KR20110006822A - Method for producing surface hydrophilized metal implant and metal implant produced thereby - Google Patents

Abstract

PURPOSE: A method for producing surface hydrophilized metal implant and metal implant produced by the same are provided to prevent the deintercalation of coating particles. CONSTITUTION: A method for producing surface hydrophilized metal implant comprises the steps of: performing blasting treatment for a mechanically-treated metal implant; performing acid corrosion for the blasting-treated metal implant; cleaning the acid-corrosion-treated metal implant by using ultrasonic wave and drying the implant under the nitrogen circumference; putting the dried metal implant into an ion-injection device; making nitrogen gas in a plasma state; and forming a hydrophilic property nitride film on the surface of the metal implant surface.

Description

METHOD FOR PRODUCING SURFACE HYDROPHILIZED METAL IMPLANT AND METAL IMPLANT PRODUCED THEREBY}

The present invention relates to a method for producing a surface-hydrophilized metal implant, and a metal implant produced by the method, the method is a metal etched after the blasting and acid etching treatment of the metal implant It includes coating by implanting nitrogen into the implant in an ion or plasma ion state.

Early dental implants used implants with pure titanium with a smooth surface. This smooth surface was not consistent in average surface roughness, which resulted in long seals and failures during the initial formation of oosseintegration. To compensate for this, a surface treatment method was introduced in which the surface roughness was constant, and the grains to be used on the surface also act as a catalyst for bone adhesion.

Titanium Plasma Spray (TPS) using titanium powder is a method of shaving an implant body with a machine and then dissolving another titanium at a high temperature and spraying it onto the implant surface. The implant surface produced by the plasma spraying method using the titanium powder has a roughness of about 15 μm, and is known to have a strong resistance to rotational force and to allow bone cells to adhere better to the implant surface. It is also relatively advantageous due to the large surface area compared to the machined surface. However, implants to which the TPS coating method is applied are not currently used due to desorption of tissues of coated titanium particles after embedding, causing problems such as inflammatory reactions.

With the introduction of TPS in the 1980s, various implants coated with hydroxyapatite were also recommended for clinical use. The hydroxyapatite coating by plasma spraying was coated with hydroxyapatite which was chemically and crystallographically identical to the mineral component of bone compared to the pure titanium implant, and thus showed an improvement in bone bonding ability and bone recovery between bone and implant. However, this can also cause particles to be separated if the bone quality is too hard, and if problems such as detachment of the coating layer occur, inflammatory reactions occur and bone absorption occurs around the implants, which causes problems of bone loss.

Sandblasting was used to increase the roughness and surface area of the implant. If plasma spraying is a method of coating small titanium powder, blasting is a method of cutting the surface of the implant to adjust the surface roughness and surface area. The process of scraping the surface of the implant to create roughness essentially avoids the problem of desorption of the coating in the coating process. Although the blasting method has the advantage of controlling the surface roughness using alumina powder, titania powder, etc. of a specific size according to the purpose, there is a disadvantage that the blasting particles remain on the surface. In order to solve the problem of residual blasting particles, acid corrosion is applied in a subsequent process. The combined process of blasting and acid corrosion is commonly referred to as sandblasted large-grid acid-etched (SLA).

Another way to solve the problem of blasting particle retention is to use absorbed particles. A method of using absorbed particles is RBM (Resorbable Blasted Media) surface treatment method. This is to use calcium phosphate powder which is completely dissolved in the body, instead of alumina powder, titania powder or the like. Even if calcium phosphate powder remains on the implant surface, it is absorbed by the body when buried in the body and thus does not cause a big problem.

The SLA surface treatment method and the RBM surface treatment method are widely used because it is easy to control the roughness of the metal surface and a uniform surface roughness is obtained. However, after the surface treatment process, when the product is exposed to air, oxygen and oxide film in the air are formed on the surface of the product, which prevents bone bonding after implanting the implant and takes a long time for the implant to stabilize. .

At present, various attempts have been made to modify the implant surface in addition to the above methods.

Korean Unexamined Patent Publication No. 10-2009-0060864 discloses a metal comprising a process of surface-treating a titanium or titanium-containing metal for use in dental implants with an alkali solution including sodium hydroxide, and annealing the alkali-treated metal. Disclosed is a surface treatment method of.

Korean Patent Publication No. 10-2009-0017693 discloses an implant for use in various surgical procedures, wherein a portion of a metal structure including titanium is laminated with a ceramic coating containing hydroxyapatite using a plasma spray system. In addition, the hydroxyapatite coating has an effect of improving bone growth on the implant, and the ceramic coating includes silver ions to provide a bactericidal effect.

However, as in the above-mentioned titanium plasma spraying, in dental implant applications, plasma spraying technology has the advantage of having an excellent bone formation effect and shortening the bone adhesion time, but the low bonding force with the implant base material is a disadvantage.

In addition, electrochemical surface oxidation technology and the like have been developed as a surface treatment technology of dental implants (Korean Patent Registration No. 10-0402919), but economic problems and difficulty in mass production are still unresolved.

The present invention improves the existing SLA method and RBM method, a method of producing a surface-hydrophilized metal implant having improved bone bonding effect and a short bone adhesion time after the implant procedure and improved the bond strength of the implant base material and its method It is to provide a dental metal implant produced by.

The present invention,

Blasting the machined metal implant,

Acid etching the blasted metal implant,

Ultrasonically cleaning the etched metal implant and drying in a nitrogen atmosphere,

Placing the dried metal implant into the ion implanter,

Making nitrogen or a nitrogen mixed gas into a plasma state,

A method of manufacturing a surface-hydrophilized metal implant comprising extracting a gas ion beam from the plasma to accelerate the extracted ion beam and irradiating the accelerated ion beam with an energy of 20-150 keV to form a hydrophilic nitride film on the surface of the metal implant. to provide.

In the present invention, the metal implant is preferably a metal containing titanium or titanium alloy.

In the present invention, the blasting treatment is preferred to form a roughness on the surface of the metal implant by blowing calcium phosphate powder having a particle size of 40-80㎛ at a pressure of 4-6 atm.

In the present invention, the blasting treatment is preferred to form a roughness on the surface of the metal implant by blowing alumina or titania powder of 40-60㎛ at a pressure of 4-6 atm.

In the present invention, the acid corrosion treatment is preferably a 70% aqueous solution of hydrochloric acid / sulfuric acid mixed acid.

In the present invention, the ultrasonic cleaning is preferably washed with ethanol for 30 minutes and then for 30 minutes with distilled water.

In the present invention, the nitrogen mixed gas is preferably a mixed gas of nitrogen to hydrogen mixing ratio of 1: 1 to 4: 1.

In the present invention, it is preferable to irradiate the accelerated ion beam at an irradiation amount of 1 × 10 ^{15 to} 1 × 10 ¹⁷ ions / cm 2.

In the surface-hydrophilized metal implant produced by the method for producing a metal implant of the present invention, a nitride film having a thickness of 10-100 nm is preferably formed on the surface.

In the method of manufacturing a metal implant of the present invention, nitrogen ion is coated between metal molecules on a metal surface by accelerated irradiation of a nitrogen ion beam, so that problems such as desorption of coating particles as in the conventional spraying method do not occur. Do not.

Nitrogen coated metal implants prepared by the production method of the present invention not only effectively prevent the surface from forming oxygen and oxide film in the air, but also the nitride film formed on the surface exhibits hydrophilicity. It has excellent adaptability to living organisms, so it has excellent bone bonding properties and early stabilization and correction effects.

An important feature of a metal implant is the time it is fused (bone adhesion) to the bone, which refers to the time it takes for the bone material to be permanently strong enough to integrate permanently into the implant surface.

Metal implants produced by RBM surface treatment or SLA surface treatment are preferably composed of titanium or titanium based alloys, for example titanium / zirconium alloys, which also contain niobium, tantalum or other tissue compatible metal additives. do. These are performed under vacuum or in an inert atmosphere, but the growth of oxides on the metal surface is difficult to avoid. These metal surfaces immediately become contaminated in air or are in a wide range of chemically stable states. The oxide film TiO ₂ formed on the surface hinders bone bonding during implant implantation, thereby delaying bone adhesion with the implant surface.

The present invention provides a metal implant with improved osteoadhesion.

The metal implant of the present invention consists of a titanium or titanium-based alloy and has a roughened hydrophilic surface.

1 is a flow chart showing the manufacturing process of the surface-hydrophilized metal implant of the present invention.

As shown in FIG. 1, in the method of manufacturing a metal implant of the present invention, a machined metal implant is prepared by first machining a titanium or titanium alloy rod through a CNC (computer numerical control) lathe into a predetermined shape. The machined metal implant is then subjected to blasting to give the implant surface a uniform roughness and then subjected to acid corrosion treatment (RBM or SLA surface treatment). The surface treated metal implants are cleaned of surface residues by ultrasonic cleaning and dried under a nitrogen atmosphere. The washed and dried metal implant is placed in an ion implantation apparatus, and a nitrogen coated surface is provided by a process of injecting an ion beam having a nitrogen or nitrogen mixed gas in a plasma state.

2 is a schematic depicting the surface hydrophilized metal implant of the present invention, showing the coating surface in a partial enlarged view in a circle.

The metal implant of the present invention is preferably a titanium alloy, specifically a titanium / zirconium alloy. It may also contain niobium, tantalum or other tissue compatible metal additives.

Structurally and functionally securing the dental implant to the bone is achieved by fine roughness by machining of the surface and / or by fine roughness by chemical corrosion (etching) or adhesion by plasma technology. How strongly the implant is secured to the bone can be determined by mechanical measurements by measuring the force required to pull or twist the implant secured to the bone to separate the bond between the implant surface and the bone material bound thereto. Osteoadhesion appears to have a decisive influence not only on the surface roughness itself but also on the surface chemistry.

As soon as the implant with fine roughness is exposed to the air, the metal component on the surface combines with oxygen in the air to form an oxide film. The presence of the dense oxide film deteriorates wettability and prevents the implant from bonding to the bone.

The thickness of the oxide film formed automatically by the oxidation reaction with air is 3-10 nm.

The surface of the metal implant according to the present invention is characterized in that a nitrogen coating is formed to a thickness greater than or equal to the thickness of an oxide film by a natural oxidation reaction before the implant having fine roughness is exposed to air. The surface effect of the metal implant of the present invention is sufficiently achieved by the nano-sized film thickness, and more preferably formed into a thickness of 10-100 nm.

According to the present invention, the surface of the metal implant in which the nitrogen coating is formed has hydrophilicity, which is excellent in biological action by osteoadhesion of an implant made of titanium or a titanium alloy.

In the method for producing a metal implant according to the present invention, the blasting treatment preferably uses calcium phosphate powder having an angular spherical shape and preferably having a particle size of 40-80 μm by the RBM method.

Alternatively, alumina or titania powder having a particle size of preferably 40-60 μm by the SLA method is used.

Roughly formed metal implants by blasting treatment are subjected to acid corrosion treatment to form surfaces with finer and more controlled roughness.

As the acid solution used for the acid corrosion treatment, an aqueous solution of hydrochloric acid, hydrofluoric acid, or a mixed acid of hydrochloric acid / sulfuric acid may be used, and preferably an aqueous solution of hydrochloric acid / sulfuric acid is used. The mixed acid is preferably an aqueous 70% acid solution.

As described above, the metal implants subjected to acid corrosion after blasting are washed with ethanol for 30 minutes by ethanol and 30 minutes with distilled shoe to remove surface residues, and then dried in a nitrogen atmosphere. The dried metal implant maintains a nitrogen atmosphere.

The process of rapidly irradiating a gas ion beam from a plasma of nitrogen or nitrogen mixed gas to form a nitride film ionizes nitrogen into a plasma state in a vacuum state, and then a nitrogen ion beam having a particle size of 10 ^-9 m (nano size) through an accelerator. Accelerating to coat the surface of the metal.

Treatment of injection coating with nitrogen ions uses an ion implantation apparatus. Preferred ion implanters comprise a source gas inlet, an ion beam generator (or plasma generator), and an ion beam accelerator, and the vacuum degree within the ion implanter chamber is 1 × 10 ⁻³ to 1 × 10 ⁻⁵ Torr. In the vacuum, the interior of the chamber is formed in a nitrogen or nitrogen mixed gas atmosphere. The nitrogen mixed gas is preferably a mixed gas of nitrogen and hydrogen. More preferred are gas mixtures having a nitrogen to hydrogen mixing ratio of 1: 1 to 4: 1.

In a nitrogen or nitrogen mixed gas atmosphere in a vacuum state, a nitrogen gas ion beam ionized with plasma is accelerated by an accelerator, and then the accelerated ion beam is irradiated to a metal implant to be processed to form a coating.

The energy of the ion beam accelerated by the ion beam accelerator is in the range of 20-150 keV, preferably in the range of 40-90 keV. The irradiation amount of the ion beam irradiated to the metal implant is 1 × 10 ^{15 to} 1 × 10 ¹⁷ ions / cm 2.

Metal implants made by the process of the invention are made to have an average surface roughness (Ra) of 1.2-2.5 μm. This roughness size will provide the appropriate surface area needed for the metal implant to osteoinize.

The metal implant of the present invention is a nitrogen-doped structure between surface metal molecules due to nitrogen ion implantation into the surface by ion implantation, and the hardness at 100 nm near the surface is doubled, and the hydrophilicity (NH) gives rise to adaptability to living organisms. Will be excellent.

In addition, the rigid, hydrophilic surface structure of the nitride membrane provides a surface that is also useful for treatment with additional bioactive materials.

In the following, the present invention is illustrated by examples.

Example 1

The machined titanium implant was blasted for 12 seconds using blast pressure 6 atm using angular spherical calcium phosphate powder with a particle size of 50 μm. Hydrochloric acid (35%) and sulfuric acid (90%) were mixed at a volume ratio of 3: 1 and prepared as an aqueous 70% acid solution. The blasted titanium implant was immersed in an aqueous acid solution at 80 ° C. for 5 minutes.

The acid-treated metal implant was ultrasonically cleaned for 30 minutes with ethanol and for 30 minutes with distilled water and then dried in a nitrogen atmosphere.

After putting the dried metal implant into the ion implanter and adding a mixed gas having a nitrogen-to-hydrogen ratio of 1: 1 in a vacuum state, the plasma inside the chamber was maintained at 1 × 10 ^-5 Torr to form a plasma to thereby generate 10mA, An accelerated gas ion beam of 40 keV energy was irradiated at a dose of 1 × 10 ¹⁶ ions / cm 2 for 5 minutes to form a nitride film. The nitride film thus formed was 42 nm thick.

Example 2

The machined titanium implant was blasted for 15 seconds using alumina powder with a particle size of 50 μm at a blast pressure of 5 atmospheres. Hydrochloric acid (35%) and sulfuric acid (90%) were mixed in a volume ratio of 1: 5 and prepared as an aqueous 70% acid solution. The blasted titanium implant was immersed in an aqueous acid solution for 1 minute at boiling temperature.

The acid-etched titanium implant was ultrasonically cleaned for 30 minutes with ethanol and for 30 minutes with distilled water and then dried in a nitrogen atmosphere.

After placing the dried metal implant into the ion implanter and adding a mixed gas of nitrogen to hydrogen mixing ratio of 2: 1 in a vacuum state, the plasma inside the chamber was maintained at 1 × 10 ^-5 Torr to form a plasma to generate 10mA, An accelerated gas ion beam of 40 keV energy was irradiated for 10 minutes at an irradiation dose of 1 × 10 ¹⁶ ions / cm 2 to form a nitride film. The nitride film thus formed was 56 nm thick.

Example 3

The machined titanium implant was blasted for 12 seconds using blast pressure 6 atm using angular spherical calcium phosphate powder with a particle size of 50 μm. Hydrochloric acid (35%) and sulfuric acid (90%) were mixed in a volume ratio of 3: 1 to prepare a 70% acid aqueous solution. The blasted titanium implant was immersed in an aqueous acid solution at 80 ° C. for 5 minutes.

The acid-treated metal implant was ultrasonically cleaned for 30 minutes with ethanol and for 30 minutes with distilled water and then dried in a nitrogen atmosphere.

After placing the dried metal implant into the ion implanter and adding nitrogen gas in a vacuum state, while maintaining the vacuum degree in the chamber at 1 × 10 ^-5 Torr, plasma was formed to generate an accelerated gas ion beam of 10 mA and 30 keV energy therefrom. The nitride film was formed by irradiating for 5 minutes at an irradiation dose of 1 × 10 ¹⁶ ions / cm 2. The nitride film thus formed was 35 nm thick.

Comparative Example 1

The machined titanium implant was prepared in the same manner as in Example 1 but with a blasting process and an acid corrosion treatment, but no treatment for forming a nitride film.

Comparative Example 2

The machined titanium implant was prepared in the same manner as in Example 2 but with a blasting process and an acid corrosion treatment, but no treatment for forming a nitride film.

Test Example 1

The wettability (or hydrophilicity) of the metal implants prepared by Examples and Comparative Examples was evaluated by measuring the contact angle of the dry metal implant surface with water. The nitride specimen-formed implant specimens according to Examples 1, 2 and 3 and the implant specimens prepared by Comparative Examples 1 and 2 (Comparative Examples) were washed with distilled water and then dried. A drop (0.2 ml) of distilled water was placed on each horizontal specimen surface, and the contact angle between the distilled water and the implant specimen was measured with a contact angle measuring instrument (Phonex 450, SEO).

The contact angles of the specimens of Examples 1, 2 and 3 were 15.5 °, 16.1 ° and 17.0 °, respectively, while the contact angles of Comparative Example 1 and 2 were 59.7 ° and 62.2 °, respectively. Therefore, the implant specimen of the present invention was excellent in wettability.

Test Example 2

The specimen of the present invention and the comparative example were embedded in New Zealand white rabbit tibia, respectively. Bone fixation after 2 and 4 weeks was measured as the force (torque) required to unscrew the embedded metal implant. As shown in Table 1 below, the bone fixation force of the specimen of the present invention was superior to the bone fixation force of the comparative example specimen.

Bone fixation force after 2 weeks (N · cm) Bone fixation force after 4 weeks (N · cm) Example 1 12 68 Example 2 10 65 Example 3 9 64 Comparative Example 1 5 60 Comparative Example 2 4 57

1 is a flow chart showing the manufacturing process of the surface-hydrophilized metal implant of the present invention.

2 is a schematic depicting the surface hydrophilized metal implant of the present invention, showing the coating surface in a partial enlarged view in a circle.

Claims (10)

Blasting the machined metal implant, Acid etching the blasted metal implant, Ultrasonically cleaning the etched metal implant and drying in a nitrogen atmosphere, Placing the dried metal implant into the ion implanter, Making nitrogen or a nitrogen mixed gas into a plasma state, And extracting a gas ion beam from the plasma to accelerate the extracted ion beam and irradiating the accelerated ion beam with an energy of 20-150 keV to form a hydrophilic nitride film on the surface of the metal implant. 10. The method of claim 1, wherein the metal implant is a metal comprising titanium or a titanium alloy. The surface-hydrophilized metal implant according to claim 1, wherein the blasting treatment is performed by blowing calcium phosphate powder having a particle size of 40-80 µm at a pressure of 4-6 atm to form roughness on the surface of the metal implant. Manufacturing method. 2. The surface-hydrophilized metal implant of claim 1, wherein the blasting treatment is performed by blowing 40-60 µm of alumina or titania powder at a pressure of 4-6 atm to form roughness on the surface of the metal implant. Manufacturing method. The method of claim 1, wherein the acid corrosion treatment is a 70% aqueous solution of a hydrochloric acid / sulfuric acid mixed acid method of producing a surface-hydrophilized metal implant. The method of claim 1, wherein the ultrasonic cleaning is performed with ethanol for 30 minutes and then with distilled water for 30 minutes. The method of claim 1, wherein the nitrogen mixed gas is a mixed gas having a nitrogen to hydrogen mixing ratio of 1: 1 to 4: 1. The method of claim 1, wherein the accelerated ion beam is irradiated at an irradiation dose of 1 × 10 ^{15 to} 1 × 10 ¹⁷ ions / cm 2. The surface-hydrophilized metal implant manufactured by the manufacturing method of any one of Claims 1-8. 10. The surface-hydrophilized metal implant of claim 9 wherein a nitride film of 10-100 nm thickness is formed.

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