Dental restorative composite material suitable for dlp 3d printing technology and preparation method thereof

Abstract

The application belongs to the technical field of dental ceramic materials, and particularly relates to a composite material suitable for DLP 3D printing technology for dental repair and a preparation method thereof. The composite material for dental repair comprises the following raw materials in parts by weight: polysilazane ceramic precursor binder: 30-50 parts; zirconium oxide: 60-90 parts; photoinitiator: 3-7 parts; thermal initiator: 2-5 parts; dispersing agent: 2-6 parts; rheological agent: 1-5 parts; silane coupling agent: 3-8 parts; sintering aid: 5-10 parts; the polysilazane precursor material is used to realize precise forming through photocuring, and then the inorganic ceramic can be controllably converted through heat treatment, the composite material has the processability of organic substances and the high temperature resistance and high stability of ceramics, the problem of easy decomposition, large shrinkage and insufficient strength of traditional organic binders at high temperatures is overcome, and a new material basis is provided for high-performance ceramic device preparation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dental ceramic materials, and particularly relates to a composite material for dental repair suitable for DLP 3D printing technology and a preparation method thereof. BACKGROUND

[0002] Traditional dental repair procedures usually require steps such as taking a mold, pouring a mold, outsourcing to a technician, etc. The entire process takes several days or even weeks, and patients need to visit multiple times, which not only prolongs the treatment period, but also increases the uncertainty during diagnosis and treatment and the psychological burden of patients. DLP photocuring 3D printing technology has great potential in the dental field due to its ultra-high printing precision (±25 μm), high efficiency and low cost, and has been widely used. Currently, this technology has been successfully applied to surgical guides, dental models and temporary restorations, greatly improving treatment efficiency.

[0003] Chinese patent CN118986751A discloses a 3D printing forming high-strength denture base and a preparation method thereof, which uses DLP 3D printing technology to solve the strength and antibacterial problems of the denture base; Chinese patent CN116144134A discloses a 3D printing antibacterial fluid photosensitive resin containing polyether ether ketone, which uses photocuring technology to print a temporary crown with a Vickers hardness of 25.6 HV, a maximum bending strength of 149.16 MPa, an elastic modulus of 6.83 GPa, and an antibacterial rate of 97.01%, thereby shortening the time of visiting a doctor. However, since the above-mentioned DLP 3D printing technology uses conventional resin composite materials, it still has problems such as insufficient mechanical properties, large polymerization shrinkage, easy aging, and difficult long-term durability to meet clinical requirements in the direct manufacturing of long-term dental restorations.

[0004] At present, an emerging technical route is to use 3D printing technology to manufacture the "green body" of the ceramic restoration, and then obtain the dense zirconia or glass ceramic restoration through high-temperature sintering. For example, Chinese Patent CN113208750A discloses a light-transmitting gradient integrated zirconia dental crown based on stereolithography 3D printing and a preparation method, which can achieve ideal aesthetic effect and realize oral hard tissue repair and reconstruction similar to natural tooth structure. Chinese Patent CN111716488A discloses a method for manufacturing hollow zirconia denture with high yield rate through 3D printing, which carries out repair design on the digital model of the denture obtained by the oral scanner, has high production precision and fast speed; hollow design is adopted, which not only reduces the weight of the denture, but also improves the yield rate of the sintering of the denture. However, one of the bottlenecks of this technology is that the printed "green body" needs to be sintered at high temperature to be formed, and after high-temperature sintering, problems such as green body cracking, deformation and insufficient support are prone to occur, because the photosensitive resin in the green body decomposes at high temperature, causing voids and internal stress in the printed body. Therefore, it is urgent to develop a high-performance dental composite material for DLP 3D printing that can meet the requirements of precise dental restoration. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a composite material suitable for DLP 3D printing technology for dental restoration, which uses polysilazane precursor material, is accurately formed through photocuring, and is controllably converted into inorganic ceramic after heat treatment, and has the processability of organic materials and the high temperature resistance and high stability of ceramic, overcoming the problems of traditional organic binders, such as easy decomposition at high temperature, large shrinkage and insufficient strength, and providing a new material basis for the preparation of high-performance ceramic devices.

[0006] Another purpose of the present application is to provide a preparation method of a composite material suitable for DLP 3D printing technology for dental restoration.

[0007] The composite material suitable for DLP 3D printing technology for dental restoration described in the present application comprises the following raw materials by weight:

[0008] Polysilazane ceramic precursor binder: 30-50 parts;

[0009] Zirconia: 60-90 parts;

[0010] Photoinitiator: 3-7 parts;

[0011] Thermal initiator: 2-5 parts;

[0012] Dispersing agent: 2-6 parts;

[0013] Rheological agent: 1-5 parts;

[0014] Silane coupling agent: 3-8 parts;

[0015] sintering aid: 5-10 parts;

[0016] The D50 of the zirconium oxide is 0.5-1.5 microns. 50 The particle size is 0.5-1 microns.

[0017] The photoinitiator is one or more of camphorquinone or ethyl 4-dimethylamino benzoate.

[0018] The thermal initiator is dicumyl peroxide.

[0019] The dispersant is one or more of BYK-2070 or BYK-111.

[0020] The rheological agent is fumed silica.

[0021] The silane coupling agent is one or more of KH-550 or KH-570.

[0022] The sintering aid is yttrium oxide.

[0023] The preparation method of the composite material for dental restoration suitable for DLP 3D printing technology comprises the following steps:

[0024] (1) Add a photoinitiator, a thermal initiator, a dispersant and a rheological agent to a polysilazane ceramic precursor binder, mix and ball mill at a speed of 200-400 r / min for 4-7 h to obtain a first slurry;

[0025] (2) Add a silane coupling agent, zirconium oxide and a sintering aid to the first slurry, mix and ball mill at a speed of 200-400 r / min for 5-9 h to obtain a printing slurry;

[0026] (3) DLP 3D printing is performed using the printing slurry to obtain a first printed blank; the printing light source power is 500-1000 mW, and the light source emission wavelength is 300-500 nm;

[0027] (4) The first printed blank is subjected to heat curing treatment to obtain a second printed blank;

[0028] (5) The second printed blank is subjected to pyrolysis treatment to obtain a composite material for dental restoration suitable for DLP 3D printing technology.

[0029] The heat curing treatment process is: respectively heating to 75-85℃, 115-125℃, 155-165℃, 195-205℃, and holding at each temperature point for 2-3 h.

[0030] The pyrolysis process is: the temperature is raised to 395-405 DEG C, 595-605 DEG C, 1095-1105 DEG C respectively at the temperature increasing rate of 2-5 DEG C / min, and the temperature is kept for 2-3h at each temperature point.

[0031] Compared with the prior art, the present application has the following advantages:

[0032] (1) The polysilazane used in the present application is an organic-inorganic hybrid ceramic precursor material, which exhibits an organic polymer state at room temperature, has good processability and formability, and can realize precise manufacturing of complex structures through processes such as photocuring molding. During heat treatment, the polysilazane undergoes a controlled ceramicization transformation, gradually transforming from an organic state to an inorganic ceramic structure, thereby realizing the integrated structural evolution from organic to inorganic. This feature makes it have both the excellent process adaptability of organic materials and the high temperature resistance and high stability of inorganic ceramics, successfully overcoming the application bottleneck of traditional organic binders, such as easy decomposition, large shrinkage and insufficient strength at high temperature, and providing a new material basis for the preparation of high-performance ceramic devices;

[0033] (2) The preparation method of the composite material for dental restoration suitable for DLP 3D printing technology in the present application adopts a low-temperature process system, which significantly reduces the thermal load in the material processing process. Compared with traditional high-temperature sintering, this method controls the processing temperature in a lower range, which on the one hand greatly reduces energy consumption, and on the other hand effectively avoids internal ceramic cracking, deformation and performance degradation caused by mismatch of thermal expansion coefficient or thermal stress concentration, thereby improving the forming success rate and long-term reliability of the restoration. This low-temperature preparation strategy ensures the performance of the material while taking into account energy consumption economy and process safety. DETAILED DESCRIPTION

[0034] The present application is further described below in conjunction with examples.

[0035] The raw materials used in the examples and comparative examples are all conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are all conventional methods in the art unless otherwise specified.

[0036] Some of the raw materials used in the examples and comparative examples are described as follows:

[0037] BYK-2070, BYK-111, purchased from Guangzhou Kangou Trade Co., Ltd.;

[0038] Polysilazane, purchased from Anzhi Electronic Material Co., Ltd.;

[0039] Fumed silica, D 50 The particle size is 0.2 μm;

[0040] Yttria, D50 The particle size is 1 μm.

[0041] Example 1

[0042] The preparation method of the composite material for dental restoration suitable for DLP 3D printing technology comprises the following steps:

[0043] (1) 3 parts by weight of camphorquinone, 3 parts by weight of dicumyl peroxide, 2 parts by weight of BYK-2070 and 2 parts by weight of fumed silica are added to 30 parts by weight of polysilazane ceramic precursor binder, and mixed ball milling is carried out at a rotating speed of 200 r / min for 6 h to obtain a first slurry;

[0044] (2) 3 parts by weight of KH-550, 60 parts by weight of zirconium oxide (D 50 The particle size is 0.5 μm) and 5 parts by weight of yttrium oxide are added to the first slurry, and mixed ball milling is carried out at a rotating speed of 300 r / min for 6 h to obtain a printing slurry;

[0045] (3) The printing slurry is used for DLP 3D printing to obtain a first printing blank; the power of the printing light source is 600 mW, and the wavelength of the light source is 350 nm;

[0046] (4) The first printing blank is subjected to heat curing treatment, and the heat curing treatment process is: respectively heating to 80℃, 120℃, 160℃ and 200℃, and keeping at each temperature point for 2 h to obtain a second printing blank;

[0047] (5) The second printing blank is subjected to pyrolysis treatment, and the pyrolysis treatment process is: heating to 400℃, 600℃ and 1100℃ at a heating rate of 3℃ / min, and keeping at each temperature point for 2 h, to obtain the composite material for dental restoration suitable for DLP 3D printing technology.

[0048] Example 2

[0049] The preparation method of the composite material for dental restoration suitable for DLP 3D printing technology comprises the following steps:

[0050] (1) 4 parts by weight of 4-dimethylaminoethyl benzoate, 3.5 parts by weight of dicumyl peroxide, 4 parts by weight of BYK-2070 and 3 parts by weight of fumed silica are added to 40 parts by weight of polysilazane ceramic precursor binder, and mixed ball milling is carried out at a rotating speed of 300 r / min for 6 h to obtain a first slurry;

[0051] (2) 4 parts by weight of KH-570, 70 parts by weight of zirconium oxide (D 5050 parts by weight of polysilazane ceramic precursor binder, 6 parts by weight of 4-dimethylamino ethyl benzoate, 5 parts by weight of dicumyl peroxide, 6 parts by weight of BYK-2070 and 4 parts by weight of fumed silica are mixed and ball milled at a rotation speed of 400 r / min for 5 h to obtain a first slurry;

[0052] (3) DLP 3D printing is performed using the printing slurry to obtain a first printing blank; the printing light source power is 700 mW, and the light source emission wavelength is 420 nm;

[0053] (4) The first printing blank is subjected to heat curing treatment, and the heat curing treatment process is: respectively heated to 80℃, 120℃, 160℃ and 200℃, and kept at each temperature point for 2 h, to obtain a second printing blank;

[0054] (5) The second printing blank is subjected to pyrolysis treatment, and the pyrolysis treatment process is: heated to 400℃, 600℃ and 1100℃ at a heating rate of 4℃ / min, and kept at each temperature point for 2 h, to obtain a composite material suitable for DLP 3D printing technology for dental restoration.

[0055] Example 3

[0056] The preparation method of the composite material suitable for DLP 3D printing technology for dental restoration comprises the following steps:

[0057] (1) 50 parts by weight of polysilazane ceramic precursor binder, 6 parts by weight of 4-dimethylamino ethyl benzoate, 5 parts by weight of dicumyl peroxide, 6 parts by weight of BYK-2070 and 4 parts by weight of fumed silica are mixed and ball milled at a rotation speed of 400 r / min for 5 h to obtain a first slurry;

[0058] (2) 6 parts by weight of KH-570, 90 parts by weight of zirconia (D 50 1 μm) and 9 parts by weight of yttria are added to the first slurry, and mixed and ball milled at a rotation speed of 400 r / min for 5 h to obtain a printing slurry;

[0059] (3) DLP 3D printing is performed using the printing slurry to obtain a first printing blank; the printing light source power is 500 mW, and the light source emission wavelength is 310 nm;

[0060] (4) The first printing blank is subjected to heat curing treatment, and the heat curing treatment process is: respectively heated to 80℃, 120℃, 160℃ and 200℃, and kept at each temperature point for 2 h, to obtain a second printing blank;

[0061] (5) The second printing blank is subjected to a cracking treatment, and the cracking treatment process is: heating to 400℃, 600℃ and 1100℃ at a heating rate of 5℃ / min, and maintaining at each temperature point for 2h, to obtain the composite material suitable for DLP 3D printing technology for dental restoration.

[0062] Comparative Example 1

[0063] The difference from Example 1 is that the polysilazane ceramic precursor binder in step (1) is replaced by an equal weight fraction of bisphenol A glycidyl methacrylate.

[0064] Comparative Example 2

[0065] The difference from Example 1 is that the D50 of the zirconia used in step (2) is 0.5μm. 50 The particle size is 3μm.

[0066] Comparative Example 3

[0067] The preparation method of the composite material suitable for DLP 3D printing technology for dental restoration comprises the following steps:

[0068] (1) The same as Example 1;

[0069] (2) The same as Example 1;

[0070] (3) The same as Example 1;

[0071] (4) The first printing blank is subjected to a heat treatment, and the heat treatment process is: heating to 400℃, 600℃ and 1100℃ at a heating rate of 3℃ / min, and maintaining at each temperature point for 2h, to obtain the composite material suitable for DLP 3D printing technology for dental restoration.

[0072] The samples prepared in the examples and comparative examples are respectively subjected to performance testing, and the testing method is as follows:

[0073] Density: tested by Archimedes drainage method;

[0074] Bending strength: tested in accordance with ISO 14704:2016, the sample specification is 35mm×4mm×3mm, the support span is 30mm, the pressure head loading rate is 0.5mm / min, 3-5 samples are tested in parallel for each group, and the average value is taken;

[0075] Fracture toughness: tested in accordance with ASTM C1421-2018;

[0076] Hardness: tested in accordance with GB / T16534-2009;

[0077] The test results are shown in Table 1.

[0078] Table 1 Performance test results

[0079]

[0080] As can be seen from Table 1, the density of the printed sample prepared by the present application is 5.0-5.3 g / cm 3 , the bending strength is 450-520 MPa, the fracture toughness is 3.2-4.0 MPa m 1 / 2 , and the hardness is 510-700 (HV10). Compared with the comparative examples, the density, bending strength, fracture toughness and hardness of the examples are better. In particular, compared with Comparative Example 1, the performance differentiation is most significant, which is mainly due to the synergistic optimization of the following aspects:

[0081] (1) In the slurry system, the present application selects polysilazane ceramic precursor as the binder of the printing slurry. The material belongs to organic-inorganic hybrid structure, exists in organic state at room temperature, has good processability and formability; and can be converted into inorganic ceramic phase in the high-temperature pyrolysis process, significantly enhances the ceramic yield and density of the final printed sample, and thus effectively improves the mechanical properties of the material;

[0082] (2) The present application simultaneously introduces a photoinitiator and a thermal initiator into the polysilazane ceramic precursor, significantly improves the crosslinking density of the polysilazane ceramic precursor by dual-mechanism initiation of polymerization. This strategy not only strengthens the construction of three-dimensional network structure, but also effectively suppresses the release of small molecule byproducts, thereby greatly reducing the polymerization shrinkage, improving the forming size accuracy and shape stability, and helping to meet the stringent requirements of dental restoratives on size consistency;

[0083] (3) By precisely controlling the addition amount of dispersant and rheological agent, the rheological properties and stability of the printing slurry are further optimized, so that it exhibits good viscosity behavior and spreading uniformity in the digital light processing (DLP) forming process, thereby ensuring the consistency of each printing layer thickness and the uniformity and stability of the final sample structure, reducing defects;

[0084] (4) The introduction of silane coupling agent significantly improves the surface activity of zirconia ceramic powder and enhances the interfacial bonding force between the ceramic particles and the polysilazane ceramic precursor. This not only effectively alleviates the interfacial stress caused by the mismatch of thermal expansion coefficients, but also reduces the formation of micro defects, thereby improving the mechanical strength and reliability of the finished sample;

[0085] (5) The silane coupling agent itself is a silicon-containing polymer compound, which can participate in the ceramic transformation in the high-temperature pyrolysis process, and its decomposition products can help to fill the micro pores, further improving the densification degree of the final ceramic part;

[0086] (6) The added sintering aid can effectively reduce the sintering temperature of the zirconia ceramic, promote the sintering densification process, inhibit the abnormal growth of the crystal grains, thereby improving the density, hardness and fracture toughness of the final ceramic restoration.

[0087] In summary, the present application significantly optimizes the printing adaptability, forming quality and final ceramic performance of the slurry through the synergistic effect of multiple components and multiple mechanisms, and is particularly suitable for DLP 3D printing process, and can efficiently and stably prepare high-performance zirconia ceramic restorations meeting the requirements of precise dental restoration.

Claims

1. A composite material for dental restoration suitable for DLP 3D printing technology, characterized in that, The ingredients include the following parts by weight: Polysilazane ceramic precursor binder: 30-50 parts; Zirconia: 60-90 parts; Photoinitiator: 3-7 parts; Thermal initiator: 2-5 parts; Dispersant: 2-6 parts; Rheology modifier: 1-5 parts; Silane coupling agent: 3-8 parts; Sintering aid: 5-10 parts; Wherein, the D of the zirconium oxide 50 The particle size is 0.5-1 μm; The photoinitiator is one or more of camphorquinone or ethyl 4-dimethylaminobenzoate; The thermal initiator is dicumyl peroxide; The method for preparing dental restorative composite materials suitable for DLP 3D printing technology includes the following steps: (1) Add photoinitiator, thermal initiator, dispersant and rheology modifier to polysilazane ceramic precursor binder, mix and ball mill to obtain the first slurry; (2) Add silane coupling agent, zirconium oxide and sintering aid to the first slurry, mix and ball mill to obtain printing slurry; (3) DLP 3D printing was performed using printing paste to obtain the first printed blank; (4) The first printed blank is subjected to thermosetting treatment. The thermosetting treatment process is as follows: the temperature is raised to 80℃, 120℃, 160℃ and 200℃ respectively, and the temperature is held for 2 hours at each temperature point to obtain the second printed blank; (5) The second printed blank is subjected to pyrolysis treatment. The pyrolysis treatment process is as follows: the temperature is raised to 400℃, 600℃ and 1100℃ respectively at a heating rate of 3-5℃ / min, and the temperature is held for 2 hours at each temperature point to obtain a dental restoration composite material suitable for DLP 3D printing technology.

2. The dental restorative composite material suitable for DLP 3D printing technology according to claim 1, characterized in that, The dispersant is one or more of BYK-2070 or BYK-111.

3. The dental restorative composite material suitable for DLP 3D printing technology according to claim 1, characterized in that, The rheology modifier is fumed silica.

4. The dental restorative composite material suitable for DLP 3D printing technology according to claim 1, characterized in that, The silane coupling agent is one or more of KH-550 or KH-570.

5. The dental restorative composite material suitable for DLP 3D printing technology according to claim 1, characterized in that, The sintering aid is yttrium oxide.

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