KR20030078480A - Method for treating surface of dental implant - Google Patents

Abstract

PURPOSE: Provided is a method for treating the surface of a dental implant to manufacture an excellent osseointegrated implant having superior surface finish and uniform surface shaping to conventional implants. CONSTITUTION: A method for treating the surface of a dental implant is characterized by blasting an implant by using calcium phosphate particles having a diameter of 40-80 mesh and followed by acid-treatment with hydrochloric acid and sulphuric acid at 70-90 deg.C for 4-6 minutes.

Description

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

The present invention relates to a surface treatment method of a dental implant, and more particularly, a mixed aqueous solution of hydrochloric acid and sulfuric acid after blasting the implant using calcium phosphate to obtain the optimum surface roughness for increasing the bone adhesion of the implant It relates to a surface treatment method of acid treatment.

Implants are artificial teeth developed to recover lost teeth, and require further development of implants with improved surface properties for permanent coupling between implants and bones and biocompatibility.

The physicochemical properties required for the optimal surface treatment of biocompatible implants include surface energy, oxide thickness, chemical composition and surface roughness. Among these properties, the relationship between surface roughness and bone overlap of implants is investigated. Many studies have been conducted, and experimental results have been reported that as the surface roughness of the implant increases, bone adhesion increases, and there is an optimal range of surface roughness that causes maximum bone adhesion. According to the results of the surface roughness and the amount of adhesion at the implant surface after controlling the surface roughness using TiO ₂ and Al ₂ O ₃ particles, Wennerberg et al. Reported that the amount of adhesion at the implant surface was proportional to the surface roughness. Although it increases in the range above a certain value, the amount of adhesion is rather decreased, and the surface roughness showing the best adhesion characteristics is reported to be about 1.5 (± 0.4) μm.

In particular, as the surface roughness of the implant increases, as a result of research showing that bone bonding increases, sandblasting is used as a method for increasing the surface roughness, and as a medium, titanium oxide, which is an oxidizing material of an element such as implant, The blasting method using TiO ₂ ) is most commonly used. However, since the titanium oxide blasting method alone does not satisfy the required surface roughness, a method using alumina (Alumina, Al ₂ O ₃ ) has also been attempted. The method using alumina has the advantage of increasing the surface roughness, but since the effect on the living body of the alumina present on the surface of the implant is not fully identified, it is not actually used in clinical practice.

Titanium plasma spray (TPS) method and hydroxyapatite (HA) coating method are used to increase the surface roughness. There is an adverse effect on the adhesion, and in the case of HA has the best surface properties, but there is a problem that absorbed into the body over time.

In addition, an acid treatment method is also implemented to increase the surface roughness, but the acid treatment alone does not satisfy the required surface roughness.

For this reason, the surface treatment method which combines the blast method and the acid treatment method is currently preferred, and it is reported that the surface of the implant thus treated has the best surface roughness [Buser D, Schenk R, Steinemann S, Fiorelline J]. , Fox C, Stich H., J. Biomedical materials Research , 1991 , 25 , 889-902].

However, as described above, detailed surface analysis of various surface treatments and acid treatments has not been performed, and precise experimental conditions have not been established.

Accordingly, the present inventors, in order to solve the above problems, after blasting the machined implant using calcium phosphate and acid treatment with a mixed aqueous solution of hydrochloric acid and sulfuric acid to treat the surface of the implant, the surface superior to the conventional implant The present invention was completed by finding that the surface of the implant, which exhibits roughness and uniform surface phenomena, can induce the most effective bone bonding, can be obtained.

It is an object of the present invention to provide a method for surface treatment of dental implants to obtain optimum surface roughness in order to increase bone adhesion of the implant.

1 is an optical photograph of an implant surface-treated by each step and the acid treatment method of the present invention,

(a) machined implants,

(b) Calcium Phosphate Blast-treated Implants

(c) Implants treated with nitric acid / fluoric acid aqueous solution after blasting

(d) Implants treated with an aqueous hydrochloric acid / sulfuric acid solution after blasting

2 is a graph showing the surface roughness curve of a machined implant,

3 is a scanning electron micrograph of a calcium phosphate blasted implant of the present invention,

(a) 2000 times magnification, (b) 4000 times magnification

4 is a graph showing the surface roughness curve of the calcium phosphate blasted implant of the present invention,

5 is a graph showing the surface roughness (Ra) value of the implant according to the concentration of the hydrochloric acid / sulfuric acid mixed aqueous solution of the present invention,

6 is a scanning electron micrograph of an implant acid treated with an aqueous hydrochloric acid / sulfuric acid solution after the blast treatment of the present invention,

(a) 2000 times magnification, (b) 4000 times magnification

7 is a graph showing the surface roughness curve of the implant acid treated with hydrochloric acid / sulfuric acid mixed aqueous solution after the blast treatment of the present invention,

8 is a scanning electron micrograph of an implant acid treated with an aqueous solution of nitric acid / fluoric acid mixed after blasting,

(a) 2000 times magnification, (b) 4000 times magnification

FIG. 9 is a graph showing surface roughness curves of implants treated with nitric acid / fluoric acid mixed solution after blasting;

10 is a scanning electron micrograph at 2000 times magnification of an implant (Ossetite ^?, Comparative Example 2) surface-treated only by a conventional acid treatment process,

11 is a scanning electron micrograph at 2000 times magnification of an implant (TPS ^?, Comparative Example 3) surface-treated with a conventional titanium plasma spray (TPS) method.

In order to achieve the above object, the present invention provides a surface treatment method of a dental implant consisting of a process of blasting the implant with calcium phosphate and then acid treatment with a mixed aqueous solution of hydrochloric acid and sulfuric acid.

Hereinafter, the present invention will be described in more detail.

The present invention provides a method for surface treatment of a dental implant having an optimum surface roughness to increase the bone adhesion of the implant, a hydrochloric acid / sulfuric acid 50-90% mixed aqueous solution after blasting the machined implant using calcium phosphate Acid treatment method is included.

Calcium phosphate blast treatment of machined implants is surface treated with blast treatment using calcium phosphate particles, which are bioactive materials. The calcium phosphate has the form of angular granules, preferably 40 to 80 mesh in diameter. Typically, parameters for surface roughness may be changed by blasting time, air pressure, etc., but the difference is limited to 10 to 15 seconds and 5 to 7 atmospheres in the present invention.

The blasted implant is subjected to acid treatment with an aqueous hydrochloric acid / sulfuric acid solution. The surface treatment of the implant using an aqueous hydrochloric acid / sulfuric acid solution is carried out with a mixed aqueous solution having a hydrochloric acid: sulfuric acid having a concentration of 50-90% in a ratio of 1: 1-5: 1 (mol / mol). According to Figure 5 , as the concentration of the hydrochloric acid / sulfuric acid mixed solution increases, the surface roughness value increases and shows the most suitable surface roughness in the above range, it can be seen that the surface roughness drops rapidly if it exceeds 90%. Preferably at a concentration of 70%. In addition, the acid treatment is preferably performed at 70 to 90 ° C. for 4 to 6 minutes, more preferably at 70 ° C. for 5 minutes.

The surface roughness of the surface-treated implant is described in more detail through the following figures.

It can be observed that the color of the implant surface changes as the implant is surface treated according to each step and acid treatment method. 1 is a view showing a micrograph of differently surface-treated implants, (a) is a machined implant, (b) is a calcium phosphate blasting implant, (c) is a blasting process The implant is acid treated with a nitric acid / fluoric acid mixed aqueous solution, and (d) is an implant acid treated with a hydrochloric acid / sulfuric acid mixed demand after the blasting process of the present invention. It can be seen that the change in color observed by changing the roughness and shape of the surface for each step and method. As the surface roughness increases with each step, the color of the implant surface becomes dark. In particular, the surface of the implant acid treated with an aqueous solution of hydrochloric acid / sulfuric acid rather than the surface of the implant acid treated with an aqueous solution of nitric acid / fluoric acid mixed. You can see this darker.

As shown in FIG . 2 , the surface roughness of the calcium phosphate blasted implant is mainly formed of broken calcium phosphate particles embedded in the implant surface during blasting, and these particles cannot be removed from the surface by ultrasonic cleaning. . It can be seen that the surface roughness is affected by the structure of the surface, and since the surface is formed of calcium phosphate, the effect due to the oxide film is expected to increase among various factors of the implant surface on the bone adhesion.

In addition, as shown in FIG. 4 , it can be seen that the roughness value Ra of the implant after the blast treatment is increased by more than two times than the machined implant of FIG. 2 , and the mean square roughness Rq, the maximum height Rt, and S, which indicates the number of peaks at 1%, also shows the same tendency as the surface roughness value.

The implant treated with the hydrochloric acid / sulfuric acid mixed solution after the blasting treatment has a crater shape of about 2 to 4 μm uniformly formed on the entire implant surface as shown in FIG. 6 , and the surface roughness value Ra is According to FIG. 7 , it is 1.30 μm, which is similar to the optimum condition for bone adhesion, and it can be seen that the surface roughness value after blasting is increased by about 2 times or more. The squared mean roughness (Rq) and the maximum height (Rt) also tend to be the same as the surface roughness values, and S, which is a value that predicts the size and uniformity of the domains formed on the implant surface, is 1015 pieces. This shows that one domain is formed on the surface of the implant at about 1 μm intervals and shows the most uniform surface structure.

The surface of the implant (Comparative Example 1) acid-treated with the nitric acid / fluoric acid aqueous solution is very different from the surface of the implant acid-treated with the hydrochloric acid / sulfuric acid solution, as shown in FIG. 9 . It can be seen that it has a shape. In addition, a surface roughness value shows the value of about 75% with respect to the acid treatment with the hydrochloric acid / sulfuric acid mixed aqueous solution of this invention. According to the examples below, the S value is 599, which is less than the blasted implant of the present invention, due to the etching of the non-uniform surface.

10 and 11 are surface roughnesses of currently available implants, and FIG . 10 is a scanning electron microscope showing surface roughnesses of implants (Osseitite ^?, 3i, USA, Comparative Example 2) surface-treated only by an acid treatment process. In the photograph, circular bones exist at intervals of about 10 μm, and only small etched shapes are observed, and overall uniform irregularities are not observed. Surface roughness was 1.06 μm according to the following example was 2.4 μm less than the surface roughness value of the present invention, it can be seen that the surface roughness slightly lacks. 11 is a scanning electron micrograph showing the surface roughness of the implant (TPS ^?, Life-Core, USA, Comparative Example 3) prepared by a titanium plasma spray (titanium plasma spray) process, a large domain of 20 ㎛ or more ) Are present on the surface, but the overall uniformity is poor. The surface roughness value Ra is very large, 2.97 μm, according to the following example, as shown in FIG. 11 , because there are domains of about 20 μm in size, and the height of these domains is up to about 22 μm ( Rt) degree. In addition, this nonuniform surface shape also affects the S value, resulting in very low values of about 480 in both cases.

An embodiment of the present invention will be described below.

However, the present invention is not limited by the examples.

<Example 1>

Blast-treated implants using calcium phosphate were prepared differently at 10% intervals in aqueous solutions with concentrations of 1% to 100% in hydrochloric acid and sulfuric acid at a ratio of 2.65: 1 (mol: mol) and then treated at 80 ° C for 5 minutes. After washing three times in distilled water and dried with inert nitrogen, the average roughness of the implant was measured.

1 and Table 1 below it can be seen the concentration of the most preferable aqueous solution of hydrochloric acid / sulfuric acid. Figure 1 and Table 1 shows the surface roughness (Ra) value of the implant according to the concentration of the hydrochloric acid / sulfuric acid mixed solution, the surface roughness value has a maximum value in the aqueous solution of 70%, the surface roughness value as the concentration increases As the concentration increases to more than 70%, the surface roughness decreases. In addition, it can be seen that the surface roughness of the implant acid-treated with an aqueous solution of 60 to 90% belongs to an optimum surface roughness range (1.1 to 1.7 mu m).

Changes in Surface Roughness of Implants with Concentrations of Hydrochloric Acid / Sulfate Solution density(%) One 20 30 40 50 60 70 80 90 100 Ra (μm) 0.88 1.00 1.03 1.07 1.10 1.22 1.30 1.23 1.10 1.03

Example 2 Surface Treatment Method of Dental Implant

The machined surface titanium implant (AVANA self-Tapping Fixture, 13 mm in length, 3.5 mm in diameter, product of Osstem Implant Co., Ltd.) was subjected to surface treatment by calcium phosphate blast and continuous acid treatment method.

(Step 1) blast treatment step

The blast processing step was performed using a blasting machine (MIC DUST.4, dominant material). Angled spherical calcium phosphate with a diameter of 50-60 mesh was used. The blasting time was 12 seconds and the air pressure was blasted at 6 atm. After blasting was completed, the implant was placed in methanol and sonicated for 5 minutes and then washed again with distilled water.

(Step 2) Acid Treatment Step

The implants subjected to the blasting process were prepared in a 70% aqueous solution of hydrochloric acid / sulfuric acid at a ratio of 2.65 / 1 (mol / mol) and acid treated at 80 ° C. for 5 minutes. After acid treatment, the mixture was washed three times with distilled water and dried over fluorinated nitrogen.

Comparative Example 1

In order to compare with the surface treatment method of the present invention, a surface treatment method of acid treatment with nitric acid / fluoric acid after blasting was performed.

(Step 1) blast treatment step

The same procedure as in Step 1 of Example 2 was performed.

(Step 2) Acid Treatment Step

The implants subjected to the blasting process were mixed with nitric acid / fluoric acid at a ratio of 2.65 / 1 (mol / mol), prepared as a 17% aqueous solution, and acid-treated at 80 ° C. for 5 minutes. After acid treatment, the mixture was washed three times with distilled water and dried over fluorinated nitrogen.

Comparative Examples 2 to 3 Implants Commercially Available

In order to compare the surface roughness and the surface shape of the present invention, a conventional screw type Osseotite ^? (3i, USA; Comparative Example 2) Implant and TPS ^? (Life-Core, USA; Comparative Example 3) The implants were surface analyzed.

Comparative Example 2 is an implant treated with acid only, and Comparative Example 3 is an implant treated with titanium plasma spray.

Experimental Example

Surface shape analysis and surface roughness of the implants prepared by the above Examples and Comparative Examples and conventionally available implants were measured.

(1) surface shape analysis

According to each step and method, a scanning electron microscope (Scanning Electron Microscope, SEM, S-2400, Hitachi) was used to observe the surface shape of the surface-treated implant, the magnification was observed at 2000 times and 4000 times.

(2) surface roughness measurement

In order to clearly observe the surface properties of the implants, the surface roughness was measured using a TopScan 3D UBM optical profiler (UBM Messtechnik GmbH, Germany), and only the surface roughness parameters for 2D were obtained. Gaussian filters were used to obtain the parameters.

In the same experiment, three implants were randomly selected and used, and the surface roughness of each implant was measured by selecting five places such as the upper and lower threads and measuring the average.

The parameters of the measured surface roughness are the average roughness Ra, the squared average roughness Rq, the maximum height Rt and the number of peaks S at the average roughness 1% value.

In order to clearly observe the surface properties of the implant, the surface properties were measured and shown in the following figures, and the surface roughness parameters (Ra, Rq, Rt and S) for each degree are shown in Table 2 below.

Surface Roughness Parameters by Surface Treatment Methods Ra (μm) Rq (μm) Rt (μm) S () Machining Implants 0.27 0.35 2.28 265 Blast treatment 0.69 0.91 5.92 664 Hydrochloric / sulfuric acid treatment 1.30 1.61 9.94 1015 Comparative Example 1 0.97 1.27 8.85 599 Comparative Example 2 1.06 1.34 9.14 482 Comparative Example 3 2.97 3.99 22.7 483 Ra: Average Roughness Rq: Squared Average Roughness Rt: Maximum Height S: Number of Peaks at Ra 1%

After the blasting treatment, the implant surface was formed according to FIG. 3 , and broken calcium phosphate particles embedded in the implant surface during the surface treatment mainly formed the surface, and these particles were strongly embedded in the surface and could not be removed even by ultrasonic cleaning. have.

The surface roughness value (Ra) is also a 0.69 ㎛ as shown in 4, it can be seen that about two-fold increased than the value (0.27 ㎛) of the machined surface roughness of the implant according to Figure 2; Square average roughness Rq, maximum height Rt, and S also show the same tendency as surface roughness value Ra.

After the blast treatment, the surface of the implant treated with a 70% aqueous solution of hydrochloric acid / sulfuric acid was observed to have a crater shape of about 2 to 4 μm uniformly formed on the entire surface of the implant as shown in FIG. 6 . can do.

In addition, the surface roughness value (Ra) was 1.30 μm, which was about twice as much as the surface roughness value after the blasting treatment, and the optimum surface roughness value was found to increase the adhesion. The squared mean roughness Rq and the maximum height Rt also tend to be the same as the surface roughness value Ra. In particular, the S value can predict the size and uniformity of the domains formed on the implant surface. As a value, 1015 peaks were detected when the acid treatment with a hydrochloric acid / sulfuric acid mixed aqueous solution. Since the total scanned length is 1000 μm, one domain is formed on the surface of the implant at about 1 μm intervals, and the most uniform surface structure is shown.

The surface of the acid treated implant (Comparative Example 1) using a nitric acid / fluoric acid mixed aqueous solution after blasting treatment has a wavy anisotropic surface shape according to FIG. 8 , and the surface roughness value (Ra) is shown in FIG. 9. Accordingly, it was 0.37 µm, 0.33 µm lower than the value treated with the hydrochloric acid / sulfuric acid aqueous solution of the present invention. The S value was found to be 599, which is less than the blasted implants (664) due to the uneven surface etching.

The surface of the implant (Comparative Example 2, Osseotite ^® ), which is surface-treated only with acid treatment currently on the market, has circular bones at intervals of about 10 μm, as shown in FIG. No uniform uneven formation was observed throughout. In addition, the surface roughness is 1.06 ㎛ showing a slightly smaller value than the optimum surface roughness, the S value is separated by about 50% compared to the value of the present invention.

The surface of the implant (Comparative Example 3, TPS ^? ) Manufactured by titanium plasma spray has many large domains of 20 μm or more on the surface as shown in FIG. 11 , but the overall uniformity is inferior. It is also observed that the surface is flat and there are no fine irregularities.

The surface roughness value Ra is 2.97 μm, which is very large, and the reason why the surface roughness is large is that there are domains having a size of about 20 μm, as shown in FIG. ) Is showing degree. In addition, this non-uniform surface shape also affects the S value and shows very low values of about 480 pieces.

The above results are summarized as follows.

(1) The surface roughness of implants treated with machining, blasting and hydrochloric acid / sulfuric acid aqueous solutions were measured to be 0.27, 0.69 and 1.30 μm, respectively, to Wennerberg et.al. The surface roughness condition (1.5 ± 0.4 µm) was best met.

(2) As the acid treatment method after the blasting process, the acid treatment at 80 ° C. for 5 minutes in a 70% hydrochloric acid / sulfuric acid aqueous solution showed the best surface roughness and uniformity.

(3) From the scanning electron micrograph and the S value, it was confirmed that the implant treated with the hydrochloric acid / sulfuric acid mixed aqueous solution after blasting had the most uniform surface shape, and according to the following examples, Comparative Examples 1 to 3 It is expected to have better osteoadhesion conditions compared to the surface properties of the implant.

As described above, the surface treatment method of acid treatment using a mixed aqueous solution of hydrochloric acid and sulfuric acid after the calcium phosphate blasting treatment of the present invention shows better surface roughness and uniform surface shape than conventional commercially available implants, resulting in osteoadhesion Excellent implants can be produced.

Claims (6)

A surface treatment method of a dental implant which is subjected to an blast treatment of an implant and then acid treated with a mixed aqueous solution of hydrochloric acid and sulfuric acid. The surface treatment method according to claim 1, wherein the blasting is performed at a pressure of 5 to 7 atmospheres using calcium phosphate particles having a diameter of 40 to 80 mesh. The surface treatment method according to claim 1, wherein the acid treatment is carried out at 70 to 90 DEG C for 4 to 6 minutes. The surface treatment method according to claim 1, wherein the aqueous hydrochloric acid / sulfuric acid solution is at a concentration of 50 to 90%. The surface treatment method according to claim 1, wherein the aqueous hydrochloric acid / sulfuric acid solution is hydrochloric acid: sulfuric acid = 1: 1 to 5: 1 (mol: mol). Dental implant obtained by the surface treatment method of claim 1.