JP2548116C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTIONTechnical field   The present invention relates to composite materials containing non-vitreous microparticles. In addition, the present invention Relates to a method for producing such a composite material.Background art   Non-vitreous small particles can be obtained from various sources, for example, US Pat. No. 3,709,70.
No. 6, No. 3,793,041, No. 3,795,524, No. 4,166,14
7, 4,217,264 and 4,306,913, and the United Kingdom
It is described in Japanese Patent Application No. 2115799. Described in such material
Some of the small particles are combined with a binder (eg, a polymerizable resin) to form a composite material.
And a few of such small particles are capable of X-ray transparent composites made using such particles.
It may contain a sufficient amount of a suitable ceramic metal oxide to render it transient.   X-ray opacity is a highly desirable property for dental composites. X-ray opacity
Transient composites can be inspected using standard dental X-ray equipment, so they are next to hardened composites.
Facilitates long-term detection of marginal defects and tooth decay in contacting tooth tissue. However,
The dental composite should have low visual opacity, i.e., it is
And should be substantially transparent or translucent. Hardened dental composite
Low visual opacity is desired to have life-like gloss. Such dental
The composite material is intended to be cured or polymerized by visible light
If deep curing (sometimes more than 2 mm deep) is required,
Requirements for uniform hardness of composite materials and for conducting curing reaction in the oral cavity
Physical properties (unless the uncured composite is exposed to light, usually from only one direction)
, And curing light must be provided by a portable device)
The composite has low visual opacity that allows for deep and complete cure
Is determined.   Another desirable property for dental composites is durability. Durability sometimes
This can be improved by increasing the percentage of filler particles in the composite. However
However, increasing the amount of filler generally causes an increase in visual opacity,
And limits visible light cure depth and cure uniformity.   Yet another desirable property for dental composites is cure stability. Two components
Non-light-curable dental composites (or “chemically-curable” composites) The cure stability of the composite material is measured when the two components of the composite are mixed.
By comparing the polymerization set times of aged and unaged samples of the composite material
Be evaluated. Curing stability of one-component photocurable dental composites has aged
Top hardness and bottom of composite samples cured to standard depth without or after aging
It is evaluated by comparing the part hardness. Poor cure stability is an important factor in the aging of composite materials.
Variation in polymerization cure time between sample and unaged sample or top cure hardness and bottom
Expressed by the difference in cure hardness. Filler particles in dental composites are sometimes composite
Interacts with other components of the material (eg, polymerizable resin and polymerization initiator) to provide curing stability
Adversely affect These interactions are unpredictable and sometimes not fully understood.   In fact, X-ray opacity, low visual opacity, high loading of filler, and curing stability
It is very difficult to formulate dental composites with such commercially useful combinations
Has been proven.Summary of the Invention   The present invention   (A) a polymerizable resin suitable for use in the oral cavity;   (B) a radiopaque dental composite comprising a mixture with non-vitreous microparticles
Material,   The non-vitreous microparticles,   (I) a plurality of amorphous minute regions composed of silicon oxide;   (Ii) a plurality of crystalline micro-domains composed of an X-ray opaque polycrystalline ceramic metal oxide;
And an area   The amorphous minute regions are substantially uniformly scattered by the crystalline minute regions.
And   The microparticles are crystalline microregions having a diameter greater than 0.4 μm or
Radiopaque dental composite material free of voids, and dental
Render the composite radiopaque while imparting low visual opacity to the composite.
Provide a way to   Small particles for use in dental composites, for example, US Pat. 7,264 and 4,306,913 and the above-mentioned British Published Patent Application No. 21.
Other investigators involved in the manufacture of those described in US Pat.
Make such particles completely amorphous to allow a good refractive index match between
I thought that. The metal oxides used for such small particles generally have a refractive index greater than 2.
Index, but this value is much larger than the refractive index of ordinary resins. The present invention
Contrary to this researcher's attempt, both amorphous and crystalline
Is provided. Low visual opacity dental composites
Ensure that the particles do not substantially contain visual opacity inclusions
Obtained by In a preferred embodiment, the crystalline microdomains of such microparticles
Substantially all of the zones have a diameter of less than about 0.4μ.Details of the Invention   The term "radiopaque" when used to describe the dental composite of the present invention
"Hardness" is used to identify composite materials from tooth tissue using standard dental X-ray equipment.
Means that the composite composite shows sufficient opacity to X-rays. X-ray opacity
Desired extent depends on the specific application and the expectations of the practitioner evaluating the X-ray film
And fluctuate. The preferred X-ray opacity can be measured by the following test. Through
Normal dental X-ray film is a 1mm thick cured composite with normal irradiation time and strength.
Exposed through the material layer. Develop X-ray negatives and equip visible light filters
The density is evaluated using a Macbeth transmission densitometer model TD504. Preferably
Has a specified densitometer reading of about 1.4 or less, preferably 0.8 or less.   As used herein, "dental composite" refers to a polymerizable (or polymerized) tree
Curable (and also containing fats, one or more filler particles, and any desired auxiliaries
Cured), the resulting composition being suitable for use in the oral cavity
Means The dental composite material of the present invention may be a multi-component chemically curable composition.
It may be a single-component ultraviolet or visible light curable composition. The present invention
Dental composite materials include anterior or posterior dentures, cavity coatings, and orthodontic brackets
Special adhesives, crown and bridge denture cements, artificial crowns and casting resins
I found a use.   Polymerizable resins suitable for use in the dental composites of the present invention can be used in the oral environment.
Sufficient strength, hydrolytic stability, and non-toxic to make it suitable for use in
Is a curable organic resin having Examples of such resins are acrylates, methacrylates
G, urethane, epoxy resin and the like, for example, US Pat. No. 3,066,112.
No. 3,539,533, No. 3,629,187, No. 3,709,866
No. 3,751,399, No. 3,766,132, No. 3,860,556
No. 4,002,669, No. 4,115,346, No. 4,259,117
No. 4,292,029, No. 4,208,190, No. 4,327,014
Nos. 4,379,695, 4,387,240 and 4,404,15.
No. 0, and mixtures and derivatives thereof. In the present invention
The preferred polymerizable resin to be used is diglycidyl methacrylate of biphenol A.
(Often called “BIS-GMA”) and triethylene glycol di
It is a mixture with methacrylate (often called "TEGDMA")
.   The "non-glassy" microparticles used here are derived from the melt
Small diameter particles (preferably having a diameter of less than about 50μ). "
"Micro area" is magnified about 100,000 to 1,000,000 times with a transmission electron microscope
To give a uniform shape (or generally give a uniform shape) when observed
Microparticles that are visible and appear to contain single crystalline or amorphous organic species
It is the part inside. The microparticles of the present invention, when observed in that manner,
A plurality of microregions of at least two distinct types (ie,
2 or more). The two types of microregions
Here, they are referred to as “amorphous minute regions” and “crystalline minute regions”. Amorphous fine
The regions are substantially uniformly interspersed by crystalline microregions; ie, amorphous
The crystalline and crystalline microregions are substantially randomly distributed throughout the individual microparticles.
Are lined up. To test individual microparticles, use a representative sample of microparticles.
(Eg, 10-100) should be examined in detail, and individual microparticles
Calcined bonds that may cause agglomeration should be broken, for example, by gentle milling.
It is.   The presence of amorphous and crystalline microregions in microparticles is determined by X-ray or electron
Or other techniques suitable for testing small amorphous or crystalline species.
Can be measured. X-ray or electron diffraction analysis
FIG. 4 shows a characteristic identification pattern of a diffraction line when tested. Amorphous fine
The region is identified by X-ray or electron diffraction analysis even when present in an array of such small regions.
Does not show a distinguishable line when observed. The microparticles of the present invention
Because it contains both amorphous and crystalline microdomains, the microparticles
Indicates a diffraction image. The presence of amorphous micro-regions in microparticles
This is confirmed by the lack of a characteristic diffraction image corresponding to the constituent chemical species. Preferably
Indicates that the amorphous microregions have a diameter of less than about 0.1 μm, and more preferably about 0 μm.
. It has a diameter of 002-0.05μ.   "X-ray opaque" metal oxide, when it is present in the microparticles of the invention
Effectively make dental composites made with the microparticles radiopaque
Is an inorganic oxide that suppresses X-ray transmission through microparticles to a sufficient extent. "
"Polycrystalline" metal oxides have a unit cell structure that is reduced by X-ray or electron diffraction analysis.
Sufficient to be recognized or identified by testing the
It has the same number of crystalline microregions. In general, crystalline microregions are the entire volume of microparticles.
About 1/2% by volume (preferably 5% by volume or more) of the amount. Actual capacity% is
It depends on the type and amount of metal oxide used. Preferably, crystalline micro domains
The region has a diameter of less than about 0.05μ when measured using X-ray or electron diffraction analysis.
And more preferably has a diameter of about 0.001 to 0.01μ.   "Ceramic" metal oxides are fired in their pure form to produce a standard air environment.
Rigid or self-supporting polycrystalline, eg stable at 23 ° C. and 50% relative humidity
An inorganic oxide that can take the form. A suitable ceramic metal oxide is Miku
Non-toxic when incorporated into microparticles and is colorless or weakly colored
Only: for example, BaO, Bi_TwoO_Three, CaO, Nb_TwoO_Five, Sb_TwoO_Five,
SnO_Two, Ta_TwoO_Five, TiO_Two, Y_TwoO_Three, ZnO, ZrO_Two, And lanthanides
Oxides (eg, CeO_Two, Ce_TwoO_ThreeAnd La_TwoO_Three), As well as mixtures or mixed oxides thereof. Good
The preferred ceramic metal oxide is HfO_Two, La_TwoO_Three, SrO, ZrO_TwoAnd it
And the like, ZrO_TwoIs most preferred. Characteristically, X in microparticles
Substantially all (for example, 90% by weight or more) of the line-opaque ceramic metal oxide is
Exists in its polycrystalline form, and is substantially free of amorphous form (eg, 1
Less than 0% by weight).   Preferred method for producing microparticles of the present invention (here "sol-gel")
The method is referred to as (1) an aqueous or organic dispersion or sol of amorphous silica and (
2) The desired X-ray opaque ceramic metal oxide or the desired X-ray opaque ceramic
Aqueous or organic organic or inorganic precursor compounds that can be calcined to
In combination with a dispersion, sol, or solution of Simply put,
The dispersion or sol of Rica is hereinafter sometimes also referred to as “silica starting material”; and
The dispersion, sol or the above-mentioned ceramic metal oxide or precursor compound for X-ray opacity
The solution is sometimes referred to hereinafter as the "ceramic metal oxide starting material." Silica starting material
The mixture of the raw material and the ceramic metal oxide starting material is dried to a solid, ground and calcined.
And re-ground to microparticles of the invention. Then apply the microparticles
The composite material of the present invention can be combined with a cutting resin.   Although aqueous or organic silica starting materials can be used in the sol-gel process,
Also, aqueous silica starting materials are preferred for economic reasons. Suitable aqueous silica starting materials
Preferably comprises about 1 to 50% by weight of colloidal silica, more preferably 15 to 35% by weight.
It is contained at a concentration of%. Suitable organosilica starting materials are ethanol, normal
Or isopropyl alcohol, ethylene glycol, dimethylformamide or
And organic solvents such as various "cellosolve" glycol ethers, preferably water
Organosol containing colloidal dispersion of silica in miscible polar organic solvent)
is there. The size of the colloidal silica particles of the silica starting material can vary, for example
0.001 to 0.1 μ, preferably about 0.002 to 0.05 μ.   Preferred silica starting materials that can be used in the present invention are E.I. I. Du Pont de Nemours Aquasol sold by the company under the trademark "Ludox". Other
Useful silica starting materials are trade names "Narco", "Siton" and "Niacol"
They are commercially available dispersions or aquasols. Yet another suitable commercially available silicon
The starting materials are described in the aforementioned U.S. Pat. Nos. 3,709,706 and 3,793,041.
No.   Preferably, the silica starting material removes unusual solids, bacterial growth and other impurities.
To be filtered. More preferably, the silica starting material will be described in detail later.
It is filtered by a fine filter. If desired, silica can be other mineralized
Compounds such as amorphous microparticles under the conditions used to produce the microparticles of the invention
Those compounds that can generate regions (eg, B_TwoO_Three) By adding
it can. The addition of such inorganic compounds may change the refractive index of the final microparticle
, And may affect the visual opacity of dental composites made with it
Note that this is not the case.   The sol-gel process uses either aqueous or organic ceramic metal oxide starting materials.
Although available, aquasols are preferred for economic reasons. Suitable commercial ceramics
Metal oxide aquasol is CeO_Two, Sb_TwoO_Five, SnO_Two, And ZrO_TwoAku
Sol, etc. Commercial ZrO_TwoAquasol is generally small (for example, 1-3% by weight).
HfO)_TwoAs foreign matter. Suitable calcinable precursor compounds are preferred
Or carboxylate (eg, acetate, formate, oxalate,
Tate, propylate, citrate, or acetylacetonate) or inorganic
It is a salt of an acid (for example, nitrate).
It depends on ease of handling. Precipitate or undesired crystalline microregions before gelation
Generate water-soluble or acid-soluble compounds or colored impurities in the microparticles.
The use of the resulting precursor compounds should preferably be avoided. Effective cost for the present invention
Typical precursor compounds are barium acetate, lanthanum nitrate, strontium nitrate, nitric acid
Tantalum and zirconium acetate.   Other metal oxides that do not themselves provide sufficient radiopacity would be desirable
For example, it may be included in the microparticle of the present invention. Such other metal oxides are, for example,
Various physical properties of the particles (eg, refractive index, hardness, density or porosity) Degree) or the physical properties of dental composites produced using it (eg,
The viscosity, or the compressive strength, tensile strength or visual opacity after curing)
It is effective for. Such other metal oxide is Al_TwoO_ThreeAnd CaO. Up
When using the sol-gel method, such other metal oxides may be replaced by other desired metal oxides.
Dispersion or sol containing (or itself containing a calcinable precursor compound)
Suitable dispersions or sols) starting from silica starting materials and ceramic metal oxides
It can be incorporated into the final microparticle by combination with the material. Hope
If such other metal oxide is silica coated with such other metal oxide
Silica sol containing particles (eg, “Nalco” 612 or 613 alumina
It is also possible to introduce by using
.   In a most preferred embodiment, the sol-gel method is performed as follows. Ma
Aquasol containing colloidal silica is the desired ceramic metal oxide for X-ray opacity.
Object (eg, ZrO_Two) Or a calcinable precursor compound (eg, zirconium acetate)
) Is mixed with a rapidly stirred sol or solution containing For some starting materials
If the order of addition is reversed, the amorphous micro-regions and crystalline micro-
This may result in non-uniform scatter of the area. The mixture does not cause uneven gelling
It should preferably be sufficiently acidic. For example, the pH is silica: silyl acetate
Preferably less than about 4.5 for the conium mixture. Then the mixture
For example, by increasing the pH, by dehydration (eg, a “rotovap”
Gel) by heating the mixture to a temperature below its boiling point
Be transformed into For example, dehydration by heating to less than about 75 ° C. can be accomplished by silica: silyl acetate
Can be used for conium mixtures.   Gels may include a significant portion of the water or other solvent present in the starting material.
No. The gel should be at a temperature and pressure sufficient to remove water or solvent without boiling the gel.
By heating, for example, by heating at 75 ° C. and ambient pressure for 20 to 24 hours.
The result is a dried or substantially dried solid. Drying is preferably in a shallow dish
Done in The dried solid breaks down into small granules. Small granules are preferably
Finely ground to facilitate removal of organic compounds. And then the granules At a temperature and pressure sufficient to remove substantially all such organic compounds, e.g.,
200-600 ° C., preferably 300-600 ° C. for 2-4 hours in air at atmospheric pressure
Heated. Measure the degree of organic compound removal using differential thermal analysis or mass spectrometry.
Wear. The resulting powder is very brittle and can be further pulverized.   Next, the powder is a polycrystalline ceramic metal oxide or a ceramic metal oxide or precursor.
Calcined at a temperature and for a time sufficient to convert to a chloride. Silicon oxide to its amorphous
Growth of crystalline microregions having a diameter greater than about 0.4μ, or
Increase the density of microparticles to prevent formation and reduce voiding
The firing time and temperature should not be excessive.
You. During the firing cycle, the microparticles have a reduced density surface area, pore volume and pore size.
Undergo significant changes. Density tends to increase during firing, surface area and pore volume
Tends to decrease. For example, a 5.5: 1 molar ratio of SiO_Two: ZrO_TwoWith microparticles
After firing to about 1000 ° C., the density reaches about 2.50 g / cc. Surface area is 40
It reaches a maximum after firing at 0 ° C. (about 175 to 200 m when measured by the BTT method).^Two/
g), which drop after firing at 950 ° C. (about 50 to 75 m).^Two/ G value), it
After firing to 1000 ° C. (approximately 4-6 m^Two/ G value)
The pore volume is 400-700 ° C. and after firing (measured by the BET method)
Reaches about 40% of the particles and then drops to substantially zero after firing to about 1000 ° C
. SiO_Two: ZrO_TwoFor microparticles, calcination is performed on polycrystalline zirconia (eg,
Tetragonal ZrO_Two) Is produced, but zircon (ZrSiO_Four) Or cristobalite
(SiO_Two) Should be done just enough to avoid the formation of crystalline microregions
. A firing temperature of about 1000-1100 ° C is preferred.   The term "milling in the green state" turns ceramic metal oxides into their polycrystalline form
Is used here to describe the micronization of microparticles before firing
You. Using pulverization in the green state is a dental composite with good cure stability
It has proven to be very useful in obtaining the material. In particular, fine pulverization in the unfired state
This is the case when both sintering and optimization of the firing temperature are used.   SiO_Two: ZrO_TwoCure stability of dental composites made from microparticles Forecasting is based on contacting an aqueous slurry of microparticles with an alizarin indicator.
Thus, it was proved effective to evaluate the pH of the microparticles after firing. finger
SiO to change the indicator to yellow (pH <6)_Two: ZrO_TwoMicroparticles have indicator
SiO that changes from pink to red (pH> 7)_Two: ZrO_TwoBetter than microparticles
Tend to be a dental composite with improved cure stability. In the above unfired state
The pulverization process is a process that changes the alizarin indicator to yellow._Two: ZrO_Twomicro
It has been found to be effective in producing particles.   In addition to the factors mentioned above, higher firing temperatures increase the hardness of microparticles
And tends to reduce water absorption. Also, the higher firing temperature depends on the firing
Dental composites made from microparticles result in faster polymerization set times.   Firing is performed, for example, in a muffle furnace in a glassy silica boat in a shallow layer (eg,
(25 mm depth). And then
To provide microparticles having a desired average particle size, for example, less than 50μ.
Re-crushed. Re-grinding can be carried out using a conventional apparatus, and preferably,
A grinding medium having the same refractive index as the black particles is used.   The relative molar ratio of silicon oxide to ceramic metal oxide in microparticles is the desired refraction
It should be adjusted to give the rate and radiopacity. Most preferred SiO
_Two: ZrO_TwoFor microparticles, SiO_TwoVs. ZrO_TwoIs preferably about 2
/ 1 or more, preferably a value of about 3/1 to 9/1, and a value of about 5/1 to 7.5 / 1.
Is most preferred. Mixtures containing other silica-to-ceramic metal oxide mixtures
For black particles, the ratio of silica to ceramic metal oxide is the desired X-ray opacity.
At the same time, achieving and achieving the desired refractive index of the microparticles and other desired physical properties.
The desired visual opacity, durability and cure stability of dental composites produced from
Should be adjusted to enable the achievement of other desired physical properties.   The relative ratio of silicon oxide to ceramic metal oxide is the
Higher silicon oxide content may also affect the polymerization cure time rate of the composite material.
Generally leads to fast setting times.   A diameter larger than about 0.4μ (the size of which corresponds to the shortest wavelength of visible light)
Crystalline microregions or foreign matter (eg, voids)
It is particularly desirable to avoid that. Such crystalline microregions within microparticles or
The presence of foreign matter is undesirable, as is the view of the dental composites produced therefrom.
Increases perceived opacity. Therefore, the microparticles of the present invention have such crystalline microdomains.
And under conditions that substantially inhibit the formation of local and foreign substances. In short,
Such crystalline microregions and foreign substances are hereinafter sometimes referred to as "visual opacity inclusions".
It is.   Blocking of visual opacity inclusions in fine filters with pore sizes less than 0.4μ
Therefore, the silica starting material and / or the ceramic metal oxide starting material are filtered.
Can be achieved by: Preferred filtration techniques are less than about 0.2-0.25μ
A series of progressively smaller "Balston" filters with a final filter of pore size
Use During sequential processing, the gel generated by the combination of starting materials may differ.
It should be kept free of material. Dried and crushed obtained from the gel
During firing of the solid, the crystalline fines are sufficiently large to produce visual opacity inclusions.
Reactions between various inorganic species within microparticles that promote the growth of small areas or visual impairments
Baking temperature to promote the formation of novel crystalline microdomains containing inclusions for clarification and
Care should be taken to avoid time. Generally, a firing temperature of about 1100 ° C. or more
Promotes the formation of visual opacity inclusions (usually with increased or new crystals
Quality micro-areas or as voids or cracks) and thus avoidance
It should be.   When used in the visible light-curable dental composite material of the present invention, the refractive index of the microparticles is
It should preferably be matched to the refractive index of the composite resin, e.g.
Within the range, more preferably within the range of about ± 0.005. Resin currently used
As such, the microparticles preferably have a refractive index of less than 1.60. micro
A preferred method for adjusting the refractive index of particles is silicon oxide versus ceramic metal oxide
It is by changing the ratio of things. The microparticle refractive index is determined by the sera in the starting mixture.
Mick metal oxide (or ceramic when using a calcinable precursor compound)
Based on the relative volume% of silicon to the equivalent It can be approximately predicted by interpolation. Microparticle refractive index is pure amorphous
Quality SiO_Two(RI 1.459) and polycrystalline morphology of microparticles
Based on the above volume% comparison with the refractive index of the ceramic metal oxide at
It changes linearly.   Solvents that cause microparticles to melt during firing and formation of non-vitreous inclusions
Should be avoided. Also, the starting mixture is preferably substantially
Contains no ion. Chloride ion is for dental use containing calcined microparticles
This can cause the composite to exhibit undesirable discoloration and reduced shelf life.
You.   When observed without magnification or under optical magnification, the microparticles of the invention have a uniform outer appearance.
A fine white or off-white powder with an appearance. Of such microparticles
Microstructure identification is preferably performed by transmission electron microscopy ("TEM").
You. Scanning electron microscopy ("SEM") generally does not reveal microstructure well
. Because in SEM the microparticles have a uniform grayish appearance
is there. However, in TEM the microstructure of the microparticles is very distinct,
And you can easily recognize it.   The drawing is a TEM image of the microparticles of Example 1 at a magnification of 300,000. sample
Mixes microparticles with aluminum powder and mixes the mixture at about 0.7-1.4MPa.
a), and heating the mixture to approximately 600 ° C. to remove the microparticles.
It was produced by embedding in a luminium matrix. Sura
The chair is cut from its matrix by a diamond saw and
It was mechanically polished to a thickness of 0μ. Then, the slice is turned into an electron beam
(By “Gatan” dual ion mill equipment)
It was finely pulverized with a beam. The ion beam pulverization is performed in an argon atmosphere.
Then both sides of the slice were pulverized simultaneously. Slices are constant during milling
, The gun voltage varies from 7KV to 4KV, and the gun angle varies from 15 degrees to 8
Fluctuated to degrees. The milled slice is operated at an accelerating voltage of 100 KV.
EOL model "100OX" photographed by transmission electron microscope.   Boundary 11 represents the outer edge of the microparticle. The amorphous amorphous microregion 13 is made of amorphous S
iO_TwoAnd is generally given a uniform shape. Extremely small amorphous regions
The slightly mottled appearance is the original colloidal silica making the sample
Inside the aquasol particles can be seen by TEM, but it is not
Crystalline ZrO_TwoSome enhancement due to transmission through small areas (not shown)
May have been. Smaller crystalline microregions 15 are smaller than microregions 13.
Black (gray) in color and tetragonal ZrO_TwoIt contains. Amorphous
The minute regions 13 are substantially uniformly dispersed by the crystalline minute regions 15. Mi
The chromium particles appear dense enough and do not show visual opacifying inclusions. then
High compressive strength of manufactured dental composites is partially due to multiple grain boundaries in microparticles
I do. Such a grain boundary is located between the adjacent amorphous and crystalline micro regions and
Between the adjacent crystalline microregions and reduces the growth of cracks through microparticles
To help or prevent.   Generally, the dental composite material of the present invention is a chemical polymerization initiation system such as a peroxide compound alone.
Or to produce suitable amines, sulfur compounds, phosphorus compounds or free radical species
Contains peroxide compounds in combination with other compounds capable of reacting with peroxide
You. Alternatively, the dental composite of the present invention may comprise a light-induced polymerization initiation system such as a ketone or
α-diketone compound alone or an appropriate amine, peroxide, sulfur compound, phosphorus compound
Ketone or α-diketone for the polymerization of dental or dental composite materials
Pair with other compounds that can react with or be sensitized by the compound
It may contain combined ketones or α-diketones. In addition, the present invention
The dental composite of the invention has suitable auxiliaries such as accelerators, inhibitors, stabilizers, pigments, dyes,
Viscosity modifiers, bulking or reinforcing fillers, surface tension depressants, wetting aids, antioxidants,
And may contain other components well known to those skilled in the art.   The amount and type of each component of the dental composite is desirable for the composite before and after curing
It should be adjusted to provide physical properties and handleability. For example, composite materials
The cure speed, cure stability, flowability, compressive strength, tensile strength and durability of
Vary the type and amount of initiator and the loading and size distribution of the microparticles Is adjusted by Such adjustments are generally made by conventional dental composites.
Performed empirically based on experiments. To use as a casting resin, a dental composite
The composite generally contains at least 45% by weight of microparticles. Other uses (eg before
Tooth or molar dentures, cavity application, orthodontic bracket adhesive, crown and bridge
Denture cements and artificial crowns) generally require higher levels of microparticle loading.
Can be. For maximum compressive strength (eg, for molars), dental composites
It is preferably “resin-bound ceramic” or “RBO”. RBO composite
In the preparation, the volume of the resin is
Should be less than the void volume found in the sample of particles. RB
O-composites inherently contain small amounts of air or other gases. RBO composite material
Generally contains at least 70% by volume of microparticles and up to 30% by volume of resin
. The RBO composite is sufficiently resinous to replace all voids in the composite
Stronger than composite material filled with (herein referred to as "resin foam composite material")
. Because, in resin foam composites, the microparticles are not
This is because there is a tendency.   In a preferred embodiment, the dental composite of the present invention comprises submicron silica particles
For example, “Aerosil”, “OX50”, “130”, sold by Degussa,
“150” and “200” silica, and “Oa” sold by Cabot
It contains pyrogenic silica, such as "b-O-Sil M5" silica. "Aeroji
OX50 "is a preferred submicron silica. Submicron silica particles
Preferably, silane treatment is performed to improve the wettability by the resin.   Dental composite containing submicron silica particles and microparticles of the invention in specific amounts
The material has particularly good handling properties in the uncured state and unexpectedly high pressure in the cured state.
It has a compressive strength and a diametral tensile strength. Submicron silica particles, microparticles and resin
The following amounts are preferred: Optimization of compressive strength and diametral tensile strength in such products depends on the amount of filler in the composite.
And surface area. The following calculation is valid. This meter
By calculation, the surface area of submicron silica particles and microparticles
Measured before and the specified weight fraction is the weight measured after the silane treatment.
Based on The term "total weight" refers to silane-treated submicron silica in composites
It means the total weight of the particles and the silane-treated microparticles. In the first stage, submit
The weight fraction of submicron silica particles in the total filler is
Multiply. In the second stage, the surface area of the microparticles is determined by the weight fraction of the microparticles in the total filler.
Multiply. Then, the product of the first stage and the product of the second stage are added together,
Times the total filler weight fraction. The result (here the "net surface area" of the composite
), Compressive strength and diametral tensile strength independent of the total filler loading
Can be used to optimize For example, "Aerosil OX50" submicro
Silica particles and SiO ZrO_TwoCompression on composites containing microparticles
Strength is about 5m net surface area^Two/ G from about 390MPa to about 7m net surface area^Two
/ G or more up to a peak value of about 440-480 MPa;
The diametral tensile strength initially increases and then decreases when the net surface area increases, i.e.,
Net surface area about 5-22m^Two/ G at about 75 MPa or more and a net surface area of about 7 to
15m^Two/ G at about 90 MPa.   The dental composite material of the present invention can be prepared by means well known to those skilled in the art, for example, Multi-component or single-component systems contained in tubes, amalgam capsules, syringes, etc.
Packaged and distributed with packages.   The microparticles of the invention are intended for non-dental uses as well as for use in dental composites
Can also be used for plastic composites. Resins suitable for use in such composite materials are
The resins listed above, as well as thermosetting or thermoplastic resins such as polyester resins,
Acetyl resin, amino resin (for example, urea-formaldehyde and melamine pho
Lumaldehyde resin), alkyd resin, cellulose resin (eg, ethyl cellulose)
Cellulose, cellulose acetate, and cellulose propionate resins), fluorocarbon
Resin, furan resin, polyurethane resin, phenol resin, polyamide resin,
Licarbamate resin, vinyl aromatic resin (for example, styrene), polyolefin resin
Fat (eg, polyethylene).   The plastic composite material of the present invention may contain other auxiliaries such as polymerization initiators, accelerators,
Stoppers, stabilizers, pigments, dyes, viscosity modifiers, bulking or reinforcing fillers, surface tension reduction
Contains agents, wetting aids, antioxidants, and other ingredients well known to those skilled in the art.
It is also possible.   Also, the microparticles of the present invention may be a metal matrix composite or ceramic composite.
US Pat. No. 3,709,706 and US Pat.
Wear for elastomeric materials of the type described in U.S. Pat.
It can also be used as a wear and / or reinforcement agent.   The following examples are provided to aid the understanding of the present invention, and
It is not intended to limit the range ofExample 1   31% by weight colloidal silica aquasol (from EI du Pont de Nemours)
1065.6 g of commercially available "Lutox LS" is 1: 1 with deionized water.
Acidified by addition of 11 g of diluted concentrated nitric acid and placed in series
And filtered through a fine filter. The first fine filter has a pore size of 2μ
And a second fine filter is a "Balston grade B" filter.
It was a "Balston grade AA" filter with a pore size of 25μ. Aqueous gill acetate
Conil (25% by weight equivalent ZrO_Two492.8 g) Diluted and filtered. Place the aqueous zirconyl acetate in a glass beaker,
Stir with a nylon blade mounted on a rod, and use an air stirrer motor
Therefore, it was circulated. Colloids are introduced into the vortex created in the stirred aqueous zirconyl acetate.
Slowly pour Liqua aquasol and equivalence SiO: ZrO_TwoHas a molar ratio of 5.5: 1
To make a mixture. The resulting mixture is stirred for 15 minutes and then
Lath was poured into a rectangular cake dish to a depth of about 25 mm. Place the dish in a forced air oven at 75 ° C
For 24 hours and then removed and inspected. Bluish white appearance at the bottom of the plate
A shabby granular powder had been produced. Place the dish in a forced air oven at 280 ° C
For 24 hours, then removed and allowed to cool to room temperature. Weakly agglomerated powder with white appearance
Remove from the dish and wrap a ceramic rod medium 12mm in diameter x 12mm in length.
Ball milling was carried out in a ceramic mill jar for a total mill time of 60 minutes.
The crush distribution obtained after 60 minutes, as revealed by sequential measurements, was only
It was already achieved with a mill time of 45 minutes. This finely pulverized powder is
Into a depth of about 19 mm in a porous silica pod and 40 in a muffle furnace.
Heat at 0 ° C. for 16 hours. Then, the temperature of the muffle furnace is set to 100 every 0.5 hour.
° C. After half an hour at 900 ° C, raise the temperature of the muffle furnace to 950 ° C over 1 hour.
And raised to 1000 ° C. over 3 hours. Remove the pods from the muffle furnace and
It was allowed to cool in the air. The calcined powder obtained was weakly agglomerated and showed a white appearance. It
Was ground in the above ceramic ball mill for 15 minutes. As the sequential measurements show
The milling distribution obtained after 15 minutes can be achieved with a milling time of 5 to 10 minutes
Was. The milled microparticles had a maximum diameter of 30μ and an average diameter of 4.5μ.
About 16% by weight of the microparticles had a diameter of less than 1μ. Weight loss measurement in mill
This indicates that attrition of the liner or milling media has not occurred, and
This indicates that the black particles cannot be easily crushed by low energy.   Slurrying 100g of microparticles with 200ml of cyclohexane for 30 minutes
To silane the microparticles. γ-methacryloxypropyl trimethoxy
5 g of silane (commercially available from Union Carbide) and n-propylamido
A mixture with 2 g of the solvent was added to the slurry. Mixing was continued for one hour. Or that The slurry in a fume hood overnight, and then further in a forced air oven at 41 ° C.
For 1 hour and 105 ° C. for 2 hours.   Visible light-curable dental composites with particularly effective performance as molar dentures are as follows:
Prepared from silanized microparticles by thoroughly mixing such components:     Component Amount (% by weight)     BIS-GMA 9.5     Triethylene glycol dimethyl methacrylate 9.5     Silane-treated microparticles 80.0     Canholoquinone 0.5     Dimethylaminophenetanol 0.5                                                                                                                      100.0   The resulting composite sample was 4.06 m covered with silicone plugs at both ends.
mI. D. Placed in a glass tube. The tube is pressurized to 0.28 MPa with air.
Was placed in a test ring. The test ring aims at the opposite surface of the tube.
The two ESPE "Elipper" dental curing beams included and included
On a turntable that allows the light to be turned 180 ° around the tube
Was mounted. The light guide for each curing beam was 3 mm away from the tube wall. Both
Operate the two curing beams simultaneously and vibrate them continuously around the tube
While the tube was exposed four times to a 20 second cure cycle from the curing light. Test tube
Removed from the ring, placed on a pair of isolation rollers, and placed in a 110 watt "liter
ー ”A part 0.6 m away from the dental operation light beam was rotated for one hour. Cured sump
Remove the tube from the tube and slice it into a cylinder with a diamond saw
Was. For the compressive strength test, a cylinder having a length of 8.23 mm was used, and the diameter was reduced.
In the tensile strength test, a cylinder having a length of 2.21 mm was used. 37 ° C cylinder
Store in distilled water for 24 hours and then ADA Specification No. According to 8 and 27
Tested. Compressive strength of composite cured samples 394MPa (4016Kg / cm^Two) And the diametral tensile strength is 80
MPa (816 kg / cm^Two).   A 1 mm thick x 20 mm diameter sample of a composite material desk is designed to cover each side of the desk.
Expose for 60 seconds at a distance of 6 mm to irradiation from an Espe "Elipper" dental curing light
Was cured by Then view the cured composite sample as follows:
The visual opacity and the X-ray opacity were evaluated.   The cured composite sample is a Macbeth densitometer model equipped with a visible light filter.
By measuring the light transmission through the desk thickness by Dell TD-504
It was measured for direct light transmission. The resulting densitometer value of 0.30 is duplicated.
Assigned as visual opacity value of composite sample. In visual inspection, cured composite
The material sample has greater translucency than a tooth tissue of comparable thickness, and a natural dentition
It could be easily colored to suit.   Cured composite material sample using Siemens "Heliodent" dental X-ray unit
Exposure to X-ray for 0.25 seconds at 7mA, 50KV peak voltage, distance about 250mm
Was done. X-ray negative is Lytton "Profex Ray" automatic film processor
Developed using 1.25 to 1.30 fill using Macbeth transmission densitometer
And the value is divided as the radiopacity value of the composite sample.
Was hit. When packed in teeth and tested by X-ray, the composite material is
It could be easily distinguished from the weave.   Additional samples of the composite material are illuminated by Espeer “Elipper” dental curing light
By exposing for 20 seconds at a distance of 0 mm, a 6 mm diameter x 2.5 mm deep
It was cured into an undermold. Barcos on the top and bottom of the sample thus cured
The indenter No. 934-1 (commercially available from Barber Colman)
Were used to obtain an average upper surface hardness value and an average lower surface hardness value of 81 and 80, respectively.   A filter having a pore size larger than 0.4μ (for example, a filter having a pore size of 2μ)
The above example was repeated with the starting material filtered or unfiltered in)
However, a dental composite material having a visual opacity of about 0.40 to 0.41 has been obtained.
did. Hardened composite samples are more opaque than comparable thicknesses of tooth tissue Had a view. The addition of pigments that match the color of the teeth generally increases visual opacity.
About 0.01-0.02 units higher and comparable thickness to the resulting composite
Would be much more opaque than tooth tissue. Barcol top and bottom hardness
The degree values are on average 80 and 75, respectively, which indicates that the degree of cure of such composites is higher.
Represents less than that obtained using the filtered sol dental composite
.Examples 2 to 14   Using the method of Example 1, various microparticles were produced from the unfiltered sol and 2
Incorporated in a chemically hardened dental composite material and has visual opacity and X-ray opacity
Was evaluated for excess. This dental composite contains 70-76% by weight microparticles.
As such, the observed visual opacity values are often obtained in Example 1.
X-ray opacity values lower than the observed value of 0.30 and observed are numerically
The value obtained was higher than 1.25 to 1.30 (i.e. lower radiopaque).
). Table 1 contains the number of the example, the ceramic metal oxide used, silica
Refractive index of ceramic metal oxide microparticles, refractive index of microparticles and resin
Manufactured from microparticles fired at 900 ° C, 950 ° C or 1000 ° C
Opacity and cure time of cured composites and microfiring at 1000 ° C
X-ray opacity of a dental composite made from the particles is described.   Repeating these examples using the filtered sol would give comparable or equal values.
Microparticle refractive index, difference between microparticle and resin refractive index, and curing time and X-ray
An opacity would have resulted. Visual opacity would have been lower. Examples 15 to 41   Using the method of Example 1, various microparticles were produced from the filtered sol and 2
Formulated into paste-based chemically cured dental composites, and has visual opacity and X-ray
The transmission was evaluated. This dental composite material is 40-80% by weight of microparticles
And Silane Treatment "Aerosil OX50" Pyrolysis Submicron Silica Particles 0-40
% By weight. Table 2 shows the numbers of the examples and the ceramic metal acids used.
, The molar ratio of silica to ceramic metal oxide, and the resulting composite
% By weight of particles, sub-micron silica particles by weight, visual opacity, compressive strength,
The values of diametral tensile strength, X-ray opacity, and Barcol hardness of the top and bottom surfaces are described.
ing. Example 42 Casting resin   Various amounts of the microparticles of Example 1 were pyrolyzed with silane treatment "Aerosil OX50"
Total filler in combination with various amounts of silica particles and a sufficient amount of the resin of Example 1
80% by weight (based on the combined weight of the filler after silanization) and the resin 20
A composite material containing% by weight was produced. 5m for microparticles^Two/ G surface area (sila
Before treatment), and the pyrogenic silica particles^Two/ G surface area (silane
After treatment). Table 3 shows the compressive strength of the obtained composite material,
Submicron silica particles and microparticles with diameter tensile strength and visual opacity
And% by volume and% by weight of the resin.   Composites containing 4 to 40% by weight of submicron silica usually have low viscosity.
This was a pourable syrup in which the surface of bubbles showing the following rise occurred. Only a few
Commercial dental composites contain more than 80% by weight of fillers,
It is a paste that can be barely stirred.Example 43 High strength molar composite material   Various amounts of microparticles and submicron silica particles combined with the resin of Example 42
Up to 90% by weight (based on the combined weight of the filler after silane treatment)
An RBC composite containing the filler was produced. Table 4 shows the composite materials obtained.
Along with its compressive strength, diametral tensile strength and visual opacity.
The volume percentages and weight percentages of Rica particles, microparticles, total filler and resin are listed
. Composite materials containing 90% by weight of filler [(41m^Two/G)(0.18/0.9)+(5m^Two/ G) (0.72 / 0.9)
] (0.9) = 11.2m^Two/ G Had a net surface area of   These composites exhibited outstanding strength values and excellent handling properties. 90 fillers
The composites containing% by weight are available for further clinical research in Bost, Massachusetts.
Sent to the Holcis Dental CenterMucacca Fasicularis Monkey Large
Piled on the molars. After 6 months, the composite showed no visually detectable wear.
The composite had a very desirable consistency in its uncured state. It is ready
Can be packed without excessive sticking and rebound into a damaged tooth, directing its clinical research
In the opinion of a consulting physician, he was more likely than any plastic composite material he had ever encountered.
At last like amalgam. " Dentists use amalgam for molars
Amalgam-like consistency is particularly desirable due to extensive training and experience in teething.
No.   Various modifications will be apparent to those skilled in the art without departing from the scope of the invention. The present invention
Is not unnecessarily limited to the exemplary embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows 300, SiO ₂ : ZrO ₂ microparticles (produced in Example 1).
It is a transmission electron microscope photograph of 000 times.

Claims (1)

Claims: A radiopaque dental composite material comprising a mixture of (1) (a) a polymerizable resin suitable for use in the oral cavity, and (b) non-vitreous microparticles. The non-vitreous microparticles comprise: (i) a plurality of amorphous fine regions made of silicon oxide; and (ii) a plurality of crystalline fine regions made of X-ray opaque polycrystalline ceramic metal oxide. Wherein the amorphous microregions are substantially uniformly interspersed by the crystalline microregions, and wherein the microparticles comprise crystalline microregions or voids having a diameter greater than 0.4 μm. A radiopaque dental composite material characterized by the absence of a radiopaque material. (2) A patent in which a dental composite material has an X-ray opacity of 1.4 or less and a visual opacity of less than 0.4 when the dental composite material is manufactured with a blending of 80% by weight of microparticles. The dental composite material according to claim 1. (3) further includes a submicron silica particles, a dental composite material according to paragraph 1 the claims total filler dental composite material has a net surface area of 5-22m ² / g. (4) Claim 1 wherein the non-vitreous microparticles have a diameter of less than 50 µm.
14. The dental composite material according to the above item. (5) a ceramic metal oxide dental composite material according to item 4 claims selected from the group consisting of _{HfO 2, La 2 O 3,} SrO, ZrO 2 and mixtures thereof. (6) The silicon oxide comprises silica, the ceramic metal oxide comprises tetragonal zirconia, the microparticles have a refractive index of less than 1.60, and the molar ratio of silica: tetragonal zirconia is 2: 1-9 The dental composite material according to claim 4, wherein the ratio is 1: 1. (7) (a) a plurality of amorphous fine regions made of silicon oxide, and (b) a plurality of crystalline fine regions made of X-ray opaque polycrystalline ceramic metal oxide. The method for producing a radiopaque dental composite material comprising microparticles substantially uniformly interspersed by the crystalline microregions, the method comprising: (B) filtering an aqueous or organic dispersion or sol of (a) with a fine filter having a pore size of less than 0.4 μm; Filtering the aqueous or organic dispersion, sol or solution of the inorganic compound precursor through a fine filter having a pore size of less than 0.4 μm, and (c) gelling the filtrates of (a) and (b) together; d) Gelled material The material is heated without boiling at a temperature and pressure sufficient to remove water or solvent to obtain an unfired powder, and (e) the unfired powder to reduce particle size. Pulverizing the powder; and (f) converting the ceramic metal oxide or the ceramic metal oxide precursor into a polycrystalline ceramic metal oxide while preventing the pulverized powder from growing or forming a crystalline microregion having a diameter of 0.4 μm or more. (G) milling the resulting fired powder to form microparticles; (h) silane treating the microparticles to improve wettability; and (i) Mixing the treated silane-treated microparticles with a polymerizable resin suitable for use in the oral cavity to form a dental composite. Made Construction method.