CN115252189A

CN115252189A - Tantalum metal dental implant and preparation method thereof

Info

Publication number: CN115252189A
Application number: CN202210885908.XA
Authority: CN
Inventors: 李小平; 李兴钰; 张亚军; 拓万勇; 刘磊; 马晶
Original assignee: Ningxia Dongfang Zhizao Technology Co ltd
Current assignee: Ningxia Dongfang Zhizao Technology Co ltd
Priority date: 2022-07-26
Filing date: 2022-07-26
Publication date: 2022-11-01

Abstract

The invention provides a preparation method of a tantalum metal dental implant, which comprises the following steps: (1) Providing a spherical tantalum powder having the following characteristics: the lower limit of the grain diameter is 15-25 mu m; the upper limit of the grain diameter is 50-60 mu m; the time for 50g of powder to pass through a standard funnel is 5-10 s; the sphericity of the powder is more than or equal to 0.8; the hollow powder rate of the powder is less than or equal to 5 percent; the apparent density is 9-11 g/cm³(ii) a (2) Processing and molding the spherical tantalum powder by adopting a 3D printing process to obtain a dental implant blank; (3) carrying out post-printing treatment on the dental implant blank; (4) carrying out vacuum heat treatment on the product obtained in the last step; the temperature of the vacuum heat treatment is 1100-1450 ℃, and the time is 60-150min.

Description

Tantalum metal dental implant and preparation method thereof

Technical Field

The invention belongs to the field of materials, and particularly relates to a tantalum metal dental implant and a preparation method thereof.

Background

The oral cavity problem is always a big problem influencing human health and life quality, and the dental implant is also seen with the continuous development of scientific fields such as oral medicine and the like. Compared with the traditional false teeth, the dental implant can well protect the original functions of teeth, does not cause damage to other healthy teeth, is tightly connected with jaw bones, is not easy to loosen or fall off, is favorable for keeping oral hygiene, has less wound and less time consumption in the operation process, and does not generate any side effect on human bodies basically. The existing dental implant is generally a dental nail prepared from titanium and titanium alloy, but titanium, titanium alloy and human bone have large differences in all aspects, and cannot be quickly combined with the human bone, so that the implantation period is long, and the dental implant is easy to loosen. The tantalum has good biocompatibility and is similar to the mechanical property of human bones, can not only grow together with the human bones quickly after being planted, but also prevent bacteria from breeding and ensure the long-term effectiveness of the implant in human bodies.

Disclosure of Invention

The inventor finds that the main problems of the existing titanium and titanium alloy implants are that the speed of the existing titanium and titanium alloy implants is low, the existing titanium and titanium alloy implants cannot well induce the growth of bone tissues, the period of the implants is long, the operation difficulty is high, and the problems of loosening and failure possibly occur after the existing titanium and titanium alloy implants are used for a long time, so that great troubles are brought to patients.

The invention provides a tantalum metal dental implant model which can induce the bone tissue of a human body to grow together, has good biocompatibility with human bone, is stably connected with alveolar bone and an abutment and is not easy to loosen, and the model is successfully prepared by combining a 3D printing process and a machining process. According to the invention, the implant with a porous structure, internal threads and external threads is designed and processed by adopting a mode of combining 3D printing and machining processes, the internal threads can be completely matched and connected with the existing base station, the implantation is easier to realize, the surgical implantation difficulty is reduced, and the burden of a patient is relieved.

In a first aspect, the present invention provides a method for preparing a tantalum metal dental implant, comprising the steps of:

(1) Providing a spherical tantalum powder having the following characteristics:

the lower limit of the particle size is 15 to 25 μm (for example, 20 to 24 μm);

the upper limit of the particle size is 50 to 60 μm (for example, 50 to 55 μm);

the time for 50g of powder to pass through a standard funnel is 5 to 10s (e.g., 5 to 7 s);

the powder sphericity is more than or equal to 0.8 (for example, the powder sphericity is more than or equal to 0.9);

the hollow powder rate of the powder is less than or equal to 5 percent;

the apparent density is 9-11 g/cm³(e.g., 9 to 10 g/cm)³)；

(2) Processing and molding the spherical tantalum powder by adopting a 3D printing process to obtain a dental implant blank;

(3) Printing the dental implant blank and then processing the dental implant blank;

(4) Carrying out vacuum heat treatment on the product obtained in the last step;

the vacuum heat treatment temperature is 1100-1450 deg.C (such as 1200-1300 deg.C), and the time is 60-150min (such as 90-120 min).

In some embodiments, the dental implant has the following characteristics:

along the length direction of the dental implant, the dental implant comprises an upper section, a middle section and a lower section;

the upper section is provided with a columnar compact base body, and external threads are arranged on the columnar compact base body;

the middle section is provided with a columnar porous matrix;

the lower end is provided with a columnar compact base body, and external threads are arranged on the columnar compact base body.

In some embodiments, the dental implant further comprises an abutment mounting hole extending from a top of the dental implant along a length of the dental implant, the abutment mounting hole having an internal thread disposed therein for engagement with an abutment.

In some embodiments, the columnar porous matrix has a porosity of 60 to 80%.

In some embodiments, the end of the lower section has a circular arc shape with a radius of 3 to 5mm.

In some embodiments, the method of preparing a dental implant has one or more of the following features:

(1) The length of the upper section is 0.2 h-0.5 h, such as 0.3 h-0.4 h;

(2) The length of the middle section is 0.2 h-0.5 h, such as 0.3 h-0.4 h;

(3) The length of the lower section is 0.2 h-0.5 h, such as 0.3 h-0.4 h;

wherein h is the total length of the dental implant.

In some embodiments, the spherical tantalum powder has the following characteristics: d10=15 μm-25 μm (e.g. 20 μm), D50=25 μm-35 μm (e.g. 30 μm), D90=45 μm-65 μm (e.g. 50-55 μm).

In some embodiments, D10, D50, and D90 represent the particle sizes corresponding to cumulative percent particle size distributions for powder samples up to 10 vol%, 50 vol%, 90 vol%.

In some embodiments, the temperature of the vacuum heat treatment is 1200 to 1400 ℃ or 1250 to 1300 ℃.

In some embodiments, the vacuum heat treatment is for a period of 80 to 120min, such as 90 to 100min.

In some embodiments, the 3D printing includes performing the following scan parameters on the filled portion:

scanning laser power 300-320W;

scanning speed 550-650 (mm/s)

The distance between the scanning lines is 0.12-0.16mm;

the width of the strip-shaped subarea is 8-12/mm;

the scanning distance of the strip-shaped subareas is 0.1-0.2 mm;

the lapping amount between the strip-shaped subareas is 0.05-0.1/mm;

the translation width of the strip is 6-8mm.

In some embodiments, the 3D printing includes one or more of the following parameters:

(1) Profile scanning laser power 190-210W, profile scanning speed 550-650 (mm/s);

(2) Filling scanning laser power is 300-320W, filling scanning speed is 550-650 (mm/s), and filling scanning line spacing is 0.12-0.16mm;

(3) The upper surface scanning laser power is 200-300W, the upper surface scanning speed is 450-550 (mm/s), and the upper surface scanning line interval is 0.10-0.14mm;

(4) The lower surface scanning laser power is 200-300W, the lower surface scanning speed is 450-550 (mm/s), and the lower surface scanning line spacing is 0.10-0.14mm.

In some embodiments, post-printing processing includes one or more of: machining, surface treatment and cleaning.

In a second aspect, the present application provides a tantalum metal dental implant prepared by any one of the methods described above.

In some embodiments, the dental implant has one or more of the following characteristics:

(1) The tensile strength is 600-700 Mpa;

(2) The yield strength is 520-620 Mpa;

(3) The elongation is 20 to 35 percent;

(4) The density is 16-17 g/cm²；

(5) The hardness HV is 220 to 230.

The invention has the beneficial effects that:

(1) The tantalum metal dental implant model can induce the growth of human bone tissues, has good biocompatibility with human bones, is stably connected with alveolar bones and an abutment, and is not easy to loosen, and the model is successfully prepared by combining a 3D printing process and a machining process. According to the invention, the implant with a porous structure, internal threads and external threads is designed and processed by adopting a mode of combining 3D printing and machining processes, the internal threads can be completely matched and connected with the existing base station, the implantation is easier to realize, the surgical implantation difficulty is reduced, and the burden of a patient is relieved.

(2) According to the method, spherical tantalum powder with specific physical and chemical properties is used as a raw material, a tantalum implant processing process flow combining a 3D printing process and a machining process is combined, a dental implant combining a porous structure and a solid structure is prepared and obtained by combining a specific vacuum heat treatment technology after printing, and the product has improved strength, hardness and density.

Drawings

Fig. 1 (a) and (b) are schematic views of a dental implant according to some embodiments;

FIG. 2 is a schematic view of an abutment installation hole of a dental implant according to some embodiments;

FIG. 3 is a 200 Xmagnification photograph of the spherical tantalum powder of example 1;

FIG. 4 is a 500 Xmagnification photograph of the spherical tantalum powder of example 1;

Detailed Description

Reference will now be made in detail to specific embodiments of the invention. While the invention will be described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to these specific embodiments. On the contrary, the embodiments are intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Reagents, methods and equipment used in the present invention are food grade reagents, methods and equipment conventional in the art unless otherwise specified. Unless otherwise indicated, the test conditions used in the examples of the present invention are those conventional in the art. The reagents used in the examples of the present invention were all commercially available unless otherwise specified.

Example 1

A tantalum product and a 3D printing preparation process are disclosed, and the process flow is as follows: powder preparation → model building → printing → post-processing → heat treatment.

1. Powder preparation

Spherical tantalum powder having a particle size distribution in the range of 22.74 μm to 50.95 μm (D10 =20 μm, D50=30 μm, D90=55 μm) is provided, with an oxygen content of 200ppm or less and a sphericity of 95% or more.

FIGS. 3 and 4 show scanning electron micrographs of spherical tantalum powder, respectively.

The chemical composition of the hetero elements of the raw material powders is shown in the following table:

TABLE 1

The physical properties of the starting powders are given in the following table

TABLE 2

Item	Measured value
		Particle size distribution (. Mu.m)	22.74μm-50.95μm
Fluidity(s)	5.9s
		Degree of sphericity	0.93
Hollow powder fraction	＜5％
		Bulk density	9.8g/cm³

* Particle size distribution detection standard reference GB/T19077-2016 particle size analysis laser diffraction method

* Standard for fluidity detection reference GB/T1482 Metal powder fluidity standard funnel method (Hall flow meter)

* Method for determining sphericity of titanium and titanium alloy powder by using sphericity detection standard reference YS/T1297-2019

* And testing the hollow powder rate detection standard by referring to a metallographic method, and carrying out sample embedding and powder throwing observation.

* The detection standard of the feeding density is judged by a funnel method according to the loose packing density of GB/T1479.1-2011 determination part 1 of the loose packing density of the metal powder.

2. Model building

According to the structure of a target product, solidworks software is used for three-dimensional modeling, an integral pillar and an internal and external thread structure are mainly drawn, 3-matic software is used for modeling a porous structure, then two parts of models are assembled into a whole, and Magics software is used for repairing.

Fig. 1 (a) and (b) respectively show schematic views of a dental implant.

As shown in fig. 1 (a) and (b), the dental implant includes an upper section 11, a middle section 12, and a lower section 13 in a top-down direction (longitudinal direction). Here, "upper/top" and "lower/bottom" mean the end of the dental implant away from the gum and the end close to the gum, respectively, in the implanted state "

The upper section 11 has a cylindrical dense base body on which external threads are provided. The external thread can be a 7.3-degree taper thread, and can be screwed down for the second time, so that the overall stability of the implant is ensured.

The middle section 12 has a columnar porous matrix 121. On one hand, the columnar porous matrix 121 can reduce the weight of the dental implant and reduce the load of the patient during use. On the other hand, the columnar porous matrix 121 makes it easier to bond bone tissues to the implant, increases the osseointegration rate, and effectively prevents peri-implantitis, and the inset shows a top view of the porous structure 121.

The lower section 13 has a cylindrical dense matrix with external threads provided thereon. The external thread is a double-thread, has a large lead, can be screwed in quickly, and shortens the operation time. The lower segment 13 has a tapered end portion with a three-edged self-tapping double-line tapered thread, and based on the structure, the implant can be directly screwed in after the gum is drilled, so that the pre-tapping process is reduced. The bottom 131 of the dental implant is in the shape of a circular arc, and the bottom structure of the circular arc can prevent the gum from being screwed through in the process of screwing the implant in the operation.

Fig. 2 is a schematic view of an abutment installation hole of a dental implant according to some embodiments. The dental implant further includes an abutment installation hole 14 extending from the top 111 of the dental implant in a lengthwise direction (from top to bottom) of the dental implant. The abutment installation hole 14 is used for installing and fixing an abutment (not shown) on the dental implant. The base mounting hole has an internal thread 141 inside, and the internal thread 141 can be combined with a base (not shown in the figure), so that the stability of the base during connection is further ensured, and looseness cannot be generated. The abutment in the abutment mounting hole 14 is located with a tapered structure 15, which can make the abutment fit with the implant more tightly.

In one embodiment, the specific dimensions of the dental implant are as follows: the total length is 14mm; the external thread of the upper section 11 is an M5 standard external thread, and the thread height is 3.5mm; the height of the external thread of the lower section 13 is 1.8mm, the thread taper of the tapered end part is 16 degrees, the height of the external thread of the tapered end part is about 1.8mm, and the radius of the bottommost protective circular arc is 3.5mm. The length of the middle section 12 is 4.5mm, the outer diameter is 5mm and the inner diameter is 3.4mm. The porosity of the columnar porous matrix 121 is 70%. The rod diameter of the porous structure is 0.4mm.

A groove connected with the base is arranged in the base mounting hole 14, and the taper of the groove is 7.3 degrees. The diameter is 3.2mm and the depth is 0.5mm. An inner hexagonal hole is further formed in the base station mounting hole 14, the inscribed circle of the inner hexagonal hole is 2.6mm, the depth of the inscribed circle is 2.5mm, and the inner hexagonal wrench torque is mainly used for transmitting the inner hexagonal wrench torque to the dental nail in the screwing-in process of the dental nail. The screw thread connected with the abutment is M2 inner hexagonal standard fine thread with the depth of 5mm.

3. Printing

The method comprises the steps of composing a designed model by using Buildstar software, setting a material bag and adjusting workpiece parameters, wherein scanning parameters of a porous structure are different from scanning parameters of a compact structure, laser scanning filling and parameters of the porous structure correspond to smaller parameters in the table below, the rest are scanning parameters of a filling entity part, the two parts need to be respectively adjusted, and after the two parts are finished, slicing processing is carried out, namely, the printing process of the model under the theoretical condition is observed, and the printing time and the required powder loading amount are predicted so as to ensure that parts are smoothly printed.

The settings of the printing parameters are as follows:

samples 1, 3 were printed using the parameters of Table 3.1

TABLE 3.1 (samples 1, 3)

Samples 2, 4 were printed using the parameters of table 3.2.

TABLE 3.2 (samples 2, 4)

Key parameters among the 3D printing parameters are explained as follows:

contour parameters: when the laser scans the power and the number of lines forming the surface area of the component, wherein the number of scanning lines (Contour STD Count) is 1, the scanning interval is 0, and when the number of scanning lines (Contour STD Count) is more than 1, the interval parameter is effective. The pitch parameter is set in a scale parameter, the Contour scan Power (Contour STD Laser Power) is a Laser Power, a plurality of different Contour scan powers and Contour scan speeds can be set, respectively, and the number of settings is a value depending on the number of scan lines.

Contour Partition Threshold (Contour STD Partition Threshold): the critical values of the upper surface and the lower surface of the laser scanning are distinguished, and only the corresponding content STD Partition On/Off parameter is effective when the corresponding content STD Partition On/Off parameter is 1. When a local Overhang (overhand) value is greater than a contour partition threshold value, the local contour is determined as a lower surface contour, and the contour partition threshold value is determined by both Layer Thickness and overhand parameters and is an absolute value.

Upper surface (Upskin), lower surface (downlnkin) parameters: according to the placing position of the component, the component is parallel to the two surfaces of the component forming substrate, the area is not scanned as the upper surface after 1 time of laser scanning, the area continuously scanned as the lower surface after the time of laser scanning, and multiple times of scanning can be carried out to meet the component forming requirement.

Supporting: in order to ensure the printing success of the component, one structure is arranged on the lower surface of the component to assist the scanning forming of the lower surface, and the structure is divided into various structures such as block-shaped linear structures, point-shaped structures, solid structures, conical structures, net-shaped structures, outline structures, tree-shaped structures and the like.

Number of padding scans (Fill Scan Count): and scanning the non-contour region of the component by the laser for times, wherein the directions of two adjacent scans are mutually vertical.

Fill scan Speed (Fill Speed): the speed at which the laser scans the area.

Line spacing (Fill Distance): and on the same scanning section, the distance between two adjacent laser lines.

Fill rotation Angle between layers (Fill Rotate Angle): after the laser scans one layer along a certain direction, the next layer can rotate a certain angle in the previous scanning direction to scan, and an included angle formed by the two layers of scanning directions is formed.

Stripe partition Width is (Stripe Width): each laser combination forms a width with a distance when the lasers are scanned.

Stripe partition scan spacing (Stripe Fill Distance): the distance between each laser in the strip width is fixed.

Bar split Overlap (Stripe Overlap): two adjacent strips are formed with a certain intersecting width distance.

Stripe shift width (Stripe Offset): the strips between adjacent layers are offset by a translation distance.

4. Post-printing processing

The post-printing treatment comprises the steps of machining, surface treatment, cleaning and the like, and is concretely as follows

After printing, the substrate is taken out of the printer, and the dental implant blank is cut off from the substrate by linear cutting, wherein the linear cutting mainly adopts molybdenum wire fast-moving wire cutting, so that the processing precision is high, the roughness of the cutting surface is good, and the dental implant cannot generate stress deformation. The support added in the printing process is removed, and the support is mainly removed manually by a technician through tools such as files, tweezers and the like.

And (4) carrying out sand blasting and polishing treatment on the dental implant blank by using a sand blasting machine and a grinding wheel machine to ensure that the surface roughness meets the requirement. And machining an internal thread used for subsequent connection with the base, an external thread at the upper end and an external thread at the lower section in the base mounting hole by adopting a machining method.

Because residue and powder are easy to remain in the porous structure, the dental implant needs to be cleaned by ultrasonic wave, and the implant is put in a beaker and completely submerged in absolute ethyl alcohol and then is cleaned in an ultrasonic cleaning machine for 0.5hr.

5. Thermal treatment

Heat treating the product in the last step in a vacuum furnace with the vacuum degree of less than or equal to 7 x 10^-3Pa, setting the heat treatment temperature to 1450 ℃ and keeping the temperature for 90min.

And (3) performance detection:

the sample obtained in step (4) is in a hard state and is not annealed by heat treatment, hereinafter denoted by Y. The sample obtained in step (5) is in an annealed state, hereinafter denoted by M.

The dental implant samples prepared above were subjected to performance tests, and samples 1 and 2 were represented by M in an annealed state, and samples 3 and 4 were represented by Y in a hard state.

The results of GB/T228-2002 'method for testing metallic materials at room temperature for tensile test' for tensile strength, yield strength and elongation and flexion are shown in Table 4:

TABLE 4

Density measurement GB/T3850-2015 "dense sintered metal sub-material and cemented carbide density measurement method" and hardness measurement GB/T230.1-2009 "rockwell hardness test of metal material" are performed as shown in table 5:

TABLE 5

	Density/(g/cm)³)	Hardness/hv
			Sample No. 1	16.47	230
Sample 2	16.467	231
			Sample 3	16.351	220
Sample No. 4	16.381	229

As can be seen from tables 4 and 5, the porous and solid combined dental implant is prepared by adopting the spherical tantalum powder with specific physical and chemical properties, the tantalum implant processing process flow combining the 3D printing process and the machining process and the specific vacuum heat treatment technology after geometric printing, and the product has improved strength, hardness and density.

The original powder is irregular-shaped powder, spheroidizing shaping is not carried out, the powder particle size distribution is wide, the fluidity is poor, a defect area is easily generated in the 3D printing powder laying process, the powder laying is not uniform, and cavities and other serious defects can be formed after sintering.

The vacuum heat treatment is key to improving the performance of a printed product, and the vacuum heat treatment at 1450 ℃ can improve the mechanical property of the dental implant and can meet the biting force of a human body.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.

Claims

1. A preparation method of a tantalum metal dental implant comprises the following steps:

(1) Providing a spherical tantalum powder having the following characteristics:

the lower limit of the grain diameter is 15-25 mu m;

the upper limit of the grain diameter is 50-60 mu m;

the time for 50g of powder to pass through a standard funnel is 5-10 s;

the sphericity of the powder is more than or equal to 0.8;

the hollow powder rate of the powder is less than or equal to 5 percent;

the loose packed density is 9-11 g/cm³；

(3) Performing post-printing treatment on the dental implant blank;

the temperature of the vacuum heat treatment is 1100-1450 ℃, and the time is 60-150min.

2. The method of manufacturing according to claim 1, the dental implant having the following characteristics:

along the length direction of the dental implant, the dental implant comprises an upper section (11), a middle section (12) and a lower section (13);

the upper section (11) is provided with a columnar compact base body, and external threads are arranged on the columnar compact base body;

the middle section (12) has a columnar porous matrix (121);

the lower end (13) is provided with a columnar compact base body, and external threads are arranged on the columnar compact base body.

3. The method of claim 4, further comprising an abutment mounting hole (14) extending from a top (111) of the dental implant along a length of the dental implant, the abutment mounting hole (14) having an internal thread (141) disposed therein, the internal thread (141) for engaging with an abutment.

4. The method according to claim 4, wherein the porosity of the columnar porous matrix 121 is 60 to 80%.

5. The method of claim 4, wherein the lower section (13) has an end portion having a circular arc shape with a radius of 3 to 5mm.

6. The method of claim 2, having one or more of the following characteristics:

(1) The length of the upper section is 0.2 h-0.5 h;

(2) The length of the middle section is 0.2 h-0.5 h;

(3) The length of the lower section is 0.2 h-0.5 h;

wherein h is the total length of the dental implant.

7. The production method according to claim 1, wherein the 3D printing includes performing the following scan parameters on the filled portion:

scanning laser power is 300-320W;

scanning speed 550-650 (mm/s)

The distance between the scanning lines is 0.12-0.16mm;

the width of the strip-shaped subarea is 8-12/mm

The scanning distance of the strip-shaped subareas is 0.1-0.2 mm

The lapping amount between the strip-shaped subareas is 0.05-0.1/mm

The translation width of the strip is 6-8mm.

8. The method of claim 1, wherein the spherical tantalum powder has the following characteristics: d10= 15-25 μm, D50= 25-35 μm, D90= 45-65 μm.

9. A tantalum metal dental implant prepared by the method of any one of claims 1 to 8.

10. The dental implant of claim 9, having one or more of the following characteristics:

the tensile strength is 600-700 Mpa;

the yield strength is 520-620 Mpa;

the elongation is 20 to 35 percent;

the density is 16-17 g/cm²；

The hardness HV is 220 to 230.