WO2007040298A1

WO2007040298A1 - Electrolyte solution for implant surface treatment, method for implant surface treatment using the same, and implant manufactured by the same

Info

Publication number: WO2007040298A1
Application number: PCT/KR2005/004391
Authority: WO
Inventors: Jin Woo Park
Original assignee: Megagen Corp.
Priority date: 2005-10-04
Filing date: 2005-12-20
Publication date: 2007-04-12
Also published as: KR100611945B1

Abstract

An electrolyte solution for implant surface treatment, a method for treating the surface of an implant using the electrolyte solution, and an implant manufactured in the implant surface treatment method are provided. The implant surface treatment method includes manufacturing and preparing an electrolyte solution for surface treatment including a predetermined mineralizer and a calcium ion supplier for supplying calcium ions, soaking an implant subject to surface treatment in the electrolyte solution for surface treatment, and forming an oxide layer combined with calcium ions of a nano structure on a surface of the implant through a hydrothermal reaction under predetermined temperature, pressure, and time conditions. The characteristic of a fine structure in units of microns essential for the biomechanical interlocking in a living body can be maintained. Also, since the bio-adaptability is superior, when used in a living body, a bone reaction is improved. Furthermore, an effect of osseointegration can be improved and a relatively superior mechanical characteristic is provided.

Description

Description ELECTROLYTE SOLUTION FOR IMPLANT SURFACE

TREATMENT, METHOD FOR IMPLANT SURFACE TREATMENT USING THE SAME, AND IMPLANT MANUFACTURED BY THE SAME Technical Field

[1] The present invention relates to an electrolyte solution for implant surface treatment, a method for treating the surface of an implant using the electrolyte solution, and an implant manufactured in the implant surface treatment method, and more particularly, to an electrolyte solution for implant surface treatment which can maintain a fine surface characteristic in units of micrometers essential for biomechanical interlocking in a living body, exhibit a superior adaptability to a living body so that an improvement in the bone reaction is expected when used in the living body, improve an effect of osseointegration, and provide a relatively superior mechanical characteristic, a method for treating the surface of an implant using the electrolyte solution, and an implant manufactured in the implant surface treatment method. Background Art

[2] In general, an implant originally signifies a replacement to recover human tissues when they are lost. For the specific field of dentistry, the implant signifies transplantation of an artificial tooth. That is, the implant is used to semi-permanently place an artificial tooth in an alveolar bone. For general prostheses or false teeth, surrounding teeth and bones are damaged as time passes. However, for the implant, the surrounding teeth tissues are not damaged and decayed teeth are not generated while the function and shape thereof are the same as those of a natural tooth. Thus, the implant can be used semi-permanently.

[3] In the operation of an artificial tooth using the implant, an implantation position is punched using a predetermined drill and an implant is implanted in a gum bone, that is, an alveolar bone, to be osseointegrated to the gum bone. Next, an abutment is coupled to the implant and the abutment is covered with a final prosthesis, thus completing the operation. The implant operation can recover a single lost tooth, enhance the function of an artificial tooth of a partially or completed teeth-less patient, improve an aesthetic feature in the recovery of dental prosthesis, and help stabilization of a set of teeth by dispersing excessive stress applied to the surrounding alveolar bone. The in-bone implant operation to replace the lose tooth proves a long-term success rate and predicament of treatment. However, the success of a long-term implant is largely affected by not only the mental status of a patient but also the state of local bone including the quality and amount of bone around the position for the operation. In relation to this matter, there has been a report that the implant failure rate is high in a position such as an upper jaw molar portion where the bone quality is inferior (Jaffin etc., 1991).

[4] Recently, there have been many efforts to reduce a treatment period and increase a success rate of an implant in a position where a local bone state is inferior. Titanium Ti and a titanium alloy mainly used as an in-bone implant material in the field of dentistry and orthopedics generally has a bionert characteristic so that a direct combination to bone is not made. Thus, a method of improving a clinical result by providing a bioactive characteristic to the implant through a surface treatment such as coating of a surface of a metal implant with a material having a bioactive characteristic has been developed.

[5] Of the above methods, a method of coating and using hydroxyapatite in a plasma thermal spray method has been most widely used. However, the method revealed many problems such as weak coupling force to an implant in relation to the weakness of coating, forming of cracks, uneven crystallization, and very weakness to inflammation, plus a problem during a clinical use thereof (Hanisch et al., 1997; Albrektsson 1998; Morscher et al., 1998).

[6] A variety of methods have been developed to replace the hydroxyapatite coating in a plasma thermal spray method due to its demerits. One or a recent study shows that a titanium oxide film coupled with calcium ions improves osteoconduction and reveals a biochemical bonding with bone (SuI, 2003).

[7] In particular, it is known that a calcium component coupled to an oxide film on the surface of a metal implant formed of titanium (Ta) and an Ta alloy improves cell adhesion by increasing protein absorption on the surface through ion combination in a physiologic pH (Ellingsen 1991; Klinger et al., 1997). Also, a calcium titanate layer on the surface of an implant improves the adhesion of osteoclastic cells forming a bone, which is suggested as a method of improving osteointegration after an implant operation. Recently, it is reported that, when an oxide titanium film combined with calcium manufactured using a hydrothermal reaction is soaked in a simulated body fluid, apatite is formed on the surface and has a bioactivity (Hamada et al., 2002).

[8] However, most of many methods to manufacture the bioactive surface of an implant needs a minimum coating thickness required to show bioactivity (Wolke et al., 1999) and fails to keep the fine surface characteristic in units of micrometers necessary for biomechanical interlocking in a living body generated by acid etching or sand blasting due to the characteristic of a treatment method (Davies, 1998; Wolke et al., 1999; Lossdorfert et al., 2004; Szmukler-Moncler et al., 2004). Disclosure of Invention

Technical Problem

[9] To solve the above and/or other problems of various surface treatment methods developed to provide bioactivity to an implant, the present invention provides an electrolyte solution for implant surface treatment which can maintain a fine surface characteristic in units of micrometers essential for biomechanical interlocking in a living body, exhibit a superior adaptability to a living body so that an improvement in the bone reaction is expected when used in the living body, improve an effect of os- seointegration, and provide a relatively superior mechanical characteristic, a method for treating the surface of an implant using the electrolyte solution, and an implant manufactured in the implant surface treatment method. Technical Solution

[10] According to an aspect of the present invention, an implant surface treatment method comprising manufacturing and preparing an electrolyte solution for surface treatment including a predetermined mineralizer and a calcium ion supplier for supplying calcium ions, soaking an implant subject to surface treatment in the electrolyte solution for surface treatment, and forming an oxide layer combined with calcium ions of a nano structure on a surface of the implant through a hydrothermal reaction under predetermined temperature, pressure, and time conditions.

[11] The mineralizer is any one of sodium hydroxide (NaOH) and potassium hydroxide

(KOH).

[12] The mole concentration of the mineralizer in the electrolyte solution is 0.1 through

1 mole/liter to prevent the decrease of crystallization of calcium on the oxide layer formed on the surface of the implant through the hydrothermal reaction.

[13] The calcium ion supplier is any one of calcium oxide (CaO) and calcium hydroxide

(Ca(OH)₂).

[14] The mole concentration of the calcium ion supplier in the electrolyte solution is

0.001 through 0.02 mole/liter to prevent the over-precipitation of the calcium ion supplier by being incompletely resolved in the electrolyte solution.

[15] The manufacturing and preparing of an electrolyte solution for surface treatment is performed one of a nitrogen atmosphere and an argon atmosphere to prevent the electrolyte solution from reacting to carbon dioxide (CO ) in the air.

[16] According to another aspect of the present invention, a solvent used in the manufacturing and preparing of an electrolyte solution for surface treatment includes deionized water which prevents the generation of calcium carbonate (CaCo ) as the electrolyte solution for surface treatment reacts to a predetermined carboxyl radical.

[17] The hydrothermal reaction has conditions of a temperature of 100⁰C or more, a pressure of 1 Bar or more, and a period of time of several through several tens of hours. [18] When the hydrothermal reaction is performed in a hydrothermal reactor coated with a predetermined Teflon, the conditions are a temperature of 121-200⁰C, a pressure of

1-15 Bar, and a time period of 6-24 hours. [19] When the hydrothermal reaction is performed in a Hastelloy C hydrothermal reactor, the conditions are a temperature of 300⁰C, a pressure of 150 Bar, and a time period of 24 hours.

[20] The implant is manufactured of pure titanium (Ti) or a titanium (Ti) alloy.

[21] The titanium (Ti) alloy is one of a group selected from Ti-6A1-4V, Ti-6Al-7Nb, Ti-

13Nb-13Zr, Ti- 15Mo, Ti-35.3Nb-5.1Ta-7.1Zr, and Ti-29Nb-13Ta-4.6Zr. [22] The method further comprises a pretreatment operation in which any one or more than two of grinding, sanding blasting, washing, drying, and keeping of the implant subject to the surface treatment are performed. [23] After the forming of the oxide layer, the method further comprises a post-treatment operation in which washing and drying of the implant is performed. [24] The oxide layer is a calcium titanate layer that is a titanium oxide layer combined with calcium ions of a nano structure. [25] According to another aspect of the present invention, an implant according to the above implant surface treatment methods has a calcium titanate layer that is a titanium oxide layer combined with calcium ions of a nano structure formed on the surface of the implant. [26] According to another aspect of the present invention, an electrolyte solution for surface treatment comprises a predetermined mineralizer of 0.1 through 1 mole/liter and a calcium ion supplier of 0.001 through 0.02 mole/liter for supplying calcium ions. [27] The mineralizer is any one of sodium hydroxide (NaOH) and potassium hydroxide

(KOH). [28] The calcium ion supplier is any one of calcium oxide (CaO) and calcium hydroxide

(Ca(OH)₂).

Brief Description of the Drawings [29] FIG. 1 is a flowchart for explaining an implant surface treatment method according to an embodiment of the present invention; [30] FIGS. 2 and 3 are SEM images of a specimen according to an embodiment of the present invention; [31] FIGS. 4 and 5 are SEM images of a specimen according to a comparative example of the present invention; [32] FIG. 6 is a graph showing the result of the X-ray diffraction analysis of the specimens of the present embodiment and the comparative example;

[33] FIG. 7 is a graph showing the result of the X-ray photoelectrons spectroscopy of the specimen of the present embodiment;

[34] FIGS. 8 and 9 are graphs showing the result of a depth profile using AES (Auger electron spectroscopy) of the specimen of the present embodiment; and

[35] FIG. 10 is a SEM image of the surface of the specimen of the present embodiment soaked in the NaOH solution (Hank's solution) for four weeks. Best Mode for Carrying Out the Invention

[36] FIG. 1 is a flowchart for explaining an implant surface treatment method according to an embodiment of the present invention. Referring to FIG. 1, the surface treatment of an implant according to an embodiment of the present invention includes a pre- treatment step (SI l), an electrolyte solution manufacturing/preparing step (S12), an implant soaking step (S 13), an oxide layer forming step (S 14), and a post-treatment step (S 15), to thereby form a calcium titanate layer that is a titanium oxide layer combined with calcium ions of a nano structure on the surface of the implant.

[37] In the pretreatment step (Sl 1), an implant that is subject to the surface treatment is grinded, sand-blasted, washed, and dried. The implant can be kept for a predetermined time until the surface treatment after drying. However, the pretreatment step (Sl 1) can be excluded from the method.

[38] In the electrolyte solution manufacturing/preparing step (S 12), a predetermined electrolyte solution for soaking the implant is manufactured and prepared. The electrolyte solution may include a calcium ion supplier to supply a predetermined mineralizer and calcium ions.

[39] The mineralizer is formed of a material exhibiting strong alkali. Any of sodium hydroxide (NaOH) and potassium hydroxide (KOH) can be used as the material. When the mole concentration of NaOH or KOH is lower than 0.1 mole/liter in the electrolyte solution, the crystallization degree of calcium titanate formed through a hydrothermal reaction which will be described later. Thus, the mole concentration of NaOH or KOH in the electrolyte solution is preferably at least 0.1 mole/liter in a range of about 0.1 through 1 mole/liter.

[40] The calcium ion supplier is a component for supplying calcium ions of strong alkali and any one of calcium oxide (CaO) and calcium hydroxide (Ca(OH) ) can be used therefor. When the mole concentration of CaO and Ca(OH) in the electrolyte solution is greater than 0.02 mole/liter, the CaO and Ca(OH) are not completely resolved in the solution so that over-precipitation is generated in the electrolyte solution. Thus, the mole concentration of the CaO and Ca(OH) in the electrolyte solution is preferably not more than 0.02 mole/liter, particularly in a range of about 0.001 through 0.02 mole/ liter.

[41] As described above, the electrolyte solution can be manufactured with a mineralizer having a mole concentration in a range of 0.1 through 1 mole/liter and a calcium ion supplier having a mole concentration in a range of 0.001 through 0.02 mole/liter. In the meantime, it is preferable to manufacture the electrolyte solution in either a nitrogen atmosphere or an argon atmosphere to prevent the electrolyte solution reacts to carbon dioxide (CO ) in the air. Also, deionized water which can prevent the electrolyte solution from reacting to a predetermined carboxyl radical to generate calcium carbonate (CaCO ) is preferably used as a solvent constituting the electrolyte solution.

[42] In the implant soaking step (S 13), implant subject to the surface treatment is soaked in the electrolyte solution for surface treatment manufactured in the above-described step S 12. The soaked implant is manufactured with a material of pure titanium (Ti) or a titanium alloy. For reference, the titanium alloy includes any one of Η-6A1-4V, Ti- 6Al-7Nb, Ti-13Nb-13Zr, Ti- 15Mo, Ti-35.3Nb-5.1Ta-7.1Zr, and Ti-29Nb-13Ta-4.6Zr.

[43] In the oxide layer forming step (S 14), an oxide layer combined with calcium ions of a nano structure is formed on the surface of the implant by generating a predetermined hydrothermal reaction in the implant soaked in the electrolyte solution . As described above, since the implant is manufactured of the pure Ti or Ti alloy, the finally formed oxide layer is a calcium titanate layer that is a titanium oxide layer of a nano structure. The hydrothermal reaction adopted in the step S 14 forming the calcium titanate layer requires predetermined temperature, pressure, and time conditions. The temperature condition is over 100⁰C, the pressure condition at least 1 Bar, and the time condition is several through several tens of hours.

[44] However, when the hydrothermal reaction is performed within a hydrothermal reactor (not shown) coated with a predetermined Teflon, the temperature condition, pressure condition, and time condition respectively are 121-200⁰C, 1-15 Bar, and 6-24 hours. When the hydrothermal reaction is performed in a predetermined Hastelloy C hydrothermal reactor, the temperature condition, pressure condition, and time condition respectively are 300⁰C, 150 Bar, and 24 hours.

[45] In the post-treatment step (S 15), the implant where the calcium titanate layer that is a titanium oxide layer combined with calcium ions of a nano structure is formed on the surface through the hydrothermal reaction is washed and dried. Ultrasonic washing can be performed using deionized water for several through several tens of minutes.

[46] The experiments for forming an oxide layer on a predetermined specimen using the above surface treatment method is described below as a present embodiment and a comparative example.

[47] <Present Embodiment

[48] First, in the present embodiment, a common pure titanium plate having a thickness of 1 mm and cut by a size of 10 X 10 mm is used. In order to see the effect of the surface treatment method on the conventional fine surface characteristic in units of micrometers, a pre treatment is performed using the following two mechanical surface treatment methods.

[49] The surface of a type of a specimen is grinded step by step by a SiC grinding paper of #1200 and ultrasonic washed for 15 minutes sequentially using distilled water, alcohol, and acetone solution. The other type of a specimen is the grinded specimen for which sand blasting is performed using hydroxy apatite particles having a size of 100 microns. Both types of specimens undergo passivation using nitric acid according to the aSTM standard F-86 and are dried, after washing, in the air on an aseptic work place for 24 hours for keeping.

[50] Next, to manufacture an electrolyte solution, CaO of 0.001-O.OlM and NaOH of

0.1- IM manufactured by Sigma Co., Ltd. are resolved in deionized water. The manufacturing of the electrolyte solution is performed in an argon atmosphere.

[51] After the electrolyte solution is manufactured, Teflon is moved to a coated hy- drothermal reactor (not shown) and the specimen is soaked in the electrolyte solution. The hydrothermal reaction is performed at temperatures of 121-200⁰C and a pressure of 1-15 Bar for 6-24 hours. After the hydrothermal reaction is performed, the removed specimen is ultrasonic washed using the deionized water for 10 minutes.

[52] After the surface treatment, to evaluate the activity of a surface of a specimen, the specimen is soaked in a simulated body fluid, that is, Hank's solution, under the conditions of pH 7.4 and a temperature of 37⁰C similar to blood plasma. The characteristic of the specimen after the surface treatment is analyzed using various analysis methods.

[53] <Comparative Example>

[54] In the comparative example, the specimen that is pretreated in the same method as the present embodiment is soaked in the electrolyte solution manufactured by resolving CaO of 0.001-0.0 IM in deionized water at an argon atmosphere without adding a mineralizer.

[55] After soaking the specimen in the electrolyte solution, hydrothermal reaction is performed at temperatures of 121-200⁰C and pressures of 1-15 Bar for 6-24 hours in a hydrothermal reactor (not shown) coated with Teflon and another hydrothermal reaction is performed at a temperature of 300⁰C and a pressure of 150 Bar for 24 hours in a Hastelloy C hydrothermal reactor.

[56] The characteristic of the specimen used in the present embodiment and the comparative example is described below.

[57] The morphological fine structure of a surface layer of a specimen

[58] FIGS. 2 through 5 show the result of the observation of the morphological fine structure of a surface layer of a specimen using a scanning electron microscopy. FIGS. 2 and 3 are SEM images of a specimen according to an embodiment of the present invention after performing a hydrothermal reaction at a temperature of 18O⁰C and a pressure of 10 Bar for 24 hours in an electrolyte solution including NaOH of 0.5M and CaO of 0.002M.

[59] In FIG. 2, a particular surface structure generated by the hydrothermal reaction is not observed from a specimen, for which #1200 SiC grinding is performed as a pre- treatment, at a low magnification rate of 1000 times, but grinding marks generated by the grinding are clearly observed. At a high magnification rate of 30,000 times (an inserted image), it is observed that a nano structure having a size of about 100 nm is generated on the surface. In FIG. 3, a typical structure including irregular depressions generated by blasting is observed from a specimen, for which sand blasting with hy- droxyapatite particles is performed as a pretreatment, at a low magnification rate of 1000 times, but a particular surface structure after the hydrothermal reaction is not observed. At a high magnification rate of 10,000 times (an inserted image), a nano structure is observed.

[60] FIGS. 4 and 5 are SEM images of a specimen according to a comparative example after performing a hydrothermal reaction at a temperature of 18O⁰C and a pressure of 10 Bar for 24 hours in an electrolyte solution including CaO of 0.005M, in which a thick layer having a spherical shape is formed.

[61] As a result, the coating of a nano structure is generated which maintains the conventional fine surface structure in units of microns as it is when the hydrothermal reaction is performed using the electrolyte solution including calcium ions to which the mineralizer is added.

[62] The result of X-ray diffraction analysis of a specimen

[63] FIG. 6 shows the result of the X-ray diffraction analysis of a specimen. In FIG. 6, graph (a) shows the result of an X-ray diffraction analysis of a specimen in the comparative example while graphs (b) through (e) show the result of an X-ray diffraction analysis of a specimen in the present embodiment. The structure of crystallization existing on the surface layer is analyzed using a thin-film X-ray diffractometer with a thin film analyzer.

[64] The graph (a) is a specimen in the comparative example to which a hydrothermal reaction is performed at a temperature of 300⁰C and a pressure of 150 Bar for 24 hours in an electrolyte solution including CaO of 0.005M. A weak peak (JCPDS #22-0153,calcium titanate, CaTiO ) of calcium titanate is observed.

[65] The graph (b) is a specimen to which a hydrothermal reaction is performed at a temperature of 15O⁰C and a pressure of 5 Bar for 24 hours in an electrolyte solution including NaOH of 0.2M and CaO of 0.005M, the graph (c) is a specimen to which a hydrothermal reaction is performed at a temperature of 18O⁰C and a pressure of 10 Bar for 24 hours in an electrolyte solution including NaOH of 0.1M and CaO of 0.002M, the graph (d) is a specimen to which a hydrothermal reaction is performed at a temperature of 18O⁰C and a pressure of 10 Bar for 24 hours in an electrolyte solution including NaOH of 0.2M and CaO of 0.002M, and the graph (e) is a specimen to which a hydrothermal reaction is performed at a temperature of 18O⁰C and a pressure of 10 Bar for 24 hours in an electrolyte solution including CaO of 0.002M. A peak of calcium titanate that is relatively clearer than the graph (a) is observed. Also, it is observed that the strength of the peak increases as the concentration of the NaOH increases. The peak of calcium titanate is not observed at all in the specimen to which the hydrothermal reaction is performed under different conditions in the comparative example. Thus, when NaOH and KOH that are strong alkali exist as the mineralizer, the crystallized calcium titanate is generated on the surface of the specimen.

[66] The result of X-ray photoelectron spectroscopy analysis of a specimen

[67] FIG. 7 shows the result of the X-ray photoelectron spectroscopy of a specimen manufactured in the present embodiment. In FIG. 7, the existence of a calcium (Ca) component is observed and a dual peak of Ca2p is observed in a high resolution spectrum (an inserted image).

[68] The result of a depth profile according to the component of a coating layer using

AES (Auger electron spectroscopy) of the specimen

[69] FIGS. 8 and 9 show the result of a depth profile using AES (Auger electron spectroscopy) of a specimen manufactured in the present embodiment. FIGS. 8 and 9 are graphs showing the component analysis according to the depth of a coating layer of a specimen to which a hydrothermal reaction is performed at a temperature of 18O⁰C and a pressure of 10 Bar respectively in an electrolyte solution including NaOH of 0.2M and CaO of 0.002M and an electrolyte solution including NaOH of 0.5M and CaO of 0.002M. It is observed that the calcium component is distributed throughout the entire layer of titanium oxide film. Also, a graded structure reducing step by step according to the depth, that is, a ratio of the calcium component gradually decreases from the surface of the uppermost layer toward a titanium radical. Also, in the same hydrothermal reaction condition, when the concentration of NaOH increases, the thickness of the titanium oxide layer combined with calcium is relatively further increased.

[70] The result of formation of apatite on the surface in a simulated body fluid of a specimen

[71] FIG. 10 is a SEM image of apatite generated on the surface after soaking a specimen in a simulated body fluid (Hank's solution) for four weeks to evaluate the bioactivity of the specimen manufactured in the present embodiment. A relatively thick apatite is formed on the entire surface after four weeks. Thus, it can be seen that the specimen manufactured has bioactivity in the evaluation.

[72] As described above, according to the present invention, the bio-adaptability of an implant is superior. Also, since the generated calcium titanate layer maintains the characteristic of a fine structure in units of microns formed in the mechanical surface treatment method as it is, a synergetic effect can be expected in improving a bone reaction when used in a living body unlike the conventional surface treatment method to provide bioactivity. Also, unlike the conventional technology, the present invention provides a mechanical characteristic having a superior coating. In addition, an effect of osseointegration can be improved. Industrial Applicability

[73] As described above, according to the present invention, the characteristic of a fine structure in units of microns essential for the biomechanical interlocking in a living body can be maintained. Also, since the bio-adaptability is superior, when used in a living body, a bone reaction is improved. Furthermore, an effect of osseointegration can be improved and a relatively superior mechanical characteristic is provided.

Claims

[1] An implant surface treatment method, the method comprising: manufacturing and preparing an electrolyte solution for surface treatment including a predetermined mineralizer and a calcium ion supplier for supplying calcium ions; soaking an implant subject to surface treatment in the electrolyte solution for surface treatment; and forming an oxide layer combined with calcium ions of a nano structure on a surface of the implant through a hydrothermal reaction under predetermined temperature, pressure, and time conditions.

[2] The method of claim 1, wherein the mineralizer is any one of sodium hydroxide

(NaOH) and potassium hydroxide (KOH).

[3] The method of claim 2, wherein the mole concentration of the mineralizer in the electrolyte solution is 0.1 through 1 mole/liter to prevent the decrease of crystallization of calcium on the oxide layer formed on the surface of the implant through the hydrothermal reaction.

[4] The method of claim 1, wherein the calcium ion supplier is any one of calcium oxide (CaO) and calcium hydroxide (Ca(OH) ).

[5] The method of claim 4, wherein the mole concentration of the calcium ion supplier in the electrolyte solution is 0.001 through 0.02 mole/liter to prevent the over-precipitation of the calcium ion supplier by being incompletely resolved in the electrolyte solution.

[6] The method of claim 1, wherein the manufacturing and preparing of an electrolyte solution for surface treatment is performed one of a nitrogen atmosphere and an argon atmosphere to prevent the electrolyte solution from reacting to carbon dioxide (CO ) in the air.

[7] The method of claim 1, wherein a solvent used in the manufacturing and preparing of an electrolyte solution for surface treatment includes deionized water which prevents the generation of calcium carbonate (CaCo ) as the electrolyte solution for surface treatment reacts to a predetermined carboxyl radical.

[8] The method of claim 1, wherein the hydrothermal reaction has conditions of a temperature of 100⁰C or more, a pressure of 1 Bar or more, and a period of time of several through several tens of hours.

[9] The method of claim 1, wherein, when the hydrothermal reaction is performed in a hydrothermal reactor coated with a predetermined Teflon, the conditions are a temperature of 121-200⁰C, a pressure of 1-15 Bar, and a time period of 6-24 hours. [10] The method of claim 1, wherein, when the hydrothermal reaction is performed in a Hastelloy C hydrothermal reactor, the conditions are a temperature of 300⁰C, a pressure of 150 Bar, and a time period of 24 hours. [11] The method of claim 1, wherein the implant is manufactured of pure titanium

(Ti) or a titanium (Ti) alloy. [12] The method of claim 11, wherein the titanium (Ti) alloy is one of a group selected from Η-6A1-4V, Ti-6Al-7Nb, Ti- 13Nb- 13Zr, Ti- 15Mo, Ti-

35.3Nb-5.1Ta-7.1Zr, and Ti-29Nb-13Ta-4.6Zr. [13] The method of claim 1, further comprising a pretreatment operation in which any one or more than two of grinding, sanding blasting, washing, drying, and keeping of the implant subject to the surface treatment are performed. [14] The method of claim 1, after the forming of the oxide layer, further comprising a post-treatment operation in which washing and drying of the implant is performed. [15] The method of claim 1, wherein the oxide layer is a calcium titanate layer that is a titanium oxide layer combined with calcium ions of a nano structure. [16] An implant according to the implant surface treatment method of any of claims 1 through 15, wherein a calcium titanate layer that is a titanium oxide layer combined with calcium ions of a nano structure is formed on the surface of the implant. [17] An electrolyte solution for surface treatment comprising: a predetermined mineralizer of 0.1 through 1 mole/liter; and a calcium ion supplier of 0.001 through 0.02 mole/liter for supplying calcium ions. [18] The electrolyte solution of claim 17, wherein the mineralizer is any one of sodium hydroxide (NaOH) and potassium hydroxide (KOH). [19] The electrolyte solution of claim 17, wherein the calcium ion supplier is any one of calcium oxide (CaO) and calcium hydroxide (Ca(OH) ).