KR102480199B1 - Selective coating method of apatite using laser and selective coating device of that - Google Patents

Abstract

The present invention provides a method for selectively forming an apatite film. The method comprises: a step (a) of supporting an implant substrate in a precursor solution for apatite formation containing Ca^2+ and PO_4^3- ions; a step (b) of emitting a laser beam to the implant substrate supported in the precursor solution; a step (c) of positioning the focus of the laser beam on a specific portion of the implant substrate to generate an energy density difference of the laser beams reaching a screw thread portion and a screw bone portion; and a step (d) of forming an apatite film by activating the reaction of Ca^2+ and PO_4^3- ions in the precursor solution in the area at which the laser beam has emitted. In addition, provided is a device for selectively forming an apatite film. The device comprises: a solution accommodation unit which accommodates a precursor solution for apatite formation containing Ca^2+ and PO_4^3- ions; a laser emitting unit which emits a laser beam to the implant substrate supported in the precursor solution; and a substrate rotating unit which rotates the implant substrate supported in the precursor solution.

Description

Selective coating method of apatite using laser and selective coating device of that}

The present invention relates to a method for forming an apatite film and an apparatus therefor, and more specifically, to a method for forming an apatite film having different thicknesses on a screw thread and a screw bone by adjusting a focal position of a laser and an apparatus using the same.

Titanium-based alloys, which are most widely used as medical metal materials, are reported to be superior to previously used biomaterials, such as low elastic modulus and excellent biocompatibility and corrosion resistance. However, since it is bioinactive, it does not directly induce bone formation, and it takes a considerable amount of treatment time to achieve bone synthesis, and the naturally formed oxidized powder is thin and disappears quickly, so it does not lead to regeneration of adjacent bone tissue. has problems with

Therefore, in order to solve the above problem that the implant cannot be directly combined with bone and to solve the disadvantage of relaxation in order to shorten the bone bonding period, bioactivity is given through implant surface treatment. Physical and chemical surface treatment is performed on the surface of titanium, which is used as the main material of implants, to further improve bioactivity, thereby shortening the healing period after implant placement in the human body. Research for more effective surface treatment is continuously being conducted. There is a situation.

At this time, hydroxyapatite is used as a material for surface treatment on the surface of titanium. Hydroxyapatite (hydroxyapatite) is a basic component constituting the hard tissue of the human body and is also used as a material for bone tissue transplantation or bone regeneration. The chemical structure of hydroxyapatite is Ca10(PO4)6(OH)2, and hydroxyapatite in human tooth enamel is mainly distributed in the outermost enamel of about 1-2 mm thickness. It is known that such hydroxyapatite can exhibit a remineralization effect and thus exhibit a function of directly filling microscopic pores of demineralized enamel.

Therefore, in order to film hydroxyapatite on the surface of a substrate such as titanium through surface treatment, anodizing, sol-gel method, plasma spraying, chemical vapor deposition (CVD) and plasma electrolysis Various methods such as oxidation (PEO-Plasma Electrolytic Oxidation) are used.

First, anodizing is a method of forming oxides and metal salts relatively thickly on the surface of a metal using an external power source. The metal for which an oxide layer is to be formed is installed on the anode, and another insoluble metal is brought into contact with the cathode so that current in the electrolyte solution When an electric current is applied for anodization by flowing a metal hydroxide at a very low voltage, a fine film is formed, and when a voltage of about 10V is applied, a metal oxide layer is formed. However, once the oxide layer is formed, the internal stress is concentrated in the metal oxide layer due to the increase in resistance, the oxide layer is destroyed at 70V, and when the voltage is raised again, a second porous oxide layer is formed. During this process, sparks are generated, forcibly Since the oxide layer is formed by applying electricity, the electrical efficiency is poor, and the local area where the spark is generated receives thermal stress, which not only adversely affects the physical properties of titanium, but also has a problem of deteriorating final physical properties due to poor adhesion.

The sol-gel method (Sol-gel) prepares a solution that becomes a gel by hydrolysis and polymerization with alcohol, water, acid, etc. to produce a film, and describes a homogeneous solution in a relatively low viscosity state. The wet coating method, such as dip-coating, which applies the sol-gel method, is a low-temperature process, and can be coated regardless of the area, and the thickness and microstructure of the film can be controlled. Although there are advantages, there are disadvantages in that a post-heat treatment process for crystallization is added, formation of a plate-shaped film is limited, and an adhesive for strengthening adhesion must be inserted into the intermediate layer in order for the film to have sufficient bonding strength with the base material.

Plasma spraying is one of the fields of thermal spraying, and refers to a process of depositing a material with a high melting point, such as metal and non-metallic ceramic, in a molten or semi-molten state on a substrate. There are no restrictions on the material and size of the base material, no deformation of the base material, on-site construction is possible, thick film coating is possible, the film thickness is easy to control, and the types of coating materials are diverse. 06 to 15%, and it is not a metallic bond, but a mechanical bond, so it has the disadvantage of being weak against impact when titanium is coated with ceramic, and it is difficult to apply implants because of its weak bonding with the parent material.

Plasma electrolytic coating surface treatment is a surface treatment method for forming a dense and mechanically stable coating layer by inducing micro-discharges on the surface of a metal material immersed in an electrolyte. As such, the properties of the coating layer formed by the plasma electrolytic coating method are controlled by various process variables including the electrolyte, and in particular, the electrolyte conditions and the amount of current density in titanium and titanium alloys are the most important factors affecting the formation and physical properties of the coating layer. The electrolyte solution used at this time is generally potassium phosphate, sodium phosphate, glycerol phosphate, or acid salt series. However, such additives generally play a role in facilitating the plasma electrolytic oxidation process by increasing electrical conductivity and pH, but may react with hydroxyapatite to lower the purity and form other compounds, thereby forming hydroxyapatite on the surface of the implant. There are problems in crystallinity of apatite and very low content in the film layer.

Japanese Unexamined Patent Publication No. 2012-030993

An object of the present invention is to provide a method of forming an apatite film with different thicknesses on a screw thread and a screw bone by adjusting the focal position of a laser and a device using the same.

In order to solve the above problems, a method for forming a selective apatite film using a laser according to the present invention includes (a) supporting a substrate for implant in a precursor solution for forming apatite containing Ca ²⁺ ions and PO ₄ ^3- ions. step; (b) irradiating a laser beam to the implant substrate supported in the precursor solution; (c) positioning the focus of the laser beam on a specific part of the substrate for implantation to generate a difference in energy density of the laser beam reaching the screw thread part and the screw bone part; and (d) forming an apatite film on the region irradiated with the laser beam while activating the reaction of Ca ²⁺ ions and PO ₄ ^3- ions in the precursor solution.

At this time, in the step (c), it is preferable to place the focus of the laser beam on the threaded portion of the substrate for implantation.

In addition, the step (d) is preferably performed in a manner in which the substrate for implant is rotated in the axial direction at a constant speed and the laser beam is scanned according to the progress speed of the screw thread.

On the other hand, the step (b) may include a step performed by a first laser beam irradiated so as to vertically contact the top of the screw thread and a step performed by a second laser beam irradiated in an inclined direction of the screw thread. can

In addition, the step (b) may further include a step performed by a third laser beam irradiated on an inclined surface of a screw thread opposite to the irradiated second laser beam.

In order to solve the above problems, an apparatus for forming a selective apatite film using a laser according to the present invention includes a solution accommodating unit for accommodating a precursor solution for forming apatite containing Ca ²⁺ ions and PO ₄ ^3- ions; a laser irradiation unit for irradiating a laser beam to the implant substrate supported in the precursor solution; and a substrate rotating unit configured to rotate the implant substrate supported in the precursor solution.

At this time, it is preferable that the laser irradiation unit generates a difference in energy density of the laser beam reaching the screw thread portion and the screw bone portion by locating the focus of the laser beam on a specific portion of the substrate for implantation.

In addition, the laser irradiation unit may position the focus of the laser beam on a threaded portion of the substrate for implantation.

Meanwhile, the substrate rotating unit rotates the substrate for implant at a constant speed in an axial direction so that the laser beam scans the screw thread portion, and it is preferable to advance the substrate according to the progress speed of the screw thread.

In addition, the laser irradiation unit, a first laser for irradiating a laser beam so as to vertically contact the top of the screw thread; a second laser beam for irradiating a laser beam in the direction of the inclined surface of the screw thread; and a third laser for radiating a laser to an inclined surface of the spiral opposite to which the laser beam of the second laser is irradiated.

According to the selective apatite film formation method using a laser according to the present invention,

First, since the laser beam is focused on a specific part of the screw thread, it is possible to form a thicker amatite film on the screw valley part of the screw thread.

Second, since the energy density of the laser beam can be increased at the top of the screw thread or the screw valley by using a plurality of lasers, it is possible to form a thicker amatite film on a specific part if necessary.

1 is a flowchart illustrating a method of selectively forming an apatite film using a laser according to the present invention.
2 is a block diagram of an apparatus for forming a selective apatite film using a laser according to the present invention.
3 illustrates the formation of an atapite film at a selective thickness on a screw thread by a difference in density of a laser beam.
4 illustrates the formation of an atapite film at a selective thickness on a screw thread by a difference in density of a laser beam as another embodiment of the present invention.
5 illustrates the formation of an atapite film with a selective thickness in the screw valley portion due to the difference in the density of the laser beam.
FIG. 6 illustrates the formation of an atapite film with a selective thickness in a screw valley portion by a difference in density of a laser beam as another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that in the accompanying drawings, the same components are indicated by the same reference numerals as much as possible. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated.

1 is a flow chart explaining a selective apatite film forming method using a laser according to the present invention, FIG. 2 is a block diagram of a selective apatite film forming apparatus using a laser according to the present invention, and FIG. 3 is a laser beam density It is a view explaining that an atapite film is formed at a selective thickness on a screw thread due to a difference, and FIG. 4 is another embodiment of the present invention, showing that an atapite film is formed at a selective thickness on a screw thread due to a difference in the density of a laser beam. FIG. 5 explains the formation of an atapite film with a selective thickness on the screw trough portion by the difference in the density of the laser beam, and FIG. 6 is another embodiment of the present invention, This explains the formation of an atapite film with a selective thickness on the screw bone portion.

First, an apparatus 1000 for forming a selective apatite film using a laser according to the present invention will be described with reference to FIGS. 2 to 6 . An apatite film forming apparatus 1000 according to the present invention includes a laser irradiation unit 100, a solution receiving unit 200, and a substrate rotation unit 300.

The solution accommodating unit 200 accommodates a precursor solution (W) for apatite formation including Ca ²⁺ ions and PO ₄ ^3- ions.

The laser irradiation unit 100 irradiates the laser beam L to the substrate I for implant supported on the precursor solution W. The precursor solution (W) for forming apatite containing Ca ²⁺ ions and PO ₄ ^3- ions reacts with the energy of the laser beam (L) to generate apatite on the surface of the substrate (I) for implantation.

The substrate rotation unit 300 rotates the implant substrate (I) supported in the precursor solution (W). The substrate rotating unit 300 has a shape including a bracket 310 for fixing the implant substrate (I). In the drawing, the bracket 310 is as if fixing the screw portion of the substrate for implantation (I), but this is only for concise illustration, and the shape and rotation method of the bracket 310 is of the substrate for implantation (I). It can be implemented in various ways depending on the form.

The present invention is for forming a thicker apatite film (A) on the screw bone portion of the screw thread (N) of the substrate (I) for implantation, and has a feature of using the difference in density of the laser beam (L). That is, the thread portion or the thread portion may be selectively thickened as needed.

The laser irradiator 100 focuses the laser beam L on a specific part of the substrate I for implantation (ie, the top of the screw thread N (see FIG. 3) or the screw bone of the screw thread N (see FIG. 5). position to generate a difference in energy density of the laser beam reaching the screw thread part and the screw bone part.

In the case of the embodiment of FIG. 3 , since the energy density of the laser beam L is high at the top of the screw thread N, the generation rate of the apatite film A is high, and the laser beam L is Since it is dispersed and the energy density is lowered, the generation rate of the apatite film (A) is low, so that it is deposited with a thin thickness.

In the case of the embodiment of FIG. 5 , since the energy density of the laser beam L is high in the screw valley of the screw thread N, the production rate of the apatite film A is high, so it is deposited thickly in the valley, and the screw thread of the screw thread N In , since the laser beam (L) is dispersed and the energy density is lowered, the generation rate of the apatite film (A) is low and deposited with a thin thickness.

The substrate rotating unit 300 rotates the substrate for implantation (I) along all surfaces of the screw thread (N) to create an apatite film (A) - that is, to expose all screw thread surfaces to the laser beam (L). It rotates at a constant speed in the axial direction. Due to this, the laser beam (L) can be scanned as if the threaded portion (360 °) is rotated.

The substrate rotating unit 300 may operate in a manner of advancing the substrate I for implantation. The apatite film (A) may be formed in such a manner that the laser irradiation unit 100 is fixed and the substrate rotating unit 300 advances while rotating the substrate I for implantation by 360°.

Simply, the substrate rotating unit 300 rotates the substrate I for implantation by 360°, and the laser irradiation unit 100 may move the position of the laser beam L and scan it.

According to another embodiment of the present invention, the laser irradiation unit 100 may use a plurality of laser beams L1, L2, and L3 to generate a difference in energy density of the laser beam reaching the screw thread portion and the screw bone portion.

Referring to FIGS. 4 and 6 , the laser irradiation unit 100 includes a first laser 110 , a second laser 120 and a third laser 130 .

The first laser 110 is disposed to irradiate the laser beam L1 so as to vertically contact the top of the screw thread N, and the second laser 120 emits the laser beam L2 in the direction of the inclined plane of the screw thread N. The third laser 130 may be arranged to irradiate the laser beam L3 in a direction opposite to the inclined surface of the screw thread N.

Three laser beams L1, L2, and L3 are overlapped on the top of the screw thread N to create a thick amatite film A at this portion. Although three lasers 110, 120, and 130 are shown in FIGS. 4 and 6, the laser irradiator 100 may be implemented using only two lasers 120 and 130 depending on the embodiment.

1 is a flowchart illustrating a method of selectively forming an apatite film using a laser according to the present invention. Even when the selective apatite film forming apparatus 1000 described in FIGS. 2 to 6 is implemented time-sequentially, it corresponds to the present embodiment, so The part described about is also applied as it is to this embodiment.

A method of selectively forming an apatite film using a laser according to an embodiment includes the steps of detecting an implant substrate (I) (S100), irradiating a laser beam (S200), generating a difference in density of a laser beam (S300), and forming an apatite film. (S400) is included.

In step S100, the substrate for implantation (I) is supported in the precursor solution (W) for forming apatite containing Ca ²⁺ ions and PO ₄ ^3- ions.

Specifically, step S100 is performed by placing the implant substrate I on the substrate rotating unit 300 and injecting the precursor solution W for apatite formation into the solution receiving unit 200 .

Subsequently, in step S200, a laser beam is irradiated to the implant substrate (I) supported in the precursor solution (W).

Subsequently, in step S300, the focus of the laser beam L is placed on a specific portion of the base material I for implantation (the top of the screw thread N or the screw bone portion) to reach the screw thread portion N and the screw bone portion. (L) causes an energy density difference of

Subsequently, in step S400, the reaction of Ca ²⁺ ions and PO ₄ ^3- ions in the precursor solution (W) is activated in the region irradiated with the laser beam (L), thereby forming an apatite film (A).

At this time, in step S300, it is preferable to position the focus of the laser beam (L) on the screw thread (N) portion of the substrate (I) for implantation.

At this time, in step S400, it is preferable to rotate the substrate for implantation (I) in the axial direction at a constant speed, and scan the laser beam (L) according to the traveling speed of the screw thread (N).

On the other hand, as described in FIG. 4, in step S200, the step performed by the first laser beam L1 irradiated so as to vertically contact the top of the screw thread N and the second irradiated in the inclined direction of the screw thread N. It includes a step performed by 2 laser beams (L2), and further includes a step performed by a third laser beam (L3) irradiated on the inclined surface of the screw N opposite to which the second laser beam (L2) is irradiated. can

For convenience of description, the laser beam irradiation step (S200), the laser beam density difference generation step (S300), and the apatite film forming step (S400) are separately described, but when the laser beam L is irradiated, Ca ²⁺ Since the precursor solution for forming apatite (W) containing ions and PO ₄ ^3- ions is activated and formed on the apatite film (A) by ion reaction, steps S200, S300, and S400 are concurrent steps.

Embodiments of the present invention disclosed in this specification and drawings are only presented as specific examples to easily explain the technical content of the present invention and help understanding of the present invention, and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art that other modified examples based on the technical idea of the present invention can be implemented in addition to the embodiments disclosed herein.

1000: Apatite film forming device
100: laser irradiation unit
200: solution receiving unit
300: base rotation unit
W: precursor solution I: substrate for implant
A: Apatite film L: Laser beam
N: thread

Claims (10)

delete delete delete delete delete a solution accommodating unit accommodating a precursor solution for apatite formation including Ca ²⁺ ions and PO ₄ ^3- ions;
a laser irradiation unit for irradiating a laser beam to the implant substrate supported in the precursor solution; and
A substrate rotation unit for rotating the implant substrate supported in the precursor solution,
The laser irradiator,
A selective apatite film forming device using a laser, characterized in that the laser beam is focused on a specific part of the substrate for implantation to generate a difference in energy density of the laser beam reaching the screw thread part and the screw bone part. delete The method of claim 6,
The laser irradiator,
A selective apatite film forming device using a laser, characterized in that the focus of the laser beam is located on the screw valley portion of the substrate for implantation. The method of claim 8,
The substrate rotating part,
Selective apatite film forming apparatus using a laser, characterized in that the laser beam rotates the substrate for implant at a constant speed in the axial direction so that the laser beam scans the screw thread portion, and advances it according to the progress speed of the screw thread. The method of claim 6,
The laser irradiator,
A first laser that irradiates a laser beam so as to vertically contact the top of the screw thread;
a second laser beam for irradiating a laser beam in the direction of the inclined surface of the screw thread; and
A selective apatite film forming apparatus using a laser, characterized in that it comprises a third laser for irradiating a laser on the inclined surface of the spiral opposite to which the laser beam of the second laser is irradiated.

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