KR20120133659A - Method for treating surface of dental alloy - Google Patents

Abstract

PURPOSE: A method for treating the surface of dental alloy is provided to use a cathode oxidation method to form nanopores, and to increase activation surface area. CONSTITUTION: In a method for treating the surface of dental alloy Organic compound adhered to the surface the ultrasonic cleaning and distilled water wash are performed to the dental implant and foreign substance are removed and dried. In H_3PO_4 for the formation of the micro-pore in the dental implant surface in which foreign substance is removed as the voltage of 180V with a nanopore. Based on 1M H3PO4 + 0.15 M NaF, electrolyte is positive electrode oxide-treated in an ordinary temperature. By using atmospheric spray method, Ha particles are sprayed and coated on the surface of the implant.

Description

Surface treatment method of dental implants {METHOD FOR TREATING SURFACE OF DENTAL ALLOY}

The present invention relates to a surface treatment method of a dental implant, and more particularly, to the surface of the dental implant hydroxyapatite (thermal spray) to the surface by thermal spray (thermal spray) to maximize the bonding with the bone hydroxyapatite) to a surface treatment method of a dental implant for improving the fusion with bone.

Dental implants, which have been recently performed, are used to make teeth by partially prosthetic prosthetics as a dental surgery tool.

In particular, the development of joint materials for fractured bones such as implants, joints, and wires, plates, and screws for artificial teeth using metal materials such as Ti alloys is being promoted.

Pure titanium, usually in contact with air and moisture in the air, forms very thin titanium oxide layers of tens to tens of nanometers, and thus exhibits excellent biocompatibility because of its primary resistance to corrosion in vivo. At the same time, the surface of the biomaterial becomes a biointerface at the same time as the implantation, and thus becomes an important place where a series of biological reactions begin and progress. Responses are an important factor in determining the success or failure of an implant. However, since the titanium surface itself has no bioactivity, the bone formation reaction is slow and the healing period is long, and the adhesion between the bone and the implant is weak. In order to solve these drawbacks, studies have been made to increase the surface area of implants, change the surface shape, or improve bone bonding strength through physical and chemical surface treatment, but do not overcome the material limitations of titanium. Therefore, since the 1990s, various surface modification attempts have been made continuously to minimize the absorption of bone around the implant and to improve the affinity and bonding strength of the surrounding soft tissues.

 Recently, the surface modification method to improve the biocompatibility of titanium implants is to increase the resistance to corrosion by improving the bioactivity by forming a thick oxide film on the surface such as heat treatment oxidation method, vacuum thin film deposition method, sol-gel method and anodization method. Although it is used, it is a method that can increase the bone adhesion by forming a titanium oxide (titanium oxide) of various thickness from tens of nanometers to several hundred micrometers on the titanium surface. Another method, in addition to the passivation oxide, is to induce a good biochemical environment around the biological interface and surroundings by attaching new materials or materials to the titanium surface to induce early cell adhesion and subsequent bone formation. Coating with calcium phosphate-based ceramics (HA), hydroxyapatite (calcium phosphates) or bioactive glass (bioactive glass).

Therefore, HA coating is one of the surface modification methods to control chemical and biological reactions by selecting materials with high bioactivity. Recently, the reason why Ti and Ti alloys are widely used for implants and medical devices is that they are lighter than other metals, and have excellent corrosion resistance and biocompatibility. However, it is required to change the surface structure of the implant in order to allow the biological tissue and bone tissue to be well bonded to the artificial implant (osseointegration) and has been pointed out as the biggest technological limitation as a biomaterial. Osteoadhesion has been studied by various methods such as erosion, sandblasting, etc., but recently, many clinical problems have occurred.

If the titanium oxide is chemically stable, HA may be slowly eluted in vivo to cause various chemical and biological reactions, and is known to have bioactivity and osteoconductivity, and such HA composition may be improved to improve histocompatibility. HA is excellent in biocompatibility because it is developed and used clinically by coating dental implants on the surface of Ti implant, but because it is a typical ceramic material, it has very low fracture toughness, fracture strength and resistance to crack propagation in solution. There is a disadvantage in that clinically easy failure due to low adhesion to Ti surface, which is a metal.

In other words, the implant surface manufactured by plasma spraying is a typical example. It is a method of dissolving HA powder at very high temperature (approximately 6000-15000 ℃), making it into a plasma state, spraying on the surface of titanium, and obtaining a thick HA layer after cooling. Although widely used and still in use worldwide, negative reports of long-term clinical outcomes are accumulating.

The biggest problem is pointed out that the coating layer is very weak. This is caused by a weak adhesion between the coating layer and the implant substrate because the coating layer is considerably thick, tens to hundreds of micrometers.

In addition, during the thermal spraying process, a large portion of HA crystals are transformed into amorphous or unstable structure, resulting in dissolution of the coating layer after embedding or microcracking at the interface between the coating layer and the lower substrate. It shows a big problem.

In order to achieve the object as described above, the present invention requires the introduction of new technologies, and since the discovery of carbon nanopores, titanium dioxide used for forming Ti nanopores is most suitable for a wide range of applications as catalysts, gas sensing and corrosion resistant materials. It is widely studied. It is a feature of the present invention to apply hydroxyapatite to the surface of the dental implant by coating hydroxyapatite on the surface by thermal spray method to maximize the bonding with the bone.

Titania nanopores (tubes) can be manufactured by a variety of methods such as hydrothermal treatment, template-assistant deposition, and electro-spinning. The production of titania nanopores by oxidation is the most effective method.

However, if a Titania nanopore array with a length of 1.1 µm was prepared by constant voltage experiments in H ₃ PO ₄ and HF solutions, the biocompatibility of dental implants could be controlled by the surface, crystallinity, crystal size, and crystal structure of titania. To improve, you must control the size of the nanopores.

To this end, the present invention provides a dental implant surface.

Step ^{1: Ti → Ti 4 + +} 4e -

Step 2: Ti ^{4 +} + 2H ₂ O → TiO ₂ + 4H ⁺

Step ^{3: Ti 4 + + 2H +} + 6F - → H 2 TiF 6

By using the method of nanopore size to adjust the alloying element, the applied potential and the applied current to suit the biocompatibility to form nanopores on the surface.

It is a technique to do.

To improve this, the formation of micropores is first performed within 10 minutes with a voltage of 180V in H ₃ PO ₄ and nanopore treatment.

Since the natural oxide film is thin and unstable, it is an ultimate goal of developing an oxide film process to artificially form the thick film and to form an artificial oxide film that can help the tissue to be combined.

As described above, the present invention can increase the bioreaction surface area of the biomaterial by forming nanopores on the surface by using anodization, and can promote the formation of an oxide film, which is a pivotal role of increasing the ability of bone adhesion. It is a very useful invention that can prevent.

1 is a reference diagram showing the process of forming nano-pores.
Figure 2-Nanopore formed Ti alloy picture at 20V.
3-Schematic diagram of a nanopore forming apparatus.
Figure 4-reference picture for showing the nanotube formation (Ti-6Al-4V alloy, 10V, 3h) state.
Figure 5-Two step surface treatment (anode oxidation (180V) 1M H ₃ PO ₄ + nanotubes (10V, 3h) 1M H ₃ PO ₄ + 1.0 wt% NaF).
Figure 6-Reference photo for showing HA coated surface condition on two-stage surface treated implants.
Figure 7-Reference photo for showing the HA coated cross-sectional state on the surface treated two-step.
8-Component analysis graph of the HA-coated cross section on the surface treated two stages.

Hereinafter, embodiments of the surface treatment method of the dental implant according to the present invention will be described in detail with reference to the drawings.

Figure 1 shows the nanopore forming process of the alloy, these forming conditions are the nanopores formed on a flat specimen. FIG. 2 is a photograph of a Ti alloy nanopore formed at 20V, and FIG. 2 shows nanopores formed on a Ti alloy surface at a voltage of 20V. Figure 3 is a schematic diagram of a device for nanopore formation, Figure 4 is a nanotube formed on the specimen (Ti-6Al-4V alloy, 10V, 3h, electrolyte: 1M H ₃ PO ₄ + 1.0 wt% NaF), 1M Treatment with H ₃ PO ₄ + 1.0 wt% NaF solution showed good growth of the cells. 5 shows the two-step surface treatment of the specimen, i.e. anodization (180V, 1M H _3). PO ₄ ) and nanotube formation (10V, 3h, 1M H ₃ PO ₄ + 1.0 wt% NaF) it can be seen that the nano-sized tube and micropore formed on the dental implant surface of the present invention.

FIG. 6 shows that the coating is performed by observing the HA-coated surface on the dental implant surface of the present invention treated with two-stage surfaces of the specimen as shown in FIG. 5 by scanning electron microscopy.

FIG. 7 illustrates the scanning electron microscope of the HA coated cross section on the surface treated with the two-stage surface treatment to enhance the adhesion of HA. As a result, HA penetrates into the pores formed by anodization and increases the adhesion strength. Able to know.

FIG. 8 shows EDS line profiles to analyze the components of the surface after HA coating after two steps of surface treatment. As a result, it can be seen that Ca and P increase in the coated portion.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Titanium has an oxide film formed on the surface of an oxide film having a thickness of several tens of micrometers in a very short time (less than a thousandth of a second). The significance of this titanium oxide film is that the titanium metal itself does not come into direct contact with tissue, but rather through a thin oxide film formed in the atmosphere. Titanium embedded in the living body has a thin oxide film in contact with the tissue, so the oxide film plays an important role in biocompatibility. The oxide film (TiO ₂ ) formed on the surface has excellent corrosion resistance and durability against chemicals, can play a catalytic role in organic and inorganic chemical reactions, and has a large dielectric constant, which is stronger than other oxides. Binding can be induced. Therefore, when the oxide film is artificially grown on the surface of the implant, the shape, thickness, mixed elements, etc., greatly affect the reaction with the hard tissue.

There is a method of forming an oxide film on the surface of titanium by anodization. Anodization is an oxide film in comparison with thermal oxidation or chemical oxidation by heat treatment in the air. Its thickness and shape can be easily adjusted and have excellent reproducibility. The formation mechanism of the oxide film formed by the anode reaction is very complicated and can be divided into three sections, but the second and third sections can be explained by the same mechanism. Period in which the change in voltage as a function of time increases linearly at the constant current density is the titanium ions eluted from the positive electrode according to the high field ionic conduction theory (Ti ^{2 +)} anion binding and (OH ^-, electrolyte anions ^-, O ₂₎ To form TiO ₂ on the anode surface. At this time, the thickness of the formed film is proportional to the applied voltage, and a film having a dense barrier layer structure is formed.

In the second step or more, the formed dense oxide film causes a breakdown phenomenon, and with the sparking, the thickness of the oxide film increases in a parabolic manner with time. At this time, unlike the dense oxide film formed in the first step is formed a lot of pores (crater).

These pores are very large (hundreds of nanometers in size), unlike pores formed in aluminum (hundreds of nanometers in size), and the formation mechanism is still unknown and is known to be very complicated. In general, a simple device that can be easily understood is that local heating occurs at a flaw in the oxide film, causing breakdown, and a high current flows through the electrode (titanium anode) and the electrolyte, and the heated electrolyte is captured in the pores, resulting in high temperature. Vaporize. A plasma composed of ionized vapors and accelerating electrons is formed in the liquid phase, and the ionized oxygen gas and titanium combine to form an oxide film and breakdown that is vulnerable due to another defect or high heat. As sparking continues around the resulting craters, this phenomenon continues on the entire surface of the titanium oxide, forming a porous oxide.

This is generally the process of forming a porous oxide film. 3 is a schematic diagram illustrating a process of forming nanopores using anodization.

After the oxide film is formed at a low voltage by using the anodization process described above, the oxide film can be grown by maintaining a low voltage to prevent breakage. So the oxide film formed is F ^- applying a constant voltage in a two-containing electrolyte major surface F ^- by ion as a first step to the dissolution occurs in the coating TiO ₂ oxide Ti → Ti ^{4 + +} 4e ^- in the step 2 Ti ^{4 +} _{+ 2H 2 O → TiO 2 +} 4H +, Ti 4 + + 2H + + 6F in three steps ^- to form the nano-pores with → H ₂ TiF _6.

The present invention will be described in more detail by way of examples.

Example

 1) Preparation of Psalms

The specimens used in this experiment were fabricated with a Ti-6Al-4V ELI, a dental implant fixture in the form of a machine. Before anodization, the specimen was used by removing and drying organic substances and foreign substances adhering to the surface by ultrasonic washing and distilled water washing in acetone and alcohol, respectively. Ti-6Al-4V alloy was used as a dental implant fixture.

 2) Micropore Formation

In order to form the first micropores were treated with a voltage of 180V in H ₃ PO ₄ within 10 minutes and nanopore treatment. Microporous formation experiments were performed using a DC power supply (KDP-1500). The test piece was used as the positive electrode and the platinum test piece was used as the negative electrode test piece. The distance between the positive electrode and the negative electrode was kept at 20 mm. The electrolyte was based on 1M H ₃ PO ₄ .

 3) Nanopore Formation

Nanopore formation experiment was performed using DC power supply (KDP-1500). The test piece was used as the positive electrode and the platinum test piece was used as the negative electrode test piece. The distance between the positive electrode and the negative electrode was kept at 20 mm. The electrolyte is based on 1M H ₃ PO ₄ + 0.15 M NaF, but in the anodization experiment, the electrolyte concentration and concentration can be considered in future experiments because the type and concentration of the electrolyte are variables of nanopore formation. All anodization experiments were performed at room temperature, and the mixture of electrolytes was maintained using a magnetic stirrer during the experiment. In order to supplement the above description, a schematic diagram of the anodizing device is shown in FIG. 3.

4) Hydroxyapatite Coating

Atmospheric pressure plasma spray method was applied to the surface of the implant treated two stages by spraying HA particles in the air. At this time, the HA powder was melted at an ultra-high temperature (about 6000-15000 ° C.), made into a plasma state, sprayed onto the titanium surface, and cooled to obtain a thick HA layer.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention. Belongs to the scope of.

Claims (1)

Removing and drying the organic implants and foreign substances adhering to the surface by ultrasonic cleaning and distilled water washing the dental implant,
Nanopore treatment at a voltage of 180 V at H ₃ PO ₄ to form micropores on the surface of the dental implant from which the foreign substances have been removed;
An electrolyte on the surface of the nano-pored dental implant is anodized at room temperature based on 1M H ₃ PO ₄ + 0.15 M NaF,
Surface treatment method of a dental implant, characterized in that the anodized dental implant surface by spraying HA particles in the atmosphere on the surface of the implant by using an atmospheric plasma spray method.

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