JPS58121205A - China material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

Much current dental research is focused on producing materials that can be used as lateral reinforcements for fillings, crowns, and 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 tooth reinforcement 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, so there is a growing need for hard tissue production. There is a general need for similar materials [H
Materials 5cienc by Albert et al.
eRe5earch 5.417 (1971)]
6 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 for plaque formation and for chemical agent substance. 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 tedious cleaning before use. Therefore, low-quality materials are used, such as powdered hydroxyl apatite, acrylic teeth, glass, and wire, on which plaque accumulates. Although plaque formation itself has probably been well studied, these materials bear little resemblance to natural tooth surfaces and are therefore not fully suited for use in discovering effective anti-plaque agents. Not suitable. For example, it is known that chemical agents that inhibit plaque formation on teeth do not necessarily have the same effect on gala and wire [Turesky et al., J.P.
eradontology 45°26ro (1972
)]. There is therefore a need for an inexpensive, readily available material that is chemically similar to tooth enamel, hard, dense, and highly polished.

Hydroxyl apatite Ca1o(PO4)6(OH)2, also known as basic calcium orthophosphate, (the inorganic phase of teeth and bones) has been proposed to be suitable for the various purposes outlined above and is in fact disclosed in US Pat. 508,81
Specification No. 6 discloses a method for obtaining hydroxylapatite for tooth enamel and its use as a denture composition by mixing it with a synthetic resin. This method is time consuming and cumbersome and is limited to the production of finely divided hydroxylapatite. Moreover, this method is of course dependent on the availability of natural tooth sources.

KuttxrIndian J, Chem, 11.6
95 (1973) disclosed a hydroxylapatite and whitlockite locking mixture produced by decomposing powdered hydroxylapatite at various temperatures.

Bett, et al. [J, Amer, Ghem, Soc.
, 89.5535 (1967)] is stoichiometrically Ca
We have described the production of granular hydroxylapatite with iP varying from 1.67 to 1.57. The material thus produced contained large crystalline pores. 1000
It was also reported that part of the calcium-deficient hydroxyl apatite changes to the itrock phase when heated to C.

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 hydroxylapatite.

However, none of the hitherto known forms of hydroxylapatite has been found to be fully satisfactory. For example, Ray and Linehan [Nature
, 247, 220 (1974):] described an elaborate hydrothermal exchange method to convert coral skeletal calcium carbonate to hydroxylapatite. The material so produced necessarily retained the highly porous properties of coral, and also had a relatively low tensile strength of about 270 to 470 psi (a significant drawback for a man-made material). .

Monroe et al. Journal of Dental
Research 50.860 (1971) reported the production of porcelain by sintering compressed tablets of hydroxylapatite. The material so produced actually contains hydroxylapatite as an ordered mosaic array of polyhedral crystallites and approximately 60% α-
It is a mixture with villockite [Caa (PO4) 2 or tricalcium phosphate] and was thought to be too porous to be suitable for use as a dental material.

Rao and Boehm [Journal of Denta
1 Research 53.1351 (1974)) disclosed a polycrystalline form of hydroxyl apatite produced by compressing powdered hydroxyl apatite in a balanced manner in a mold and isothermally sintering the compact. The resulting porcelain was porous and had a maximum compressive strength of approximately 17,000 psi.

Bhaskar et al. [oral Surgery 32y
336 (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.
A gelatinous precipitate of calcium phosphate with a molar ratio of calcium to phosphorous between the estimated molar ratio in hydroxylapatite and that in witlockite is formed, and this precipitate is separated from the solution and heated to at least 1000C. but below a temperature at which appreciable decomposition of the hydroxylapatite occurs, and maintaining this temperature for a sufficient time to effect sintering and substantially maximum densification of the product. Consisting of

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 new hydroxyluano-tight porcelain bodies into tooth reinforcement compositions results in dense fillings with expansion coefficients virtually equal to 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 cumbersome 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 novel product of the present invention, due to its characteristics, is ideally suited for making discs, plates, rods, etc., which are of great use in the testing of 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 known reproductions of Whitlock stone. It is highly absorbable 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 delta phase is gradually reabsorbed from the implant and replaced by natural biological hard tissue.

This new physical form of hydroxylua/gutite is distinct from biological and geological forms and from all previously known synthetic forms described below.

The average crystal size is approximately in the range of 0.2-3 microns, and the density is approximately 3.10-3.14.17/cm”
It is a strong, hard, dense, white, translucent, etc. material made of virtually pure hydroxyl anodite, characterized by the absence of pores and fissures along its smooth curved surface. It is composed of oriented, polycrystalline sintered porcelain.

Moreover, when normally manufactured, the above materials are approximately 35.
Compressive strength from 000 to 125,000 psi, as low as 3.0
00-30,000 psi tensile strength, 10-1
Linear thermal expansion coefficient of 2 ppm/'C, approximately 470-500
Knoop hardness, 6 x 106 psi
It has an elastic modulus of , and is not birefringent under polarized light.

This new hydroxylua/1! Initial measurements of the tight porcelain indicate that it consists of virtually pure microcrystalline hydroxylapatite in a random isotropic device, with approximately 35,000
~75,000 psi compressive strength, ~3.000 ~
50,000 psi tensile strength, approximately 10-12 p
It has a coefficient of linear thermal expansion of pm/C, a Knupp hardness of about 470-500 and a modulus of elasticity of about 6 x 106 psi, and is characterized by the presence of cracks along a smooth curved surface and the absence of birefringence under polarized light. It was shown to be a strong, hard, dense, white, translucent porcelain material.

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 and synthetic hydroxylapatites produced by hydrothermal processes are macrocrystalline, cracked along the plane, and birefringent. Biological hydroxylapatite has its most purified state (
i.e., tooth enamel), which generally contain significant amounts of carbonate ions, are arranged asymmetrically in the form of spiral-shaped injection columns, and therefore fracture in straight lines along the interfaces of these enamel columns, with a diameter of 150 (llpsi) It is distinguished by its relatively low tensile strength.

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 material of the present invention has no effect on dental crowns, dentures, artificial bones, artificial joints, cannulae, prosthetic limb attachment devices that can bond to bone and penetrate the skin, dental plaque, caries formation, arthritis, and other surfaces and bones. It can be cast or machined into test surfaces to study disease-causing diseases. When suitably milled, the novel porcelain of the present invention can be used as a synthetic cancellus for repairing bone defects, or as an abrasive, and when combined with standard resins can be used as surface reinforcing compositions as described below. Can be used as

As test surfaces for evaluation of plaque inhibitors, the porcelains 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 sintering them. This sintered product can be highly polished using standard polishing techniques and then used as a substrate in the evaluation of plaque inhibitors by methods previously described such as Turesk7. After use, this porcelain body is simply repolished and becomes the new test surface.

When manufactured normally, the porcelain of the invention is not only dense but also non-porous, and although non-porous is essential for dental applications, there is some porosity in the implant. This is advantageous in that it allows fluid circulation and tissue ingrowth. Varying degrees of porosity can be imparted to the porcelains 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 5-25% by weight is mixed with the gelatinous precipitate of hydroxylapatite. During the subsequent sintering process, this organic material burns off, 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 by Hodosh et al.
Journal pf the AmericanDe
ntal As5ocation 70.662C1
[965]]. Alternatively, the porcelain of the present invention may be formulated with a polymerizable binder or binding polymer as described below, and this composition
No. 09,867 (published on 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
It is composed of hydroxyl apatite with a weight ratio of 2 to 86 kg as a second phase, and is characterized by having no pores and having cracks along its smooth curved surface. , a hard, dense, white, isotropic, polycrystalline sintered ceramic product.

Whitlockite, also known as tricalcium chloride/acid, is an inorganic substance with the chemical formula Ca3(PO4)2 and exists in either the α or β crystalline phase. As used herein, “vitlockite” refers to α or β phase, or a mixture of these two phases.

The two-phase porcelain of the present invention is a nonporous polycrystalline material regardless of the relative concentration of hydroxylapatite and witlockite it contains.However, hydroxylapatite and witlockite have different physical properties. The physical properties of this two-phase porcelain, such as density and optical properties, appear to depend on the relative amounts of hydroxylapatite and witlockite.

For example, the theoretical density of witlockite is lower than that of hydroxylapatite, so the observed density of a sample of biphasic porcelain containing about 40% hydroxylapatite and 60% witlockite is 2,981! /crn@
In the case of a porcelain sample containing only hydroxylapatite, it was 5.1 (11.9/cm'').

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 witlockstone contained in man-made products composed of the biphasic porcelain of the present invention is eventually reabsorbed and replaced by natural biological hard tissue ingrowth. Of course, the extent of tissue ingrowth will depend on the amount of Whitlockite contained 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.

This two-phase porcelain can also be made acid resistant by fluorination, as will be described below regarding the hydroxylapatite porcelain.

The above-mentioned novel porcelain body of hydroxylapatite has a pH of
Hydroxyl apatite having a molar ratio of calcium to phosphorus of approximately 1.62 to 1.72 is precipitated from an aqueous medium having a calcium to phosphorus ratio of approximately 10 to 12, and the precipitated hydroxyl apatite is separated from the solution. The hydroxyl athrite can be prepared by heating it at a temperature sufficient for a sufficient period of time to achieve sintering and maximum densification thereof 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 may be supplied by ammonium hydrogen phosphate, ammonium phosphate, phosphoric acid, etc. In the method of the present invention, calcium nitrate and ammonium hydrogen phosphate are calcium ions.

Each is a preferred source of phosphate ions.

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 hydroxyl ξtite is produced by interaction in an aqueous solution with a pH of about 10-12 at a molar ratio of 67-1. The method described by Hayek et al.
(1963)) meet 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 phosphorous ratio of the suspended hydroxylapatite to a value of about 1.62 to 1.72. put.

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, then boiled at room temperature for 1 hour.
Leave for 5-20 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 drying wet hydroxylapatite, it is usually
It is noted that a further shrinkage of approximately 25% occurs during sintering, as described below. This fact must naturally be taken into account when shaping or molding materials.

Slowly heat the wet product to 1000'-125'
Sintering temperatures of 0C can be achieved. At this temperature all residual water will be gone.

Sintering and maximum densification of the product is achieved by maintaining the temperature between 1000 DEG and 1250 t:' for approximately 20 minutes to 6 hours.

It is usually preferred to isolate the dry product prior to sintering. For example, about 90° to 900 t of wet product:
' for about 6 to 24 hours or until the moisture content drops to about 2%. 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 to 2 parts. The hydroxylapatite obtained by this method is brittle and porous, but has some 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 10'Ocm' and 3m thick are easily obtained. Separation or fracturing during drying will cause the suspension of freshly precipitated hydroxylapatite to have an approximately 0.4-0.
This can be minimized or prevented by adding 6 parts by weight of organic binders (eg collagen, powdered cellulose or cotton).

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 indistinguishable from those of the product 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 usually convenient at this stage to further cut or shape the dried hydroxyl apatite into the desired shape for the R-finished 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 reduced to about 10,000 to
Sinter at 1250C for approximately 20 minutes to 6 hours (temperature and time are inversely related).

Sintering is preferably carried out at 1100° to 1200C for approximately 0.5 to 1 hour. The hard and dense ceramic products 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.

It is only in this sticky gelatinous state that hydroxylapatite can be shaped or molded and then dried and sintered to produce macrofoam ceramics. Dry granular or granular hydroxylapatite cannot be reconstituted into this gelatinous state. For example, if powdered hydroxylapatite is suspended in water and filtered, a non-stick granular filter cake is obtained that easily dries, crumbles, and forms into macrofoam ceramics.
It cannot be shaped or changed. Moreover, although powdered hydroxyl acetite can be mechanically compressed into compacts (e.g. tablets), the product obtained when sintered by the method of the present invention is highly porous and can be pressed against a smooth flat surface. It doesn't crack, it just crumbles into a rough soup.

Hydroxyapatite formed in aqueous media is a complex, although the process is not completely understood.
It is generally believed that calcium and phosphate ions first combine to form calcium-deficient hydroxylapatite, where the calcium to phosphorus ratio is about 1.5. In the presence of calcium ions, this slowly converts to hydroxylapatite, which has a calcium/calcium ratio of 1.67. [Eane S et al. & Na
ture208.365 (1965) and Bet, t,
et al., J. AmereChem, Soc, 89,
5535 (1967)] That is, in order to obtain a pottery product consisting of an extremely pure hydroxylapatite, the initial gelatin precipitate of hydroxylapatite must be prepared so that its calcium to phosphorus ratio is approximately 1.62 to 1.72. In the method of the present invention, it is important to keep the solution in 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 witrockite. 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 yields semitranslucent ceramic products consisting of virtually pure hydroxylapatite, considering that the method of formation of human 90 xylapatite in an aqueous medium is not completely understood, calcium and phosphorus It may be beneficial to monitor the formation of hydroxylapatite to ensure that the desired stoichiometry with is achieved and that, when sintered, the product consists of virtually pure hydroxylapatite. This was done by taking out a part of the human 9-xyl apatite suspension, separating the product, drying and sintering it as described above, and subjecting the resulting ceramic product to elemental analysis and X-ray analysis. easily achieved.

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

That is, unsintered hydroxyl apatite with a desirable calcium to phosphorus ratio of 1.62 to 1.72 can be converted into a ceramic article of the invention by heating at a temperature of at least 1000 t:'.

1000t: 2 to 3 for complete sintering and maximum densification
while at 1200t:' the process takes 20~
It will be completed in 30 minutes. If the temperature is substantially lower than 1000 tll', the sintering will be incomplete regardless of the heating time, and if heated above 1250 tll' for more than 1 hour, some of the hydroxylapatite will decompose into whitlockite.

The above-mentioned two-phase ceramic product consisting of hydroxylapatite as the first phase and witlockite as the second phase has a pH of about 10 to
approximately 1.44 to 1.60 preferably 1 from an aqueous solution of 12
．． A calcium phosphate compound having a calcium to phosphorus molar ratio of 46 to 1.57 is precipitated, the precipitate is separated from the solution, and the resulting solid is heated at a temperature and for a period of time sufficient to cause its sintering and maximum densification. It can be produced by heating.

Required stoichiometric value, i.e. Ca/P=1.44-1.60
A calcium phosphate compound with a pH of 10 to 12 is prepared by combining calcium ions and phosphate ions using the same calcium ion source and phosphate ion source as described in the production of single-phase human 90 xylapatite. Obtained by interacting. 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 left in contact with the stock solution for a period not to exceed about 4 hours, or allowed to interact, provided that the molar ratio of calcium to phosphorus in the precipitate does not exceed about 1.60. It can be manufactured by

The calcium phosphate precipitate is separated from the solution, washed, optionally shaped or formed into a convenient shape, and, if desired, dried prior to sintering, as described in the preparation of the monophasic ceramic product human 90 xylapatite.・Isolate.

The freshly precipitated calcium phosphate suspension 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 rpm for about 20 minutes to 3 hours.

The amount of whitlockite contained in the ceramic product produced by the process depends on when the precipitate is separated from the raw solution, and is about 2 to 86 mm. When isolated, its calcium to phosphorus ratio is 1.55, and the pottery ultimately produced therefrom contains about 86% witlockite.If the product is isolated 2 hours after precipitation, Bass has a calcium to phosphorus ratio of 1.57;
The resulting ceramic products contain about 61 units of whitlock stone.

Isolation of the product at 4.5 hours of precipitation ultimately yields a ceramic product containing about 2 modulus witlockite, which can be determined by X-ray diffraction with a minimum concentration sensitivity of 2-6%. It is almost 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 unit ratio 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 10 molar ratio of about 60 to
Except that it produces ceramic products consisting of 0% hydroxylapatite and about 50-70% witlock stone.
It is conveniently carried out as described for the production of the monophasic ceramic product hydroxylapatite.

The ceramic product of the present invention can be produced by combining the characteristics of the two methods described above.
The Witlock δ phase is further enriched by interacting with phosphate ions at a molar ratio of 50 to 1.60 to 10 and isolating the precipitated calcium phosphate compound within a short time (preferably about 5 minutes to 4 hours after precipitation). You can do it.

The ceramic products thus produced consist of approximately 10-60% hydroxylapatite and 70-90% witlockstone.

Hydroxyl apatite is known to decompose at about 1250 C to form whitlockite, and therefore the monophasic ceramic product of the present invention, hydroxyl apatite, is decomposed at about 1250 C.
Prolonged heating at C or above partially decomposes the hydroxylapatite to form whitlockite, which provides an alternative method for making the two-phase ceramic products of this 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, peroxide such as Nzoyl, etc.)
Reactive diluents such as , G, tri and tetraethylene glycol dimethacrylate, U.S. Patent No. 3.277
．． Hardening agents such as N-3-oxohydrocarbon-substituted acrylamides, metal acetylacetonates, tertiary amino acids [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
(present in weight coefficient). It is not necessary (・ is a surface active comonomer or a locking agent (
keying agent) For example, US Patent 3,2
00. '142 (granted August 10, 1965), the reaction product of N-phenylglycine and glycidyl methacrylate, methacryloxypropyltrimethoxysilane, 6,4-epoxycyclohexylethyltrimethoxysilane, Vinyltrichlorosilane and the like can be added to the composition in an amount of 0.05 to 10% by weight 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 hydroxylapatite 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 dental reinforcement art, such as human 90xethyl methacrylate, polymethyl methacrylate, polymacrylic acid, propylene glycol fumarate phthalate unsaturated polyester (e.g. 2 3 L S 8275 sold by A11ied Chemical Co, Pi
5elec'tron 580001 sold at ttsburgh PlateGlass).

Styrene-modified unsaturated polyester (e.g. G11dde
n G11dpol 1008. Cr-136,40
S50), epoxy resins (e.g. C1ba Arald
ite 6020゜Union Carbide ER
L 2774), and U.S. Patent No. 3,066.11
No. 2 Cl No. 27, November 27, 962) is mixed with a bisacrylate monomer made from glycidyl methacrylate and bisphenol A as shown in the specification.

The resin may consist of a single comonomer or a mixture of two or more comonomers. Dye if desired.

Additives such as inorganic pigments, fluorescent agents, etc. may be added to the above compositions according to principles known in the materials industry. Resin, porcelain hydroxylapatite, and optional ingredients (
For example, it is convenient to blend silane binders, dyes, inorganic pigments or fluorescent agents) prior to addition of fluxes, hardeners, crosslinkers, promoters or accelerators. However, this mixing order of the components is not absolute (the above components can also be blended at the same time. The composition thus produced can be used as a tooth filling material or tooth enamel using conventional techniques.

It can be used as a cavity filling, a pulp capping agent, and can be cast in an appropriate mold to make a denture or a set thereof.

Materials used in the oral cavity are corrosion resistant
This is of course a big advantage. The purpose is to obtain approximately 0.01-1% fluoride iodine/(
e.g. ammonium fluoride or stannous fluoride)
- #) to a suspension of freshly precipitated hydroxylapatite. The porcelain produced by calcining the resulting product resists attack by lactic, acetic or citric acid or by standard in vitro methods for determining corrosion resistance. Alternatively, corrosion resistance can be imparted by exposing the final porcelain to a 0.5-5% aqueous solution of sodium fluoride for about 12 hours to 5 days. Preferably,
The porcelain body is placed in an approximately 5% aqueous solution of sodium fluoride for approximately 4 hours.
Leave it for a day.

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 tooth reinforcement compositions as described above. This results in a barium- or strontium-treated hydroxyl apatite porcelain that facilitates the detection of filling teeth. Magnesium (also incorporated into the apatite crystal lattice) promotes the crystallization of witlockite, while magnesium (also incorporated into the apatite crystal lattice) It is known to retard the crystallization of hydroxylapatite [Eanes et al., Ca1c, 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 13M 1.63 N calcium nitrate (0,212 mol) and 125 WLl of concentrated ammonia was added 16.75 g (0,127 mol) of ammonium hydrogen phosphate, 400 al. A mixture containing water and 150 rItt 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. Rubber the filter cake
m) and then dried at 95 U overnight. A sample of the resulting hard, porous and brittle cake was electrofiltered for 11 minutes.
It was heated for 5 minutes to reach a final temperature of 1230 t:', and then cooled to room temperature to obtain a strong, hard, white translucent ceramic product.

Standard elemental analysis of this final ceramic product and dry hydroxyluano-tite before sintering revealed Ca 10 (PO4) 6
The following results based on (OH)2 were obtained.

8k, Tashita Yul-Fu Hido Ca 39.89% 37.4% 696%
P 1.85% 17.5% 18.9
%H2O0% 1%...Ca/P
1.667 1.65 1.62 Examination of a thin section of this ceramic product under a polarizing microscope at 160X and 352X showed that it contained virtually no whitlockite. The absence of birefringence and discernible structural characteristics such as crystallite shape, orientation, and interfaces indicated a microcrystalline structure. Comparison with the results of optical microscopic observation of thin sections of sintered compressed tablets reported by Monroe (supra) showed that the two materials are structurally dissimilar.

X-ray diffraction measurements were carried out in a conventional manner. Calculate the spacing between planes,
Donna et al. [Crystal Data, AC
AMonogram No. 5.668 (196
3) was found to be virtually identical to the value for human 90xylapatite given by ).

The X-ray data further showed that whitlockite was not present in values greater than about 2-6% (minimum concentration sensitivity of the diffractometer).

Example 2 (79.21C0.60 mol) ammonium hydrogen nophosphate was dissolved in 153Qm7 of distilled water, and the pH was adjusted to 11-12 with 750d of concentrated ammonia.

Furthermore, distilled water was added to dissolve the precipitated ammonium phosphate to make the total amount 5200R1. Enrich the pH as needed1
Adjusted to 1-12. The pH of this solution was adjusted in advance to 12 with a concentrated ammonia solution of Habo 601, and the pH was adjusted to 90.
The solution was added dropwise over 30 to 40 minutes to a vigorously stirred solution containing 1 mol of calcium nitrate in 0 d of distilled water, and then diluted with distilled water until the total amount reached 1800. After the addition was complete, the resulting gelatinous suspension was stirred for an additional 10 minutes, then boiled for 10 minutes, removed from the heat source, covered, and left at room temperature for 15-20 hours. The supernatant liquid was removed by decantation, and the remaining suspension was drained at 200 Orp.
Centrifuged for 10 minutes at m. 800 m of the obtained sludge
1 of distilled water, and centrifuged again at 2000 rpm for 10 minutes. Add distilled water to the remaining solid to bring the total volume to 9.
It was set to 00-. With vigorous shaking, a homogeneous suspension with virtually no large debris or aggregates was obtained. This suspension pours all its power into Blafner f-to at once,
Passed under mild vacuum. When the filtration cake started to crumble, a dam was used to increase the degree of vacuum. After an hour, we removed the dam.
Transfer the perfect sawagashi cake with no cracks to a flat surface and
Dry at 0 to 95C for 15 hours to a temperature of 90 to 100. A white, porous, brittle hydroxylapatite piece of li' was obtained. A piece of 1 to 4 cIrL with no cracks or fissures was placed in an electric oven, the temperature was raised to 120 Or over 100 minutes, and then the oven and its contents were allowed to cool to room temperature. A hard, dense, non-porous, white, translucent porcelain was thus obtained.

Dry, unsintered human Ca 39.89'% 36.5, 36.8%
31.7, 38. O%P 18.5%
21.7% 22.8.19.0,188Ca
/P1.667 1.30.1.31 1.08,
1.55, 1.56 After carrying out the above analysis, it was discovered that the analytical technique used was not able to completely dissolve the sample and therefore the results were inaccurate and could vary. Despite the above analytical data, the substantial homogeneity of this sample was confirmed by the following electron microscopy data. Moreover, the product of Example 6, 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 enhancing a collodion replica of the sample surface with chromium and then coating with carbon. Transmission electron microscopy of this replica sample revealed a fairly uniform grain size with no pores, or a secondary phase present at the grain interfaces or within the grains in an amount exceeding about 0.5% (the minimum concentration sensitivity of the electron microscope). A precipitate was revealed.

The porcelain sample was then polished with SiC paper to 600 grit and then polished with micrometer diamond # on a metallographic wheel covered with a delicate nylon cloth.
I made it a burst. The sample was then etched with 4% hydrofluoric acid for 60 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 by the usual method, and each was 56°462
psi±16.733 psi and 6.5 x 10
It turned out to be psl.

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 was a linear line between 25C and 225C, and the value was 11 x 10''/ll: ±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 isotropic.

The porosity was determined qualitatively by immersing the test material in Fuchsin dye for 15 minutes, washing with water, drying, and examining it 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 - the novel porcelain of Rikiki's 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 pores on the surface causes the surrounding paper to turn blue. When this test was carried out simultaneously on the porcelain of the present invention, sintered compressed tablets of hydroxylapatite and natural teeth, the lidmus paper in contact with the sintered compressed tablet turned blue; The presence of trapped ammonia was shown.

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

Example 6 304 g of white, brittle, porous hydroxylapatite was obtained using 6 moles of calcium nitrate and 1.8 moles of ammonium hydrogen phosphate as starting materials using the method described in Example 2. .

Analysis Calculated value Measured value Ca39.89 40.0 P 1B;5 18.6 Ca/P 1.667 1.661100t:
Sintered for 1 hour at 10 J
A translucent porcelain of i'/cm' was produced. X-ray diffraction showed the material to be homogeneous hydroxylapatite. Electron microscopy reveals a particle size distribution of 0.7
~6 microns, revealing the absence of pores or second phase precipitate.

Example 4°A About 509 hydroxyl apatite was precipitated from an aqueous solution using half the amount of the method of Example 2. After centrifugation and decantation, remove the remaining inorganic sludge by 1E.
The mixture was resuspended in sufficient water to make the solution and homogenized in a Waring Brengu.

0.51 powdered cellulose (<0.0.
5μ) and blended for 6 minutes in a Waring blender. 100ml of hydroxylapatite homogeneous aqueous suspension was then added and the resulting mixture was blended for an additional 5 minutes. Then, pass through the raw suspension,
The filter cake was dried and sintered using the method of Example 2. The 20f filter cake showed no crumbling after drying, and the ceramic product produced by sintering was slightly porous as indicated by the 7 comb/dye test described above.

CD, 200 tnl of 5.9 shredded surgical cotton
of water to obtain a mixture and diluted in Waring Brengu with 4
Blend for 5 minutes or until a nearly homogeneous texture is obtained. 100 r/n 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 passed through a tube, and the filtered cake was dried and sintered by the method of Example 2. The resulting ceramic product was intact and visibly porous.

EXAMPLE 5 A mixture containing 59 collagen (Bovine Achilles 111) in 300 mA water was blended in a Waring Brengu for 5 minutes. This collagen occluded a large amount of water and formed a thick gelatinous mass.

A small amount of chopped collagen (20-609) remained in the suspension.

B This finely divided collagen suspension (250ml
1001 of the homogeneous aqueous suspension of hydroxylapatite described in Example 4A.
+7! and blended in a blender 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.

Approximately 20% concentrated gelatinous collagen was blended in a Waring Brewing machine for 6 minutes with 150 rnt 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 and strong (and apparently porous.

Example 6 A ceramic product sample prepared according to Example 2 was left in a 1% aqueous solution of sodium fluoride for 12 hours.

These materials were exposed to 10% lactic acid along with untreated porcelain and natural teeth. After 6 days, Fluorite 9 treated porcelain was shown to be actually 1 less susceptible to lactic acid damage than untreated porcelain or natural tooth enamel.

When left in a 1% sodium fluoride aqueous solution for 6 days.

After 6 days, the damage caused by the lactic acid attack was not visible, and after a month it had degraded only slightly. On the other hand, the untreated sample was highly degraded.

Example 7 Approximately 50 g 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 5001. The resulting suspension was divided into 10 equal portions, each diluted with 5'Omt of water and treated with ammonium fluoride as follows.

Samples 1.2.3.4 and 5 were treated with ammonium fluoride aqueous solutions containing 0.000859 Fe/rnE at 0, 0.1. 0,5. 1.0 and 2.0rILl
added. Samples 9 and 10 were treated with 2.0 and 4 ammonium fluoride aqueous solutions containing 0.0459 F0 shoulders, respectively.
．． 0mA processed. The suspension was then shaken on a rotating shaker for 15 hours and filtered. The f-filtered cake was subjected to 15 partial pressure using a dam, dried at 95C for 2 days, and then heated in an electric furnace to a temperature of 1200T::. The obtained porcelain was finely ground and sieved using a 325 mesh screen.

80rng of each powder sample was added to 23tZ' with a pH of 4.
1 of sodium lactate buffer solution (0.4M) and shaken on a pre-k (Burrell) wrist-actuated shaker. At 2, 9, 25, and 40 minutes after mixing, 6 ml of each sample mixture was removed, immediately filtered to remove undissolved samples, 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 Sample 1 was left in 1 d of sodium fluoride for 4 days. Separate the solids and wash thoroughly with water;
The sample was dried and then subjected to dissolution analysis as described above. The results are included in Table A.

Although the experimental conditions described above are not close to in viv conditions, it is possible to accurately evaluate the relative effects of fluoride/concentration if the conditions are chosen to sufficiently dissolve the sample within a certain period of time. The in vitro dissolution rate of porcelain hydroxylapatite is expected to be lower than the observed rate in lactate buffer.

Table A Relative solubility of fluorinated porcelain human 90 xyl apatite 1
0 - 9.2 18.5 32.0 39.
72 17 19 9.2 1.8.8 29
．． 3 69.03 85 19a 8.917
．． 6 30.0 38.34 170 190 1
0.3 18.3 30.5 37.55 340
216 9.9 1B, 1 29.7 35.26
850 226 8.8 17.1 27.7
33.07 1.700 470 7.9 1B,
1 25.7 29.88 17.0001.460
6.7 12.1 19.7 23.39 18.0
001.700 6.3 11.5 19.7 23
．． 31A + 3.7 7.1
13.7 18.7a Clearly incorrect analysis value Example 8゜ Ca/P is 1.6 with a thickness of about 6 to 4 m made according to Example 2
A large piece of dried filtration cake of 4-1.66 mm was evaluated and broken into rectangular slabs approximately 14-15 mm wide and 7-8 mm wide, with a small hole punched from one end. 100 of these flat plates
The sheets were then sintered as in Example 2 and polished to a high gloss using standard beading techniques. 3.12-3.
The porcelain body with a density of 14.9/an” is
It was a rectangular plate with a length of 0 to 11 lengths, a width of 4 to 5 days, and a thickness of 2 to 611 meters, with a hole at one end and a fixed length of wire attached through the hole. This plate can therefore be suspended at any desired depth in a test tube and was used as a test surface in the plaque inhibitor evaluation, as described above.

Example 9 A solution containing 0.24 mol of ammonium hydrogen phosphate in 6001 distilled water was purified with 340 mb of concentrated ammonia.
Adjust to H11.4 and bring the final volume to -11280 II with distilled water.
It was set as Lt. The resulting solution was dissolved in 360 FILl of distilled water, previously adjusted to a pH of 1l with concentrated ammonia.
60 moles of calcium nitrate in a vigorously stirred solution.
The solution was added dropwise over several minutes and diluted with distilled water to make 720 ml. Stir the resulting suspension without boiling it,
250 rill portions were removed periodically and the product was isolated, washed and dried as described in Example 2. All samples were then heated at 1ioot:' for 1 hour, and the composition of the resulting ceramic products was determined by X-ray diffraction. The results are shown in Table B.

Table B 1 5 minutes 36.6 18.22
45" --- 62 hours 66.6 18.044.
5" --- 57" -37,0170 67" 17 hours 37.2 17.07
24"-37,417,1848"
-37,416,8a These values are the minimum concentration sensitivity of the X-ray diffractometer (2-6%) Phase hydroxyl whitlockite observed by X-ray diffraction 1.55 17 83-
21 791.57 3
9 61- 98
2a1, 68 98 2
al, 69 100 01.
69 100 01.72
Close to 1000. Therefore, its accuracy is questionable.

Example 10 A Using the method of Example 2, 0.6 mol of calcium nitrate and 0
．． using 2 moles of ammonium hydrogen phosphate.

A hard and, of course, porous product was obtained with the following elemental composition:

Ca=3 s, s 5%; P=19.77%; Ca/P
=1.52 Heating this substance at 1200U for 1 hour,
Consists of approximately 40% hydroxylapatite and 60% whitlockite, as shown by line diffraction.
A strong, hard, non-porous, white, somewhat opaque porcelain was obtained.

B When the above reaction was carried out by reversing the order of addition of the starting materials, approximately 40% of hydroxylapatite and 60% of
It consists of 1.52 a/P and 2.
A product with a density of 9821/crrt' was obtained.

Example 11 A solution of 0.0625 moles of ammonium hydrogen phosphate in 150 rnt of distilled water was treated with 951 of concentrated ammonia and brought to a final volume of 6201 with distilled water. The obtained solution was mixed with 0.1 mol of calcium nitrate and 2 ml of distilled water.
．． 5- into a vigorously stirred solution containing concentrated ammonia.
It was added dropwise over 0 minutes. The resulting suspension was stirred for 5 minutes, then cooled in water for 45 minutes, the suspended solids were isolated, washed and dried as described in Example 2, and had the following elemental composition: A hard, brittle, porous, white solid was obtained.

Ca=35.4%; P=18.59%; Ca/
A substance with P = 1.4 is heated at 13500 for 1 hour,
X#! A strong, hard, non-porous, somewhat opaque ceramic product was obtained, consisting of approximately 14% hydroxylapatite and 86% witlockite as shown by diffraction.

The products of Examples 1-11 correspond to the products of the invention and have their physical properties as described above.

The products produced according to Examples 1, 2.3.5B, and 6-8 are strong, hard, dense, white, translucent porcelains with virtually pure, pore-free, isotropic multi-component porcelain. It is made of xylapatite, has a compressive strength of 35,000 to 125,000 psi, a tensile strength of 3,000 to 30,000 psi, and a coefficient of thermal expansion of 10 to 12 ppm/C.
Knoop hardness of 470-500 and approximately 6 x 1
It has an elastic modulus of 0.06 psi and is characterized by the presence of cracks along smooth curves and the absence of birefringence under polarized light.

The products manufactured according to Examples 4 and 50 are the same as those manufactured according to Examples 1 and 2.
．． 3.5B and 6-8, although they introduce cavities or holes of varying number and size. 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.

Example 12 A composition suitable as a tooth enamel and filling material was prepared as follows.

A condensation product of N-phenylglycine and glycicine methacrylate (described in U.S. Pat. No. 3,200,142,
2.0 g of powdered porcelain hydroxyl apatite was added to the solution containing NPC-GMA). After vortexing for 5 minutes, the ethanol was evaporated in vacuo at room temperature, and the remaining solid was dried over 1.5 HII for 2 hours.

B. 80 ■ samples of the above material were mixed with 0.4 ■ of benzyl peroxide and hydroxyethyl methacrylate and the reaction product of bisphenol A and glycidyl methacrylate (as described in U.S. Pat. No. 3,066,112, 60~ of a 1:2 mixture with Bis-GMA). The resulting mixture was placed in a cylindrical steel mold and cured in 6-5 minutes. Compressive strength was measured on four cylindrical frames made in this way.

The average value was 24,350 psi.

Example 13 60 parts of powdered porcelain hydroxylapatite, 16 parts of hydroxyethyl methacrylate, 27 parts of a condensation product of bisphenol A and glycidyl methacrylate, 0,
6 parts of N,N-bis-(2-hydroxyethyl)-p-
Toluidine and 0.8 parts of peroxide thoroughly blended the mixture consisting of Nzoyl to obtain a thin, free-flowing solution that served as a sealant for tooth holes and crevices. This was poured into a cylindrical steel mold and cured after about 6 minutes. The compressive strength of seven cylindrical frames manufactured in this way was measured. The average value was 20,400 psi.

Example 14 The following is an example of a formulation that serves as a dental filling.

0.5 g of powdered porcelain hibiroxylapatite 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. To 120 μ of powdered hibiloxylapatite thus treated, 0.6 μ of f-hibenzoyl peroxide was added, and then 40 μ
A mixture of rnQ [consisting of a condensation product of bisphenol A and glycidyl methacrylate, triethylene glycol dimethacrylate and N,N-his-(2-hydroxyethyl)-p-toluidine. Product name Epoxyli
Lee Pharmaceutical in teoHL-72
sold by als] was added. The resulting mixture was rolled out to a smooth base, placed in a cylindrical steel mold, and left for 4 hours. The cylindrical frame was removed from the mold and six pieces were tested, and the average compressive strength was 22,300 p.
I discovered that si.

Example 15 1 g of powdered porcelain hydroxyl apatite was added to a solution containing 60 rng of a condensation product of N-phenylglycine and glycicine methacrylate in 7 ml of ethanol while stirring. Ethanol was evaporated in vacuo at room temperature. To the thus treated mixture containing 180~ of powdered porcelain hibiroxylapatite and 6.0~ of peroxide is added 60 parts of the condensation product of bisphenol A and glycidyl methacrylate and 40 parts of triethylene. 74 cm of the mixture containing glycol dimethacrylate was added, and the resulting aggregate was rolled out with a spatula to form a smooth paste, which was placed in a cylindrical steel mold.

It was left for 6 hours. The cylindrical plugs were removed from the mold and tested in four pieces and found to have an average compressive strength of 22.30' Opsi.

Example 16 A composition useful as a dental and orthodontic cement or as a temporary tooth filling was prepared by combining 100% powdered porcelain hydroxylapatite, 600% zinc oxide and 300% zinc oxide.
It was made by mixing a 40% aqueous solution of polyacrylic acid. The resulting mixture was placed into a cylindrical steel mold and cured in approximately 6-5 minutes. The cylindrical plugs were removed from the mold and tested in four pieces and found to have an average compressive strength of 12.400 psi. The other five bodies were found to have an average radial tensile strength of 1630 psi. 40% aqueous yY +)
Acrylic acid and zinc oxide are produced by the West German ESPE (e,
m.

A commercially available polycarboxylate cement available under the trade name Durelon ■ from bHl was obtained as a liquid component and a solid component, respectively.

Example 17 A composition suitable as a dental cement and filling material was prepared by mixing a mixture containing 6 parts by weight of 40% aqueous polyacrylic acid and 6 parts by weight of zinc oxide of powdered porcelain hydroxylapatite. Manufactured. 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. Product name D
These were obtained as liquid and solid components of a commercially available JV carboxylate cement available from Urelon.

Example 18 The following is an example of a tooth filling composition.

Ingredients Weight% Styrene-modified polyester resin 292 (Glidde
n Glidpol Cr- 136) Benzoyl peroxide 0.7 Styrene
0.6 Methacryloxypropyltrimethoxysilane 1.5 Porcelain Hydroxylapatite 68.0 Example 19 The following is an example of a composition useful as a dental cement, socket filler, and pulp capping agent.

Ingredients Weight% Epoxy resin 67 (U
nion Carbide ERL27.74) N-3
-oxo-1,1-dimethylbutyl acrylic 26 amito9 porcelain hydroxyl amitite
10 Example 20 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 60 minutes. Next, let the mold cool for about 15 minutes, and finally rinse it with cold tap water.
er).

The biological compatibility of the novel porcelain hydroxyl apatite of the present invention was confirmed by transplantation studies. When the porcelain fragments produced 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 slowed after 28 days (as shown). There wasn't.

A porcelain hydroxylapatite olet prepared in a manner similar to that described in Example B was surgically implanted into the femur of a dog. The implants were periodically observed by X-ray in vivo. After 1 and 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.

Patent Applicant: Sterling Drug Incorporated

Claims (1)

Claims: Clause 1: Consisting of substantially pure hydroxylapatite with an average crystal size of about 0.2 to 6 microns, having a density of about 6.10 to 3.1411/m" and substantially There are no holes, and the fissures have eyes along the smooth curved surface.
a finely divided, translucent, isotropic polycrystalline sintered porcelain of approximately 10-90% by weight containing a dentally acceptable polymerizable binder or binding polymer; A tooth reinforcing composition comprising a polymerizable or polymerized binder. Section 2 Consists of hydroxyl apatite of about 10 to 90 parts by weight as a first phase and whitlockite of about 2 to 86 parts by weight as a second phase, with virtually no porosity and no visible fissures along the curved surface. containing a dentally acceptable polymerizable binder or bonding polymer, finely divided, strong, hard,
A tooth reinforcement characterized by comprising a dense, isotropic, polycrystalline sintered two-phase porcelain of about 10-90% by weight and a dentally acceptable polymeric or polymerized binder. Composition for use.