light Cured Denture Reline Example 7 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of accelerator and radiation cure initiator paste formed as described in Example 5 to form 20 g of a denture refine composition. The polymerizing denture reline composition contains 0.5 percent by weight benzoyl peroxide.
60.12 g x,7,9-trimethyl-4,13-dioxo-3,1 ~-dioxa-5,12-diazahexa-decane-1,16-dioidimethacrylate (iJDIVIA), 0.01 g 3-methacryloxy-propyl-trimethoxysilane, 0.03 g butyiated hydroxytoiuene, 35.44 g poly(methyl methacrylate-co-ethylene dimethacrylate-co-ethyl meth-acrylate-co-styrene) (49.2:0.8:34.0:1 fa.0) (cured bead polymer), 3.6 g of silicon dioxide and 0.01 g pigment, 0.0g g camphorquinone, 0.15 g (2-hydroxy-4-methoxyphenyl) benzophenone, and 0.125 g dihydroxyethyl-p-t0luidine. The polymerizing composition is extruded from the static mixer and placed upon a denture surface, after 2 minutes the denture is positioned in a patients mouth and 212~~~~.
allowed to cure for 3 minutes. A portion of the polymerizing composition is formed into a disk. A 3.4 times actual size photographic enlargement of the disk is shown in Figure 5. The denture is then removed and radiation cured in a TRIAD 2000 light curing unit for 5 minutes. See Table 7 for formula percentages and properties ingredient.
Static iVlixed Redox and Lig~~ht Cured Denture Reline Example 8 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of accelerator and radiation cure initiator paste formed as described in Example 6 to form 20 g of a denture reline composition. The polymerizing denture reline composition contains 0.5 percent by weight benzoyl peroxide.
60.12 g 7,7,5-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexa-decane-1,16-dioldimethacrylate (UDMA), 0.01 g 3-methacryioxy-propyltrimethoxysilane, 0.03 g butylated hydroxytoluene, 35.44 g poly(methyl methacrylate-co-ethylene dimethacrylate-co-ethyl meth-acrylate-co-styrene) (45.2:0.8:34.0:16.0) (cured bead polymer), 3.6 g of silicon dioxide and 0.01 g pigment, 0.05 g camphorquinone, 0.15 g (2-hydroxy-4-methoxyphenyi) benzophenone, and 0.25 g dihydroxyethyl-p-toluidine. The polymerizing composition is placed upon a denture surface, after 2 minutes 'the denture is positioned in a patients mouth and allowed to cure for 3 minutes. The denture is then removed and radiation cured in a TR9AD 2000 light curing unit for 5 minutes. See Table 7 for formula ingredient percentages arid properties.

2~~~~~
Fland Soatulation Denture Reline Composition Example 9 g of the paste composition formed as in Example 4 and 10 g of the paste composition formed as in Example a are mixed by hand until homogenous upon a parchment pad using a spatula to form a polymerizing composition, which is shaped into a disk. A
~.4 times actual size photographic enlargement of the disk is shown in Figure 6. fee Table 7 for properties.
Hand S~ ap tulation Redox and Light Cured Denture Reline Example 10 10 g of the paste composition formed as in Example 4 and 10 g of the paste composition formed as in Example 6 are mixed by hand on a pad using a spatula to form a polymerizing composition.
Portion of the polymerizing composition placed upon a denture surface, after 2 minutes the denture is positioned in a patients mouth and allowed to cure for 3 minutes. The denture is then remoered and radiation cured in a TRIAD 2000 light curing unit for 5 minutes. fee Table ~ for properties ~tati~llldixed Redox and fight Cured Denture Example 11 10 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of acceleratar and radiation cure initiator paste formed as described in Example 5 to form 20 g of a denture reline composition. The polymerizing denture reline composition contains 0.5 percent by weight benzoyl peroxide.

2~.~~~~~
60.12 g 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexa-decane-1,16-dioldimethacrylate (UDMA), 0.01 g 3-methacryloxy-propyl-trimethoxysilane, 0.03 g butylated hydroxytoluene, 35.44 g poly(methyl methacrylate-co-ethylene dimethacrylate-co-ethyl meth-acrylate-co-styrene) (49.2:0.8:34.0:16.0) (cured bead polymer), 3.6 g of silicon di~xide and 0.01 g pigment, 0.09 g camphorquinone, 0.15 g (2-hydroxy-4-methoxyphenyl) benzophenone, and 0.125 g dihydroxyethyl-p-toluidine. The polymerizing composition is extruded through a static mixer and placed in a denture mold half, after 2 minutes the denture mold halves are positioned together and allowed to cure for 10 minutes. The denture is then remo~red and radiation cured in a TRIAD 2000 light curing unit for 5 minutes.
Static Mixed Redox and light Cured Temporar~Bridge Example 12 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of accelerator and radiation cure initiator paste formed as described in Example 5 to form 20 g of a denture reline composition. The polymerizing denture reline composition has 0.5 percent by weight benzoyl peroxide. 60.12 g 7, 7, 9-trimethyl-4,13-d ioxo-3,14-d ioxa-5,12-d laze hexadecane-1,16-dioldimethacrylate (UDMA), 0.01 g 3-methacryloxypropyl-trimethoxysilane, 0.03 g butylated hydroxytoluene, 35.44 g poly(methyl methacrylate-co-ethylene dimethacrylate-co-ethyl methacrylate-co-styrene) (49.2:0.8:34.0:16.0) (cured bead polymer), 3.6 g of silicon dioxide and 0.01 g pigment, 0.09 g camphorquinone, 0.15 g (2-hydroxy-4-methoxyphenyi) benzophe-2~26~~:~
none, and 0.125 g dihydroxyethyl-p-toluidine. The polymerizing composition is placed in mold created by vacuum molding a sheet of thermoplastic polystyrene over a model of a dentition to be replicated and allowed to cure for 5 minutes. The temporary bridge is then removed from the mold and radiation cured in a TRIAD 2000 light curing unit for 10 minutes.
static ~tlixed Redox and L~ht Cured Crown Example 13 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of accelerator and radiation cure initiator paste formed as described in Example 5 to form 20 g of a denture reline composition. The polymerizing denture reline composition has 0.5 percent by weight benzoyl peroxide. 60.12 g 7, ~,9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-dioldimethacrylate (UDMA), 0.01 g 3-methacryloxypropyl-trimethoxysilane, 0.03 g butyla~ted hydroxytoluene, 35.44 g poly(methyl methacrylate-co-ethylene dimethacrylate-co-ethyl methacrylate-co-styrene) (49.2:0.3:34.0:16.0) (cured bead polymer), 3.6 g of silicon dioxide and 0.01 g pigment, 0.09 g camphorquinone, 0.15 g (2-hydroxy-4-methoxyphenyl) benzophe-none, and 0.125 g dihydroxyethyl-p-toluidine. The polymerizing composition is extruded from a static mixer into an alginate impression, placed in the mouth and allowed to cure for 5 minutes.
The temporary crown is then removed from the mold and radiation cured in a TRIAD 2000 light curing unit for 5 minutes.

2~26~~~
Static Mixed Redox and Microwave Cured Denture Example 14 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of accelerator and radiation cure initiator paste formed as described in Example 5, except that benzopinacole is substituted for camphorquinone, to form 20g of a denture reline composition. The polymerizing denture reline composition has 0.5 percent by weight benzoyl peroxide. 60.12g y,~',9-trimethyl-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,10-dioldimethacrylate (tJDMA), 0.01 g 3-methacryloxypropyl-trimethoxy-silane, 0.038 butylated hydroxytoluene, 35.448 poly(methyl methacrylate-co-ethylene dimethacrylate-co-ethyl methacrylate-co-styrene) (49.2:0.S:34.0:16.0) (cured bead polymer), 3.68 of silicon dioxide and 0.01 g pigment, 0.09 g benzopinacole, 0.15 g (2-hydroxy-4-meth~xyphenyl) benzophenone, and 0.125 g dihydroxy-ethyl-p-toluidine. The polymerizing composition is extruded through a static mixer and placed in a prepared denture mold with teeth embedded in one half, after 2 minutes the denture mold halves are pressed together and allowed to cure for 15 minutes. The denture mold is 'then removed from the metal flask and post-cured in a 500 watt microwave curing oven a minutes. The denture is then removed from the mold and polished.

5,~~,,ti~ Mixed Redox and heat Cured Denture Example 15 10 g of catalyst paste formed as described in Example 4 is mixed in the static mixer with 10 g of accelerator and radiation cure 2~J

initiator paste formed as described in Example 5, to form 20 g of a denture composition. The polymerizing denture composition has 0.5 percent by weight benzoyl peroxide, 60.12 g 7,7,x-trimethyi-4,13-dioxo-3,14-dioxa-5,12-diazahexadecane-1,16-dioldimethacrylate (UDMA), 0.01 g 3-methacryloxypropyl-trimethoxysiiane, 0.03 g butyiated hydroxytoluene, 35.44 g poly(methyi methacrylate-co-ethylene dimethacrylate-co-ethyl methacrylate-co-styrene) (40.2:0.3:34.0:16.0) (cured bead polymer), 3.6 g of silicon dioxide and 0.01 g pigment, 0.15 g (2-hydroxy-4-methoxyphenyl) benzo-phenone, and 0.125 g dihydroxyethyl-p-toluidine. The polymerizing composition is extruded from a static mixer and placed in a prepared denture mold (with teeth embedded in one half), after 2 minutes the denture mold halves are pressed together and allowed to cure for 10 minutes. The denture flask is then placed in a heat curing unit (hot water bath) at 72.3 ° C ( 1 F3° F) for 1 1 /2 hours followed by hour immersion in boiling water. The denture is then removed from the mold and polished. The molded denture material has a flexural strength of 102 I~J9Pa, a flexural modulus of 3120 f'~lfPa. The molded denture a deflection (at break) of C.1 mm and an impact strength of J/m.
The mechanical properties of the heat-cured material are determined by testing the flexural strength and impact strength of rectangular bars 13.13 mm x 11.2 mm x 35 mm) produced in steel molds. Bars of the denture material are prepared by extruding material into the bar mold cavities, then positioning the top plate and allowing the material to self cure for 10 to 15 minutes. After the initial self-cure, the bar molds (with top and bottom plates) are 2~26~~:
placed in a spring clamp. The denture material is fully-cured by placing the steel mold into a hot water bath at 72.8°C (163°F~
for 1 1 /2 hours followed by immersion in boiling water for 1 /2 hour.
The bars of denture material are then removed from the steel mold and sanded to size with silicon carbide paper 4120 grit followed by 4~Q grit). The final dimensions of each bar is 2.85 mm x 1~-11 mm x 85 mm. The flexural strength properties are determined using an Instron IVBodel 4341 at a crosshead speed of 2.54 mm per minute.
The unnotched Izod impact strength is determined on a T.M.I.
Impact Test Machine Mode! 43-01 by using the halves of the 85 mm bar broken in flexure.
Work Time and Set Time Compared for Products Formed bar Static and Hand Mixinr~
Work Time and Set time, measures of the polymerization rate, are shown in Tables 2, 3 and 7 for mixing by static mixing and hand spatuiation egual masses of the Catalyst Paste of Example 4 and the Paste of Example 5 or 6, which contain different dihydroxy-p-toluidine concentrations. For static mixing a twelve element static mixer is used. Hand spatulation is carried out on a mix pad. The Work Time is measured as the time when the materia9 no longer peaks up from the surface when probed by a sharp instrument.
The Set Time is the time when the sample becomes solid i.e. the probe does not penetrate the surface of the material.

2126~~~
'fable 2 lillOFiK TIME
Composition Dihydroxy-pWork Work time Difference equal time using volumes of toluidineusing Hand Spatulationin work pastes of time Example (Percent Static Mix (percent) by Mix wei ht) (Minutes)(Minutes) 4 and 5 ' 0.125 3.25 8.25 92 ~. and 8 0.250 1.00 1.75 75 TaT ale 3 ~E'f TiME
Composition Dihydroxy-p-Set timeSet 'time Difference equal using volumes of toluidineusing Hand in set pastes of time Example (Percent Static Spatuiation(percent) by Mix Mix wei ht) (Minutes)(Minutes) 4 and 5 0.125 4.25 7.25 70 4 and 6 0.250 1.75 2.25 29 The results in Table 2, 3 and 7 show advantageously faster polymerization rate using the static mix method which avoids the inhibitory effect of excess air incorporated in the polymerizing composition during hand spatulation. The rate of polymerization is most sensitive to the mix method at the lower dihydroxy-p-toluidine level.
('Lc~ll~r ;~~~ilii~y for Products Formed b~ static and Hand Mixin~~, Preferably dental products in accordance with 'the invention have a total color change less than 1.0 as measured on the CIELA~
scale. The color stability of catalyst and base mixed with the static mixer are compared with hand spatulated material. The color ~~.~~J~i stability test is performed by exposing 5~ mm by ~.5 mm disks of the polymerized materials to a sun lamp as designated by American ~ental Association Specification fVo. 12. The color change from the color stability test is measured by CIELAS ~E total color change with the results shown in Tables 4 and 7:
Ta 1e 4 COLOR STAI3iLiTY
Total Calor change (CIELAB BE) volumes Dihydroxy-Static band SpatulationPercent of Mix pastes p-toluidine(Total Mix, DE Change Color in CompositioniPercentChange)~E(Total ColorColor by a ual ofi wei ht) Chan e1 Exam les 4 and 5 0.125 0.74 1.31 77 4 and B 0.250 2.04 2.34 15 The total color change 0E was less than 1 for the static mix material, a change that is not perceptible, at the lower dihydroxy-p-toluidine level. The spatulated polymerizable composition shows perceptible change. The higher dihydroxy-p-toluidine level showed much greater color change for both mix methods.
Air Entrapment in Products formed bpi Static and Hand P~Jlixina Air entrapment during hand spatulation results in porosity of the product formed. Air is not entrapped in a product formed by static mixing, see Figure 5. Increased porosity is visually shown in Figures 2, S, 4. and 6. Figures 2-5 are photographically enlarged portions of the discs of denture reline products showing their grain 21~~~~:.'~
structures in Figure 7. Entrapped air is visually apparent in Figures Z, 3, 4 and 6. Increased porosity is shown by percent difference in specific gravity between hand mixing and static mixing. The percent difference in specific gravity was greater when static mixing of the composition is used than when hand spatulation of the composition is used. The comparison for percent difference in specific gravity is shown in Table 5:
Table 5 SPECIFIC i~~A9l~TY CB~Ai~C~E
CompositionDihydroxy-pStatic Nand Percent Difference Mix in equal volumestoiuidine(SpecificSpatulationSpecific fravity Nf9ix of pastes Gravity)(Specific of Exam les 6ravit D

4 and 8 0.125 1.188 1.178 0.85 Shelf Life The shelf life is determined using the Arrhenius equation at 23°C, 37°C, 43°C, 50°C and 60°C for compositions stored in two polypropylene cylinders having a piston closing one end. Shelf life is determined by cooling the composition to 23°C. The piston is removed fram both cylinders. A pointed probe (50 mm by 1 mm diameter) is inserted into the composition to check for thickening (gellation) at regular time intervals. Shelf life (at each temperature) is the time from initial formulation to just before gellation is first detected in both of the cylinders. The shelf life for example at ~3°C
is determined by an Arrhenius plot of the log of the shelf life at each temperature versus the inverse of absalute temperature extended to 3~.

2~.~b~~
2~°C as shown in Fagain et al. Shelf life shows a significant decrease in the package at the higher dihydroxy-p-toluidine level as shown in Tables 6 and 7.
Table 6 ~SHI=~F LIFF
Composition Dihydroxy-pShelf Shelf life equal life at at volumes of toluidine 60C 28C
pastes of Example (percent by wei ht) > 8 hours> 1200 Days 4 and 5 0.125 5.5 hours850 Days 4 and 6 0.250 This static mixing method allows the use of a lower dihydroxy-p-toluidine levels to attain the required setting time than spatulation, thus resulting in improved color stability, shelf life and porosity.

212~~~:
T~~v ~
~ENTURE RELINE
Example 7 8 9 10 1 2 3 .

(Astron)(Extorel)(Bosworth) Composition (See (Percent Smith et al) b Wei ht) Benzo Peroxide0.5 0.5 0.5 0.5 7,7,9-Trimethyl-4,13-60.12 60.1260.1260.12 dioxo-3,14-dioxa-5,1 diazahex-adecane-1,18-dioldimethacrylate (UDMA) 3-Methacryloxy-0.01 0.01 0.01 0.01 ro Itrimethox -silana butylatad 0.03 0.03 0.03 0.03 h drox oluone Poly(methyl 35.44 35.4 35.4435.4 moth-aorylate-cc-ethylene dimathacrylate-co-ethyl methacrylato-co-atyrene) (49.2:0.8:34.0:16.0) (cured bead of er) Silicon dioxide3.6 3.6 3.B 3.6 I mant 0.01 0.01 0.01 0.01 Cam hor uinone0.09 0.09 0.09 0.09 (2-hydroxy-4-0.15 0.15 0.15 0.15 methoxypheny)) Benao henone Dihydroxyethyl-p-0.125 0.2500.1250.250 toluidine Mixin methodStaticStaticHand HandHand Hand Hand Starting Paste/Paste/PastolPaste!Powder)Powder/Powder/
Consistency Pests PastePastePasteLi Li Li uid uid uid Produot Charactaristioa Work Time 3.25 1.00 6.35 1.759.5 (minutes) Set Time 4.25 1.75 7.25 2.25NlA
(minutes) Flexural 93 51 22 Strength (MPs) Flexural 2720 1580 1280 Modulus (MPs) hn sot Stren106 35 22 th ()/m) Color Stablllty0.7 2 1.3 2.3 (total color ohan o AE) Shelf Life 1200 850 at 23C

(De a) S eoifio 1.188 1.178 ravi Visually no no yeo yea yes yes yes perceptible air entro ment ~~.'~6~~:~
The properties of the polymerizing and cured composition, working time and setting times, color stability and shelf life at 23°~C, are as shown in combined table. Polymerization proceeds more rapidly after passing through a static mixer than after mixing with hand spatuiation on a mixing pad.
It should be understood that while the present invention has been described in considerable detail with respect to certain specific embodiments thereof, it should not be considered limited to such embodiments but may be used in other ways without departure from the spirit of the invention and the scope of the appended claims.

Claims (27)

1. A method of forming a dental product, comprising: providing a first polymerizable paste composition comprising an oxidizing agent and at least one polymerizable acrylic compound, and a second polymerizable paste composition comprising a reducing agent and at least one polymerizable acrylic compound, mixing said polymerizable paste compositions in a static mixer to form a polymerizing paste composition having a redox catalyst system for the polymerization of said acrylic compound, forming and curing said polymerizing paste composition to provide a dental product.

2. The method of Claim 1 wherein said dental product is a dental appliance, denture, denture reline, dental crown, dental bridge, or dental restorative.

3. The method of Claim 1 wherein said oxidizing compound of said free radical generating catalyst system comprises a peroxide.

4. The method of Claim 1 wherein said catalyst system includes a photoinitiator.

5. The method of Claim 1 wherein said free radical generating catalyst system comprises an amine.

6. The method of Claim 5 wherein said radiation initiated catalyst system comprises camphorquinone and said reducing agent is dihydroxyethyl-p-toluidine.

7. The method of Claim 1 wherein said first composition includes a stabilizer effective to prevent polymerization prior to said mixing.

8, The method of Claim 1 wherein said static mixer is connected in fluid flow communication with each said polymerizable paste composition and each said polymerizable paste composition is substantially free of solvent.

9. The method of Claim 1 wherein each said container has an oxygen permeability coefficient at least about 0.4 x 10-10cm2/sec (cm Hg).

10. The method of Claim 1 wherein each said polymerizable paste composition in each said container has a shelf life of at least 180 days.

11. The method of Claim 3 wherein said catalyst system comprises benzoyl peroxide, benzopinacole or tertiary butyl perisononanoate.

12. The method of Claim 1 wherein each said polymerizing composition is moldable for about 3 minutes before hardening to form said dental product.

13. The method of Claim 1 wherein said dental product is post-cured in a heat curing oven.

14. The method of Claim 1 wherein said dental product has a specific gravity at least 0.5% greater than a corresponding product formed by hand spatulation of said polymerizable paste compositions, and forming and curing the spatulated paste composition.

15. A device for forming a dental product: comprising, a static mixing conduit, a first container having a first chamber enclosing a first polymerizable paste composition comprising an oxidizing agent, and at least one polymerizable acrylic compound, and a second container having a second chamber enclosing a second polymerizable paste composition comprising at least one polymerizable acrylic compound and a reducing agent adapted to form a free radical polymerization catalyst system with said oxidizing agent, said static mixing conduit enclosing a static mixing member, said first and second containers being adapted to be connected in fluid flow communication with said static mixing conduit.

16. The device of Claim 15 wherein said dental product is a dental appliance, denture, denture reline, dental crown, dental bridge, or dental restorative.

17. The device of Claim 15 wherein said catalyst system is a free radical generating catalyst system having a stabilizer effective to prevent polymerization prior to said mixing.

18. The device of Claim 15 wherein said catalyst system includes a photoinitiator.

19. The device of Claim 15 wherein said free radical generating catalyst system comprises an amine.

20. The device of Claim 17 wherein said radiation initiated catalyst system comprises camphorquinone and said reducing agent is dihydroxyethyl-p-toluidine.

21. The device of Claim 20 wherein said oxidizing compound of said free radical generating catalyst system comprises a peroxide.

22. The device of Claim 15 wherein said catalyst system comprises benzoyl peroxide, benzopinacole or tertiary butyl perisononanoate.

23. The device of Claim 15 wherein said static mixer is connected in fluid flow communication with each said polymerizable paste composition, and each said paste composition is substantially free of solvent.

24. The device of Claim 15 wherein each said container has an oxygen permeability coefficient at least about 0.4. x 10 -10cm2/sec (cm Hg).

25. The device of Claim 15 wherein each said polymerizable paste composition in each said container has a shelf life of at least 180 days.

26. The device of Claim 15 wherein each said polymerizing composition is moldable for about 3 minutes before hardening to form said dental product.

27. The device of Claim 15 wherein each said polymerizing composition has a viscosity of at least 5000 centipoise.