Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L24/00—Surgical adhesives or cements; Adhesives for colostomy devices
  • A61L24/04—Surgical adhesives or cements; Adhesives for colostomy devices containing macromolecular materials
  • A61L24/06—Surgical adhesives or cements; Adhesives for colostomy devices containing macromolecular materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K6/00—Preparations for dentistry
  • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
  • A61K6/884—Preparations for artificial teeth, for filling teeth or for capping teeth comprising natural or synthetic resins
  • A61K6/887—Compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/14—Macromolecular materials
  • A61L27/16—Macromolecular materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
  • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
  • C08F20/10—Esters
  • C08F20/22—Esters containing halogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
  • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/18—Introducing halogen atoms or halogen-containing groups
  • C08F8/20—Halogenation

Definitions

• This invention relates to radio-opaque plastics material; more particularly, this invention relates to radio-opaque plastics material suited, inter alia, to use in the fabrication of denture base, to processes for preparing such materials, to methods of fabricating denture base therefrom, to dentures comprising such materials; and to cements for endoprosthesis comprising such materials.
• the plastics material generally used in the fabrication of denture base is poly(methyl methacrylate).
• Poly(methyl meth aerylate) is a highly satisfactory material in most respects for use as denture base: thus, it has adequate strength for most applications, high translucency (and hence aesthetic acceptability), and can readily be fabricated by the dental technician in simple low-cost moulds to give dimensionally accurate, well-fitting dentures.
• a disadvantage of poly(methyl methacrylate) is that it is radiolucent; and this has serious implications in matters of personal safety for denture wearers involved in a traumatic incident wherein they ingest all or part of their denture. Thus, the patient is often unaware that this has happened and when symptoms occur later (for example, sepsis, vomiting, coughing fits ) X-ray diagnosis will reveal nothing.
• This invention seeks to provide a radio-opaque plastics material in which the aforementioned disadvantages are reduced or overcome. According, therefore, to one aspect of the present invention there is provided a homo- or copolymer of a (meth) aerylate ester into which atoms, especially halogen atoms, capable of absorbing X-radiation are incorporated by covalent bonding, the resulting polymer having a viscosity average molecular weight greater than 400,000.
• atoms, especially halogen atoms capable of absorbing X-radiation are incorporated by covalent bonding
• Halogen atoms capable of absorbing X-radiation are chlorine, bromine and iodine atoms. Chloro-substituted polymers of the invention are found to be less effective than the corresponding bromo- ones while the iodo-substituted polymers tend to be too labile, eliminating iodine; accordingly, bromo-substituted polymers are preferred. A mixture of halo-substituents, such as both chloro-and bromo- substituents, may be present in the polymers of the invention.
• the polymers of this invention are capable of absorbing X-radiation, as herein defined, it is preferred that they comprise at least 5% by weight, preferably at least 10% by weight, of halogen. In practice, it is found 15% to 20% by weight of halogen gives very satisfactory results, though up to 30%, or even up to 55% by weight, of halogen may be used.
• the alkenyl group is an unsubstituted alkenyl group of the formula:
• the homo- or copolymer of this invention preferably comprises the (hydro)halogenation, preferably the (hydro)bromination, product of the substituted or unsubstituted alkenyl ester; for example a mono- or vie di-haloalkyl, preferably mono- or 2,3 di- halopropyl, especially mono- or 2,3 di-bromopropyl, (meth)aerylate.
• the polymer of this invention may be a homopolymer, such as poly(mono- or vie di-haloalkyl (meth)acrylate, preferably poly (mono- or 2,3 di-halopropyl(meth)aerylate), especially poly(mono- or 2,3 di-bromopropyl(meth)aerylate).
• it may be a random, block or graft, preferably random or block, copolymer with one or more further (meth)aerylate esters, other vinyl monomers, or polymers, for example elastomers, polysaccharides or homo- or copoly [(meth)aerylate esters].
• a radio-opaque polymer as aforesaid which comprises a toughening dispersed elastomeric phase.
• the elastomer comprises a polymerised unsubstituted or halo-substituted diene; suitably the elastomer may be grafted to the radio-opaque moiety and, where the elastomer is halo-substituted, will enhance the radio-opacity.
• Suitable elastomers comprise polybutadienes such as natural rubber, butadiene/styrene rubbers such as styrene/ butadiene block copolymers which may comprise less than 40% by weight of polymerised styrene, butadiene/aerylonitrile rubber or butyl rubber.
• the further (meth)aerylate esters, other vinyl monomers or polymers, for example elastomers, where present, may comprise from 5% to 80% by weight, preferably from 20% to 50% by weight, of the copolymer.
• the polymer of this invention should have a viscosity average molecular weight from 400,000 to 15,000,000 preferably from 500,000 to 12,000,000. Below the lower limit the polymers tend to exhibit an undesirable lack of dimensional stability. Above the upper limit there are processing difficulties.
• the polymers of this invention may be blended with one or more other compatible polymers, especially homo-or eopoly [(meth)-acrylate esters! such as poly(methyl methacrylate).
• a process for the preparation of a homo- or copolymer as hereinbefore defined which process comprises anionically polymerising one or more (meth)acrylate esters in the presence of, as catalyst, an alkali metal hydrocarbyl; covalently bonding to the polymer so formed atoms capable of absorbing X-radiation, and, if desired, polymerising the product with one or more further (meth)-acrylate esters, other vinyl monomers or polymers and/or blending the radio-opaque polymer so formed with one or more other compatible polymers, especially homo- or eopoly [(meth)acrylate ester].
• the alkali metal is lithium; and that the hydrocarbyl moiety is a lower alkyl moiety.
• R 1 and R 2 which may be the same or different, each represent a (-M) group conjugated with the ethylenic bond.
• R 1 or R 2 represents an aryl group; it is particularly preferred that R 1 and R 2 both represent phenyl groups.
• the temperature of the reaction mixture is maintained from -100°C to -40°C, preferably from -80°C to -60°C.
• the process of this invention is preferably performed on a (meth)acrylate ester which is a substituted or unsubstituted alkenyl ester, as hereinbefore defined. Where this is so and where it is desired that the atoms capable of absorbing X-radiation are halogen atoms these may readi-ly be covalently bonded to the polymer by (hydro)halogenation, especially (hydro)bromination, of the alkenyl groups which are found to remain unchanged during the anionic polymerisation. It is highly desirable that all reagents used in the process of this invention are anhydrous.
• This invention further provides a process as hereinbefore defined which additionally comprises incorporating an anionically copolymerisable species into the reactant mixture.
• the anionically copolymerisable species may comprise a further (meth)acrylate ester or other vinyl monomer, for example styrene or (meth)acrylonitrile, which may be added ab initio, thereby resulting in a random copolymer, or after the initial (meth)acrylate ester is polymerised, thereby resulting in a block copolymer.
• this invention provides a process as hereinbefore defined which additionally comprises incorporating a copolymerisable polymer, for example an elastomer, a polysaccharide or a homo- or eopoly [(meth)acrylate ester], and if desired a grafting monomer, for example methyl (meth)acrylate, into the reactant mixture with a free radical initiator, for example a peroxide such as benzoyl peroxide and a chain transfer agent, for example an alcohol or mercaptan such as tertiary dodecyl mercaptan.
• a copolymerisable polymer for example an elastomer, a polysaccharide or a homo- or eopoly [(meth)acrylate ester]
• a grafting monomer for example methyl (meth)acrylate
• a process for the preparation of a homo- or copolymer as hereinbefore defined which process comprises radical polymerising, preferably at an elevated temperature such as from 40o to 100oC, preferably 50o to 80oC, one or more (meth)acrylate esters into which atoms, especially halogen atoms, capable of absorbing X-radiation are incorporated by covalent bonding; and, if desired, polymerising the product with one or more further (meth)acrylate esters, other vinyl monomers, or polymers and/or blending the radio-opaque polymer so formed with one or more other compatible polymers, especially homo- or eopoly [(meth)acrylate ester].
• a free radical initiator for example a peroxide such as benzoyl peroxide, is preferably present.
• the atoms capable of absorbing X-radiation for example halogen atoms, preferably bromine atoms, may be incorporated in the acid moiety or the alcohol moiety, or indeed both but preferably the latter, of the ester; preferably the alcohol moiety is mono- or poly-bromo substituted.
• the ester may be formed by reacting the corresponding acid halide or anhydride with a corresponding homo or poly- halo substituted alcohol; for example by reacting (meth)acryloyl chloride with 2,3-dibromopropanol. Such materials have particularly good optical properties.
• This invention also provides a radio-opaque homo- or copolymer, or polymer blend, whenever prepared by the process of this invention.
• the radio-opaque homo- or coplymer, or polymer blend of this invention may be in the form of beads, crumbs, sheets, rods, blocks or other forms of stock.
• This invention further provides a dough moulding process for the preparation of a cured radio-opaque polymeric mass, especially a denture base, which process comprises mixing a radio-opaque homo- or copolymer, or polymer blend, according to the invention with a liquid (meth)acrylic ester in the presence of a curing sgent, for example a glycoldi-(meth)acrylate such as ethylene glycoldi-(meth)acrylate in an amount of less than 10%, preferably less than 6%, by weight of the dough; and permitting the dough to cure, preferably at an elevated temperature and in a mould.
• a curing sgent for example a glycoldi-(meth)acrylate such as ethylene glycoldi-(meth)acrylate in an amount of less than 10%, preferably less than 6%, by weight of the dough.
• This invention also provides a raio-opaque denture base whenever prepared by the process of this invention.
• this invention provides a cement, for example for joining fractured or coapted bone or endoprosthesis comprising a radio-opaque homo- or copolymer of this invention.
• beadsmade from the radio-opaque homo- or copolymer and containing 0.9% benzoyl peroxide, once sterilised either by gamma radiation or formaldehyde vapour, can be dough moulded with methyl methacrylate monomer containing about 2% of a tertiary aromatic azine.
• the dough described will set to a hard and robust mass in about five to seven minutes.
• Such a system may be used as a cement for endoprosthesis and has the advantage over radiolucent cements of being visualised on X-ray plates.
• Tetrahydrofuran (200 ml) was purified by heating under reflux for three hours over lithium aluminium hydride, the reflux condenser being protected from moisture with a calcium chloride drying tube. The mixture was cooled and then the tetrahydrofuran was distilled under reduced pressure onto a sodium mirror where it was kept sealed under vacuum.
• the apparatus was next immersed in an acetone bath cooled to -70oC and the contents of the flask were stirred vigorously with a magnetic stirrer.
• Butyllithium (5.0 ml of a 1.6 M solution in hexane) was added, and an orange colour developed immediately which darkened to deep red over a period of 10 minutes.
• the allyl methacrylate (62.8g) was then added over a period of two minutes; after approximately five minutes the solution had begun to thicken and the reaction was allowed to proceed for an hour at -70oC.
• the reaction was terminated by the addition of methanol (5.0 ml) and the polymer isolated by precipitating into petroleum ether (b.p. 60-80 C). The polymer, poly(allylmethacrylate), was filtered off and dried under vacuum at room temperature, yield 62.2g (99%).
• Poly(allylmethacrylate) (20g) was dissolved in carbon tetrachloride (600 ml) at room temperature. The solution was then filtered, cooled to 0°C, and a slight excess of bromine (26g) in carbon tetrachloride (100 ml) was added with vigorous shaking. An immediate orange precipitate was formed and the mixture was left at 0°C for 48 hours. The crude orange dibromide was filtered off, washed with carbon tetrachloride and dried at room temperature, yield 44.6g (98%). The product was dissolved in chloroform and reprecipitated into petrol ether (b.p.
• Example 1 in a form familiar to dentaltechnicians. To facilitate curing after dough moulding benzoyl peroxide was incorporated inside the beads.
• the polymer (40g) was dissolved in chloroform (300 ml) and added to a stirred solution of gelatine (18g) and Tepol (6g) in water (600 ml) at 50°C. The mixture was stirred under a stream of nitrogen and the temperature was raised slowly to 70°C at such a rate (over five hours) as to prevent excessive foaming of the mixture. When the internal temperature had reached 70°C, water (400 ml) was added and the mixture was then poured into a 1.1 measuring cylinder and the polymer beads allowed to settle out overnight. The polymer beads were washed repeatedly by suspending them in hot water and allowing them to settle out. Finally the polymer beads were filtered off and dried in vacuum at room temperature to give 80-90% yield. EXAMPLE 4
• A is a specimen of a conventional radio-opaque poly(methyl meth acrylate) marketed under the trade mark "TREVALON”: B is a 20:80% by weight block of brominated poly(n-allyl meth acrylate) with methyl methacrylate; C is a 30:70% by weight block of brominated poly(n-allyl meth acrylate) with methyl methacrylate;
• D is a 40:60% by weight block of brominated poly(n-allyl meth acrylate) with methyl methacrylate
• E is a 50:50% by weight block of brominated poly(n-allyl methacrylate) with methyl methacrylate
• F is poly(methyl methacrylate).
• the polymer beads (15g) were added to methyl methacrylate (7.5g), containing 5% ethylene glycoldi-methacrylate and 0.5% benzoyl peroxide, mixed thoroughly and left to stand. All four brominated samples gelled within four minutes to give a slightly translucent rubbery dough that could be easily packed into a mould and after curing (seven hour delay, three hours at 100oC) gave translucent products. Relevant material properties are tabulated in Table 1.
• Tetrahydrofuran 200 ml was distilled from a sodium mirror under reduced pressure into a reaction flask equipped with a PTFE stirrer bar and diphenyl ethylene (0.5 ml) was added followed by a solution of butyl lithium in hexane (5.0 ml of 1.6 M solution). Allyl methacrylate (35g) was added and the red colour was discharged to give a pale yellow solution that thickened appreciably. Methyl methacrylate (15g) was added and the thick solution stirred for one hour at -70oC.
• Example 6 The procedure described in Example 6 was followed using 200 ml of tetrahydrofuran; 0.4 ml 1.1-diphenyl ethylene, 5.0 ml of butyl lithium (1.6) and 20g of allyl methacrylate. After the allyl methacrylate had been allowed to polymerise for one hour at -70°C, 30g of methyl methacrylate was added, and the solution was stirred for a further hour at -70oC.
• Example 8 2.1 parts of the polymer bead material prepared in Example 8 were mixed with 1 part of monomeric methyl methacrylate containing 5% ethylene glycol dimethacrylate as a cross-linking agent and 0.5% benzoyl peroxide and the dough. so formed could be packed into conventional plaster moulds, used for moulding denture base materials, heat cured at 100oC to give a white-translucent tough acrylic material.
• This material exhibits typical craze whitening associated with rubber modified glassy polymer and relevant material properties are tabulated in Table 2 together with those of other acrylic denture base materials.

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• Health & Medical Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Animal Behavior & Ethology (AREA)
• Veterinary Medicine (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Organic Chemistry (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Polymers & Plastics (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Plastic & Reconstructive Surgery (AREA)
• Surgery (AREA)
• General Chemical & Material Sciences (AREA)
• Dermatology (AREA)
• Transplantation (AREA)
• Graft Or Block Polymers (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Materials For Medical Uses (AREA)
• Dental Preparations (AREA)

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• 1981
  • 1981-09-24 JP JP56503015A patent/JPS57501430A/ja active Pending
  • 1981-09-24 GB GB8128837A patent/GB2085012A/en not_active Withdrawn
  • 1981-09-24 WO PCT/GB1981/000203 patent/WO1982001006A1/en not_active Application Discontinuation
  • 1981-09-24 EP EP81902641A patent/EP0073765A1/en not_active Withdrawn

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