High-strength titanium alloy dental bracket and method for manufacturing the same

Abstract

This invention discloses a high-strength titanium alloy dental bracket, made from the following raw materials by weight percentage: Al 5.70%-6.30%, V 3.75%-4.40%, Fe 0.05%-0.10%, O 0.12%-0.15%, with the balance being Ti and impurities. This invention also discloses a method for preparing the high-strength titanium alloy dental bracket, specifically including the following steps: (1) weighing; (2) casting; (3) casting. This invention uses the self-developed high-strength medical titanium alloy material TC4ELI as the material and is based on a new vacuum casting method (differential pressure casting method). It has low cost, a shortened manufacturing cycle, and can meet the requirements for manufacturing high-reliability and high-rigidity dental brackets.

Description

Technical Field

[0001] This invention relates to the field of biomedical device manufacturing technology, and more specifically to a high-strength titanium alloy dental bracket and its preparation method. Background Technology

[0002] The most common application of biomedical metallic materials is in dentistry, particularly in dental restoration and treatment. In recent years, advancements in medical biomaterials and dental implant technology have led to a significant increase in the use of titanium. Clinically, if two or more teeth are missing, and the loss is not consecutive, a fixed prosthesis mounted on a dental framework is generally used for treatment.

[0003] Traditionally, dental braces are made of polymer plastics. However, for patients with multiple missing teeth, the strength and rigidity of polymer plastic braces are insufficient, requiring them to be made very thick. This results in a strong foreign body sensation and severe discomfort for the patient. Furthermore, polymer plastics age in the mouth, becoming more brittle and easily damaged or broken when chewing food, leading to a short lifespan.

[0004] In recent years, the use of metal dental braces has become increasingly common, primarily made of nickel-chromium stainless steel. Their disadvantages include a relatively high density, making larger braces unsuitable. Furthermore, stainless steel braces can leach heavy metals such as chromium, which are detrimental to health, and they also have a metallic odor that patients find particularly unpleasant.

[0005] Currently, some hospitals use pure titanium, which has a lower specific gravity, to manufacture dental brackets. However, ordinary pure titanium has low strength and is prone to deformation under pressure when chewing food, causing gum discomfort and denture loss.

[0006] Titanium alloy dental braces can be customized to suit various patient oral conditions, including full-mouth, half-mouth, and one-third-mouth braces. However, they share common characteristics: complex structures and significant variations in wall thickness, placing high demands on the strength, rigidity, toughness, and elasticity of the titanium alloy used in their manufacture. Furthermore, titanium alloy dental braces are ultra-thin components; for wearer comfort, the portion in contact with the gums can be as thin as 0.1-0.2 mm, making traditional precision casting methods impossible. In addition, casting titanium alloy dental braces presents challenges: firstly, titanium alloy has a high melting point (>1650℃), exceeding the refractoriness of traditional refractory materials; secondly, molten titanium alloy is highly reactive, reacting chemically with most refractory materials, easily leading to surface defects in the castings.

[0007] Therefore, how to develop a titanium alloy dental bracket with strong comprehensive performance is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a high-strength titanium alloy dental bracket and its preparation method, so as to overcome the shortcomings of the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A high-strength titanium alloy dental bracket is made from the following raw materials in weight percentages: Al 5.70%-6.30%, V 3.75%-4.40%, Fe 0.05%-0.10%, O 0.12%-0.15%, with the balance being Ti and impurities.

[0011] The beneficial effect of this invention's high-strength titanium alloy dental bracket lies in the fact that the TC4ELI titanium alloy used in the bracket is the α+β two-phase titanium alloy with the best overall performance. When used in the cast state, not only its strength, toughness, and stiffness must be considered, but also its casting performance, fluidity, and microstructure. Therefore, the titanium alloy of this invention must meet the requirements for use in terms of main composition and impurity control. To improve fluidity, iron must be strictly controlled. To achieve a fine microstructure, trace amounts of grain-refining element B (<0.01%) are added, and the control of interstitial impurities is even more stringent.

[0012] The mechanical properties of the high-strength titanium alloy dental bracket of this invention are: σb 890-1100MPa, δ18-21%, Ψ25-28%, and hardness / HRC 32-38.

[0013] Furthermore, the high-strength titanium alloy dental bracket is made from the following raw materials by weight percentage: Al 6.25%, V 4.30%, Fe 0.08%, O 0.14%, with the balance being Ti and impurities.

[0014] Furthermore, the high-strength titanium alloy dental bracket is made from the following raw materials by weight percentage: Al 6.10%, V 4.20%, Fe 0.06%, O 0.12%, with the balance being Ti and impurities.

[0015] Furthermore, the high-strength titanium alloy dental bracket is made from the following raw materials by weight percentage: Al 5.98%, V 4.01%, Fe 0.05%, O 0.12%, with the balance being Ti and impurities.

[0016] Furthermore, the weight percentages of the aforementioned impurity components are: N < 0.002%, H < 0.001%, and C < 0.005%.

[0017] A method for preparing a high-strength titanium alloy dental bracket specifically includes the following steps:

[0018] (1) Weighing

[0019] Weigh each raw material according to the weight percentage of the above-mentioned high-strength titanium alloy dental bracket to obtain titanium alloy metal;

[0020] (2) Casting mold

[0021] Take an oral impression, cast a plaster model of the teeth, and create a digital model of the oral cavity using 3D scanning. Design the structure and dimensions of the titanium alloy dental bracket based on the position of the upper and lower teeth. Design a high-purity graphite casting pattern for the dental bracket based on the digital design of the dental bracket. Disassemble the casting pattern into different casting module patterns. Cut the casting using high-purity graphite electrode squares / rods according to the casting module patterns. Input the digitized casting module patterns into the computer of a CNC (Computer Numerical Control) machining center. Machin the high-purity graphite modules using the CNC machining center. Degas the graphite modules under vacuum and high temperature. Assemble the casting modules into a complete titanium alloy dental bracket casting for later use.

[0022] (3) Casting

[0023] The titanium alloy dental bracket mold is sealed with aluminum foil, evacuated, and placed in a titanium alloy casting melting furnace while maintaining a vacuum seal. The furnace door is closed, the furnace is evacuated again, and the titanium alloy metal is melted using consumable electrodes. The vacuum pump is turned off, and argon gas is introduced to a slight negative pressure. After melting, the crucible is quickly inverted to allow the molten titanium alloy metal to enter the pouring cup. The molten titanium alloy metal melts and breaks through the aluminum foil sealed in the gating system. Under the action of pressure difference, the molten titanium alloy metal rapidly fills the mold cavity. The furnace is cooled to room temperature, the furnace door is opened, the high-purity graphite mold is cleaned, the titanium alloy dental bracket is removed, the gating system is removed, and the mold is inspected, cleaned, sandblasted, ultrasonically cleaned and polished. The performance is then tested to obtain the finished product.

[0024] Furthermore, in step (2) above, the temperature of the vacuum high-temperature graphite module degassing treatment is >950℃.

[0025] Furthermore, in step (3) above, the vacuum is evacuated to below 3 Pa.

[0026] The beneficial effect of adopting the above-mentioned further technical solution is that the principle of the vacuum suction casting method (pressure difference casting method) of the present invention is as follows: the titanium alloy tooth bracket mold is completely sealed with aluminum foil in advance, and the entire mold and cavity are evacuated to the ultimate vacuum degree of less than 3Pa using a vacuum pump. By utilizing the pressure difference between the argon gas in the titanium alloy casting melting furnace and the mold cavity, the titanium alloy molten metal is rapidly melted and breaks through the aluminum foil of the casting system of the mold, so that the titanium alloy molten metal quickly fills the cavity, achieving the purpose of rapid forming.

[0027] Furthermore, in step (3) above, the specific steps of melting titanium alloy metal with consumable electrode are as follows: a small water-cooled copper crucible vacuum consumable electrode solidification furnace is used to machine the titanium alloy metal into a consumable electrode with a diameter required by the solidification furnace design. The consumable electrode is melted under vacuum conditions with high current and low voltage DC arc initiation. A titanium alloy molten pool with a titanium alloy protective shell is formed in the water-cooled copper crucible. When the melting amount meets the requirements, the crucible is pneumatically flipped quickly so that the titanium alloy molten metal can be quickly poured into the casting. Furthermore, the high current is 2000-8000A and the low voltage is 10-25V.

[0028] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This invention uses the self-developed high-strength medical titanium alloy material TC4 ELI as the material and is based on a new vacuum casting method (differential pressure casting method) casting process. It has low cost, shortened manufacturing cycle, and can meet the requirements for manufacturing high-reliability and high-rigidity dental brackets.

[0030] 2. This invention uses high-purity graphite electrode material as the casting material for manufacturing titanium alloy dental brackets. Considering the complexity of the dental bracket structure and the difficulty of mold separation, a split casting assembly is adopted for manufacturing. The positions of the split casting modules are fixed by positioning pins when they are assembled.

[0031] 3. This invention uses vacuum suction casting (differential pressure casting method), which greatly improves the filling speed of molten metal and solves the manufacturing problem of ultra-thin-walled titanium alloy dental brackets. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] High-strength titanium alloy dental brackets are made from the following raw materials by weight percentage: Al 6.25%, V 4.30%, Fe 0.08%, O 0.14%, N < 0.002%, H < 0.001%, C < 0.005%, with the balance being Ti.

[0035] The preparation method of the above-mentioned high-strength titanium alloy dental bracket specifically includes the following steps:

[0036] (1) Weighing

[0037] Weigh each raw material according to the weight percentage of the above-mentioned high-strength titanium alloy dental bracket to obtain titanium alloy metal;

[0038] (2) Casting mold

[0039] The dentist takes a dental impression (negative mold), casts a plaster model of the teeth (positive mold), and creates a digital model of the oral cavity using 3D scanning. Based on the position of the upper and lower teeth, the structure and dimensions of the titanium alloy dental bracket are designed. Based on the digital design of the dental bracket, a high-purity graphite casting pattern is designed for casting the dental bracket. The casting pattern is then broken down into different casting module patterns. According to the casting module patterns, high-purity graphite electrodes are used for cutting. The digitized casting module patterns are input into the CNC machining center computer, and the high-purity graphite modules are machined using the CNC machining center. The high-purity graphite modules are then degassed under vacuum high-temperature conditions at >950℃. The casting modules are then assembled into a complete titanium alloy dental bracket casting for later use.

[0040] (3) Casting

[0041] The titanium alloy tooth bracket mold is sealed with aluminum foil. A vacuum pump is used to evacuate the entire mold and cavity to a vacuum level below 3 Pa. Maintaining this vacuum seal, the mold is placed in a small water-cooled copper crucible vacuum consumable electrode solidification furnace. The furnace door is closed, and the furnace is evacuated again. The titanium alloy metal is machined into a consumable electrode with the diameter required by the solidification furnace design. Under vacuum conditions, the consumable electrode is melted using a 5000A high-current, 20V low-voltage DC arc-starting process. A molten titanium alloy pool with an outer titanium alloy protective shell is formed inside the water-cooled copper crucible. The vacuum pump is turned off, and argon gas is purged to a slight negative pressure. After melting, the water-cooled copper crucible is quickly inverted, allowing the molten titanium alloy to enter the pouring cup. The molten titanium alloy melts and breaks through the aluminum foil sealed within the gating system. Under pressure differential, the molten titanium alloy rapidly fills the mold cavity. The furnace is cooled to room temperature. The furnace door is opened, the high-purity graphite mold is cleaned, the titanium alloy tooth bracket is removed, the gating system is removed, and the mold is inspected, cleaned, sandblasted, ultrasonically cleaned and polished. Performance is tested to obtain the finished product.

[0042] Example 2

[0043] High-strength titanium alloy dental brackets are made from the following raw materials by weight percentage: Al 6.10%, V 4.20%, Fe 0.06%, O 0.12%, N < 0.002%, H < 0.001%, C < 0.005%, with the balance being Ti.

[0044] The preparation method of the above-mentioned high-strength titanium alloy dental bracket specifically includes the following steps:

[0045] (1) Weighing

[0046] Weigh each raw material according to the weight percentage of the above-mentioned high-strength titanium alloy dental bracket to obtain titanium alloy metal;

[0047] (2) Casting mold

[0048] The dentist takes a dental impression (negative mold), casts a plaster model of the teeth (positive mold), and creates a digital model of the oral cavity using 3D scanning. Based on the position of the upper and lower teeth, the structure and dimensions of the titanium alloy dental bracket are designed. Based on the digital design of the dental bracket, a high-purity graphite casting pattern is designed for casting the dental bracket. The casting pattern is then broken down into different casting module patterns. According to the casting module patterns, high-purity graphite electrodes are used for cutting. The digitized casting module patterns are input into the CNC machining center computer, and the high-purity graphite modules are machined using the CNC machining center. The high-purity graphite modules are then degassed under vacuum high-temperature conditions at >950℃. The casting modules are then assembled into a complete titanium alloy dental bracket casting for later use.

[0049] (3) Casting

[0050] The titanium alloy tooth bracket mold is sealed with aluminum foil. A vacuum pump is used to evacuate the entire mold and cavity to a vacuum level below 3 Pa. Maintaining this vacuum seal, the mold is placed in a small water-cooled copper crucible vacuum consumable electrode solidification furnace. The furnace door is closed, and the furnace is evacuated again. The titanium alloy metal is machined into a consumable electrode with the diameter required by the solidification furnace design. Under vacuum conditions, the consumable electrode is melted using a 2000A high-current, 25V low-voltage DC arc-ignition system. A molten titanium alloy pool with an outer titanium alloy protective shell is formed inside the water-cooled copper crucible. The vacuum pump is turned off, and argon gas is purged to a slight negative pressure. After melting, the water-cooled copper crucible is quickly inverted, allowing the molten titanium alloy to enter the pouring cup. The molten titanium alloy melts and breaks through the aluminum foil sealed within the gating system. Under pressure differential, the molten titanium alloy rapidly fills the mold cavity. The furnace is cooled to room temperature. The furnace door is opened, the high-purity graphite mold is cleaned, the titanium alloy tooth bracket is removed, the gating system is removed, and the mold is inspected, cleaned, sandblasted, ultrasonically cleaned and polished. Performance is tested to obtain the finished product.

[0051] Example 3

[0052] High-strength titanium alloy dental brackets are made from the following raw materials by weight percentage: Al 5.98%, V 4.01%, Fe 0.05%, O 0.12%, N < 0.002%, H < 0.001%, C < 0.005%, with the balance being Ti.

[0053] The preparation method of the above-mentioned high-strength titanium alloy dental bracket specifically includes the following steps:

[0054] (1) Weighing

[0055] Weigh each raw material according to the weight percentage of the above-mentioned high-strength titanium alloy dental bracket to obtain titanium alloy metal;

[0056] (2) Casting mold

[0057] The dentist takes a dental impression (negative mold), casts a plaster model of the teeth (positive mold), and creates a digital model of the oral cavity using 3D scanning. Based on the position of the upper and lower teeth, the structure and dimensions of the titanium alloy dental bracket are designed. Based on the digital design of the dental bracket, a high-purity graphite casting pattern is designed for casting the dental bracket. The casting pattern is then broken down into different casting module patterns. According to the casting module patterns, high-purity graphite electrode rods are used to cut the material. The digitized casting module patterns are input into the CNC machining center computer, and the high-purity graphite modules are machined using the CNC machining center. The high-purity graphite modules are then degassed under vacuum high-temperature conditions at >950℃. The casting modules are then assembled into a complete titanium alloy dental bracket casting for later use.

[0058] (3) Casting

[0059] The titanium alloy tooth bracket mold is sealed with aluminum foil. A vacuum pump is used to evacuate the entire mold and cavity to a vacuum level below 3 Pa. Maintaining this vacuum seal, the mold is placed in a small water-cooled copper crucible vacuum consumable electrode solidification furnace. The furnace door is closed, and the furnace is evacuated again. The titanium alloy metal is machined into a consumable electrode with the diameter required by the solidification furnace design. Under vacuum conditions, the consumable electrode is melted using an 8000A high-current, 10V low-voltage DC arc-starting process. A molten titanium alloy pool with an outer titanium alloy protective shell is formed inside the water-cooled copper crucible. The vacuum pump is turned off, and argon gas is purged to a slight negative pressure. After melting, the water-cooled copper crucible is quickly inverted, allowing the molten titanium alloy to enter the pouring cup. The molten titanium alloy melts and breaks through the aluminum foil sealed within the gating system. Under pressure differential, the molten titanium alloy rapidly fills the mold cavity. The furnace is cooled to room temperature. The furnace door is opened, the high-purity graphite mold is cleaned, the titanium alloy tooth bracket is removed, the gating system is removed, and the mold is inspected, cleaned, sandblasted, ultrasonically cleaned and polished. Performance is tested to obtain the finished product.

[0060] Performance testing

[0061] The hardness of each of the high-strength titanium alloy dental brackets prepared in Examples 1-3 was measured.

[0062] The results are shown in Table 1.

[0063] Table 1 Hardness of finished high-strength titanium alloy dental brackets in Examples 1-3

[0064] project Example 1 Example 2 Example 3 Hardness / HRC 37 35 33

[0065] As shown in Table 1, the finished products obtained in Examples 1-3 of the present invention have high hardness, which can meet the requirements for manufacturing high-reliability and high-rigidity dental brackets.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-strength titanium alloy dental bracket, characterized in that, Specifically, the following steps are included: (1) Weigh the raw materials with the following weight percentages: Al 5.70%-6.30%, V 3.75%-4.40%, Fe 0.05%-0.10%, O 0.12%-0.15%, with the remainder being Ti and impurities; (2) Casting mold Take an oral impression, cast a plaster model of the teeth, and create a digital model of the oral cavity using 3D scanning. Design the structure and dimensions of the titanium alloy dental bracket based on the position of the upper and lower teeth. Design a high-purity graphite casting pattern for the dental bracket based on the digital design of the dental bracket. Disassemble the casting pattern into casting module patterns for different positions. Cut the casting using high-purity graphite electrode squares / rods according to the casting module patterns. Input the digitized casting module patterns into the computer of a CNC machining center. Machin the high-purity graphite modules using the CNC machining center. Degas the graphite modules under vacuum and high temperature. Assemble the casting modules into a complete titanium alloy dental bracket casting for later use. (3) Casting The titanium alloy dental bracket mold is sealed with aluminum foil, evacuated, and placed in a titanium alloy casting melting furnace while maintaining a vacuum seal. The furnace door is closed, the furnace is evacuated again, and the titanium alloy metal is melted using consumable electrodes. The vacuum pump is turned off, and argon gas is introduced to a slight negative pressure. After melting, the crucible is quickly inverted to allow the molten titanium alloy metal to enter the pouring cup. The molten titanium alloy metal melts and breaks through the aluminum foil sealed in the gating system. Under the action of pressure difference, the molten titanium alloy metal rapidly fills the mold cavity. The furnace is cooled to room temperature, the furnace door is opened, the high-purity graphite mold is cleaned, the titanium alloy dental bracket is removed, the gating system is removed, and the mold is inspected, cleaned, sandblasted, ultrasonically cleaned and polished. The performance is then tested to obtain the finished product.

2. The method for preparing a high-strength titanium alloy dental bracket according to claim 1, characterized in that, In step (1), the following raw materials by weight percentage are weighed: Al 6.25%, V 4.30%, Fe 0.08%, O 0.14%, with the remainder being Ti and impurities.

3. The method for preparing a high-strength titanium alloy dental bracket according to claim 1, characterized in that, In step (1), the following raw materials by weight percentage are weighed: Al 6.10%, V 4.20%, Fe 0.06%, O 0.12%, with the remainder being Ti and impurities.

4. The method for preparing a high-strength titanium alloy dental bracket according to claim 1, characterized in that, In step (1), the following raw materials by weight percentage are weighed: Al 5.98%, V 4.01%, Fe 0.05%, O 0.12%, with the remainder being Ti and impurities.

5. A method for preparing a high-strength titanium alloy dental bracket according to any one of claims 1-4, characterized in that, In step (1), the weight percentage of the impurity components is: N < 0.002%, H < 0.001%, C < 0.005%.

6. The method for preparing a high-strength titanium alloy dental bracket according to claim 1, characterized in that, In step (2), the temperature of the vacuum high-temperature graphite module degassing treatment is >950℃.

7. The method for preparing a high-strength titanium alloy dental bracket according to claim 1, characterized in that, In step (3), the vacuum is evacuated to below 3 Pa.

8. The method for preparing a high-strength titanium alloy dental bracket according to claim 1, characterized in that, In step (3), the specific steps of melting titanium alloy metal with consumable electrode are as follows: a small water-cooled copper crucible vacuum consumable electrode solidification furnace is used to machine the titanium alloy metal into a consumable electrode with a diameter required by the solidification furnace design. The consumable electrode is melted under vacuum conditions with high current and low voltage DC arc starting. A titanium alloy molten pool with a titanium alloy protective shell is formed in the water-cooled copper crucible. When the melting amount meets the requirements, the crucible is pneumatically flipped quickly so that the titanium alloy molten metal can be quickly poured into the casting.

9. The method for preparing a high-strength titanium alloy dental bracket according to claim 8, characterized in that, In step (3), the high current is 2000-8000A; the low voltage is 10-25V.