Novel dental restoration composition

Abstract

The invention discloses a novel dental restoration composition which is prepared by taking a UDMA-TEGDMA-bisphenol A diglycidyl methacrylate copolymer as a matrix, combining silicon dioxide, dental glass fillers (SiO2-B2O3, Al2O3-Na2O and ZrO2), a silane coupling agent, a photoinitiator and a pigment according to a specific proportion and optimizing components and a process. The mechanical strength, the biocompatibility and the stability after curing of the material are obviously improved. The composition is suitable for the fields of dental caries filling, dental crown repairing and the like, and has high wear resistance, low water absorption and aesthetic suitability.

Description

Technical Field

[0001] This invention relates to the field of medical dental materials technology, specifically to a novel dental restorative composition. Background Technology

[0002] Dental restorative materials are the core carriers for restoring tooth shape and function, and their performance directly affects treatment outcomes and patients' quality of life. With the development of oral medicine, traditional materials have gradually revealed the following key shortcomings:

[0003] Traditional resin-based materials, such as bisphenol A glycidyl ether resin (Bis-GMA), suffer from poor toughness and high brittleness due to their low crosslinking density. For example, the tensile strength of pure Bis-GMA is only 38.1 MPa, far below the clinical requirement of over 50 MPa. Inorganic fillers (such as silica and glass powder) tend to agglomerate and have weak bonding with the resin matrix, leading to filler detachment after material wear, forming file-like protrusions that accelerate wear on opposing teeth. While high filler content (>50%) increases strength, it also dramatically increases paste viscosity (>1000 mPa·s), reducing workability. Low filler content sacrifices wear resistance. Traditional photoinitiation systems (such as α-hydroxy ketones) require high-energy light irradiation (>600 mW / cm²). 2 Insufficient curing depth (<2mm) and incomplete deep curing lead to microcracks.

[0004] Although feldspar ceramics have translucency close to that of natural tooth enamel, they lack mechanical strength (flexural strength <100MPa) and are prone to chipping. Zirconia ceramics require precise sintering and veneer processes, which are costly and time-consuming, making it difficult to achieve minimally invasive restorations. Traditional ceramic materials lack osteoinductive properties and cannot promote periodontal tissue regeneration, which can easily lead to secondary caries after long-term use.

[0005] Stress concentration at the resin-filler interface leads to delamination failure of the material during engagement cycles. For example, the wear rate of nanofiller-reinforced resin is still as high as 0.12 mm. 3 / N·m, which is 3 times that of natural tooth enamel; resin matrix is ​​easily hydrolyzed (e.g., Bis-GMA has a degradation rate of >5% / year in saliva), and discoloration and decreased strength occur after long-term use; traditional materials require multi-step layered curing, and the restoration of a single tooth takes more than 40 minutes, resulting in a poor patient experience.

[0006] Introducing a rubber phase (such as silicone rubber) can improve toughness, but it can lead to a mismatch in the elastic modulus of the material, causing interfacial cracking. Some patents use SiO2-ZrO2 composite fillers, but they do not solve the problem of volume expansion caused by ZrO2 phase transformation, resulting in poor long-term material stability. Although the dual curing (photo-thermal) strategy can improve the conversion rate, thermal side reactions can cause monomer release, increasing the risk of cytotoxicity. Summary of the Invention

[0007] The purpose of this invention is to provide a novel dental restorative composition.

[0008] To achieve the above objectives, this invention provides the following technical solution: A novel dental restorative composition, by weight percentage, comprising the following components: 10%-30% of a [UDMA-TEGDMA-bisphenol A diglycidyl methacrylate] copolymer; 5%-15% of silica; 20%-40% of dental glass fillers (SiO2-B2O3, Al2O3-Na2O, ZrO2); 3%-8% of a silane coupling agent; 0.5%-2% of a photoinitiator; 0.1%-5% of a pigment; and the balance being solvent. The basic formulation of the composition is defined, encompassing the resin matrix, fillers, additives, and solvents. By using a ternary copolymer of UDMA (providing toughness), TEGDMA (adjusting viscosity), and bisphenol A diglycidyl methacrylate (enhancing hydrolysis resistance), the problems of high brittleness and yellowing of traditional resins are solved. Silica (wear-resistant) and glass fillers (SiO2-B2O3 for acid resistance, Al2O3-Na2O for toughening, and ZrO2 for wear resistance) synergistically enhance mechanical properties, avoiding the limitations of single fillers. Solvent balance controls viscosity (500-1000 mPa·s) for ease of clinical application.

[0009] Furthermore, the copolymer has a weight-average molecular weight of 5,000-20,000 and a molar ratio of (2-4):1:(1-3). This limits the molecular weight and monomer ratio of the copolymer. A molecular weight of 5,000-20,000 ensures a balance between resin flowability (low molecular weight) and crosslinking density (high molecular weight), avoiding excessive viscosity due to excessively high molecular weight. A high UDMA content (2-4:1) improves toughness, bisphenol A diglycidyl methacrylate (1-3) enhances chemical resistance, and TEGDMA (1) regulates reactivity.

[0010] Furthermore, the silica particles have a diameter of 50-200 nm and are pretreated with a silane coupling agent. This involves nano-sized silica and surface modification. The 50-200 nm filler improves dispersibility, reduces agglomeration, and enhances interfacial bonding strength. The silane coupling agent (such as KH-550) forms chemical bonds through hydrolysis and condensation, improving the compatibility between the filler and the resin and reducing interfacial stress concentration.

[0011] Furthermore, the mass ratio of SiO2-B2O3, Al2O3-Na2O, and ZrO2 in dental glass fillers is (40-60):(20-30):(10-20). This precise ratio of composite fillers is crucial. SiO2-B2O3 (40-60%) provides acid resistance, protecting against corrosion in the oral environment. Al2O3-Na2O (20-30%) enhances filler strength and reduces the coefficient of thermal expansion. ZrO2 (10-20%) improves wear resistance and reduces wear after long-term use.

[0012] Furthermore, the silane coupling agent is γ-glycidoxypropyltrimethoxysilane or vinyltrimethoxysilane. This limits the type of coupling agent. Containing epoxy groups, it exhibits strong reactivity with the resin matrix, enhancing mechanical strength. It also synergistically enhances surface hydrophobicity in conjunction with the photoinitiation system.

[0013] Furthermore, the photoinitiator is a complex system of α-hydroxy ketones and tertiary amines. Two-component photoinitiators (such as CQ+EDMAB) absorb 400-500 nm light to initiate free radical polymerization. This accelerates initiator decomposition and lowers the curing threshold to 50 mJ / cm². 2 The following steps aim to improve the efficiency of deep curing.

[0014] Furthermore, the pigments are inorganic oxides or organic dyes, with an addition amount ≤1%. Pigment type and dosage restrictions apply. It exhibits excellent lightfastness and colorfastness, avoiding the degradation problems associated with traditional dyes (such as azo dyes). It minimizes the impact on the mechanical properties of the resin matrix while achieving aesthetic compatibility.

[0015] Furthermore, the preparation method includes the following steps: (1) copolymerization; (2) mixing of filler and coupling agent; (3) adding initiator and pigment, and degassing. A stepwise mixing process is used. Oxygen inhibition is avoided to ensure uniform copolymer molecular weight. The filler particle size D90 < 200 nm improves dispersion uniformity (CV < 5%) and reduces stress concentration points. The bubble residue rate is < 0.1%, avoiding microporous defects after curing.

[0016] Furthermore, in step (1), the copolymerization temperature is 60-80℃, and the time is 4-8 hours. Reaction conditions are limited. The reaction rate and side reactions (such as double bond crosslinking) are balanced at 60-80℃ to avoid monomer volatilization due to high temperature. The 4-8 hours ensure a monomer conversion rate >95% and residual monomer <1%.

[0017] Furthermore, the composition can be used for dental fillings, crown restorations, or enamel coatings. Applications are expanded. High flowability (low viscosity) allows for adaptation to complex cavity morphologies. High abrasion resistance (wear rate <0.1mm). 3 The N·m thickness matches the properties of natural tooth enamel. An ultra-thin cured layer (<50μm thickness) achieves aesthetic restoration.

[0018] This invention provides a novel dental restorative composition with the following beneficial effects: the UDMA-TEGDMA-bisphenol A diglycidyl methacrylate terpolymer (molar ratio 2-4:1:1-3) combines high toughness (elongation at break >200%) with hydrolysis resistance, and the tensile strength is increased to over 50 MPa.

[0019] Silica (50-200nm) pretreated with silane coupling agent synergistically enhances wear resistance with dental glass filler (SiO2-B2O3:Al2O3-Na2O:ZrO2=40-60:20-30:10-20), reducing wear rate by 40%.

[0020] Stepwise mixing (polymer → filler → photoinitiator) combined with vacuum degassing improves the uniformity of filler dispersion (D90-D10 < 50 nm) and meets clinical requirements (viscosity < 500 mPa·s).

[0021] A composite photoinitiator (α-hydroxy ketone + tertiary amine) achieves low energy (<500 mJ / cm²). 2 Rapid curing (curing depth > 3mm), deep curing rate > 95%.

[0022] Inorganic oxide pigments (addition amount ≤1%) replace traditional dyes. After 500 cycles of hot and cold (-10℃~70℃), the color difference ΔE is <1.5, and there is no yellowing phenomenon. Detailed Implementation

[0023] Example 1: High-toughness dental filling material

[0024] Composition and process:

[0025] According to the formulation of claim 1, the molar ratio of UDMA:TEGDMA:bisphenol A diglycidyl methacrylate in the copolymer is 3:1:2, the silica particle size is 100nm (pretreated with KH-550), and the dental glass filler has a SiO2-B2O3:Al2O3-Na2O:ZrO2 ratio of 50:25:25. The photoinitiator is a compound of CQ (0.8%) and EDMAB (1.2%), and the pigment addition is 0.5%.

[0026] Performance testing:

[0027] Tensile strength: 53.1 MPa (39% improvement compared to traditional Bis-GMA-based materials)

[0028] Wear rate: 0.07mm 3 / N·m (no cracking after 500 cycles of hot and cold cycling)

[0029] Handling: Viscosity 620 mPa·s, suitable for injection filling of caries cavities.

[0030] Application scenario: filling deep caries in posterior teeth, with a marginal fit of over 95% for the restoration.

[0031] Example 2: Ultra-durable dental crown restorative material

[0032] Component optimization:

[0033] The proportion of bisphenol A diglycidyl methacrylate in the copolymer was increased to 30% (molar ratio UDMA:TEGDMA:bisphenol A = 2:1:3), ZrO2 in the dental glass filler was increased to 15%, and the silane coupling agent was changed to KH-151 (vinyl type). The photoinitiator was a 1:1 mixture of α-hydroxy ketone (CQ) and tertiary amine (EDMAB).

[0034] Performance advantages:

[0035] Wear rate: 0.05mm 3 / N·m (28% lower than in Example 1)

[0036] Compressive strength: 85MPa (no deformation under simulated bite force)

[0037] Transparency: Light transmittance ≥75% (suitable for anterior aesthetic restorations).

[0038] Test method: ISO 20795 bending test, bending modulus 3.2 GPa.

[0039] Example 3: Low water absorption enamel coating material

[0040] Process improvement:

[0041] 5% nano-silica (50nm particle size) was introduced into the copolymer, and the proportion of SiO2-B2O3 in the dental glass filler was 60%, increasing the total filler content to 45%. After pretreatment with silane coupling agent, vacuum degassing was performed (-0.09MPa, 30 minutes).

[0042] Performance data:

[0043] Water absorption rate: 0.21% (after 24 hours of soaking)

[0044] Color difference ΔE: 0.9 (after 500 cycles of heating and cooling)

[0045] Curing depth: 3.8mm (light intensity 500mW / cm²) 2 Irradiate for 40 seconds).

[0046] Application: Repair of micro-abrasion of tooth enamel, with thickness controllable between 20-50μm.

[0047] Example 4: Rapidly Curing Temporary Repair Material

[0048] Component adjustment:

[0049] The photoinitiator was replaced with a blend of Irgacure 819 (2%) and BPO (1%), increasing the TEGDMA content in the copolymer to 20% (molar ratio UDMA:TEGDMA:bisphenol A = 3:2:1), and reducing the total filler content to 30%.

[0050] Operational advantages:

[0051] Curing time: 30 seconds (light intensity 1000mW / cm²) 2 )

[0052] Operating temperature: Cures at room temperature, no heating required.

[0053] Viscosity: 380 mPa·s (suitable for one-time molding of complex cavities).

[0054] Test standard: ASTM D2471 Curing rate test.

[0055] Example 5: Aesthetically Compatible Dental Restorative Materials

[0056] Innovative Design:

[0057] The pigments are inorganic oxides (TiO2:ZrO2 = 3:1), the proportion of Al2O3-Na2O in dental glass fillers is increased to 30%, and the proportion of bisphenol A methacrylate diglycidyl ester in the copolymer is 25%.

[0058] Aesthetic performance:

[0059] Color stability: ΔE < 1.2 (accelerated aging by UV radiation for 500 hours)

[0060] Surface gloss: 65 GU (similar to natural tooth enamel)

[0061] Biocompatibility: Cytotoxicity rating is 0 (ISO 10993).

[0062] Application: Veneer repair, color matching VITA color chart A2-D4.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel dental restorative composition characterized in that: By weight percentage, the following components are included: 10-30% of [dimethylamino acid urethane (UDMA)-triethylene glycol dimethylacrylate (TEGDMA)-bisphenol A dimethacrylate diglycidyl ester] copolymer; 5-15% of silica; 20-40% of dental glass filler, which contains SiO2-B2O3, Al2O3-Na2O and ZrO2 complex components; 3-8% of silane coupling agent; 0.5-2% of photoinitiator; 0.1-5% of pigment; The balance is solvent.

2. A novel dental restorative composition as claimed in claim 1, wherein: The weight average molecular weight of the [UDMA-TEGDMA-bisphenol A dimethacrylate diglycidyl ester] copolymer is 5,000-20,000, and the molar ratio of UDMA, TEGDMA and bisphenol A dimethacrylate diglycidyl ester is (2-4):1:(1-3).

3. A novel dental restorative composition as claimed in claim 1, wherein: The particle size of the silica is 50-200 nm, and the surface is pretreated with a silane coupling agent.

4. A novel dental restorative composition as claimed in claim 1, wherein: The mass ratio of SiO2-B2O3, Al2O3-Na2O and ZrO2 in the dental glass filler is (40-60):(20-30):(10-20).

5. A novel dental restorative composition as claimed in claim 1, wherein: The silane coupling agent is γ-glycidyl ether propyl trimethoxysilane or vinyl trimethoxysilane.

6. A novel dental restorative composition as claimed in claim 1, wherein: The photoinitiator is a complex system of α-hydroxy ketone compounds and tertiary amine compounds.

7. A novel dental restorative composition as claimed in claim 1, wherein: The pigment is an inorganic oxide pigment or an organic dye, and the addition amount is not more than 1% of the total mass of the composition.

8. A novel dental restorative composition as claimed in claim 1, wherein: The preparation method comprises the following steps: (1) copolymerization of UDMA, TEGDMA, bisphenol A dimethacrylate diglycidyl ester under inert atmosphere to obtain a prepolymer; (2) mixing silica, dental glass filler and silane coupling agent, dispersing by ball milling and then adding into the prepolymer; (3) adding photoinitiator and pigment, stirring uniformly, vacuum degassing to obtain the dental restoration composition.

9. A novel dental restorative composition as claimed in claim 8, wherein: The temperature of the copolymerization reaction in step (1) is 60-80℃, and the reaction time is 4-8 hours.

10. A novel dental restorative composition as claimed in claim 1, wherein: The dental restoration composition is used for preparing dental restoration materials, including caries filling, crown restoration or enamel coating.