LIQUID PHASE FOR THE PREPARATION OF A CEMENT APPLICABLE IN BONE SURGERY AND STOMATOLOGY.

Claim 1. liquid phase for the preparation of a cement sealing

autopolymérisale

whose

phàse

solid consists of a polymer and/or copolymer acrylic, applicable to prosthetic implants, characterized in that it is in the form of a collodion polymer and/or an acrylic copolymer in at least one acrylic monomer, comprising at least 65% by weight of acrylic monomer and between 15% and 35% by weight of polymer and/or

copoIymère

acrylic, lo and 2. liquid phase according to claim 1, characterized in that it comprises at least 25% by weight of polymer and/or acrylic copolymer.3. liquid phase according to claim 1 or 2, characterized in that the IC is an acrylic ester monomer is

méthacryislique

, preferably methyl methacrylate, and/or

FacryIate

ethyl, propyl or butyl.4. method of preparing the liquid phase according to claim 1, characterized in that the polymerization is carried out partial in the monomer by voluntary stop the reaction.Solid phase for use in conjunction with the liquid phase according to claim 1, characterized in that the polymer making up the antenna is selected from methyl polymethacrylates, ethyl, propyl and butyl, and ISI AE corresponding copolymers.6. solid phase according to claim 5, characterized in that it comprises a mineral filler.ective of each of the liquid and solid phases of acrylic cements.Firstly, la liquid phase comprised a monomer, such as methyl methacrylate to which could be S adjunct some additives, such as polymerization accelerator, dyes...Then, the solid phase was composed, essentially of a polymer in the form of a powder

bianche

, such as polymethyl methacrylate, and of some additives are present in low amounts, such as a radical polymerization initiator, optionally a contrast agent-ray sensitive "X.", of biocidal agents to limit the risk of infection, andc.The relative amounts of liquid and solid phases, brought into presence during the preparation of the cement, were of the order of 1:2 by weight.Across their reputation; it appears undeniable that such cements have been originally apparent in progress of prosthetic implants, since they have proved tolerable by the human organism, practical by a conglomerate fast which solely not exceed fourteen minute, but without being able to prove their qualities over time.However, it has been in use, that these luting cements had some major drawbacks, sufficiently damaging for life threatening operated or cause injury to local heavy and irreversible to the origin of the rejection by the host bone and by the surrounding tissues.Firstly, the polymerization of such acrylic cements is very exothermic, and when it is carried out "in-situ", it causes, for a short time of 4 to 5 min, rising dramatically and localized temperature that can reach the threshold of 100 °c. Although the amount of cement used is limited to unity, this increase in temperature is sufficient to cause, upon about 65 °c, melting and dissolution of human fat and the coagulation.Gold, some medical publications issued this idea worried that the increased temperature beyond 100 °c was free from inconvenience since it was compensated by the lower temperature of the medium recipient and that, upon batches, it has failed to reach the aforementioned critical

températnres

.More than this, the liquid monomer, such as methyl methacrylate, is a potent human fat solvent, and the more so as the temperature of the medium increases by facilitating its diffusion, and as it exudes cement when the polymerization "in-situ", it dissolves the said fats and passes into a blood the ISI operated by driving them.Therefore, severe side effects could be observed at the time of implantation of prostheses. These side effects are manifested yet today by a rapid fall and the tension of the operated, the Aliant in some cases to the demilitarization of cardiac pumping,

cur

and stoppage of the patient's death. They manifest themselves also by embolisms greasy, a result of the presence of the fat peripheral blood back into the lung, and against which the surgeon and the resuscitator are in trouble.But beyond the aforementioned

alléas

, exist other

inconvérients

, although less important, whose manifestations flow naturally from the exothermicity of the reaction. In many cases, it has been found that the exothermicity of the polymerization reaction induces large lesions burn, to surrounding tissue, but also necrosis

superficielIes

layers contacting the bone cement.Gold, it was noticed by more that the exothermicity gave rise much burn bone which may evolve in three long time already, the ordinarily skilled artisan medical has created and developed multiple prostheses partial and total occlusions, such as those of the knee, elbow, shoulder, hip, and so on, to be substituted for said natural joints 3s human skeletal, rendered failed by diseases, aging or other accidental.Gold, because it is hard to adapt the prosthesis to the bone, or due to the poor bone

corticalospongieux

, implantation of prostheses suchre uests required separate luting cements, tolerable by the human body, which can be easily handled at the time of surgery, of "in-

sitn

" provides fast, after curing and having good mechanical characteristics. 4s therefore, for many years, the surgery and chemistry have attempted to develop luting cements composed of polymer materials which are tolerable by humans and durable over time, so that occurrences of

teile

unsealing and rejection are the less frequent possible. I. as well as in bone surgery, the surgeon and the dental surgeon were conducted using luting cements composed of a liquid phase consisting of a monomer, methyl methacrylate, and a solid phase formed essentially of polymethylmethacrylate. The SS literature teaches that both phases thus

dëfinies

were sterilized, kept separate bulbs and bags, and mixed at the time of use. Ai ' obtained after mixing, the resulting material had the consistency of a creamy which could be used in this form, or in the form of a kneadable mass hand, after an idle period adequate, in such a way as if starting the polymerization.Thereafter introduced into the bone cavity, this material, paste

oncteuse

is kneadable mass, starting to polymerize "in-situ" by giving a hard mass and resistant which provided the cohesion between the prosthesis and the host bone of the skeleton.This same literature also discloses the origins of

compodirections

: the first corresponding to a superficial burns and reversible healing in the three months after the procedure and

laisss

hill. a prosthetic implant is stable, the second revealing a burn deeper whose healing times may be estimated more than six months, during which time the patient may have an intercurrent infection, whereas the third corresponds to a deep and irreversible bone necrosis, leaving the death of the bone and bone surgeons understood consequences which can often takes four or five years after. As stadiums the

brülure

, hooking qualities the sealing material to the bone vary substantially. Therefore appear risks some of

desceIlement

prostheses with the obligation of a new surgical procedure.Very conscious risks arising from too much the exothermicity of the polymerization reaction "in-situ", and controls the existence of fatalities during intervention of prosthetic implants, but conscious also that the luting cements polymethyl methacrylate further offered a very large product safety with respect to the human body, the surgery and chemistry have attempted to develop sufficient to such cements that their use is not restricted or stopped by the foregoing effects.Thus it has been proposed a fixing cement

amé2slioré

based on polymethylmethacrylate comprising a liquid phase consisting of an aqueous emulsion of methyl methacrylate and a solid phase consisting of polymethylmethacrylate. Because the amount of heat released during the polymerization "in-situ" of the mixing of the two phases is dependent on the amount of monomer present, it seemed possible to decrease the elevated reaction temperature by absorbing part of the heat released during the reaction by water present in large quantities in the monomer.This cement appears yet for the ordinarily skilled artisan as a palliative, but not as a true solution to the aforementioned inconveniences.Because if it has been found that such a product has been found a substantial lowering of the reaction temperature, and to decrease the risk of burns surrounding tissue necrosis of the host bone, it has also been found by the practitioner that some of the aforementioned difficulties persisted and other disadvantages, to minor character, appeared.Thus for example that the bone cement during initial

uvre

appeared too fluid to be readily handled, this large fluidity promoting flow within the host bone well beyond the area concerned, and making it almost mandatory the use of a cement quantity much larger than normal for OS secure fixation of the prosthesis. This flow becomes thereby pest.In addition, it is well known in the field of biochemistry, deferral of a bodily fluid in the living tissue, is significantly enhanced by the presence of water, and this, SSs all the more in the presence of an emulsion down surface tension. Gold, upon polymerization "in-situ" the sealing mentioned, whose liquid phase is an emulsion of methyl methacrylate in water, it occurs (and it is a known in the chemistry of the polymerization emulsions) a

hétérogénéïté

of the reaction medium, by breaking the emulsion with water releasing and methyl methacrylate. Thus, this monomer from which said that it was particularly active since strong solvent human fat, sees its migration in the vascular system of the operated particularly

favoriste

by the presence of water, further aggravating the fall voltage, stoppages of

cur

, emboli greasy andc.640,552 although improvements have been made cements used for securing orthopedic implants or stomatology, they were not sufficient to permit the surgeon to intervene in peace,

c'est

to say, without risking the danger mentioned local and general.Therefore, it became imperative for security of the operated, that the cement employed for sealing the bone implants, is accepted by the human body, that it is sufficiently pasty to be easily handleable by the practitioner, that its 0 polymerization temperature "in-situ" is lower than the temperature of human fat mobilization, and that finally the hazardous monomer it can pass into the vascular system, by preventing its migration by diffusion during the polymerization.e continuing its research in this field, the incumbent been developed a liquid phase for a cement sealing self-cure, applicable to prosthetic implants, belonging to the group of acrylic, which virtually eliminates the above drawbacks.This liquid phase is made

ùn

collodium a polymer and/or

eopolymère

acrylic in at least one monomer. It comprises at least 65% by weight of acrylic monomer and between 15% and 35% by weight of polymer and/or copolymer acrylic, but preferably between 25% and 35%.Said viscous phase can be achieved by either dissolving low temperature of the polymer and/or copolymer not having a free radical in the monomer, either by the partial polymerization of the monomer, performed by stopping the reaction according to a known means, such an extract is obtained within the ranges mentioned dry.The monomer used for making the viscous liquid phase preferably belongs to group consisting of acrylic and methacrylic esters, such as for example acrylates and methacrylates of methyl, ethyl, propyl, and butyl, these esters being selected such that their toxicity becomes as small as possible.The polymeric material in the preparation of the viscous liquid phase is, in general, a polymer or copolymer of acrylic and/or methacrylic acid. But it may be a mixture of polymer and/or copolymer acrylic and methacrylic. Amongst the materials greater, can be quoted methyl polymethacrylates, ethyl, propyl and butyl and their copolymers.The viscous liquid phase forming a collodion may also contain adjuvants such as conventional catalysts for polymerization and cross-linking agents.The polymerization catalysts are well known to the skilled artisan and include: the peroxides

benzoïle

first of all the peroxide, percarbonates to which are appended tertiary amines, as for example to nn

teile

'

diméthylparatoluidine

.The cross-linking agents are also well known to the skilled artisan and include all products of organic origin capable of cross-linking simultaneously two chains and having at least two free double bonds. Such is the case, for example, ethylene glycol dimethacrylate, trimethylolpropane diallyl ether, tetra

allyloxyéthane

.As has already been said, the cement has also the viscous liquid phase constituted by a collodion, a solid phase formed by an acrylic polymer or copolymer or mixtures thereof, optionally accompanied by a mineral filler. 11 they typically polymethyl methacrylate in the form of a powder or fine granules, whose particle size is not critical and may easily reach 500 micron. The owner has actually been observed to said particle size were to be selected for the subsequent handling of the cement. Further, the owner 640,552 noticed the interest that represents in some cases the addition of mineral filler, for example, that consisting of alumina.According to the mechanical qualities desired, the solid phase can further comprise various adjuvants which may also be mentioned the cross-linking agents, polymerization catalysts, and also agents contrasts ray sensitive "X.", of biocidal agents, colorants and the like.In general, the sealing material is obtained by mixing the viscous liquid phase constituted by, a collodion-O and the solid phase, in ratios ranging from 1:2, 5 and 1:0, 5 in weight, but the ratio is preferably 1:1, 5.In practice, the two phases being held separately in sterile containers in the weight proportions near cited, the mixing is carried out year when ready for use, by stirring, to obtain a homogeneous paste which can be easily handled by the practitioner.The plug terminates generally in 15 minutes, thereby giving time to the representative bring

piace

in the cement in the cavity provided, it being understood that this duration depends on the ambient temperature.The polymerization of the cement sealing, once triggered, is manifested by a relatively low heating, which never exceeds

latempérature

2s human fat mobilization,

c'est

to say about 65 °c.For some uses, and in order to further improve the mechanical properties of the sealing material, it may be desirable to add a small amount of short fibers, such as for example carbon fibers, acrylic fibers, .the fibers of polyamides, polyester fibers, andc.The sealing material thus manufactured qualities especially high and appreciable by the ordinarily skilled artisan and his patient.In addition, such cement offers another advantage, particularly valuable and advantageous for the subsequent good hold of the prosthesis; because the viscous phase consists of the collodium, results in a decrease in the elevation of Turkish

tempéras

, by controlling the speed of polymerization.Thus the maximum temperature does not exceed 65 °c, still much lower than that found for cements usually used. Since it is believed that the reduced burn living tissue and necrosis of the host bone, making it possible to expect a resumption bone, and fixation of the prosthesis providing it with enhanced longevity and safety.Examples I to 9 was accomplished mass of 67 g of cement sealing by mixing collodium 27 g of polymer and 40 g of solid polymer, in powder form. Collodion was obtained as follows:- in the examples 1 to 5, dissolution of 30% polymethyl methacrylate in 70% of the methyl methacrylate monomer at a temperature of about 20 °c and under a constant agitation of the medium, by giving a viscous substance of 500 centipoise at 20 °c.- in the examples 6 to 8, dissolving polymethyl methacrylate in 70% of the monomer consisting of 80/20 mixture of methyl methacrylate and butyl giving a viscous substance of 300 centipoise at 20 °c.- in the example 9, the solid phase included also an inorganic filler consisting of alumina.The cement was obtained by mixing and polymerizing of firstly, the new combination of a liquid phase 3s two phases in the presence weight ratio viscous constituted by a collodion and from solid phase summarized in the following table, as well as dispersed in this collodium

eatalyseurs

of at the time of polymerization, cross-linking agents, and opacifying surgery, prevents bleeding in the ray "s".patient of the hazardous monomer important U.S. methacrylamidopropyltrimonium ' exothermicity of the polymerization reaction has been ETL methyl, due to the less amount of the solvent used 40 followed by measuring initial temperatures and maximum

uvre

and primarily its retention in Collodion. Therefore, at

cur

of the reaction medium.the appreciable decrease in the diffusion of monomer limit finally, polymerization times were also very appreciable risks are, measured and are expressed in minutes.Viscous phase forming collodium stage sol1de Table I examples of n " 1, 2 3, 4 5, 6 7, 8 9 composition in weight percent %%%%%%%%% 30% polymethyl methacrylate in methyl methacrylate and butyl acrylate 39, 39.5 38.5 500 PO 20 °c 80/20 resin to 30% polymethyl methacrylate in methyl methacrylate 40, 40 38, 37 40, 38.5 20° C. to 300 cp ΔNn ' DlM

éthylparatoluidine

0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 zirconium dioxide 6 barium sulfate 4.5 methyl polymethacrylate<500 e. 59, 56 58, 58 29 copolymer of methyl methacrylate and butyl < 500 59, 57.6 59, 58 g of benzoyl peroxide 0.3 0.3 0.3 - 0.3 0.3 0.4 0.4 0.4 0.4

Triméthylolpropanediallyle

ether 1, 2 diallyl maleate methylene bis acrylamide 1.5 2.5 mineral filler: alumina 29 IC centeredly exothermicity measured by difference between:initial temperature °C 25, 25 25, 25 25, 25 25, 25 maximum temperature recorded °C 54, 53 51, 52 52, 49 50, 53 48 time in min end reaction 15, 14 13, 14 14, 15 13, 15 16,640 552 by contrast, five types of cements, and b, and c, d and e belonging to the prior and currently employed for sealing prostheses have been

experiméntés

. Their compositions, expressed in percent by weight, and their exothermicity and the setting time, have been logged in the table 2 below:Table 2 current

Cirnents

AB hypoventilation C.%%%%%% by weight formula in polymethylmethacrylate 200, 65.4 57.6 69, 63 polymethylmethacrylate polyacrylate

Péroeydeméthacry

m6thyle 200 T-benzoyl] methyl ATEs ΔNn '

Diméthylparatoluidine

zircon dioxide barium sulfate exothermicity initial temperature °C temperature max.. recorded °C reaction time in min end 64, 0.4 0.32 0.33 28, 29 32, 0.7 0.72 0.6 7, 4.5 0.25 0.3 30.7 35.4 0.6 0.6 11, 14 13, 20 19, 25 25, 25 90, 80 78, 85 90