JPH025723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates generally to photopolymerizable compositions (or materials), and more particularly to dental photopolymerizable compositions.

Photopolymerizable compositions known for dental use generally include a mixture of an acrylic ester of a thermoset bisphenol compound, an acrylic monomer diluent, and a photopolymerizable initiator and accelerator. Compositions of this type are generally two-component systems. U.S. Pat. No. 3,709,866 discloses such a two-component system in which one component containing the initiator is separated from the rest of the composition and the dentist combines the two components in fixed proportions immediately before use. Mix. This method is necessary to maintain a certain shelf life of these dental materials. Homogeneity of the mixture is almost impossible when mixing a drop of initiator with a nearly solid composition. Failure to create a uniform mixture will result in irregularities in the tooth restoration. U.S. Patent No. 3 by Osborn and Trecker,
No. 759,807 uses a combination of an organic carbonyl compound and an amine, more specifically a benzophenone and a tertiary amine as an initiator and promoter, respectively. Although these compositions are polymerizable, they have a slow curing rate and cannot be used as filling materials for dental cavities. U.S. Pat. No. 3,539,533 to Lee and Swartz et al. discloses a dental composition system containing a diglycidyl ester derivative of bisphenol A, an acrylic binder, and a filler using benzoyl peroxide or other suitable catalyst. It has been described that crosslinking occurs with However, the compressive strength of the composition is only 1830
Kg/cm ² (26000psi). Furthermore, currently commercially available dental composite materials are characterized by two-phase systems: paste-paste, paste-liquid, liquid-liquid or powder-liquid. The properties of these final products depend on how well and quickly the mixing is done. During mixing of the two phases, air enters the compound and acts as a polymerization inhibitor, causing mechanical defects in the restorative material and slowing down the curing rate. Furthermore, non-uniform mixing degrades the properties of the filler. These drawbacks are completely eliminated by the invention.

Accordingly, it is an object of the present invention to provide a uniform, one-paste dental filling material that does not require mixing or activation by the dentist before use and has a long shelf life.

It is also an object of the present invention to provide a dental restorative material with high compressive strength.

Furthermore, it is an object of the present invention to provide new initiators and promoters for photopolymerizing acrylic esters.

Furthermore, it is an object of the present invention to provide a dental material with a fast hardening rate.

It is also an object of the invention to provide a material system with a large depth of cure, especially in the case of highly filled and highly pigmented dental materials.

It is also an object of the present invention to provide an X-ray opaque dental material that is cured by irradiation with actinic radiation.

Furthermore, it is an object of the present invention to provide a single component dental composition for use as a pit and fissure sealant, bonding agent, cavity liner and restorative enamel.

The above objects and other objects are achieved according to the invention by glycidyl ether derivatives of bisphenol A,
This is accomplished by providing a composition containing an acrylic diluent, a filler or mixed fillers, and a mixture of an alpha-diketone initiator and a tertiary amine promoter.

The advantages of this method will become apparent upon consideration of the following description. Photopolymerizable compositions have recently become increasingly used as restorative materials for filling dental cavities. The composition generally comprises a monomeric resin, a filler or mixed filler containing unsaturated sites capable of polymerization, which upon irradiation with actinic radiation generates free radicals and reacts with the double bonds of the monomers. It consists of an initiator that initiates the polymerization, and an accelerator that increases the photoreaction rate of the composition. The resin used to prepare this single paste is
Derived from the reaction of diglycidyl ether of bisphenol A with methacrylic acid or acrylic acid: This glycidyl methacrylate derivative of bisphenol A is known as bisphenol A-bis(3 methacrylate-2-hydroxypropyl) ether. This resin acts as a binder for the photopolymerizable dental composition (hereinafter this resin will be referred to as bis-GMA). Modified versions of this resin can also be used.

The diluent monomer is selected from alkyl methacrylates, alkylene dimethacrylates, trimethacrylates, alkyl acrylates, alkylene diacrylates, and triacrylates. Examples of suitable monomers are: Methyl methacrylate Ethyl methacrylate Butyl methacrylate n-propyl methacrylate Isopropyl methacrylate 1,3-butylene dimethacrylate Ethylene glycol monomethacrylate Ethylene glycol dimethacrylate Triethylene glycol dimethacrylate 1,6-hexane glycol Diacrylate Tetraethylene glycol diacrylate Tetramethylene glycol dimethacrylate,
etc.

One or more of these monomers can be used. The diluent monomer is converted into bis-GMA by irradiation with actinic radiation in the presence of a photoinitiator and accelerator.
Copolymerize with. Accelerators increase the rate of this reaction.

Another component present in the composition of the invention is
A polymerization inhibitor that prevents premature polymerization of bis-GMA resin and diluent monomers, and is present in very small amounts. Suitable polymerization inhibitors include hydroquinone (HQ), methyl ether of hydroquinone (MEHQ), butylated hydroxytoluene (BHT), and triphenylstyrene.

Photoinitiators are generally photosensitive carbonyl compositions. The initiators used in the present invention are α-diketones and their derivatives having the following general formula: R-COCO-R' where R and R' are the same or different and represent aliphatic or aromatic groups and their derivatives. It is a derivative. A few examples of them are given below: CH ₃ COCOCH ₃ Biacetyl CH ₃ COCOCH ₂ CH ₃ 2,3-pentanedione C ₆ H ₅ COCOC ₆ H ₅ Benzyl CH ₃ OC ₆ H ₄ COCOC ₆ CH ₃ 4 , 4'-dimethoxybenzyl (C ₆ H ₆ COCOC ₆ H ₅ ) ₂ O 4,4'-oxydibenzyl These photoinitiators are slightly yellowish. Since these are present in small amounts, the final polymerized product is almost colorless.

Photopromoters are compounds that promote photoreactions in the presence of an initiator. The promoters are amines (primary, secondary and tertiary amines) and diamines, such as dimethylpara-toluidiine, N,N'-dimethylbenzylamine, N-methyldibutylamine, triethylamine, trihexylamine. , etc. Examples of diamines include N, N, N',
N'-tetraethyl ethylenediamine, N,N,
Examples include N',N'-tetramethyl/1,6-hexanediamine.

In the absence of the aforementioned photoinitiators, these amines do not act to induce photopolymerization. Although all of the above amines along with the aforementioned photoinitiators accelerate the reaction to some extent, tertiary amines (e.g., triethylamine, trihexylamine, etc.) have been found to be optimal in terms of polymerizing deep into the composition. . Amines having aromatic groups are not preferred because they become slightly colored when exposed to light for a long time.

Combinations of benzophenones and amines, which are well known in the prior art, when applied to bis-GMA systems either do not result in polymerization or have slow cure rates. We have found that by using a unique combination of α-diketone as a photoinitiator and an amine as a polymerization accelerator and using actinic radiation as an activator, a filler material with high compressive strength can be obtained.

Photopolymerizable dental restorations can have up to 85% refractory filling material. At least 25% of the filler is barium aluminum silicate (100% can also be used). This filler provides sufficient actinic opacity to the repaired material if a minimum of 6.5% barium oxide is present in the composition.
Other filling materials include lithium, aluminum,
There are silicates. The particle size distribution of these fillers is
It ranges from less than 5μ to about 40μ. These fillers are silanized to increase the bond between the inorganic filler and the organic matrix material. This silane binder is
It has the general formulas RSiX ₃ , R ₂ SiX ₂ , and R ₃ SiX. where X is halogen, alkoxy or hydroxy group and R is vinyl, methacrylate, allyl, methacrylic itaconate, maleate,
Acrylate, itaconate, maleate acrylate aconitrate, fumarate, alkyl, aryl, alkenyl actonate, cinnamate and citraconate, sorbate, or glycidyl groups. Once silanization is complete,
A monomolecular coating of binder forms on the surface of the filler, which improves the adhesion between the filler and the resin matrix. Many other fillers such as quartz and alumina can also be used.

The tooth restorative material of the present invention is polymerized by exposure to an energy source that activates a photoreaction. The active radiation source in the present invention is an ultraviolet examination lamp (trade name: Spectroline B-100) manufactured by Spectronics, Inc. of the United States. This Spectroline B-100 is a 100 watt high pressure mercury vapor lamp that irradiates (or emits) between 3200 Å and 4200 Å.
Has wavelength capability. The spot bulb used in this lamp is cooled by a fan.
Place the material about 10cm away from the lamp and heat it with the lamp for 20 to 20 minutes.
The average weight of the fully polymerized filling material after irradiation for 30 seconds is about 0.2-0.3 g. Under these conditions the material is polymerized to a depth of about 2 mm.

Experiments in the Examples were conducted with various formulation components in the ranges shown below: Parts by weight Resin (including inhibitor) 10-25 Diluting monomer (including inhibitor) 2-5 α-diketone or its derivative 0.001-1 Amine 0.01-1 Filler 70-85 The composition was made as follows: The resin was mixed with the diluent monomer, photoinitiator and accelerator, and it was mixed with a Teflon rod in a glass container. Mix thoroughly. When the mixture is fairly homogeneous, add the barium aluminum silicate and mix well. Finally, add the remaining filler to 3 to 4
Add in batches, mix well, and store for one week until testing. The well-mixed sticky paste is packed into a cylindrical polytetrafluoroethylene split mold (12.5 mm high x 6 mm diameter, open at both ends). Cover the top and bottom edges with Mylar strips and press to a smooth surface. Both ends of the Mylar coating are exposed to the Spectroline B-100 lamps approximately 10 cm apart for 15 seconds each. Next, open the mold and irradiate each end of the sample with active radiation for 15 seconds. The total irradiation time is therefore 1 minute. After aging for 10 minutes, the polymerized composition was tested, its compressive strength was about 1890-2310Kg/ ^cm2
(27000-33000psi). The compressive strength of the sample is approximately 2800 after aging for 2 weeks.
Kg/cm ² (40000psi). After long-term aging, its strength reaches approximately 3,150 kg/cm ² (45,000 psi).

Example 1 % by weight bis -GMA resin (contains 200 ppm MEHQ) 18 Methyl methacrylate (contains 100 ppm MEHQ) 3 4,4'-oxydibenzyl 0.2 Trihexylamine 0.2 Barium aluminum silicate 23 Lithium aluminum silicate 55.6 This composite Compositions were prepared as described above and the strength of the polymerized product was measured under a Spectroline B-100 lamp. The intensity is 1750Kg/1/2 minute irradiation
cm ² (25,000psi), 2100Kg/cm ² after 1 minute of irradiation
(30000psi) and 2570Kg/ ^cm3 (36,
700psi).

Example 2 % by weight bis -GMA resin (contains 200 ppm MEHQ) 18 1,3-butylene dimethacrylate (contains 50 ppm MEHQ) 3 4,4'-dimethoxybenzyl 0.08 N-methyldibutylamine 0.2 Barium aluminum silicate 23 Silicic acid Lithium Aluminum 55.72 The strength of this composite composition was measured as described above. One minute of irradiation with a Spectroline B-100 lamp resulted in approximately 2100 Kg/cm ² (30000 psi).

Example 3 % by weight Bis-GMA resin (excluding MEHQ 200ppm) 18 Triethylene glycol dimethacrylate (including MEHQ 100ppm) 3 Benzyl 0.08 N-methyldibutylamine 0.2 Barium aluminum silicate 23 Lithium aluminum silicate 55.72 Spectroline B-100 The strength of the material polymerized by irradiation with a lamp for 1 minute is approximately 2070Kg/cm ²
(29500psi).

Example 4 The diluent monomer of Example 3 was replaced with the same amount of 2-ethylhexyl acrylate. Spectroline B
The intensity when irradiated with -100 lamp for 1 minute is approx.
It was 2120Kg/cm ² (32000psi). Generally, acrylate monomers are more reactive than methacrylate and dimethacrylate monomers.

Example 5wt % bis-GMA resin (contains MEHQ 200ppm) 18 Methyl methacrylate (contains MEHQ 100ppm)
3 Benzophenone 0.4 Triethylamine 0.4 Barium aluminum silicate 23 Lithium aluminum silicate 55.2 This mixture was irradiated with a Spectroline B-100 lamp for 4 minutes, but no curing was observed.

Example 6 A similar test was conducted using benzyl instead of benzophenone in Example 5. Similarly, the mixture is approximately 1.3cm
The strength of the polymerized material was approximately 2320 kg/cm ² (33000 psi) when filled in a 1/2 inch mold and irradiated with a Spectroline B-100 lamp for 1 minute.

Example 7 The procedure of Example 5 was repeated using diphenyl triketone (C ₆ H ₅ COOC ₆ H ₅ ) in place of benzophenone. The strength of the polymerized material irradiated for 1 minute with Spectroline B-100 lamp was only 520Kg/cm ²
(7400psi).

Example 8wt % bis -GMA resin (contains MEHQ 200ppm) 18 Methyl methacrylate (contains MEHQ 100ppm)
3 4,4'-Oxydibenzyl 0.05 Tetraethylethylenediamine 0.09 Barium aluminum silicate 23 Lithium aluminum silicate 55.86 Diamines were used in this example. The strength of the polymer material exposed to the spectroline for 1 minute is approximately 2100 kg/
cm ² (30,000 psi).

Example 9wt % Bis-GMA resin (contains MEHQ 200ppm) 18 Methyl methacrylate (contains MEHQ 100ppm)
3 4,4'-Oxydibenzyl 0.2 Diisopropylamine 0.2 Barium aluminum silicate 23 Lithium aluminum silicate 55.6 In this case a secondary amine is used. After mixing,
The mixture was filled into a 12.5 mm x 6 mm Teflon mold as described above and the Mylar covered ends were irradiated for 15 seconds with a Spectroline B-100 lamp. When the mold was opened, the sample cracked in the middle, indicating a slow reaction. Therefore, each Mylar-covered end was irradiated for 30 seconds, and after opening the mold without damaging the sample, each end was irradiated for an additional 30 seconds. Therefore, the total irradiation time is 2 minutes. The compressive strength under these conditions was approximately 1830 Kg/cm ² (26000 psi).

Example 10 The procedure of Example 9 was repeated with the primary amine n-butylamine. The intensity of irradiation for 2 minutes is 1130Kg/cm ²
(16000psi). Thus, tertiary amines are found to be the amines of choice.

Example 11 In this example, different types of resins are used. That is, glycidyl ether of bisphenol A and glacial acrylic acid were reacted, and a mixed composition was prepared using the reaction product bisphenol A-bis(3-acrylate-2-hydroxypropyl) ether.

wt% bisphenol A-bis(3-acrylate-2-
Hydroxypropyl) ether (MEHQ100ppm
18 1,6-hexanediol diacrylate (contains HQ200ppm) 3 Benzyl 0.08 Trihexylamine 0.2 Barium aluminum silicate 23 Lithium aluminum silicate 55.72 This mixture is treated as described above and spectroline The intensity of the material irradiated for 1 minute with a B-100 lamp was approximately 2220 Kg/cm ² (31500 psi).

Example 12 % by weight Bis-GMA resin (contains 200 ppm MEHQ) 23.9 1,6-hexanediol diacrylate (contains 200 ppm) 3.9 Benzyl 0.1 Trihexylamine 0.26 Silica 0.26 This mixture was irradiated for 1 minute with a Spectroline B-100 lamp. The compressive strength of is approximately 1900Kg/cm ²
(27000psi).

The optimal composition for dental filling materials is shown below: wt% bis -GMA resin (contains 200 ppm MEHQ) 18 1,6-hexanediol diacrylate (contains 100 ppm MEHQ) 2.8 Benzyl 0.08 Trihexylamine 0.2 Barium aluminum silicate 23 Lithium Aluminum Silicate 55.82 Using a mechanical stirrer, weigh 5 lbs.
Kg) was prepared and tested in the manner described above. When the mixture was irradiated with a Spectroline B-100 lamp for 1 minute, the strength of the polymer material was approximately 2250.
Kg/cm ² (32,000psi).

When the blended composition prepared according to the optimum method was aged in the dark and at room temperature for more than three years, it retained the hardening and strength properties of the new material (freshly made). This confirms the long shelf life of the product.

Dentists can use the blended composition without addition or mixing, resulting in restorations that are essentially free of occluded air bubbles. This eliminates many mechanical defects and improves the finish of the repair to provide a smooth solid surface. The smooth surface prevents contamination and bacterial accumulation and improves texture.

Irradiation with a wavelength of 2970 to 3200 Å causes skin burns and carinogenesis. This narrow band of light causes adverse photoreactions. 3200Å
When the polymerization reaction was repeated after completely filtering out the light of wavelengths up to 100 nm, no change in the intensity of the polymer was observed. When measuring with various optical filters placed between the lamp and the material, the wavelength was 4000 to 4500.
It was found that the most effective polymerization occurs with light in the visible region.

The curing test was repeated using a GE visible light source, a tungsten-halogen lamp.
In that case, light was focused onto the material through a fiber bundle about 15 cm (1/2 ft) long. The results showed that tungsten-halogen lamps cured the material more effectively than mercury lamps.

In addition to composite restorative materials, the present invention provides one-phase (previously two-phase systems) pit and fissure sealants, bonding agents, cavity liners, and restorative coatings (these are referred to as coating materials). )I will provide a. All of these compositions include a photopolymerizable aromatic resin such as bis-GMA, a monomer diluent such as a methacrylate, dimethacrylate, acrylate or diacrylate, a photoinitiator, and a photoaccelerator.
These dental materials differ from the aforementioned restorative materials in that they do not contain fillers. These materials polymerize in the oral cavity upon irradiation with actinic radiation.

Pit and fissure sealants, cavity liners, anti-fog materials or binders are generally 70-80% (by weight) bis-GMA resin inhibited with MEHQ,
30-20% (by weight) methyl methacrylate, 0.01
~1% (wt) photoinitiator and 0.01-1 (wt)
Contains % accelerator.

Its optimal composition is shown below: Bis-GMA resin (suppressed with 200ppm MEHQ)
75 parts methyl methacrylate (suppressed with 100 ppm MEHQ) 25 parts benzyl 0.5 parts trihexylamine 0.5 parts This non-filling mixture is used as a pit and crack sealant.
Used as a bonding agent, cavity liner and repair enamel material. Although other methacrylates, acrylates, dimethacrylates, diacrylates, or triacrylates can be used as the diluent monomer, the use of methyl methacrylate has the best properties as a thin film. By varying the amount of methyl methacrylate, the viscosity of the mixture can be adjusted. This single-component sealant system has a one-year shelf life in an airtight, light-resistant bottle.

Although the best mode has been described above, its composition can be varied in various ways. Increasing the amount of filler increases the strength but thickens the paste. Also, as the amount of benzyl increases, the strength increases. Excess benzyl
It should be avoided because it turns yellow and polymerizes when the material is exposed to light. The above-described combination of initiator and accelerator is used to photopolymerize various monomer resins.

Thus, the dental material according to the invention gives the dentist the freedom of choice to use sufficiently intense visible light to polymerize the material to avoid the potential dangers that may occur when using ultraviolet light. (J.
of American Dental Association, Vol.92,
(See April 1976 issue).

Although the dental filling material of the present invention has been described and explained in terms of specific component proportions and specific methods, it is clear that various changes and improvements may be made within the scope of the present invention.

Claims (1)

[Claims] 1 Consists of the following (a), (b), (c), (d) and (e),
A one-paste photopolymerizable, dental restorative composition characterized in that it is polymerized by light in the visible range with a wavelength in the range of 3200 Å to 4500 Å: (a) a glycidyl methacrylate derivative of bisphenol A; b) a diluent monomer copolymerizable with said component (a); (c) copolymerization of said component (a) and a diluent monomer selected from the group consisting of α-diketones and their derivatives; a photoinitiator for photoinitiation; (d) an accelerator selected from the group consisting of tertiary amines and diamines to promote photoinitiation of the copolymerization of component (a) with a diluent monomer; and (e) Inorganic fillers consisting of barium aluminum silicate and/or lithium aluminum silicate. 2 The inorganic filler comprises at least
A composition according to claim 1 comprising 6.5% by weight of barium oxide. 3. The composition of claim 1, wherein the inorganic filler comprises up to 85% by weight of the composition. 4. Any one of claims 1 to 3, wherein the diluting monomer is a monofunctional, difunctional, or trifunctional acrylate or methacrylate.
The composition described in Section. 5. The composition according to claim 4, wherein the diluting monomer is 1,6-hexane glycol diacrylate. 6. The composition according to any one of claims 1 to 5, wherein the α-diketone is benzyl. 7. A composition according to any one of claims 1 to 6, wherein the accelerator is a tertiary amine. 8. The composition according to claim 7, wherein the tertiary amine is trihexylamine. 9. The composition according to claim 1 or any one of claims 3 to 8, wherein the ingredients are in the following proportions (by weight). Glycidyl methacrylate derivative of bisphenol A 10-25 Diluent monomer 2-5 Photoinitiator 0.001-1 Accelerator 0.01-2 Barium aluminum silicate <85 Lithium aluminum silicate <85 10 The ingredients are as follows A composition according to claim 9 consisting of proportions (by weight). Bis-GMA resin (contains 200ppm MEHQ)
18 1,6-hexanediol diacrylate (contains 100 ppm MEHQ) 28 Benzyl 0.08 Trihexylamine 0.2 Barium Aluminum Silicate 23 Lithium Aluminum Silicate 55.82