DE1766918B - Method for applying linings to removable plastic dentures - Google Patents

Description

The invention relates to a method for applying linings with a soft Contact layer on removable plastic dentures on the basic skeleton made of polymethyl methacrylate or the like.

It is known, in dental technology, to have removable dentures with a soft contact layer on the sides of the prosthesis facing the oral mucous membranes to avoid painful Pressing on the points of contact with the mucous membrane and especially with the soft and hard ones Prevent dividing the palate and gums.

It is known (German patent specification 928 246), predominantly hydrophobic soft for these purposes To provide layers, e.g. B. from polymeric esters of acrylic and methacrylic acid with higher aliphatic Alcohols, plasticized polyvinyl chloride, ethylene glycol dimethacrylate and finally also from hydrogels, which are produced by copolymerization of glycol monomethacrylate or acrylate with less than 2% of a glycol dimethacrylate or acrylate arise.

In this case, the prepolymer consists of a solution of the polymeric glycol methacrylates in the

ίο appropriate monomer and from the active filler. It is used in such a way that it od on the basic skeleton made of polymethyl methacrylate. Like. In a common split mold for the production of dentures is stacked, whereupon the polymerization is accomplished. Because the monomeric glycol monomethacrylate is partially converted into the polymethyl methacrylate diffuses and polymerizes there, a good connection is achieved, but this is achieved by strong Swelling of the hydrogel layer in water is subsequently impaired. However, through this swelling an undesirable change in volume as well as a change in the surface relief of the soft Hydrogel layer caused, and the resulting high tangential tension can be unfavorable Cases even lead to the separation of the hydrogel layer from the polymethacrylate base.

Through the use of hydrophobic copolymers, what is known as "internal plasticization" occurs Set by the usual plasticizers, which means that although a great elasticity and Softness occurs in a wide temperature range, but mechanical processing can only be carried out with difficulty is.

The invention is based on the object of eliminating these known deficiencies and a hydrogel for relining that is hard after drying out and can easily be worked on afterwards leaves. In the further treatment, the underlay is made soft and pliable again, to be able to adapt in the oral cavity.

This object is achieved according to the invention in that as a dough-like mixture for the hydrogel layer a mixture of hydrophilic, soluble, uncrosslinked glycol monomethacrylate or acrylate polymer is used with liquid glycol monomethacrylate or acrylate that contains 0.05 to 2% of a crosslinking agent, a polymerization initiator and water-soluble but substantially anhydrous Solvent of the uncrosslinked polymeric glycol monomethacrylate or acrylate and at the same time of the polymethyl methacrylate in such an amount that an approximately equal swelling of the resulting hydrogel, such as water, is created in equilibrium with the hydrogel, whereby the Solvent is completely washed out with water after the polymerization.

According to a further measure of the invention, the hard base made of polymethacrylate is made before applying the dough-like mixture for the hydrogel layer with a mixture of glycol monomethacrylate or acrylate coated with the monomer of the hard base one or more times. Ethylene glycol monoacetai or glycerol diacetal are preferably used as solvents.

In practice it has proven to be useful that the mixture for the hydrogel layer on the

Polymer-monomer mixture for the hard denture corner is applied in the split mold before the latter has completely hardened.

According to a further measure of the invention, the soluble polymer is in dry, powdery !!, a peroxide compound-containing state shortly before use with the monomer-solvent mixture made into a paste, with the latter optionally adding a reducing agent. The advantages achieved by the invention are in particular that the polymer according to the invention Component, namely the uncrosslinked glycol monomethacrylate polymer, primarily to achieve the appropriate viscosity of the mixture when applied. Compared to the known The prepolymer has the following advantages: When producing a storable viscous solution no polymerization initiator is brought in. so that the risk of spontaneous gelation is essential is decreased, even if the temperature is temporary is increased. It also enables the use of the separately produced soluble polymer the above-mentioned two-component process by adding the powdery soluble polymer an «, organic or inorganic peroxy compound and optionally the mixture of monomer with a solvent, a reducing agent, such as. B. a tertiary amine or a sulfinic acid is added. To the mixing of the liquid mixture with the powdery soluble polymer sets the polymerization of the monomer very soon, with the soluble polymer in the resulting three-dimensional The structure of the hydrogel is copolymerized.

The ability of the soluble polymer to fully interact with the monomer of the type described above Forming a uniform, cross-linked, insoluble hydrogel is particularly beneficial here. Surprisingly the hydrogels produced in this way do not differ from those produced by direct three-dimensional copolymerization of the same monomers formed with the same crosslinking agents will.

The method according to the invention also allows repairs and a so-called rebasing to be carried out, which consists in the fact that the usual hard denture, possibly after grinding, is subsequently provided with a soft hydrogel layer. The rebasing can be done either in a Plaster of Paris or directly in the patient's mouth.

According to the foregoing, a particular advantage of the invention is that the hydrogel according to the invention is hard and can easily be edited afterwards by grinding, milling, etc. The hydrogel, which is in contact with the mucous membrane, only becomes after swelling in aqueous liquids sdll. again soft and elastic. The swollen hydrogel Hai also has the advantage that it does not slip in contact with the mucous membranes, but rather well hold on to it. A very special advantage in comparison with the known hydrophobic soft copolymers is that the swollen hydrogel according to the invention does not have unpleasant odors absorbed, such as B. essential oils from onions. Garlic and other vegetables.

According to the invention, the expression "glycol" not just Älhyleiiglj! ·. · '.. but all Few of us partially water-soluble aliphatic glycols such as diethylene glycol, triethylene glycol, propylene glycols, 1,1-butylene glycol and also mixtures thereof Roger that. By a suitable choice of the glycol component, the swelling capacity of the resulting hydrogel can be varied within wide limits.

Glycol methacrylates and their soluble polymers are preferred because they have excellent hydrogels physical properties and high chemical resistance. You also have the advantage that the hydrogels produced from them have been proven to be completely harmless by testing over several years became. The corresponding hydrogels made from glycol acrylates are the methacrylates in most Properties very similar. They just have a higher swelling capacity and lower chemical properties Stability, but this is unimportant with dentures. As already said, the swelling capacity by copolymerization of the glycol monoacrylate with z. B. methyl methacrylate or the like. Or can be regulated as desired by the choice of glycol.

If a further comonomer is to be added to the monomeric glycol acrylate or methacrylate, one must choose one which is well compatible with the uncrosslinked glycol methacrylate or acrylate polymer. The comonomer must not precipitate the uncrosslinked polymer; on the contrary, it should as far as possible increase its solubility. So z. B. the methyl methacrylate, which has excellent affinity for the hard base of polymethyl methacrylate, is unusable in this case in a higher amount because it falls the polymeric, soluble, uncrosslinked glycol methacrylate or acrylate from its solution, similar to saturated hydrophobic esters such . B. butyl acetate or ethyl acetate. The chains of the polymeric glycol methacrylate or the like remain wrapped up when interacting with such hydrophobic esters and tend to aggregate. The polymer then only acts as a filler, which tends to worsen the mechanical properties of the resulting hydrogel and the connection with the basic skeleton. Diglycol or triglycol monoesters of acrylic acid or of a-alkylated acrylic acids are better suited, but since the swellability in water is increased by copolymerizing such strongly hydrophilic comonomers, their addition is limited to a maximum of about 25% of the monomeric component.

The monomeric component together with the soluble, uncrosslinked polymer forms the resulting Hydrogel and also ensures an intimate connection of the hydrogel with the hard base in which it partially penetrates and polymerizes in it. This creates numerous covalent bonds between the polymethyl methacrylate of the pad and the corresponding hydrogel. These ties are partly due to the existence of "frozen" macro radicals and the presence of unspent! Given methyl methacrylate in the pad. On the other hand, however, there are also grafted ones and block copolymers as a result of chain transfer to the polymethyl methacrylate within the surface layer, which is swollen with the monomer and solvent. This becomes a gradual one Transition created between the hydrophobic base and the hydrogel; the degradation of the tanuential tension in all levels of the

, · J K »fr, rr-htpti are also 'venn by chance after the

Binding layer contributes to a reliable connection g ^ urchen s, ^ _{n back}

of the two materials. The strength of the ^{ver W} ^ los can of course be normal

bond is then added, even at maximum overall sources ^m _t eand fillers,

sufficient. °

The crosslinking agents are primarily 5. · ,, j

Glycol dimethacrylates or diacrylates into consideration: öeisp v.

On the one hand, their properties are very satisfactory, _oete ii _t en plaster mold is made in the usual way

on the other hand, they are anyway in the corresponding In I _nW ending of a separating layer (e.g. from a

And let present Glykolmonoestcrn therefrom ^un X ^r .j: ^"W S _{s for} eiösung) the basic skeleton of a

very difficult to remove completely. ι ° ^ "^ !, ίεη denture made from a mixture of

The soluble, uncrosslinked glycol methacrylate or ^ hmb ^ rerZa.np polymethyl methacrylate polymer can be produced by two methods: ^pu ^ f ™ t- _d monomeric methyl methacrylate. First, you can get a completely pure ^ "* ^m £ Z ™ _{at & t] s} chidit necessary space or methacrylate Glykolmonoacrylat, steUt not a comparison, the ^ ur y s _{spacer film secured;.} Contains _the cross-linking agents, polymerize The Po ymen- 15 may sation by emer emg g ^ _q ^. ^ ^ in this case in any previous "" t "" em ne spacer film is angediu of solvent or without a solvent take place form "■ ^ _{the ly neither at this.}

however, ""'™ harbors the greatest night-time with this method. ^ ₆ methyl methacrylate still to the poly-

the fact that one such pure Glykolmonoester only mensierende Metnymie y ^

very difficult to manufacture. The diester forms «, ^m " «^ _r ^^ X ^ Da ₈ AnkleK-nϊί

namely, it is very easy not only to show rubber or pouch J _{can also get through}

of the monoester, but even with the vacuum polymer dough to «« = polyethylene or

distillation of the same, since the reesterification requires an insertion emer thin fo ^^ us ^ o ^ yamyMi ^ or

typical equilibrium reaction is. v ^ be veined Then both parts of the

Far more comfortable, therefore, the other method is the 5 verhmde ^ ~ ^ _{eat to the} excess

consists in that you press a mixture of a glycol J ° ^r ^ _m ^ traLu. The polymerization

monomethacrylate or monomethacrylate with corresponding f ^ SEmäraen triggered. Then the

Diester eliminated in the presence of a good solvent co- vnrd ^ '^ f ^r _{spacer film} ^8, and more

polymerized, whose interaction parameter χ against- ^ ™ f _p ^o ™ ^ _n - _S a _t i _{on is} completed, the space becomes

above the resulting copolymer lower than 30 before the l oiymerisdiiu tpiofnrmieen Gemisrh

0.5 is. The method is e.g. in the French after the D.stanzfohe with ^ ^m J ^e f ^ ^m ^ ^en ^ ^mi ^ ^h

Patent specification 1523 779 explained in more detail. This Me- for the production of the Hydr

Incidentally, method also allows the properties of the form to be ^^ '^

-soluble polymer by copolymerization with subsequent of the ^tei g ^fo ™ ^'s _F g ^{(^ mii} "^ KXS Wassef the SIi

to change their comonomers as desired. 35 Then ^ JJS ^ SnSSS ₃ ÄuS

The third component of the mixture then forms a sieucii ™ «"

common solvent of the soluble glycol- at boiling en is then ^^ dj Fonn

methacrylate or acrylate polymer and the corresponding cold water ^{and v0} ™ 8 f. »™ ^e · ° ^ie

corresponding monomer. This component is the same-finished denture is then m of 2 to 3 days

early a solvent (or at least a good 40 diluted distilled water ^ »f ^ ^b « J «

Swelling agent) of the polymethyl methacrylate, from hydrophilic solvent -m this FaHe ethylene-

from which the basic skeleton of the denture was completely removed

is. This component serves two purposes: The dough-like mixture for making de

Firstly, it facilitates the penetration of the monomeric hydrogel layer. It was prepared in the following way.

Component in the basic skeleton of the prosthesis and 45 1 part of dry uncrosslinked Pdy (ethylene

thus a firm connection of the hydrogel layer with glycol methacrylate) ™ \ $ ^^ £ ™ J £ J ^e ^

of the pad, and secondly, it secures in the absence of weight M ⁼ . ² ? ° ?? η · κ ⁸ ^ vS fZ PrH S

the name of what he has the same swelling of the resulting 0.1 mm, containing 10 · /. Dibenzoyl peroxide is m

Hydrogel, which later equilibrates with water a part of ethylene glycol monoacetate (^ de.ntervall

is achieved. As a result, when using the: hn- ₅ c 183 to 193 ° C / 760 mm Hg) and a part of ethylene

prosthesis the maximum strength of the connection glycol monomethacrylate (containing 0 35 «/. des ver

guaranteed with full swelling. It is divided into wetting ethylene glycol dimethacrylate)

Note that the hydrogel layer on the hydro- The hydrogel layer created in this way is subject to the

phobic pad only in anhydrous or almost water-free wash, practically no significant yolumver-

can be polymerized in the free state. The 53 changes and adheres very firmly to the hard skeleton

The amount of solvent is therefore chosen. made of polymethyl methacrylate. that the swelling achieved during the polymerization

degree approximates the equilibrium swelling in example 2

Water corresponds. .. _. .

As the solvent used was water-soluble, 60-minute dentures became thicker must be and "afterwards completely displaced by water from the hydrogel layer to be polymerized is, its eventual toxicity, or grinding, plays with a mixture of equal volume Taste ei »borrowed no role. For this share of Melhylmethacrylal and Athyk-nglyKOI-Gruncle can / .. B. ^ GlycoImonoacetate, glacial acetic acid or monomethacrylal (with 0.35 "/" diester) _- to ^:, /; Dimethylformamide can be used without hesitation, whereupon the mixture according to Example I is coated. Ls, however, are also completely harmless. The Anpolymensicrcn of the Ilydrogel-I Solvent present, namely Glyceriiuliazelate, layer was in a usual split plastering :; in which no undesired side effects are carried out, which were previously used for this purpose with HiIL-

7 8

The same prosthesis made before grinding was dimelhacrylal, 89.5 parts methanol, 0.45 parts azo. Further treatment was carried out according to Example 1. bis-isobutyronitrile. The cooled solution was poured into a prosthesis rebased with hydrogel ten times the amount of cold water, the collected, swollen precipitate was decanted, ^{and washed three times with a bis ρ ie 1 3 5} 20% aqueous ethanol solution

and at 20 ° C under reduced pressure of a water

The process according to Example 1 was dried using a vacuum pump. The polymer was then

repeated difference that instead of the uncrosslinked, ground and mixed in a mixture of equal people

polymeric ethylene glycol methacrylate is copoly- gen of anhydrous glycerol diacetate (mixture of

mer with 25% methyl methacrylate was used. io both isomers) and ethylene glycol monomethacry-

This copolymer was dissolved by solution polymerizate (with 0.4% ethylene glycol dimethacrylate),

tion in dimethylformamide according to the above cited On one part of the soluble polymer were 2 parts

French patent. In addition, the liquid mixture obtained. Before applying

5% of the monomeric glycol methacrylate was used to represent the hydrogel layer

Methyl methacrylate added, since the latter with the 15 0.01 part of dibenzoyl peroxide in concentrated GIy-

soluble ethylene glycol methacrylate methyl methacrylic diacetate solution and 0.5 parts of finely divided

latcopolymer is compatible. The finished hydrogel is silicon oxide stirred into the viscous solution,

less soft and swells less in water than that at the same time the usual red pigment was added

according to example 1 or 2. sets. Further treatment was carried out according to Example 1.

Example 4 Example 7

The procedure according to Example 3 was followed, only with the. The procedure according to Example 2 was carried out with the

Difference that 20% of the monomeric ethylene glycol difference repeats that the liquid component kolmethacrylates through diethylene glycol methacrylate 25 glycerine diacetate instead of ethylene glycol diacetate and have been replaced. As a result, the swellability was also 2% of diethylaminoethyl acetate as Water approximately to the value of the Hvdrogels after reducing agent contained. The doughy mixture Example 1 increased. was quickly put on the abraded dentures

brings and the grafting in the mouth of the pa-

Example 5 3 Tients completed instead of in the plaster mold. After 10

The dentures could be removed in minutes

The procedure of Example 1 was with the Un-. She became completely different after an hour repeats that the liquid component constant removal of the glycerol acetate and the from 1 part of ethylene glycol monoacrylate (with 0.5% remainder of the redox system used as initiator Diester) and 1 part azeline (commercial mixture 33 in 50% ethanol and then thoroughly in water of 1,2- and 1,3-glycerol diacetate) washed together. The prosthesis rebased in this way corresponded with would. The finished hydrogel layer adhered firmly to its hydrogel layer, precisely following the profile of the palate, the hard polymethyl methacrylate and had good properties. All parts in the examples are physical weight Properties. share unless otherwise stated.

40 As hard polymers of the prosthesis can besides

Example 6 other than the usual polymethyl methacrylate

similar polymers, such as polymethylethacrylate, poly-

Uncrosslinked, soluble ethylene glycol methacrylate methyl acrylate, polybenzyl methacrylate, polyethylene polymer was made by boiling for 6 hours under re-methacrylate and others, as well as corresponding mixed flow prepared from the following mixture: 10 parts of ethy- 45 polymers are used without the process of ablenglykolmonomethacrylat, 0.05 part of ethylene glycol to have to change.

Claims (5)

Patent claims: 1. Method of applying relines with a soft contact layer removable plastic dentures on the basic skeleton made of polymethyl methacrylate or the like, characterized in that a dough-like mixture for the hydrogel layer Mixture of hydrophilic, soluble, uncrosslinked glycol monomethacrylate or. -acrylate polymer is used with liquid glycol monomethacrylate or acrylate, which is 0.05 to 2%> a crosslinking agent, a polymerization initiator and a water soluble, but essentially anhydrous solvent of the uncrosslinked polymeric glycol monomethacrylate or acrylate And at the same time of the polymethyl methacrylate. The like. In such an amount that one approximately the same swelling of the resulting hydrogel, like water, in equilibrium with the Hydrogel is formed, the solvent being completely washed out with water after the polymerization will. 2. The method according to claim 1, characterized in that the hard base made of polymethyl methacrylate or the like. Before applying the dough-like mixture for the hydrogel layer with a mixture of glycol monomethacrylate or acrylate is coated one or more times with the monomer of the hard base. 3. The method according to claim 1, characterized in that the solvent is ethylene glycol monoacetate or glycerine acetate is used. 4. The method according to claim 1 and 3, characterized in that the mixture for the hydrogel layer on the polymer-monomer mixture for the hard prosthetic skeleton before the complete one Curing the latter is applied in the split form. 5. The method according to claim 1 to 4, characterized in that the soluble polymer in dry, powdery state containing a peroxide compound shortly before use is made into a paste with the monomer-solvent mixture, the latter optionally being a Contains reducing agents.