JPS5941946B2 - porcelain - Google Patents

Abstract

1522182 Calcium phosphate ceramics STERLING DRUG Inc 22 July 1975 [2 Aug 1974 7 July 1975] 30706/75 Heading C1A A polycrystalline, sintered ceramic for use as a bone or tooth substitute is made by reacting calcium ion with phosphate ions in aqueous medium at pH of 10-12 to produce a gelatinous calcium phosphate precipitate having a Ca:P molar ratio of 1À44-1À72, separating the precipitate from the solution and heating the precipitate to above 1000‹C but below the temperature at which appreciable decomposition of hydroxylapatite occurs and maintaining said temperature for a sufficient time to effect sintering and maximum densification. When the Ca:P molar ratio is in the range 1À62-1À72 a translucent, isotropic, polycrystalline hydroxylapatite having an average crystalite size of 0À2-3 microns, a density of 3À1-3À14 g/cm<SP>3</SP>, substantially no pores and having cleavage along smooth curved planes is obtained. When the Ca:P ratio is in the range 1À44-1À60, preferably 1À46-1À57 a dense isotropic two-phase ceramic is obtained comprising 14-98% hydroxylapatite and 2-86% whitlockite, said ceramic having substantially no pores and having cleavage along smooth curved planes. The reactants are preferably Ca(NO 3 ) 2 and (NH 4 ) 2 HPO 4 . 0À4-0À6% of an organic binder, e.g. collagen, may be added to the precipitate to prevent cracking during drying. Porous forms of the ceramic may be made by including 5-25% by weight of organic binders such as powdered cellulose, starch, cotton or collagen to the precipitate. Fluoride ions may be introduced into the ceramic, e.g. by standing in 0À5-5% aqueous NaF for 12 hours-5 days.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a porcelain material, and more particularly to a porcelain material used in biphasic medicine and orthodontics.

Much current dental research is focused on producing materials that can be used as fillers, crowns, and braces for dental crowns, or as artificial filling materials for bone.

Dental research is also directed toward inhibiting plaque formation and treating tooth decay and periodontal ligament disease.

Quartz is currently used as a double-strength composition.

Filling materials such as alumina, silicates, and glass beads have little chemical or physical resemblance to tooth enamel.

A particular drawback of these materials is that they do not match the coefficient of linear expansion of the teeth, which results in exposed tooth boundaries and the formation of new cavities.

Furthermore, in the field of surgical prostheses (currently dominated by high-strength, non-corrosive alloys), tissue receptivity and adhesion have not yet been completely resolved, making it even more difficult to adapt to the generated hard tissue. There is a general need for similar materials (H
Written by Albert et al.

Materials 5science Re5earc
h 5.417 (1971), l.

In research directed toward the discovery of effective anti-plaque chemotherapeutic agents, there is a need for standard test materials with tooth-like surfaces, both in terms of plaque formation and the substance of the chemical agent.

Natural teeth have been used for this purpose, but they suffer from the drawbacks of being fragile, relatively difficult to obtain in large quantities, and requiring extensive cleaning before use.

Therefore, powdered hydroxylapatite, where plaque accumulates,
Other materials have been used, such as acrylic teeth, glass, and wire.

Although plaque formation itself has probably been well studied, these materials bear little resemblance to natural tooth surfaces and are therefore difficult to use when discovering effective anti-plaque agents. is not suitable.

For example, it is known that chemical agents that inhibit plaque formation on teeth do not necessarily have the same effect on glass and wire (Turesky et al., J. Periodon).
tology 43.263 (1972)).

There is therefore a need for an inexpensive, readily available material that is chemically similar to tooth enamel, hard, dense, and highly polished.

Hydroxyapatite Ca1g (po4)a (OH)2 also known as basic calcium orthophosphate
It has been proposed that the (inorganic phase of teeth and bone) is suitable for the various purposes outlined above, and in fact U.S. Patent No. 2.508,
No. 816 discloses a method for obtaining hydroxylapatite for tooth enamel and its application as a denture composition by mixing it with a synthetic resin.

This method is time consuming and laborious and is limited to the production of finely divided hydroxylapatite.

Moreover, this method is of course dependent on the availability of natural tooth sources.

Kuttx (Indian J, Chem, 11,6
95 (1973) disclosed a mixture of hydroxylapatite and Whitlockite produced by decomposing powdered hydroxylapatite at various temperatures.

Bett et al. (J, Amer, Chem, Soc, 89
゜5535 (1967)) has a stoichiometric Ca/p of 1.
．． The production of granular hydroxylapatite varying from 67 to 1.57 is described.

The material thus produced contained large crystalline pores.

It has also been reported that when heated to 1000°C, part of calcium-deficient hydroxylapatite transforms into the five-phase Huitlock.

U.S. Pat. No. 3,787,900 discloses bone and tooth reinforcement consisting of a refractory compound and a calcium phosphate compound (eg witlockite).

Several attempts have been made to provide hard and strong microbodies of hydroxyapatite.

However, none of the hitherto known forms of hydroxylapatite has been found to be fully satisfactory.

For example, ROY and Linehan (Nature,
247, 220 (1974)) described an elaborate hot water exchange method to convert coral skeleton calcium carbonate to hydroxylapatite.

The material so produced necessarily retains the highly porous properties of coral and also has approximately 270 to 470 pSi
It had a relatively low tensile strength (a major drawback for an artificial material).

Monroe et al. (Journal of Dental
Research 50, 860 (1971))
We reported the production of porcelain by sintering compressed tablets of hydroxyapatite.

The material so produced is actually a mixture of hydroxylapatite as an ordered mosaic arrangement of polyhedral crystallites and about 30% α-willockite [ca3(PO4)2 or tricalcium phosphate]. However, it was thought that it was too porous to be used as a dental material.

Rao and Boehm (Journal of Dent
alResearch 53.1351 (1974)
) disclosed a polycrystalline body of hydroxylapatite produced by compressing powdered hydroxylapatite while maintaining equilibrium in a mold and sintering the compact in a homovolute manner.

The resulting porcelain is porous and approximately L7,000 psi
It had a maximum compressive strength of

Bhaskar et al. (Oral Surgery 32.3
36 (1971)] described the use of biologically reduced calcium phosphate porcelain to fill bone defects.

This material is highly porous, resorbs from the injection site, and lacks the strength of metal or non-degradable porcelain injections.

The present invention provides a method of making polycrystalline sintered porcelain.

This method involves reacting calcium ions and phosphate ions in an aqueous medium at a pH of about 10-12 such that the molar ratio of calcium to phosphorus is approximately equal to that in hydroxylapatite and in witlockite. forming a gelatinous precipitate of calcium phosphate in between, separating this precipitate from the solution, and adding at least one
000° C. but below a temperature at which substantial decomposition of the hydroxylapatite does not occur, and for a time sufficient to achieve sintering and substantially maximum densification of the product. Consists of maintaining.

One aspect of the present invention provides a novel hydroxylapatite porcelain that is hard, dense, shiny, and comprised of virtually pure hydroxylapatite.

It is chemically very similar to tooth enamel.

Moreover, this new material can be produced in a relatively simple manner from inexpensive starting materials and is obtained homogeneously, thereby avoiding the undesirable changes inherent in natural teeth.

Incorporation of the novel porcelain body of hydroxylapatite into a double-strength composition results in a dense filling material with a coefficient of expansion virtually equal to that of natural tooth enamel.

The dental and surgical implants of the present invention are hard, strong, and completely biocompatible and can be formulated into any desired shape without the need for high pressure or other elaborate techniques.

Moreover, as will be discussed in more detail below, any degree of porosity can be imparted to the material as desired, thereby allowing tissue ingrowth.

As can be seen, the characteristics of the novel product of the invention make it ideally suited for making discs, plates, rods, etc. for use in testing dental antiplaque agents.

Another aspect of the present invention provides a novel two-phase porcelain comprising hydroxylapatite and witlockite.

As will be described more fully below, this two-phase porcelain is hard, dense, non-porous, biocompatible, easily assembled into any desired shape, and is compatible with the known resorption of Whitlock stone. It is highly resistant and serves as a partially resorbable surgical implant.

Although it is advantageous for surgical implants to have some porosity to allow fluid circulation and tissue ingrowth, this porosity necessarily reduces the mechanical strength of the implant.

The two-phase porcelains of the present invention are dense, mechanically strong and virtually non-porous, yet permit fluid circulation and tissue ingrowth.

The contained Witlock 5 phase is slowly reabsorbed from the implant and replaced by natural biological hard tissue.

This new physical form of hydroxylapatite is distinguished from biological and geological forms, and from all previously known synthetic forms described below, and has an average crystal size in the range of approximately 0.2 to 3 microns. Yes, density is approximately 3.1
0 to 3.14 g/cyit, and is a strong, hard, dense, white material made of virtually pure hydroxylapatite, characterized by the absence of pores and fissures along its smooth curved surface. , consisting of a translucent, isotropic, polycrystalline sintered porcelain.

Moreover, when normally manufactured, the above materials are approximately 35.
Compressive strength of 000 to 125,000 pSi, Habo 3
Tensile strength of ,000~30,00psi, about 1
Linear thermal expansion coefficient of 0-12 ppm/℃, approximately 470-50
Knoop hardness of 0, 6 x 106 p
It has the elastic modulus of Si and does not exhibit birefringence under polarized light.

Initial measurements of this new hydroxylapatite porcelain indicate that it consists of virtually pure microcrystalline hydroxylapatite in a random, isotropic device, with approximately 35,000 to 7
5,000 psi compressive strength, 3,000-50
,000 ps i tensile strength, approximately 10-12 p
p m/'CIIJ:) Coefficient of linear thermal expansion, approximately 470~
500 hardness and a modulus of elasticity of approximately 6X10' psi, the presence of cracks along a smooth curved surface,
and strong, characterized by the absence of birefringence under polarized light.
It was shown to be a hard, dense, white, translucent porcelain.

As used herein, "dense" indicates that the particles are highly compacted, with virtually no voids or unfilled areas.

In contrast to the above forms of hydroxylapatite, geological hydroxylapatite and synthetic hydroxylapatite produced by hydrothermal processes are macrocrystalline, fissured along the plane, and birefringent.

Biological hydroxylapatite generally contains a significant amount of carbonate ions in its most refined state (i.e. tooth enamel) in the apatite lattice, which are arranged asymmetrically in the form of spiral ejecta columns, and therefore these It fractures in a straight line along the interface of the enamel column and is distinguished by its relatively low tensile strength of 1500 psi.

In addition to the above-mentioned properties of the novel porcelain of hydroxylapatite provided by the present invention, this material is completely biocompatible and is therefore particularly suitable as a dental and surgical artificial material.

That is, the porcelain of the present invention can be used for dental crowns, dentures, artificial bones, artificial joints,
Cannulae, prosthetic limb attachment devices that can attach to bone and penetrate the skin, can be cast or machined into test surfaces to study dental plaque, bidontia, arthritis, and diseases affecting fine teeth and bone.

When properly ground, the novel porcelain of the present invention can be used as a synthetic cancellus for repairing bone defects.
It can be used as a bone, as an abrasive, and when combined with a standard resin, as a double-strength composition as described below.

As a test surface for evaluation of plaque inhibitors, the porcelain of the present invention can be formulated in any suitable size and shape, preferably one that can be easily inserted into a standard test tube.

This is conveniently accomplished by cutting or machining large plates of dried filter cake to the appropriate size and then sintering.

This sintered product can be highly polished using standard polishing techniques and then used as a substrate in the evaluation of plaque inhibitors by the previously described method of Turesky et al.

After use, this porcelain body is simply repolished and becomes the new test surface.

When manufactured normally, the porcelain of the present invention is not only dense but also non-porous, and although non-porous is essential for dental applications, some degree of porosity may be present in the implant. is advantageous in that it allows fluid circulation and tissue ingrowth.

Varying degrees of porosity can be imparted to the porcelain of the present invention in a manner similar to that described by Monroe et al. (supra).

For example, an organic material such as starch, cellulose, cotton, collagen, etc. in an amount of about 5 to 25 parts by weight is mixed with the gelatinous precipitate of hydroxylapatite.

During the subsequent sintering process, this organic material burns off, thereby creating holes and structures in the otherwise non-porous ceramic product.

Alternatively, holes can be produced by drilling or machine-drilling holes and openings in the solid porcelain.

In this manner, a porcelain denture having this aspect of the invention can be rendered porous at the injection point.

The exposed tooth surface, on the other hand, remains non-porous.

The injection was performed as described by Hodosh et al. (Journal of th
eAmerican Dental As5ocia
tion 70, 362 (1965)).

Alternatively, the porcelain of the present invention may be formulated with a polymerizable binder or binding polymer as described below and this composition
, No. 609,867 (published October 5, 1971), it can be used as a coating for metal implants by the method described in the specification.

The second feature of the present invention is that the second phase is about 14 to 98
% by weight of hydroxylapatite and about 2 as the second phase.
It is composed of ~86% by weight of wittanku stone, has no pores,
It is also a strong, hard, dense, white, and polycrystalline sintered product, which is characterized by the presence of cracks along its smooth curved surface.

Whitlockite, also known as tricalcium phosphate, is an inorganic substance with the chemical formula Ca3 (P 04 )2.
Exists in either the α or β crystalline phase.

In this specification, "wittankite" means α is either β phase,
Or it refers to a two-phase mixture.

The two-phase porcelain of the present invention is a nonporous polycrystalline material regardless of the relative concentrations of hydroxylapatite and witlockite contained therein.

However, since hydroxylapatite and witlockite have different physical properties, the physical properties of this two-phase porcelain, such as density and optical properties, are likely to depend on the relative amounts of hydroxylapatite and witlockite. It will be done.

For example, the theoretical density of witlockite is lower than that of hydroxylapatite, so the observed density of a sample of biphasic porcelain containing approximately 40 parts hydroxylapatite and 60 parts witlockite is 2,98 ji/cr7t.
and in the case of a porcelain sample containing only hydroxylapatite, it was 3.10 g/i.

The two-phase porcelain is compatible with living organisms and is therefore suitable as a surgical artificial material.

That is, the material is cast or machined into a desired shape suitable for filling an artificial bone or joint, or a space or defect in the bone.

The whitlockite contained in man-made products composed of the biphasic porcelain of the present invention will eventually be resorbed and replaced by natural biological hard tissue ingrowth.

Of course, the extent of tissue ingrowth will depend on the amount of whitlockite included in the porcelain and reabsorbed.

When manufactured normally, the two-phase porcelain of the present invention is non-porous.

However, if desired, varying degrees of porosity can be imparted to the porcelain as previously described in the novel hydroxylapatite porcelain body.

Fluorination, as described below for the porcelain hydroxylapatite, can also make this two-phase porcelain acid resistant.

The above-mentioned novel porcelain body of hydroxylapatite has a pH of
hydroxylapatite having a molar ratio of calcium to phosphorus of approximately 1.62 to 1.72 is precipitated from an aqueous medium of approximately 10 to 12, the precipitated hydroxylapatite is separated from the solution, and the hydroxylapatite thus obtained is can be prepared by heating it at a temperature sufficient for a sufficient time to achieve its sintering and maximum densification without substantial decomposition.

For example, hydroxylapatite has a pH of about 10-12.
is precipitated from an aqueous medium by reacting calcium ions with phosphate ions.

Calcium- or phosphate-containing compounds that supply calcium and phosphate ions in the aqueous medium have their respective counterions readily separated from the hydroxylapatite product and are not themselves incorporated into the hydroxylapatite lattice. Any is suitable, provided that it would otherwise interfere with the precipitation or isolation of virtually pure hydroxylapatite.

Compounds that supply calcium ions include, for example, calcium nitrate, calcium hydroxide, calcium carbonate, and the like.

Phosphate ions are supplied by ammonium hydrogen phosphate, ammonium phosphate, phosphoric acid, and the like.

In the method of the present invention, calcium nitrate and ammonium hydrogen phosphate are preferred sources of calcium ions and phosphate ions, respectively.

The preparation of the claimed novel hydroxylapatite is conveniently carried out as follows.

First, add calcium nitrate and ammonium hydrogen phosphate to 1
．． A gelatinous precipitate of hydroxylapatite is produced by interaction in an aqueous solution with a molar ratio of 67-1 and a pH of about 10-12.

The method described by Hayek et al. (Inorgan
io 5 syntheses 763 (1963)) meets this purpose.

The gelatinous suspension of hydroxylapatite thus obtained is left in contact with the stock solution for a sufficient period of time to bring the calcium to phosphorus ratio of the suspended hydroxylapatite to a value of about 1.62 to 1.72. .

This is conveniently accomplished by stirring the suspension at room temperature for 24 hours or more, boiling for 10 to 90 minutes, or a combination of boiling and subsequent standing at room temperature.

Preferably, the suspension is boiled for 10 minutes and then left at room temperature for 15-20 hours.

The hydroxylapatite is then separated from the solution by suitable means (eg, centrifugation, vacuum filtration).

The gelatinous product thus collected contains a large amount of absorbed water, much of which can be removed by applying pressure.

If desired, the resulting wet clay-like material can be cut or molded into convenient shapes, or alternatively cast in suitable molds.

When wet hydroxylapatite is dried, it typically shrinks by about 25%, and during sintering, which will be described below, it shrinks by an additional 25%.
Note that contraction occurs.

This fact must naturally be taken into account when shaping or molding materials.

Slowly heat the wet product to 1000° to 125°
A sintering temperature of 0° C. can be achieved.

At this temperature all residual water will be gone.

Sintering and maximum densification of the product is achieved by maintaining a temperature of 1000° to 12500° C. for approximately 20 minutes to 3 hours.

It is usually preferred to isolate the dry product prior to sintering.

For example, a wet product at about 90° to 900°C for approximately 3 to 2
It can be dried for 4 hours or until the moisture content is reduced to 0 to about 2 parts.

It is generally preferred to use drying conditions of 90 DEG to 95 DEG C. for about 15 hours, or until the moisture content is reduced to about 1-2%.

The hydroxylapatite obtained by this method is brittle and porous, but has considerable mechanical strength.

Some separation or crumbling of the clay-like material may occur during drying, especially when thick filter cakes are used.

However, pieces of 100i and 37nr/l thickness are easily obtained.

Segregation or crumbling during drying can be minimized or prevented by adding about 0.4 to 0.6 weight percent of an organic binder (eg, collagen, powdered cellulose, or cotton) to the precipitated suspension of hydroxylapatite.

Approximately 0.5% collagen is preferred. During the subsequent sintering process, this organic binder volatilizes and the physical properties of the ceramic product appear to be virtually unchanged from those produced in the absence of such binder.

Of course, with virtually any amount of organic binder, the aforementioned porous porcelain product may be obtained.

Other conventional organic and inorganic binders known in the ceramic industry may also be used.

Taking into account the shrinkage that occurs during sintering, it is also usually convenient at this stage to roughly cut or shape the dried hydroxyl apatite into the desired shape as the final product.

The hydroxylapatite body must be uniform and free of defects prior to sintering.

The presence of cracks or fissures can cause the pieces to fracture during the sintering process.

The product is then sintered at about 1000 DEG to 1250 DEG C. for approximately 20 minutes to 3 hours (temperature and time are inversely related).

Sintering is preferably carried out at 1100° to 1200°C for approximately 0.5 to 1 hour.

The hard, dense ceramic product thus produced can then be polished or mechanically treated in the usual manner.

In the above method it is essential that the hydroxylapatite be produced as a gelatinous precipitate from an aqueous solution.

This is because it is only in this sticky gelatinous state that hydroxylapatite can be shaped or molded and then dried and sintered to produce macrofoam ceramics. It cannot be reconstituted to this gelatinous state.

For example, if powdered hydroxylapatite is suspended in water and filtered, a non-stick granular filter cake is obtained that dries easily, crumbles, and shapes, molds, or cannot be changed.

Furthermore, although powdered hydroxylapatite can be mechanically compressed into compacts (e.g. tablets), the product obtained when sintered by the method of the invention is highly porous;
It does not break along a smooth plane, but simply breaks into coarse pieces.

Hydroxyapatite, which forms in aqueous media, is a complex, and although the process is not completely understood, calcium ions and phosphate ions are first combined to create a calcium to phosphorus ratio of approximately 1.5. It is generally believed to form deficient hydroxylapatite.

In the presence of calcium ions this slowly converts to hydroxylapatite with a calcium to phosphorus ratio of 1.67.

(Eanes et al., Nature Sakedan 8,365 (1
965) and Be t t et al.

J, Amer, Chem, Soc, 89, 553
5 (1967)), that is, to obtain a ceramic product consisting of virtually pure hydroxylapatite, the initial gelatin precipitate of hydroxylapatite is reduced to a calcium to phosphorus ratio of about 1.62 to 1.72. It is essential in the method of the present invention to maintain contact with the stock solution for a sufficient period of time.

If it deviates significantly from this range (1.62 to 1.72), ceramic products with reduced translucency will be obtained.

For example, when hydroxylapatite is precipitated at room temperature and collected within two hours after precipitation, its calcium to phosphorus ratio is about 1.55 to 1.57, and the final ceramic product made from it is opaque; According to X-ray diffraction, it is found to be a mixture containing hydroxylapatite and wittonite.

In fact, as will be discussed in more detail below, materials having a calcium to phosphorus ratio of about 1.44 to 1.60 are useful in the production of the two-phase ceramic products described above.

That is, although the method of the present invention results in translucent ceramic products consisting of virtually pure hydroxylapatite, the desirable combination of calcium and phosphorus is important considering that the method of formation of hydroxylapatite in an aqueous medium is not completely understood. It may be beneficial to monitor the formation of hydroxylapatite to ensure that stoichiometry is achieved and that the product, when sintered, consists of virtually pure hydroxylapatite.

This is easily accomplished by removing a portion of the hydroxylapatite suspension, separating the product, drying and sintering as described above, and subjecting the resulting ceramic product to elemental and X-ray analysis. .

The humidity and time of sintering are also essential to the method of the invention.

That is, unsintered hydroxyl apatite having a desirable calcilum to sulfur ratio of 1.62 to 1.72 can be converted into the ceramic article of the present invention by heating at a temperature of at least 1000<0>C.

At 1000°C, complete sintering and maximum densification takes 2-3 hours, while at 1200°C the process is completed after 20-30 minutes.

If the temperature is substantially lower than 1000°C, sintering will be incomplete regardless of the heating time, and if heated above 1250°C for more than 1 hour, some of the hydroxylapatite will decompose into whitlockite.

Hydroxylapatite in the first phase and wito in the second phase
The above-mentioned two-phase ceramic product made of stone has a pH of about 10.
A calcium phosphate compound having a calcium to phosphorus molar ratio of approximately 1.44 to 1.60, preferably 1.46 to 1.57, is precipitated from an aqueous solution of ~12, this precipitate is separated from the solution, and the solid thus obtained is It can be produced by heating at a temperature and time sufficient to effect its sintering and maximum densification.

Required stoichiometric value, i.e. Ca/p=1.44-1.60
A calcium phosphate compound with a pH of 10 to 12 is produced by interacting calcium ions and phosphate ions using the same calcium ion source and phosphate ion source as described in the production of single-phase hydroxylapatite. It can be obtained by

Calcium nitrate and ammonium hydrogen phosphate are the preferred agents.

For example, for two-phase ceramic products, calcium nitrate and ammonium hydrogen phosphate are mixed in a molar ratio of 1.67 to 10, without heating the initial gelatin precipitate as described in the production of single-phase ceramic product hydroxylapatite. , and remain in contact with the stock solution for a period not to exceed about 4 hours, or otherwise interact, provided that the calcium to phosphorus molar ratio of the precipitate does not exceed about 1.60. It can be manufactured by

As described for the production of monophasic ceramic hydroxylapatite, the calcium phosphate precipitate is separated from the solution, washed, optionally shaped or molded into a convenient shape, and, if desired, dried and dried prior to sintering. Let go.

The freshly precipitated suspension of calcium phosphate can also be treated with organic binders or fluorite ions as described for single-phase hydroxylapatite.

Sintering is performed by heating at about 1000° to 1350° C. for about 20 minutes to 3 hours.

The amount of witlockstone contained in the ceramic products thus produced is approximately 2-83%, depending on when the precipitate is separated from the raw solution.

For example, when the product is isolated 5 minutes after precipitation, its calcium to phosphorus ratio is 1.55, and the ceramic product ultimately produced therefrom contains about 83 parts of witlockite.

If the product is isolated 2 hours after precipitation, its calcium to phosphorus ratio is 1,57 and the resulting ceramic product is approximately 6
Contains 1% of l-o'inkite.

Isolating the product 4.5 hours after precipitation ultimately yields a porcelain product containing about 2% witlockite, an amount that is negligible for X-ray diffraction where the minimum concentration sensitivity is in the order of 2-3. Undetectable.

Of course, if the product is kept in contact with the neat solution for more than about 7 hours, the final ceramic product will be essentially single-phase hydroxylapatite.

Alternatively, the two-phase ceramic products obtained according to the present invention contain calcium ions and phosphate ions of approximately 1.50 to
It can be produced by reacting at a molar ratio of 1.60 to 10.

In this method, the molar ratio of calcium to phosphorus in the calcium phosphate precipitate cannot exceed a value of about 1.60, regardless of the time the precipitate is left in contact with the stock solution.

That is, the production of the two-phase ceramic product of the present invention involves mixing the reactants, namely calcium nitrate and ammonium hydrogen phosphate, in a proportion of approximately 1.5
0 to 1.60 to 1 in a molar ratio of about 30 to 5
It is conveniently carried out as described for the production of monophasic hydroxylapatite, except that the ceramic is made of 0 modulus hydroxylapatite and about 50-70% witlockite.

By combining the characteristics of the two methods described above, the ceramic product of the present invention can be produced by combining the characteristics of the two methods described above.
Further enrichment of the whitlock stone by interacting with phosphate ions in a 0-1.60 to 10 molar ratio and isolating the precipitated calcium phosphate compounds within a short time (preferably about 5 minutes to 4 hours after precipitation) be able to.

The ceramic product thus produced consists of approximately 10-30% hydroxyapatite and 70-90% whitlockstone.

It is known that hydroxylapatite decomposes at about 1250°C to form whitlockite, and therefore the monophasic ceramic product of the present invention, hydroxylapatite, has a temperature of about 1250°C.
Prolonged heating at or above 0.degree. C. partially decomposes the hydroxylapatite to form whitlockite, which provides an alternative method for making the two-phase ceramic products of the present invention.

The present invention also includes the porcelain hydroxylapatite of the present invention,
The present invention relates to tooth reinforcement compositions comprising blends with polymerizable or polymeric binders that meet oral cavity conditions.

The tooth reinforcement compositions of the present invention contain about 10-90% by weight (preferably 60-80%) of the finely divided porcelain hydroxylapatite, with the balance being about 10-90% by weight of a dentally acceptable polymer. polymeric binder and a known suitable polymerization catalyst (e.g. aliphatic ketone peroxide, benzoyl peroxide, etc.)
Reactive diluents such as , G, tri and tetraethylene glycol dimethacrylate, US Pat. No. 3,27
No. 7,056 (granted October 4, 1966), curing agents such as N-3-oxohydrocarbon-substituted acrylamides, metal acetylacetonates, tertiary amines (N,N- bis-(2-hydroxyethyl) p-toluidine, etc.), or a crosslinking agent such as zinc oxide (approximately 0.01 to 45% of the total composition);
It is a combination of weight coefficient (weight).

Although not essential, surface-active comonomers or locking agents (K
eyeing agent) For example, US patents 3, 2
00,142 (granted August 10, 1965), the reaction product of N-phenylglycine and glycidyl methacrylate, methacryloxypropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane , vinyltrichlorosilane, etc. can be added to the composition by weight of 0.05 to 10 weight percent of the total composition.

The bonding or locking agent facilitates the bonding of the porcelain to the resin and the tooth filling composition to the natural tooth.

For example, the porcelain hydroxyapatite of the present invention is divided into suitable particle sizes of about 5 to 100 microns using conventional grinding techniques, and then an appropriate amount of standard resin known in the art, such as hydroxyethyl methacrylate, polymethyl methacrylate, polyacrylic acid, propylene glycol fumarate phthalate unsaturated polyester (e.g. 23LS8275 sold by Allie Alled Che Co, Pittsburgh)
5 sold at Plate Glass
electron 580001), styrene-modified unsaturated polyester (e.g. G11dden G11dp
ol1008. G-136°4C850), epoxy resin (e.g. GibaAradite 6020.Uni
on Carbide ERL 2774) and bisacrylate monomers made from glycidyl methacrylate and bisphenol A as shown in U.S. Pat. No. 3,066,112 (granted November 27, 1962).

The resin may consist of a single monomer or a mixture of two or more comonomers.

If desired, additives such as dyes, inorganic pigments, fluorescent agents, etc. can be added to the compositions according to principles known in the materials art.

resin. It is convenient to blend the porcelain hydroxylapatite and any optional ingredients (such as silane binders, dyes, inorganic pigments or fluorescent agents) prior to the addition of fluxing agents, hardeners, crosslinking agents, accelerators or accelerators.

However, this mixing order of components is not absolute;
The above components can also be blended simultaneously.

The compositions thus produced can be used as tooth filling materials, tooth enamel, cavity fillings, pulp capping agents using conventional techniques, or can be cast in suitable molds to make dentures or sets thereof. can.

Materials used in the oral cavity are corrosion resistant
stance ) is of course a great advantage.

For this purpose, about 0.01-1% of fluoride ions (e.g. ammonium fluoride or stannous fluoride)
This is easily achieved in the practice of the present invention by adding to the precipitated suspension of hydroxylapatite.

The porcelain produced by calcining the resulting product resists attack with lactic acid, acetic acid or citric acid or standard in vitro methods for determining corrosion resistance.

Alternatively, corrosion resistance can be achieved by coating the final porcelain with sodium fluoride.
．． It can be applied by exposure to a 5-5% aqueous solution for about 12 hours to 5 days.

Preferably, the porcelain body is left in an approximately 5% aqueous solution of sodium fluoride for approximately 4 days.

Besides organic and inorganic binders and fluorite ions, the porcelain of the invention can also contain small amounts of other elements, which do not change the essential properties of the porcelain but can impart useful properties to it. Of course, this is obvious to those skilled in the porcelain industry.

For example, it is known to incorporate barium and strontium into apatite crystal lattices and that these elements are significantly more opaque to X-rays than calcium.

Therefore, the addition of a small amount of barium or strontium ions to the calcium ions prior to reaction with the phosphate ions will cause sufficient absorption of X-rays when used in double-strength compositions as described above. , which results in a barium or strontium treated hydroxyapatite porcelain which facilitates the detection of filled teeth.

Magnesium (also incorporated into the apatite crystal lattice) is known to promote the crystallization of lyllite while retarding the crystallization of hydroxyl apatite (Eanes et al.).

Calc, Ti5s, Res, 2.32 (1968)
).

For example, the addition of small amounts of magnesium ions to calcium ions prior to reaction with phosphate ions promotes the formation of witlockite, thus resulting in a biphasic porcelain rich in witlockite.

The porcelain material obtained as described above was characterized based on one or more of the following:

Elemental analysis, density, X-ray diffraction, transmission electron microscopy, polarized light microscopy and physical properties.

The invention is illustrated by the following examples.

The invention is not limited to these examples.

Example 1 To a stirred mixture containing 130 ml of 1.63 N calcium nitrate (0,212 mol) and 1251111 concentrated ammonia was added 16.7 El (0,127 mol) of ammonium hydrogen phosphate, 400 ml of distilled water and 1507'I
A mixture containing 1 liter of concentrated ammonia was added dropwise over about 20 minutes.

The resulting suspension was boiled for 10 minutes, cooled in a water bath and filtered.

The filter cake was pressurized with a rubberdam and then dried at 95° C. overnight.

The resulting hard, porous, and brittle cake sample was electrofiltered for 115 minutes to a final boiling temperature of 1230°C, and then cooled to room temperature to yield a strong, hard, white, translucent ceramic product. .

Standard elemental analysis of this final ceramic product and dried hydroxyl apatite before sintering revealed that Ca1o (PO4)6(OH
) The following results were obtained based on 2.

A thin section of this ceramic product was examined using a polarizing microscope at 130X and 35X.
A 2X test showed that it contained virtually no witlock stone.

The absence of birefringence and discernible structural characteristics such as crystallite shape, orientation, and interfaces indicated a microcrystalline structure.

By comparing the results of optical microscopic observation of a thin cross section of a sintered compressed tablet reported by Monroe (mentioned above), 2.
It was shown that the two substances are structurally dissimilar.

X-ray diffraction measurements were carried out in a conventional manner.

Calculate the interplane spacing and use Donna et al. (Crystal
Data, ACA Monogram No., 5.66
8 (1963)) for hydroxylapatite.

The X-ray data further indicated that whitlockite was not present in values greater than about 2-3 factors (the minimum concentration sensitivity of the diffractometer).

Example 2 79:1 (0.60 mol) of ammonium hydrogen phosphate was dissolved in 1500 yd of distilled water and the pH was adjusted to 11-12 with 750 ml of concentrated ammonia.

Furthermore, distilled water was added to dissolve the precipitated ammonium phosphate to make the total volume 3200 ml.

The pH was adjusted again to 11-12 as needed.

This solution was preadjusted to pH 12 with 30 ml of concentrated ammonia solution, and then added to 900 ml of distilled water.
30 moles of calcium nitrate in a vigorously stirred solution.
It was added dropwise over ~40 minutes, and then diluted with distilled water until the total volume was 1800 ml.

After the addition is complete, add one more gelatinous suspension to the gelatinous suspension produced.
Stir for 0 minutes, then boil for 10 minutes, remove from heat, cover, and let stand at room temperature for 15-20 hours.

The supernatant was removed by decantation, and the remaining suspension was centrifuged at 200 rpm for 10 minutes.

The obtained sludge was resuspended in 800 ml of distilled water and
Centrifuged again for 10 minutes at 0 rpm.

Distilled water was added to the remaining solid to make the total volume 900 ml.

Vigorous shaking resulted in a homogeneous suspension with virtually no large fragments or aggregates.

The entire suspension was poured at once into a flask and filtered under a weak vacuum.

When the overflow cake started to crumble, a dam was used to increase the degree of vacuum.

After one hour, the dam was removed and the complete, unbroken filter cake was transferred to a flat surface and dried at 90-95°C for 15 hours to form a white, porous, brittle hydroxylapatite piece of 90-i oo, p. I got it.

For cracks and fissures, put the pieces with no holes into an electric furnace.
The humidity was increased to 1200° C. over 100 minutes, after which the furnace and its contents were allowed to cool to room temperature.

A hard, dense, non-porous, white and translucent porcelain was thus obtained.

After performing the above analysis multiple times, it was determined that the analytical technique used was not able to completely dissolve the sample and therefore the results were inaccurate.
It has been discovered that it can become thicker.

Despite the above analytical data, the substantial homogeneity of this sample was confirmed by the following electron microscopy data.

Moreover, the product of Example 3, produced by a method virtually identical to that of Example 2, has the expected analytical values and is further characterized as homogeneous hydroxylapatite by X-ray diffraction and electron microscopy. was given.

A two-step replica sample was made by engraving a collodion replica of the sample surface with chromium and then coating with carbon.

Transmission electron microscopy of this replica sample revealed fairly uniform grain sizes with no pores, or the presence of secondary particles present at the grain interfaces or within the grains in amounts exceeding about 0.5% (the minimum concentration sensitivity of the electron microscope). A phase precipitate was revealed.

The porcelain samples were then polished to a 600 grit with SiC paper and then polished to a 3 micrometer diamond paste on a metallized wheel covered with a fine nylon cloth.

The sample was then etched with 4% hydrofluoric acid for 30 seconds.

A replica was then made from this polished and etched surface, which was then observed under an electron microscope.

However, again, no second phase was observed at the grain interface, somewhat indicating small second phase particles within the grain agglomerates.

The compressive strength and elastic modulus were measured using the usual method, and each was 56.462.
psi±16.733psi and 6.3×106 ps
It turned out that i.

Tensile strength was measured using a standard three-point bending test and was 9.650.
It was found to be psi±3,320 psi.

It was found that the coefficient of thermal expansion is a linear line between 25°C and 225°C, and the value is 11 XI 0-67°C ± 10%.

The hardness was found to be 480 using the standard Knoop method.

This same value was obtained regardless of the direction of the applied force, indicating that the material is of the first type.

Soak the test substance in Tsukushin dye for 15 minutes, wash with water,
After drying, porosity was determined qualitatively by checking for traces of residual dye.

This test was conducted simultaneously on a nonporous porcelain of the invention, a sintered compressed tablet of hydroxylapatite, and a natural tooth.

The sintered compressed tablets showed significant retention of dye, whereas the novel porcelain of the present invention and natural teeth showed no visible retention of dye.

In an alternative method, the test material was soaked in 6N aqueous ammonia, then washed with water, dried and wrapped in damp lidmus paper.

Ammonia trapped in the surface pores causes the surrounding IJ l-mass paper to turn blue.

When this test was carried out simultaneously on a sintered compressed tablet of one of the materials of the present invention, hydroxylapatite, and natural teeth, the lidmus paper in contact with the sintered compressed tablet turned blue, which caused it to become trapped in the tablet. It was shown that ammonia was present.

No color change was observed with the novel porcelain of the present invention or with the lidmus paper in contact with natural teeth.

Example 3 Using the method described in Example 2 and starting with 3 moles of calcium nitrate and 1.8 moles of ammonium hydrogen phosphate, 304 g of white, brittle, porous hydroxylapatite was obtained.

Sintered at 1100℃ for 1 hour, hard and white with a density of 3.1
A translucent material of 09/cyyr was produced.

X-ray diffraction showed the material to be homogeneous hydroxylapatite.

Electron microscopy revealed a particle size distribution between 0.7 and 3 microns, with no pores or second phase precipitate.

Example 4 A About 51 hydroxyl apatites were precipitated from an aqueous solution using half the amount as in Example 2.

After centrifugation and decantation, the residual inorganic sludge was resuspended in enough water to bring the total volume to 11 and homogenized in a Waring Blengu.

B 0.5.9 powdered cellulose (0.5μ) was added to 200ml of water and blended for 3 minutes in a Waring blender.

10 of hydroxylapatite homogeneous aqueous suspension
0ml was then added and the resulting mixture was blended for an additional 5 minutes.

The resulting suspension was then filtered and the slurry cake was dried and sintered as in Example 2.

The porcelain cake showed no crumbling after drying, and the porcelain product produced by sintering was slightly porous as indicated by the Tsuksin dye test described above.

A mixture was obtained by including 0.5 g of chopped surgical cotton in 200 ml of water and blended in a Waring Blengu for 45 minutes or until a fairly homogeneous suspension was obtained.

1007711 of the homogeneous aqueous suspension of hydroxylapatite described in Example 4A was then added and blending continued for an additional 15 minutes.

The resulting suspension was filtered, and the filtered cake was prepared in Example 2.
It was dried and sintered using the method described above.

The resulting ceramic product was intact and visibly porous.

Example 5 A 5! in 300ml of water! ! of collagen (beef Achilles Ken) was blended for 5 minutes in a Waring Bregu.

This collagen occluded a large amount of water and formed a thick gelatinous mass.

A small amount of chopped collagen (20-30 ~) remained in the suspension.

B This finely divided collagen suspension (250ml
) and 100 TL of the homogeneous aqueous suspension of hydroxylapatite described in Example 4A.
1 and blended in a Waring Brengu for 5 minutes.

The resulting mixture was filtered, and the filter cake was dried and sintered according to Example 2.

The resulting ceramic product was intact and virtually non-porous.

A concentrated gelatinous collagen of approximately 20 parts C was blended in a Waring Blengu for 6 minutes with 150 ml of the hydroxylapatite homogeneous aqueous suspension described in Example 4A.

The resulting mixture was filtered and the filter cake was dried and sintered as in Example 2.

The dry cake before sintering was intact and had considerable mechanical strength.

The porcelain obtained by sintering was hard, strong, and porous, giving it the appearance of a moon.

Reference Example 1 The ceramic product sample produced in Example 2 was left in a 1% sodium fluoride aqueous solution for 12 hours.

These materials were exposed to 10% lactic acid along with untreated porcelain and natural teeth.

After three days, fluoride-treated porcelain was shown to be virtually less susceptible to lactic acid damage than untreated porcelain or natural tooth enamel.

When it was left in a 1% sodium fluoride aqueous solution for 3 days, the damage caused by lactic acid attack was not visible after 3 days, and it decomposed only slightly after 1 month.

On the other hand, the untreated sample was highly degraded. Reference Example 2 Approximately 5i of hydroxylapatite was precipitated from an aqueous solution using half the amount as in Example 2.

After centrifugation, the inorganic sludge was suspended in an amount of water sufficient to bring the total volume to 500 ml.

The resulting suspension was divided into 10 equal portions, each diluted with 50 ml of water and treated with ammonium fluoride as follows.

0.00085g for samples l, 2.3.4 and 5
0.0.1.0.5.1.0 and 2.0 rul of ammonium fluoride aqueous solutions containing Fe/ml were added, respectively.

Samples 9 and 10 were treated with ammonium fluoride aqueous solutions containing 0.045 g of Fe/7 nl at 2.0.4.
0 ml was added.

The suspension was then shaken on a rotary shaker for 1.5 hours and filtered.

The sawagi cake was pressurized for 15 minutes with a dam and dried at 95℃ for 2 days.
Then, it was heated in an electric furnace to a temperature of 1200°C.

The obtained porcelain was finely ground and sieved using a NO. 325 mesh screen.

80 ~ of each powder sample was mixed with 80 ml of a sodium lactate buffer solution (0.4 M) with a pH of 4.1 at 23 °C;
Shake on a Burrell wrist actuated shaker.

After 25 and 40 minutes of mixing, 3 ml of each sample mixture was removed, immediately filtered to remove undissolved sample, and the amount of dissolved porcelain was determined by colorimetric analysis.

The results are shown in Table A. For comparison purposes, the sintered part of Sanflu 1 was left in 1 ml of 5-sulfur sodium fufluoride for 4 days.

The solid was separated, washed thoroughly with water*, dried, and then subjected to dissolution analysis as described above as sample IA.

The results are included in Table A.

Although the above-mentioned experimental conditions are of course not close to the 1 nviv conditions, if they are selected to sufficiently dissolve the sample within a certain period of time, accurate evaluation of the relative effect of fluoride ion concentration can be made.

For example, the in vitro dissolution rate of porcelain hydroxylapatite is expected to be significantly lower than the observed rate in strong lactate buffer.

Example 6 A sample made according to Example 2 with a thickness of about 3 to 4 mrn and a Ca/P of 1
．． A large piece of dried filter cake of 64-1.66 was evaluated and broken into rectangular plates approximately 14-1S mrn long and 7-8 mm wide and a small hole was punched from one end.

1000 of these flat plates were then sintered as in Example 2 and polished to a high gloss using standard beading techniques.

3.12-3.14. ? A porcelain body with a density of /i is
Wabo 10-11mm length, 4-Smvt width, 2-3mmf
It was in the form of a rectangular plate with a hole at one end through which a length of wire was attached.

This plate can therefore be suspended at any desired depth in the test tube and was used as the test surface in the plaque 1 fungicide evaluation, as previously described.

Example 7 A solution containing 60,071 liters of distilled water and 24 mol of ammonium hydrogen phosphate was adjusted to pH 1.4 with 34,011 liters of concentrated ammonia, and the final volume was adjusted to 1.2 liters with distilled water.
It was set to 80m1.

The resulting solution was added dropwise over 30 minutes to a vigorously stirred solution of 0.4 mol of calcium nitrate in 360 ml of distilled water, previously adjusted to pH 11 with concentrated ammonia, and diluted to 720 ml with distilled water.

Stir the resulting suspension without boiling,
50 ml portions were withdrawn periodically and the product was isolated, washed and dried as described in Example 2.

All samples were then heated at 1100° C. for 1 hour, and the compositions of the resulting ceramic products were determined by X-ray diffraction.

The results are shown in Table B.

Example 8 A Using the method of Example 2, 0.3 mol of calcium nitrate and 0
．． Using 2 moles of ammonium hydrogen phosphate, a hard, naturally porous, product with the following elemental composition was obtained.

Ca=38.85%; p=i9.77%: Ca/P-1
,52 This material was heated at 1200° C. for 1 hour to yield a strong, hard, nonporous material consisting of approximately 40% hydroxylapatite and 60% witlockite as shown by X-ray diffraction. A white, somewhat opaque porcelain was obtained.

B When the above reaction was carried out with the order of addition of the starting materials reversed, the reaction mixture consisted of about 40 parts hydroxylapatite and 60 parts witlockite, with a Ca/P of 1.52 and 2 parts.
．． A product with a density of 9 s 2 g/= was obtained.

Example 9 A solution of 0.0625 mol of ammonium hydrogen phosphate in 150 TLl of distilled water was treated with 95 ml of concentrated ammonia and brought to a final volume of 320 mA' with distilled water.

The resulting solution was added dropwise over 30 minutes to a vigorously stirred solution containing 0.1 mol of calcium nitrate and 2.5 ml of concentrated ammonia in 180 ml of distilled water.

The resulting suspension was stirred for 5 minutes and then soaked in water for 4 minutes.
After cooling for 5 minutes, the suspended solid was isolated, washed and dried as described in Example 2 to yield a hard, brittle, porous, white solid with the following elemental composition: .

Ca=35.4%; P=18.59%; Ca/P=
The material in step 1.4 was heated at 1350°C for 1 hour, and as shown by X-ray diffraction, it consisted of approximately hydroxylapatite with a ratio of 14 and whitlockite with a ratio of 86.
A strong, hard, non-porous and somewhat opaque ceramic product was obtained.

The products of Examples 1-9 and Reference Examples 1-2 correspond to the products of the present invention and have their physical properties as described above.

The products produced according to Examples 1, 2, 3.5B and Reference Examples 1-2 and Example 6 are strong, hard, dense, white translucent porcelains that are virtually pure, non-porous, and isotropic. It is made of hydroxylapatite with a diameter of 35,000 to 125,000 yen.
000 psi compressive strength, approximately 3,000-30
,000 ps i tensile strength, approximately 10-12 mm
It has a coefficient of linear thermal expansion of pm/°C, a Knoop hardness of approximately 470-500 and a modulus of elasticity of approximately 6 x 106 psi, and is characterized by the presence of cracks along smooth curves and the absence of birefringence under polarized light. shall be.

The products manufactured according to Examples 4 and 5C are those of Examples 1 and 2.
, 3.5B, Reference Examples 1-2, and Example 6, although they are made of the same material as those manufactured by Example 6, they introduce spaces or holes of various numbers and sizes.

It is of course obvious that the introduction of pores into such products reduces their physical properties, such as compressive strength, tensile strength, elasticity and hardness.

Reference Example 3 A composition suitable for tooth enamel and filling material was prepared as follows.

201nJ in 7ml of ethanol? ,N-7e=7
17 Into a solution containing the condensation product of glycine and glycicine methacrylate (described in U.S. Pat. No. 3,200,142, where it is called NPG-GMA), 2.0 g of powdered ceramic Added material hydroxylapatite.

After vortexing for 5 minutes, the ethanol was evaporated in vacuo at room temperature and the remaining solid was dried at lmmHg for 2 hours.

B. An 80 drop sample of the above material was mixed with 0.4 Y of benzyl peroxide and hydroxyethyl methacrylate, the reaction product of bisphenol A and glycidyl methacrylate (as described in U.S. Pat. No. 3,066,112, 30~30 of a 1:2 mixture with Bis GMA) was mixed.

The resulting mixture was placed in a cylindrical steel mold and cured in 3-5 minutes.

The compressive strength was measured on four cylindrical plugs made in this way.

The average value was 24,350 psi.

Reference Example 4 60 parts of powdered porcelain hydroxylapatite, 13 parts of hydroxyl ethyl methacrylate, 27 parts of a condensation product of bisphenol A and glycidyl methacrylate, 0
．． 3 parts of N,N-bis-(2-hydroxyethyl) -
A mixture consisting of p-toluidine and 0.8 parts benzoyl peroxide was thoroughly blended to obtain a thin, free-flowing disposal that served as a tooth hole and crevice sealant.

When this was poured into a cylindrical steel mold, it hardened after about 3 minutes.

The compressive strength of seven cylindrical stoppers thus manufactured was measured.

The average value was 20.400 psi.

Reference example 5 The following is an example of a disposal material that can serve as a dental filling.

0.5 g of powdered porcelain hydroxyl apatite was added to 5 ml of 2-propatool.

The 2-propertool was vacuum evaporated at room temperature to remove all water of hydration from the surface of the porcelain.

The powdered hydroxylapatite of 120 η thus treated was mixed with benzoyl peroxide of 0.3~ and then a mixture of ~40 [a condensation product of bisphenol A and glycidyl methacrylate, triethylene glycol dimethacrylate and N,N-bis-( 2-hydroxyethyl)-p-
) Consisting of Ruijin.

Product name: Epoxylite ■HL-72 Lee Ph
[Sold by Arma Ceuticals] was added.

The resulting mixture was rolled out into a smooth paste, placed in a cylindrical steel mold, and left for 4 hours.

The cylindrical stopper was removed from the mold, three pieces were tested, and the average compressive strength was found to be 22.300 psi.

Reference Example 6 To a solution containing 30Tn9 of a condensation product of N-phenylglycine and glycicine methacrylate in 7ml of ethanol, 1g of powdered hydroxyl apatite was added with swirling.

Ethanol was evaporated in vacuo at room temperature.

To a mixture containing 180 ~ of powdered porcelain hydroxylapatite thus treated and 3.0 m9 of benzoyl peroxide, 60 parts of a condensation product of bisphenol A and glycidyl methacrylate and 40 parts of triethylene glycol dimethacrylate were added. Add 74 m9 of a mixture containing
The resulting aggregate was spread with a spatula to form a smooth paste, which was placed in a cylindrical steel mold and left for 3 hours.

After taking out the cylindrical frame from the mold and testing 4 pieces, 22
, 300 psi of average compressive strength.

Reference Example 7 A composition useful as a dental and orthodontic cement or as a temporary tooth filling was prepared by combining powdered porcelain hydroxylapatite of 10.07n9, zinc oxide of 300 and
It was made by mixing an aqueous solution of 40% polyacrylic acid.

When the resulting mixture is placed in a cylindrical steel mold, it is approximately 3-5
Hardened in minutes.

After taking out the cylindrical frame from the mold and testing 4 bodies, 12
．． It was found to have an average compressive strength of 400 psi.

The other five bodies were found to have an average radial tensile strength of 1630 psi.

40 Water-reactive polyacrylic acid and zinc oxide are available under the trade name Du r e l from West Germany's ESPEG, m, b, h.
o n% of commercially available polycarboxylate cements were obtained as liquid and solid components, respectively.

Reference Example 8 A composition suitable as a dental cement and filling material was mixed with a mixture containing 6 parts by weight of 40 hydrophobic polyacrylic acid, 6 parts by weight of powdered porcelain hydroxylapatite, and 4 parts by weight of zinc oxide. It was manufactured by

The resulting composition had a cure time of approximately 5-10 minutes.

40% aqueous polyacrylic acid and zinc oxide are manufactured by ESPE G, m, b, H, West Germany under the trade name Durelo.
H--obtained as liquid and solid components of commercially available polycarboxylate cements, respectively.

Reference example 9 The following is an example of a tooth filling composition.

Ingredients Weight ratio styrene modified polyester resin 29.2 (G
l 1dden Gl 1dpol G-136) Benzoyl peroxide 0.7 Styrene
0.6 MEC 1 month leaf xypropyltrimethoxysilane 1.5 porcelain hydroxyl abatite l-68,0 Reference Example 10 The following is an example of a composition useful as a dental cement, socket filler, and pulp capping agent.

Component Weight% Epoxy resin (Union Carbide)
67ERL2774) N-3-oxo-1,1-dimethylphthyl acrylic 23
Porcelain hydroxyl y<”;i”! 'To 1゜Reference example 1
1 The following is an example of a composition suitable for construction of a denture or set thereof.

A mixture containing 150 to 200 meshes of 60 parts by weight of porcelain hydroxylapatite and 40 parts by weight of powdered polymethyl methacrylate is blended with approximately 15 parts by weight of the liquid monomer methyl methacrylate, and the resulting mixture is
It was left in a closed container at room temperature until it no longer adhered to the walls of the container and had a non-tacky plastic consistency.

The mixture was then filled into a suitable mold, the mold and its contents were immersed in water, heated to boiling temperature for about 1 hour, and maintained at that temperature for 30 minutes.

Next, the mold was left to cool for about 15 minutes, and finally it was soaked in cold tap water (ta
The mixture was cooled with pWater).

The biological compatibility of the novel porcelain hydroxyl apatite of the present invention was confirmed through transplantation studies.

When the porcelain fragments prepared by the method of Example 1 were injected intraperitoneally into rats or subcutaneously inserted into the backs of rabbits, no inflammatory reaction occurred, and resorption of the porcelain was 28%.
Days later it was not shown at all.

A surgically implanted single-module hydroxyl apatite pellet prepared in a manner similar to that described in Example 3 into the femur of a dog was periodically observed in vivo by X-ray.

One day later, after 6 months, the animals were sacrificed and the femurs containing the implants were separated.

The femur was sectioned at its implantation site and examined under light and scanning electron microscopy.

After 1 month and 6 months, the implant shows normal healing, strong attachment of the new bone to the implant surface (no intervening fibrous tissue), no inflammation or foreign body reaction, and no resorption of the implant material. characterized by.

The present invention includes the following aspects.

The method of claim 1, wherein: (1) the precipitate is heated to a temperature of at least about 1050°C.

(2) The ratio of reactants used in the reaction is selected such that a precipitate is formed having a calcium to phosphorous molar ratio substantially of hydroxylapatite.
The method described in.

(3) the temperature is about 105% for about 20 minutes to 3 hours, so that the precipitate has a calcium to phosphorus molar ratio of about 1.62 to 1.72;
The method according to (2) above, wherein the temperature is maintained at 0° to 1250°C.

(4) Increase the temperature to about 1100° to 120° for about 0.5 to 1 hour.
The method according to (3) above, wherein the temperature is maintained at 00°C.

(5) 1.44~1.60, preferably 1.46~
A method as claimed in claim 1 and wherein a precipitate having a calcium to phosphorus molar ratio of 1.57 is formed and the precipitate is heated to a temperature of about 1350° C. for about 20 minutes to 3 hours. .

(6) Calcium ions are supplied by calcium nitrate, and phosphate ions are supplied by ammonium hydrogen phosphate.
).

(7) The method according to claims and (1) to (6) above, wherein the solid mass of precipitate subjected to sintering does not crack or split to the extent that the mass does not fracture during sintering.

(8) The method according to claims and (1) to (7) above, wherein a shaped article is produced by cutting, shaping or molding the precipitate while it is in an agglomerated gelatin state before sintering.

(9) The method described in the claims and (1) to (8) above, wherein a shaped article is produced by cutting or shaping the gelatinous precipitate after preliminary drying.

(10) The method described in the claims and (1) to (9) above, in which the product is left in a 0.5 to 5 aqueous solution of sodium fluoride for about 12 hours to 5 days. The method according to claims and (1) to (9) above, wherein a fluorine ion source is added to the precipitate before separation.

(12) The method according to claims and (1) to (11) above, wherein about 0.4 to 0.6 weight factor of an organic binder is added to the precipitate, and the binder is volatilized during heating. .

(13) The organic binder is collagen.

The method described in the claims and (1) to (12) above.

04) Add about 5 to 25 parts by weight of organic binder to the precipitate;
This binder is volatilized during heating.

Claims for producing perforated porcelain and (1) to
The method described in (I3).

05) Claims and the above (1) to (14) wherein the organic binder is powdered cellulose, cotton or collagen.
).

Claims (1)

Claims: 1. Calcium ions and phosphate ions are reacted in an aqueous medium at a pH of about 10-12 such that the molar ratio of calcium to phosphorus is between 1.72 and 1.44. In a process for the production of macroscopic polycrystalline sintered porcelain, which comprises forming a gelatinous precipitate of calcium phosphate, separating out integral areas of this precipitate and, if desired, subjecting it to a cutting, shaping or molding treatment. , The separated precipitate is heated to at least 1000°C and 1350°C.
A process characterized by heating at a temperature of up to 0.degree. C. and maintaining this temperature for a sufficient time to achieve sintering and to achieve substantially maximum densification of the product. 2 Reacting calcium ions and phosphate ions in an aqueous medium at a pH of about 10-12 to form a gelatinous precipitate of calcium phosphate with a calcium to phosphorus molar ratio between 1.72 and 1.44. In the process of producing macroscopic polycrystalline sintered porcelain, which consists in dissolving the integral area of this precipitate and, if desired, subjecting it to a cutting, shaping or molding treatment, the separated precipitate is reduced to a low level. 1000℃ and 1350℃
and maintain this temperature for a sufficient time to achieve sintering and substantial maximum densification of the product, and about 0.4-0.6% by weight. adding an organic binder to the precipitate;
A method characterized in that the binder is volatilized during the heating step. 3 Reacting calcium ions and phosphate ions in an aqueous medium at a pH of about 10-12 to form a gelatinous precipitate of calcium phosphate with a calcium to phosphorus molar ratio between 1.72 and 1.44. The method consists of forming a product and separating a region of this precipitate and, if desired, subjecting it to a cutting, shaping or molding process. In the method for producing macroscopic polycrystalline sintered porous porcelain, the separated precipitate is heated to a temperature of at least 1000'C and 135°C.
Heating at a temperature of up to 0°C, this temperature achieves sintering,
and maintaining the product for a sufficient period of time to achieve substantial maximum densification of the product, adding about 5 to 25% by weight of an organic binder to the precipitate, and allowing this binder to volatilize during the heating step. How to characterize it.