WO2024019344A1

WO2024019344A1 - Selective apatite film forming method using laser and selective apatite film forming apparatus

Info

Publication number: WO2024019344A1
Application number: PCT/KR2023/008674
Authority: WO
Inventors: 이상윤
Original assignee: 주식회사 덴탈알파고
Priority date: 2022-07-19
Filing date: 2023-06-22
Publication date: 2024-01-25
Also published as: KR102480199B1

Abstract

The present invention provides a selective apatite film forming method using a laser and a selective apatite film forming apparatus, the selective apatite film forming method comprising the steps of: (a) immersing an implant substrate in an apatite-forming precursor solution including Ca²⁺ ions and PO₄ ^3- ions; (b) irradiating laser beams to the implant substrate immersed in the precursor solution; (c) generating a difference in the energy density of the laser beams that reach screw crest portions and screw root portions by positioning the foci of the laser beams on a specific part of the implant substrate; and (d) forming an apatite film in areas into which the laser beams are irradiated as the reaction of Ca²⁺ ions and PO₄ ^3- ions in the precursor solution is activated.

Description

Selective apatite film forming method and selective apatite film forming device using a laser

The present invention relates to a method and device for forming an apatite film, and more specifically, to a method for forming apatite films of different thicknesses on screw threads and screw bones by controlling the focal position of a laser, and to a device using the same.

Titanium-based alloy, which is the most widely used medical metal material, is reported to be superior to previously used biomedical metals, including low elastic modulus, excellent corrosion resistance and excellent biocompatibility. However, because it is bioinert, it does not directly induce bone formation, requires a considerable amount of treatment time to achieve bone integration, and the naturally formed oxidized powder is thin, so it disappears quickly and does not lead to regeneration of adjacent bone tissue. It has problems.

Therefore, in order to solve the above-mentioned problem of the implant not being able to directly combine with bone and to solve the disadvantage of loosening in order to shorten the period of bone integration, bioactivity is given to the implant through surface treatment. The surface of titanium, which is used as the main material of implants, is treated physically and chemically to further improve bioactivity, thereby shortening the healing period after implants are placed in the human body. Research for more effective surface treatment is continuously conducted. There is a situation.

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

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

First, anodizing is a method of forming relatively thick oxides and metal salts 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 to create an electric current in the electrolyte. When an electric current is applied for anodization by flowing , the metal hydroxide forms a fine film at a very low voltage, and when a voltage of about 10V is applied, a metal oxide layer is formed. However, once the oxide layer is formed, the resistance increases and internal stress is concentrated in the metal oxide layer, and the oxide layer is destroyed at 70V. When the voltage is raised again, a second porous oxide layer is formed. During this process, sparks are generated and forced Electricity is applied to form an oxide layer, so electrical efficiency is poor, and the local area where the spark is exposed to thermal stress not only has a negative effect on the physical properties of titanium, but also has a problem of poor adhesion, which deteriorates the final physical properties.

The sol-gel method is to prepare a solution that becomes a gel through hydrolysis and polymerization with alcohol, water, and acid to produce a film. A homogeneous solution is described in a state of relatively low viscosity. Wet coating methods such as dip-coating, which applies the sol-gel method by coating on a substrate and gelling it to form a film, are low-temperature processes and allow coating regardless of area and control the thickness and microstructure of the film. There are advantages, but there are disadvantages that a post-heat treatment process for crystallization is added, the formation of a flat film is limited, and an adhesive to strengthen the adhesion must be inserted into the middle layer in order for the film to have sufficient bonding strength with the base material.

Plasma spraying is a field of thermal spraying and refers to a process of welding materials with high melting points, such as ceramics, which are metals and non-metals, on a substrate in a molten or semi-molten state. There are no restrictions on the material and size of the base material, there is no deformation of the base material, on-site construction is possible, thick film coating is possible, the film thickness is easy to control, and there are various types of coating materials, but the advantages are that the porosity of the tissue is low. It occurs in 06~15% and has the disadvantage of being weak to impact when titanium ceramic coating is made of a mechanical bond rather than a metallic bond, and its application to implants is difficult because its adhesion to the base material is weak.

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

The purpose of the present invention is to provide a method for forming apatite films of different thicknesses on screw threads and screw bones by adjusting the focal position of a laser, and a device using the same.

In order to solve the above problems, the method of 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 implant base to generate a difference in energy density of the laser beam reaching the screw thread portion and the screw bone portion; and (d) forming an apatite film in the area irradiated with the laser beam by activating the reaction of Ca ²⁺ ions and PO ₄ ^3- ions in the precursor solution.

At this time, in step (c), it is preferable to focus the laser beam on the threaded portion of the implant base.

In addition, step (d) is preferably performed by rotating the implant base at a constant speed in the axial direction and scanning the laser beam in accordance with the speed of the screw thread.

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

In addition, step (b) may further include a step performed by a third laser beam irradiated to the slope of the thread opposite to where the second laser beam is irradiated.

In order to solve the above problem, a selective apatite film forming device using a laser according to the present invention includes a solution receiving portion that accommodates a precursor solution for forming apatite containing Ca ²⁺ ions and PO ₄ ^3- ions; a laser irradiation unit that irradiates a laser beam to the implant substrate supported in the precursor solution; and a base rotating unit that rotates the implant base supported in the precursor solution.

At this time, it is preferable that the laser irradiation unit focuses the laser beam on a specific part of the implant substrate to generate a difference in energy density of the laser beam reaching the screw thread portion and the screw bone portion.

Additionally, the laser irradiation unit may focus the laser beam on the threaded portion of the implant base.

Meanwhile, the base rotating unit rotates the implant base at a constant speed in the axial direction so that the laser beam scans the screw thread portion, and preferably advances in accordance with the progress of the screw thread.

In addition, the laser irradiation unit includes a first laser that irradiates a laser beam to perpendicularly contact the top of the screw thread; a second laser beam that irradiates a laser beam in the direction of the slope of the screw thread; And it may include a third laser that irradiates a laser to the slope of the thread opposite to where the laser beam of the second laser is irradiated.

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

First, by focusing the laser beam on a specific part of the screw thread, it is possible to form a thicker amatite film on the corrugated part of the screw thread.

Second, by using multiple lasers, the energy density of the laser beam can be increased at the top or valley of the screw thread, so it is possible to form a thicker amatite film in a specific part as needed.

1 is a flowchart explaining a method of selectively forming an apatite film using a laser according to the present invention.

Figure 2 is a block diagram of a selective apatite film forming device using a laser according to the present invention.

Figure 3 explains that an attapite film is formed at a selective thickness on the screw thread due to a difference in the density of the laser beam.

Figure 4 illustrates another embodiment of the present invention, where an attapite film is formed at a selective thickness on the screw thread due to a difference in density of the laser beam.

Figure 5 illustrates that an attapite film is formed at a selective thickness in the screw valley area due to a difference in the density of the laser beam.

Figure 6 illustrates another embodiment of the present invention in which an attapite film is formed at a selective thickness in the screw valley area due to a difference in the density of the laser beam.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. At this time, note that in the attached drawings, identical components are indicated by identical symbols whenever possible. Additionally, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components are exaggerated, omitted, or schematically shown in the accompanying drawings.

Figure 1 is a flowchart explaining a method of selectively forming an apatite film using a laser according to the present invention, Figure 2 is a block diagram of a selective apatite film forming apparatus using a laser according to the present invention, and Figure 3 is the density of the laser beam. It is a diagram explaining the formation of an attapite film at a selective thickness on a screw thread due to a difference, and Figure 4 is another embodiment of the present invention, showing an attapite film being formed at a selective thickness on a screw thread due to a difference in the density of a laser beam. It is an explanatory drawing, and Figure 5 explains that an attapite film is formed with a selective thickness in the screw valley area due to the difference in density of the laser beam, and Figure 6 is another embodiment of the present invention, showing the difference in density of the laser beam. This explains the formation of an attapite film with a selective thickness in the screw groove area.

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

The solution receiving portion 200 accommodates a precursor solution (W) for forming apatite containing Ca ²⁺ ions and PO ₄ ^3- ions.

The laser irradiation unit 100 radiates a laser beam (L) to the implant substrate (I) supported in the precursor solution (W). The apatite forming precursor solution (W) 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 implant substrate (I).

The substrate rotating unit 300 rotates the implant substrate (I) supported in the precursor solution (W). The base rotating part 300 has a shape including a bracket 310 that fixes the implant base (I). In the illustration, the bracket 310 is shown as fixing the screw portion of the implant base (I), but this is only for simplification, and the shape and rotation method of the bracket 310 are similar to those of the implant base (I). It can be implemented in various ways depending on the form.

The present invention is intended to form a thicker apatite film (A) on the screw bone portion of the screw thread (N) of the implant base (I), and has the feature of using the difference in density of the laser beam (L). In other words, the thread portion or the screw valley portion can be selectively thickened as needed.

The laser irradiation unit 100 focuses the laser beam (L) on a specific part of the implant base (I) (that is, on the top of the screw thread (N) (see FIG. 3) or the screw bone (see FIG. 5) of the screw thread (N). By positioning it, a difference in energy density of the laser beam reaching the screw thread portion and the screw bone portion is generated.

In the case of the embodiment of FIG. 3, the energy density of the laser beam (L) is high at the top of the screw thread (N), so the production rate of the apatite film (A) is high, and the laser beam (L) is generated at the valley of the screw thread (N). Since it is dispersed and the energy density is lowered, the formation rate of the apatite film (A) is low and it is deposited in a thin layer.

In the case of the embodiment of FIG. 5, the energy density of the laser beam (L) is high in the valley part of the screw thread (N), so the production rate of the apatite film (A) is high and deposited thickly in the valley part, and the apatite film (A) is thickly deposited in the valley part. In this case, the laser beam (L) is dispersed and the energy density is lowered, so the apatite film (A) is deposited in a thin layer due to a low production rate.

The base rotation unit 300 is used to create an apatite film (A) along all surfaces of the screw thread (N) - that is, to expose all screw surfaces to the laser beam (L). Rotate at a constant speed in the axial direction. Because of this, the laser beam (L) can be scanned as if the screw thread (360°) rotates.

The base rotating unit 300 may operate by advancing the implant base (I). The laser irradiation unit 100 is fixed and the substrate rotating unit 300 rotates the implant substrate (I) by 360° and moves forward to form the apatite film (A).

Simply, the base rotation unit 300 simply rotates the implant base (I) by 360°, and the laser irradiation unit 100 may be carried out by moving the position of the laser beam (L) and scanning 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 arranged to irradiate the laser beam (L1) so as to perpendicularly contact the top of the screw thread (N), and the second laser 120 radiates the laser beam (L2) in the direction of the slope of the screw thread (N). The third laser 130 may be arranged to irradiate the laser beam L3 in the direction of the slope opposite to the screw thread N.

Three laser beams (L1, L2, L3) overlap on the top part of the screw thread (N) to create a thick amatite film (A) in this part. 4 and 6 show three

lasers

110, 120, and 130, but depending on the embodiment, the laser irradiation unit 100 may be implemented using only two

lasers

120 and 130.

Figure 1 is a flowchart explaining the 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 in time series, it corresponds to the present embodiment, so the laser irradiation unit 100, the solution receiving unit 200, and the substrate rotating unit 300. The parts described herein also apply to this embodiment.

The method of selectively forming an apatite film using a laser according to an embodiment includes an implant base (I) detection step (S100), a laser beam irradiation step (S200), a density difference generation step of the laser beam (S300), and an apatite film forming step. Includes (S400).

In step S100, the substrate for implant (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 apatite forming precursor solution (W) into the solution receiving unit 200.

Next, 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 part (the top or the screw bone part of the screw thread (N)) of the implant base (I), and the laser beam reaches the screw thread (N) part and the screw bone part. (L) creates an energy density difference.

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

At this time, in step S300, it is desirable to position the focus of the laser beam (L) on the thread (N) portion of the implant base (I).

At this time, in step S400, it is desirable to rotate the implant substrate (I) in the axial direction at a constant speed and scan the laser beam (L) in accordance with the advancing speed of the screw thread (N).

Meanwhile, as explained in FIG. 4, in step S200, the step is performed by the first laser beam L1 irradiated to perpendicularly contact the top of the screw thread N, and the second laser beam irradiated in the slope direction of the screw thread N 2. It includes a step performed by a laser beam (L2), and further includes a step performed by a third laser beam (L3) irradiated to the slope of the screw line (N) opposite to which the second laser beam (L2) is irradiated. You can.

For convenience of explanation, the laser beam irradiation step (S200), the laser beam density difference generation step (S300), and the apatite film formation step (S400) are described separately. However, when irradiation of the laser beam (L) begins, Ca ²⁺ Since the precursor solution (W) for forming apatite containing ions and PO ₄ ^3- ions is activated and formed on the apatite film (A) by ionic reaction, steps S200, S300, and S400 are steps that proceed simultaneously.

The embodiments of the present invention disclosed in the specification and drawings are merely provided as specific examples to easily explain the technical content of the present invention and to facilitate 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 in addition to the embodiments disclosed herein, other modifications based on the technical idea of the present invention can be implemented.

Claims

(a) supporting a substrate for implant in a precursor solution for forming apatite containing Ca 2+ ions and PO 4 3- ions;

(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 implant base to generate a difference in energy density of the laser beam reaching the screw thread portion and the screw bone portion; and

(d) A method of forming an apatite film selectively using a laser, comprising the step of forming an apatite film by activating the reaction of Ca 2+ ions and PO 4 3- ions in the precursor solution in the area irradiated with the laser beam.
In claim 1,

In step (c),

A method of forming a selective apatite film using a laser, characterized in that the focus of the laser beam is placed on the screw bone portion of the implant substrate.
In claim 2,

In step (d),

A method of forming a selective apatite film using a laser, characterized in that the implant substrate is rotated at a constant speed in the axial direction and the laser beam is scanned in accordance with the progress of the screw thread.
In claim 3,

In step (b),

A selective method using a laser comprising a step performed by a first laser beam irradiated so as to perpendicularly contact the top of the screw thread, and a step performed by a second laser beam irradiated in a slope direction of the screw thread. Apatite film formation method.
In claim 4,

In step (b),

A method of forming a selective apatite film using a laser, characterized in that it further comprises a step performed by a third laser beam irradiated on the slope of the thread opposite to where the second laser beam is irradiated.
A solution receiving portion that accommodates a precursor solution for forming apatite containing Ca 2+ ions and PO 4 3- ions;

a laser irradiation unit that irradiates a laser beam to the implant substrate supported in the precursor solution; and

A selective apatite film forming device using a laser including a base rotating unit that rotates the implant base supported in the precursor solution.
In claim 6,

The laser irradiation unit,

A selective apatite film forming device using a laser, characterized in that the focus of the laser beam is placed on a specific part of the implant substrate to generate a difference in the energy density of the laser beam reaching the screw thread portion and the screw bone portion.
In claim 7,

The laser irradiation unit,

A selective amatite film forming device using a laser, characterized in that the focus of the laser beam is placed on the screw bone portion of the implant substrate.
In claim 8,

The base rotating part,

A selective amatite film forming device using a laser, characterized in that the implant substrate is rotated at a constant speed in the axial direction so that the laser beam scans the screw thread portion, and is advanced in accordance with the advancing speed of the screw thread.
In claim 7,

The laser irradiation unit,

a first laser that irradiates a laser beam to perpendicularly contact the top of the screw thread;

a second laser beam that irradiates a laser beam in the direction of the slope of the screw thread; and

A selective apatite film forming device using a laser, comprising a third laser that irradiates a laser to the slope of the thread opposite to where the laser beam of the second laser is irradiated.