CN103361702A - Method for surface modification of dental implant - Google Patents

Abstract

This invention book mainly discloses a method for modifying the surface of a titanium metal dental implant. A titanium dioxide/hydroxyapatite composite coating with biocompatibility and bioactivity is prepared on the surface by a multi-electrode method. This technology is suitable for Modification of most medical metal surfaces. The main steps are as follows: (1) Ultrapure water, acetone, and absolute ethanol ultrasonically clean the mechanical surface threaded titanium dental implant and then dry it; (2) Use a multi-electrode method to anodize a layer on the surface of the implant Titanium dioxide nanotube arrays with uniform arrangement and uniform pore size are used as a buffer layer; (3) The hydroxyapatite coating is electrodeposited in the calcium-phosphorus electrodeposition solution by multi-electrode method, and the prepared hydroxyapatite coating has a distribution Uniformity, high purity, and good biological activity; (4) The material obtained through the above process is subjected to high-temperature vacuum sintering treatment. The titanium dioxide/hydroxyapatite coating composite coating obtained through the above steps has good bonding strength and excellent biological activity, so that the dental implant after surface modification has a wider and long-term application prospect.

Description

A Method of Surface Modification of Dental Implant

technical field

The invention relates to a method for modifying the surface of a titanium metal dental implant. A titanium dioxide/hydroxyapatite composite coating with biocompatibility and bioactivity is prepared on the surface by a multi-electrode method. This technology is suitable for Modification of most medical metal surfaces.

Background technique

Titanium and its alloys have good biocompatibility and are one of the most important medical metal materials. They are mainly used in orthopedic surgery and dental restoration materials, such as artificial knee joints, bone joints and denture metal nails. However, because titanium itself does not have biological activity, it cannot effectively promote the healing of wounds and the growth of surrounding bone tissue. Secondly, it cannot effectively form bone bonds with surrounding tissues, and the bonding strength with surrounding tissues is low, which is not conducive to its long-term use. . Hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , HA) is the main component of human bones, and it accounts for more than 95% of human tooth enamel. Hydroxyapatite has good biocompatibility and composition Osteoinductive, often used in bone tissue filling materials, but due to its high brittleness and low strength, hydroxyapatite limits its physical application. Combining the advantages of metal titanium and hydroxyapatite, a layer of biocompatible hydroxyapatite is coated on the titanium surface to form a hydroxyapatite/titanium composite material, which has the biocompatibility of hydroxyapatite It has the properties of sex and induction of bone tissue growth and has the strength and toughness of metal titanium, which is expected to become a new generation of biomedical materials.

Due to the large difference between the surface expansion coefficient of titanium metal and hydroxyapatite, if hydroxyapatite is directly deposited on the surface of metal titanium, cracking and falling off will occur due to the large difference in expansion coefficient after sintering, so we use titanium dioxide nanotube layer as a buffer layer, and can well combine metal titanium and hydroxyapatite, so that it has excellent bonding properties. At the same time, when the hydroxyapatite coating is corroded in the living body, the titanium dioxide still has good corrosion resistance and biological activity. At present, the methods for preparing titanium dioxide for the buffer layer mainly include plasma spraying, magnetron sputtering and physical and chemical vapor deposition. We use the in-situ growth method of anodic oxidation on the titanium surface to prepare uniformly arranged and uniformly sized titanium dioxide nanotubes on the surface. The array has the advantages of high bonding strength, uniform distribution, uniform size, and a certain pore size, which can well realize the physical bonding of the hydroxyapatite coating.

At present, the methods for preparing hydroxyapatite coating mainly include plasma spraying method, magnetron sputtering method, electrophoretic deposition method and biomineralization method, etc. We use electrochemical deposition method to prepare hydroxyapatite coating, electrochemical deposition The method has the advantages of low cost, simple production process, high purity of prepared components, mild and controllable conditions, etc., and has certain research and application prospects.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a titanium dioxide/hydroxyapatite gradient coating on the surface of a titanium dental implant by electrodeposition of a multi-cathode constant current method, which aims to obtain dense and uniform titanium dioxide with very high bonding strength / Hydroxyapatite gradient coating. The preparation of titanium dioxide nanotubes by multi-cathode anodic oxidation method and the deposition of hydroxyapatite coating by constant current electrochemical method comprise the following steps:

(1) The threaded titanium dental implant was ultrasonically treated with acetone and absolute ethanol, ultrasonically etched, ultrasonically cleaned with deionized water, and dried for later use;

(2) Prepare a 5w% hydrofluoric acid solution as an anodic oxidation electrolyte, use a titanium dental implant as a working electrode, and a plurality of platinum electrodes as counter electrodes are evenly distributed around the titanium dental implant, and the electrode spacing is 4cm. Stir (80r/min) and anodize by constant potential method for 1h, take out deionized water and ultrasonically clean, dry and set aside.

(3) Take calcium nitrate tetrahydrate and ammonium dihydrogen phosphate and dissolve them in distilled water respectively to obtain a uniform calcium-phosphorus solution, adjust the pH=4.2 with ammonia water, and finally obtain a uniform calcium-phosphorus electrodeposition solution;

(4) In the above-mentioned calcium-phosphorus electrodeposition solution, a saturated calomel electrode is used as a reference electrode, a plurality of platinum sheets are used as counter electrodes, and the oxidized titanium dental implant to be coated is used as a working electrode. Galvanostatic electrochemical deposition was carried out in an electrolytic cell. The electrode working distance is 2cm, the current is 0.007A, and the deposition time is 2700s.

(5) Vacuum sintering of the obtained titanium implant coating material: heating up to 600 °C, heating rate of 10 °C/min, holding for 2 hours, and then cooling with the furnace to obtain a titanium implant with a titanium dioxide/hydroxyapatite composite coating body material.

The above processes are all carried out under a constant temperature state (<90°C).

Compared with the prior art, the beneficial effects of the present invention are: (1) the titanium dioxide nanotube array obtained is evenly distributed, the pore size is consistent, and has certain corrosion resistance and biological activity; the hydroxyapatite coating is fine and uniform, and the purity High, with good biological activity. (2) Titanium dioxide nanotube arrays are used as a transition coating, which can well alleviate the disadvantages of thermal expansion coefficient mismatch between hydroxyapatite and titanium base, and significantly enhance the bonding strength of the composite coating. (3) The obtained composite coating has good bonding strength, meets the standards for use of biological materials, has good biological activity, is non-toxic, and is beneficial to its long-term use.

The accompanying drawings are as follows

The EDS energy spectrum figure of Fig. 1 embodiment of the present invention titanium dioxide nanotube

The SEM photograph of the titanium dioxide nanotube of Fig. 2 embodiment of the present invention

Figure 3 EDS energy spectrum of titanium dioxide/hydroxyapatite gradient coating according to the embodiment of the present invention

Figure 4 is the SEM photograph of the titanium dioxide/hydroxyapatite gradient coating according to the embodiment of the present invention.

Fig. 5 SEM photos of the surface topography of the threaded dental implant after the embodiment of the present invention is fabricated

Fig. 6 is a schematic diagram of a device utilizing four platinum electrodes according to an embodiment of the present invention

Detailed ways

The present invention will be further described below in conjunction with embodiment.

Example 1

(1) Clean the mechanically threaded titanium dental implant with absolute ethanol, acetone, deionized water and ultrasonic cleaning for 10 minutes; then use the acid solution of HF:HNO ₃ :H ₂ O=1:3:6 Perform acid etching; finally use deionized water and ultrasonic cleaning for 10 minutes. Take out with tweezers and blow dry, set aside.

(2) Prepare 5w% hydrofluoric acid solution at room temperature as the electrolyte for anodic oxidation, use titanium implants as working electrodes, and 4 platinum electrodes as counter electrodes evenly distributed around the titanium dental implants with a working distance of 4 cm. Under magnetic stirring (80r/min), adopt 20V voltage, anodize by constant potential method for 1h, take out deionized water and ultrasonically clean, dry and set aside.

(3) Weigh 4.9592 g of calcium nitrate tetrahydrate and 1.4379 g of ammonium dihydrogen phosphate, and dissolve them in distilled water respectively. The above two solutions were prepared into a 1000ml mixed solution, and the beaker was placed on a magnetic stirrer to stir, and the pH of the solution was adjusted to 4.2 with ammonia water to obtain a uniform electrolyte solution. Put the electrolyte solution into an electrolytic cell, and carry out electrochemical deposition on the titanium dental implant obtained in (2), with a saturated calomel electrode as a reference electrode, and 4 platinum sheets as counter electrodes, and the oxidized titanium implant to be coated The titanium implant was used as the working electrode, and galvanostatic electrochemical deposition was performed in the electrolytic cell of the three-electrode system (as shown in Figure 6). The electrode working distance is 2cm, the current is 0.007A, the deposition time is 2700s, and the electrolyte temperature is 65°C.

(4) Wash the coating material obtained in (3) with distilled water, dry it in a far-infrared oven for 2 hours, and then sinter it in vacuum: raise the temperature to 600°C, the heating rate is 10°C/min, keep it warm for 2h, and then cool it with the furnace , to obtain a titanium dental implant material with a titanium dioxide/hydroxyapatite composite coating.

The electrode distribution of this embodiment is shown in Figure 6; the SEM photos and EDS spectra of the obtained coating material are shown in Figures 1, 2, 3, 4, and 5, respectively.

Figure 1 and Figure 2 are SEM and EDS images of titanium dioxide nanotube arrays on the surface of titanium dental implants. It can be seen that titanium dioxide nanotube structures with uniform distribution, uniform size and pore size of about 100 nm are prepared on the surface of titanium dental implants. Figure 3 and Figure 4 are the SEM and EDS images of the titanium dioxide/hydroxyapatite composite coating. The SEM photos show that the hydroxyapatite coating has small grains, dense and uniform distribution, no agglomeration, and certain pores , suitable for the adhesion growth of bone cells, EDS energy spectrum shows that the coating contains Ca, P and a small amount of Ti elements. Figure 5 shows the surface morphology of the titanium implant with titanium dioxide/hydroxyapatite composite coating after the process is completed. The surface has a certain roughness, which is conducive to the attachment, survival and differentiation of cells, and the coating is uniform.

Example 2

The number of platinum electrodes in Example 1 can be more than two or ring electrodes as counter electrodes.

Claims (3)

1. A method for surface modification of medical dental implants. A multi-electrode method is used to prepare a biocompatible and bioactive titanium dioxide/hydroxyapatite composite coating on the surface. This technology is suitable for most medical metal surfaces modification. Including the following steps: (1) Clean the threaded titanium implant on the mechanical surface with absolute ethanol, acetone, deionized water and ultrasonic cleaning for 10 minutes; then use the acid solution of HF:HNO ₃ :H ₂ O=1:3:6 Acid etching; finally use deionized water and ultrasonic cleaning for 10 minutes. Take out with tweezers and blow dry, set aside. (2) Prepare a 5w% hydrofluoric acid solution at room temperature as the electrolyte for anodic oxidation, use titanium implants as anodes, and four platinum electrodes as cathodes are evenly distributed around the titanium implants. The working distance between the anode and the cathode is 4cm. Under magnetic stirring (80r/min), use 20V voltage, anodize by constant potential method for 1h, take out deionized water and ultrasonically clean, dry and set aside. (3) Weigh 4.9592 g of calcium nitrate tetrahydrate and 1.4379 g of ammonium dihydrogen phosphate, and dissolve them in distilled water respectively. The above two solutions were prepared into a 1000ml mixed solution, and the beaker was placed on a magnetic stirrer to stir, and the pH of the solution was adjusted to 4.2 with ammonia water to obtain a uniform electrolyte solution. Put the electrolyte solution into an electrolytic cell, and carry out electrochemical deposition on the titanium implant obtained in (2), with a saturated calomel electrode as a reference electrode, and 4 platinum sheets as negative electrodes, and the oxidized titanium to be coated The implant is the positive electrode, and the galvanostatic electrochemical deposition is carried out in the electrolytic cell of the three-electrode system. The working distance between the anode and the cathode is 2cm, the current is 0.007A, the deposition time is 2700s, and the temperature of the electrolyte is 65°C. (4) Wash the coating material obtained in (3) with distilled water, dry it in a far-infrared oven for 2 hours, and then sinter it in vacuum: raise the temperature to 600°C, the heating rate is 10°C/min, keep it warm for 2h, and then cool it with the furnace , to obtain a titanium implant material with a titanium dioxide/hydroxyapatite composite coating. 2. according to the method that a kind of multi-electrode electrochemical deposition prepares titanium dioxide/hydroxyapatite composite coating according to claim 1, it is characterized in that, in the technology of its anodic oxidation and electrodeposition, adopt greater than or equal to two cathode electrode. 3. A method for preparing a titanium dioxide/hydroxyapatite composite coating by multi-electrode electrochemical deposition according to claim 1, characterized in that the titanium implant to be coated can be in the shape of a mechanical thread or a cylinder.

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