JP2003277806A - Method for manufacturing long sintered compact for orthodontic element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a long sintered compact for an orthodontic element by which a high-density, high-quality orthodontic element with a wide range of material selection can be obtained, and manufacturing can be facilitated even in the case of the element with a complicated shape. <P>SOLUTION: The method for manufacturing the long sintered compact for the orthodontic element comprises the following steps. A step (1A) where a long formed body containing raw-material powder (metal powder or ceramic powder) is prepared using extrusion. A step (2A) where the long formed body is subjected to debinding to prepare a long binder-removed body. A step (3A) where the long binder-removed body is sintered to obtain the long sintered compact. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a long sintered body for an orthodontic member for obtaining an orthodontic member.

[0002]

2. Description of the Related Art Orthodontic brackets and wires for orthodontics are known as dental instruments (dental parts) used in the oral cavity.

An orthodontic bracket (hereinafter simply referred to as "bracket") has a base portion that is adhesively fixed to a tooth and an engaging portion formed on the upper portion of the base portion, and is formed in the engaging portion. The wire is inserted into the slot and the wire is tensioned to correct the dentition.

Such a bracket is made of a metal material or ceramics and has been manufactured (worked) by the following method.

[1] A method of obtaining a desired shape by machining a plate material made of metal or ceramics. [2] A method of obtaining a desired shape by subjecting a metal plate material to electric discharge machining. [3] A method in which a compound obtained by kneading a metal or ceramic powder and a binder is injection-molded into a desired shape (MIM), and the resulting molded body is degreased and sintered.

However, in the above method [1], since all brackets having a complicated shape are manufactured by machining, there is a problem that the manufacturing takes a lot of time and labor and is not suitable for mass production. Further, ceramics have a high hardness and are difficult to machine, and there is a problem that applicable materials are limited.

Further, even in the above method [2], it takes a lot of time and labor to manufacture a bracket having a complicated shape, and since the material needs conductivity, it is applied to a ceramic one. There is a problem that you cannot do it.

Further, the method [3] has a problem in that, for example, when manufacturing brackets having different lengths, a molding die must be prepared for each bracket.

[0009]

An object of the present invention is to provide a long sintered body for an orthodontic member, which is easy to manufacture, suitable for mass production, and capable of obtaining an orthodontic member having a wide selection of materials. It is to provide a manufacturing method.

[0010]

The above objects are achieved by the present invention described in (1) to (10) below.

(1) Using a compound containing the raw material powder, a step of obtaining a long compact having a cross-sectional shape corresponding to the cross-sectional shape of the orthodontic member by extrusion molding, and the long compact. On the other hand, a method for producing a long sintered body for an orthodontic member, comprising a step of performing a degreasing treatment and a step of sintering the degreased body that has been degreased to obtain a long sintered body. .

(2) Manufacturing of the elongated sintered body for orthodontic member according to (1), wherein at least one groove is formed in the finally obtained elongated sintered body. Method.

(3) The elongated sintered body for orthodontic member according to (1) or (2) above, wherein at least one ridge is formed in the finally obtained elongated sintered body. Manufacturing method of sintered body.

(4) The method for producing a long sintered body for an orthodontic member according to any of (1) to (3), wherein the raw material powder is a metal powder or a ceramic powder.

(5) The raw material powder is Ti or Ti.
The method for producing a long sintered body for an orthodontic member according to any one of (1) to (3) above, which is a powder of a system alloy.

(6) The long sintered body finally obtained is
C: 0.01-0.5 wt%, O: 0.02-0.8 wt
%, N: 0.005-0.6 wt%, The method for producing a long sintered body for an orthodontic member according to (5) above.

(7) The total content of C, O and N is
The method for producing a long-sized sintered body for an orthodontic member according to the above (6), which has a content of 0.035 to 1.2 wt%.

(8) The method for producing a long sintered body for an orthodontic member according to any one of the above (1) to (3), wherein the raw material powder is a powder of stainless steel.

(9) The long sintered body for an orthodontic member according to any one of (1) to (8) above, wherein the porosity of the finally obtained long sintered body is 7 vol% or less. Body manufacturing method.

(10) The method for producing a long sintered body for an orthodontic member according to any one of (1) to (9) above, wherein the orthodontic member is a bracket.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a long sintered body for an orthodontic member according to the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a process diagram showing an embodiment of a method for producing a long sintered body for an orthodontic member of the present invention, and FIG. 2 is a production process for a long sintered body for an orthodontic member of the present invention. A perspective view showing an example of a long sintered body for orthodontic member manufactured by the method, FIG.
It is a perspective view showing the example of composition of the orthodontic member (orthodontic bracket) obtained from the elongate sintered body for orthodontic members.

First, as an example of an orthodontic member, an example of the configuration of an orthodontic bracket will be described with reference to FIG. As shown in FIG. 3, an orthodontic bracket (hereinafter simply referred to as “bracket”) 1 includes a plate-shaped base portion (bracket base, bracket stem) 2 and an engaging portion (projection formed from the base portion 2). Tie wing) 3 and.

A slot (groove) 4 into which a wire (not shown) is inserted is formed in the center of the engaging portion 3. The slot 4 extends in a direction parallel to the longitudinal direction of the elongated sintered body 10 for an orthodontic member, which will be described later.

Further, the engaging portion 3 is provided with another slot (groove) 5 which intersects with the slot 4 and extends in a direction orthogonal to the longitudinal direction of the elongated sintered body 10 for orthodontic member. There is. With these slots 4 and 5, the engaging portion 3
Are two pairs of claw-shaped protrusions 31 and 3 that spread outward.
It is divided into 2, 33 and 34.

Incidentally, the slots 4 and 5 in the present embodiment.
The cross-sectional shape of each is rectangular, but is not limited to this and may be, for example, V-shaped or U-shaped.

Such a bracket 1 is used by adhering and fixing the bottom surface (back surface) 6 of the base portion 2 to a tooth with an adhesive. In order to increase the adhesive strength, the bottom surface 6 of the base 2 may be formed with minute irregularities. This unevenness is
For example, grooves formed in a streak shape or a grid shape, and convex portions (projections) or concave portions (dimples) arranged regularly or irregularly (dotted points) can be cited.

Next, an embodiment of a method of manufacturing a long sintered body for an orthodontic member (hereinafter simply referred to as "long sintered body") will be described with reference to FIGS.

[1A] Manufacture of Molded Product In the present invention, a molded product is manufactured by an extrusion molding method (extrusion molding) using a mixture (compound) containing raw material powders.

This extrusion molding method is a processing method in which a compound is supplied into a cylinder of an extrusion molding machine, pressurized and extruded from the mouth of a die (molding die), and continuously extruded while regulating the cross-sectional shape. Is. This processing method has an advantage that a long molded body can be continuously manufactured.

In particular, in the case of extrusion molding in which a cylinder and a molding die are heated, the extrusion resistance of the mixture can be reduced and the moldability is excellent, which is more preferable.

The production of a molded body by the extrusion molding method will be described below. First, a raw material powder and a binder (organic binder) are prepared, and these are kneaded by a kneader to obtain a kneaded product.

Examples of the raw material powder include metal powder and ceramic powder. Examples of the metal material forming the metal powder include Ti or a Ti-based alloy, stainless steel, and the like, but Ti is superior in terms of biocompatibility.
Alternatively, a Ti-based alloy is preferable.

The average particle size of the metal powder is not particularly limited, but is usually preferably 0.5 to 150 μm or less, and 1-1.
It is more preferably about 00 μm.

In the present invention, the metal powder having a relatively small particle size can be used because it is formed by extrusion molding. As a result, the sintered density of the sintered body can be increased and high strength can be obtained.

The method for producing the metal powder is not particularly limited, and for example, those produced by the water or gas atomizing method, the reducing method, the carbonyl method, or the pulverizing method can be used.

Next, the ceramic material constituting the ceramic powder (hereinafter simply referred to as “ceramic material”) is not particularly limited, and examples thereof include ZrO ₂ (including partially stabilized zirconia), Y ₂ O ₃ and Al. Examples include oxide ceramics such as ₂ O ₃ and TiO ₂ , and calcium phosphate ceramics such as hydroxyapatite.

The average particle size of the ceramic powder is not particularly limited, but is usually preferably 30 μm or less,
About 10 μm is more preferable.

In the present invention, since extrusion molding is used, even ceramic powder having a small particle diameter can be easily molded. As a result, the sintered density of the sintered body can be increased and high strength can be obtained.

The method for producing the ceramic powder is not particularly limited, and examples thereof include pulverization, spray pyrolysis method, coprecipitation method,
Those manufactured by the glass crystallization method or the sol-gel method can be used.

As the binder, for example,
Polyolefin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, acrylic resin such as polymethylmethacrylate, polybutylmethacrylate,
Styrene resins such as polystyrene, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polyether, polyvinyl alcohol, various resins such as copolymers thereof, various waxes, paraffins, higher fatty acids (eg stearic acid) , Higher alcohols, higher fatty acid esters, higher fatty acid amides, and the like, and one kind or a mixture of two or more kinds thereof can be used.

Further, a plasticizer may be added. Examples of the plasticizer include phthalic acid esters (eg, DOP, DEP, DBP), adipic acid esters, trimellitic acid esters, sebacic acid esters, etc., and one or more of these may be mixed. Can be used.

When kneading, various additives such as a lubricant, an antioxidant, a degreasing accelerator, and a surfactant are added, if necessary, in addition to the raw material powder, the binder and the plasticizer. be able to.

The kneading conditions vary depending on various conditions such as the composition and particle size of the metal powder or ceramic powder to be used, the composition of the binder and the additive, and the compounding amount thereof, but an example thereof is the kneading temperature: 35 to 270. ℃, kneading time: 1
It can be about 0 to 240 minutes.

In the present invention, since the extrusion molding method is used, higher fluidity is not required as compared with the powder injection molding method (MIM method and the like), so that the content of the binder and the like in the compound can be further reduced. Thereby, firstly, a sintered body having a small porosity and a high sintering density is obtained, and a high-strength orthodontic member is obtained. In addition, since the number of pores on the surface is reduced, the orthodontic member is less likely to have food residue, germs and the like. Secondly, when it is made of Ti or a Ti-based alloy, the amount of C and the amount of O in the sintered body can be reduced, and an orthodontic member with high toughness can be obtained.

Next, the kneaded product obtained above is extruded by an extruder to produce a long molded product having a desired cross-sectional shape.

In this case, the cross-sectional shape of the molded body is determined by selecting the extrusion die (molding die) attached to the extrusion molding machine. This cross-sectional shape is constant over the entire length of the long molded body. The cross-sectional shape and dimensions of the molded body to be manufactured are determined in consideration of the amount of shrinkage of the molded body due to subsequent degreasing and sintering.

The length of the long molded body is not particularly limited and may be, for example, about 20 to 400 mm.

The extrusion molding conditions vary depending on various conditions such as the composition and particle size of the raw material powder used, the composition of the binder and the compounding amount thereof, but as an example, the cylinder temperature is preferably 100 to 350 ° C. Degree, the molding die temperature is preferably about 30 to 150 ° C., the extrusion speed is preferably about 0.1 to 50 mm / sec, and the extrusion pressure is preferably 1
000kgf / cm ² or less.

Here, in order to improve the moldability, it is preferable that the molding die temperature is set to a relatively low temperature as described above and the compound is cooled and solidified in the die.

The content of the raw material powder in the compact is 70-9.
It is preferably about 8 wt%, more preferably about 80 to 98 wt%. If it is less than 70 wt%, the shrinkage rate when the molded body is sintered increases and the dimensional accuracy decreases. On the other hand, if it exceeds 98 wt%, the content of the binder is relatively reduced, so that the fluidity at the time of molding becomes poor, and extrusion molding becomes impossible or difficult, or the composition of the molded body becomes non-uniform.

[2A] Degreasing Treatment of Molded Body The long shaped body obtained in the above step [1A] is subjected to degreasing treatment (debinding treatment).

The degreasing treatment is not particularly limited, but may be a non-oxidizing atmosphere, for example, under reduced pressure (vacuum) (for example, 1 × 10 ² to 1 × 10 ⁻⁶ Torr), or nitrogen gas,
The heat treatment is performed in an inert gas such as argon gas.

In this case, the degreasing condition is preferably about 150 to 750 ° C. for about 20 to 2200 minutes, more preferably about 250 to 650 ° C. for about 50 to 50 ° C.
It will be about 1300 minutes.

Degreasing by such heat treatment may be carried out in a plurality of steps (stages) for various purposes (for example, to shorten degreasing time). In this case, for example, a method of degreasing the first half at low temperature and the latter half at high temperature, and a method of repeatedly performing low temperature and high temperature can be mentioned.

Further, the pressure of the atmosphere during degreasing may be changed by combining with the above-mentioned heat treatment. In this case, for example, decompressing the first half of degreasing (for example, 1 × 10
^-3 Torr), the second half of degreasing may be performed under normal pressure, or the method may be performed by alternately repeating depressurization and atmospheric pressure.

As described above, by changing the degreasing conditions, it is possible to more efficiently degrease the molded body.

This degreasing treatment is carried out by another method, for example, a specific component in the binder or additive is treated with a predetermined solvent (liquid,
It may be carried out by eluting with (gas).

[3A] Sintering of molded body The long degreased body obtained as described above is fired and sintered in a furnace to obtain a long sintered body (metal sintered body or ceramic sintered body). To manufacture.

The raw material powder is diffused and grain-grown by sintering to form crystal grains. In this case, the voids disappear, and a dense, ie, high density, low porosity sintered body is obtained as a whole.

The sintering temperature in sintering is preferably 950 to 750 when the metal composition is Ti or a Ti-based alloy.
1500 ° C, more preferably 1000-1450 ° C
In the case of stainless steel, preferably 1000
˜1550 ° C., more preferably 1050 to 1500
It is set to about ℃, and in the case of ceramics, preferably 130
0 to 2200 ° C, more preferably 1400 to 185
It is set to about 0 ° C.

The sintering temperature may be changed (increased or decreased) with time within or outside the above-mentioned range.

The sintering time is preferably about 30 to 480 minutes, more preferably 6 at the above-mentioned sintering temperature.
It is about 0 to 300 minutes.

The sintering atmosphere is not particularly limited, but when the raw material powder is a metal powder, it is preferably under reduced pressure (vacuum) or a non-oxidizing atmosphere. This prevents characteristic deterioration due to oxidation of metal and contributes to reduction of porosity of the sintered body. Further, when the raw material powder is ceramics, it is preferable that the raw material powder is in the air or in an inert gas atmosphere. This contributes to the reduction of the porosity of the sintered body.

A preferable sintering atmosphere is 1 Torr or less (more preferably 1 × 10 6) when the raw material powder is a metal powder.
^-2 to 1 × 10 ^-6 Torr) under reduced pressure (vacuum), or 1 to 7
An inert gas atmosphere of 60 Torr of nitrogen gas, argon gas or the like, or a hydrogen gas atmosphere of 1 to 760 Torr is preferable. 1 to 76 when the raw material powder is ceramics
An atmosphere of an inert gas such as 0 Torr of nitrogen gas or argon gas or an atmosphere of 1 to 760 Torr is preferable.

By performing the sintering under the above conditions, the porosity of the long sintered body can be reduced. The porosity of the obtained long sintered body is preferably 7 vol% or less,
It is more preferably 5 vol% or less. The reduction of the porosity contributes to the densification of the long sintered body, and also provides high strength, high dimensional accuracy, prevention of sintering defects, and good appearance.
Sintering efficiency is good, sintering can be performed in a shorter sintering time, and productivity is improved.

The sintering may be performed in two steps or more. For example, sintering conditions (sintering temperature, sintering time,
It is possible to perform primary sintering and secondary sintering in which at least one of the sintering atmosphere and the like) is different. In this case, the sintering temperature of the secondary sintering can be higher than the sintering temperature of the primary sintering. Thereby, the efficiency of sintering is further improved, and the porosity can be further reduced.

As described above, the long sintered body 10 for obtaining the bracket 1 is manufactured. This long sintered body 10
As shown in FIG. 2, is a long sintered body whose longitudinal direction is the extrusion direction during extrusion molding, and its cross-sectional shape is constant. A groove corresponding to the slot 4 is formed in the long sintered body 10. In addition, each protrusion 31 to the engaging portion 3
The ridges 35 and 36 for forming 34 are formed, and the grooves 7 and 8 are formed inside the ridges 35 and 36, respectively.

Such a long sintered body 10 is cut into a desired length, and if necessary, the slot 5 is formed and the bottom surface 6 is processed by machining or the like to form the bracket 1.

A plurality of (for example, about 5 to 100) brackets 1 can be obtained from one long sintered body 10. In this case, the brackets 1 are not limited to have the same length, but may have different lengths. Further, the widths of the slots 5 in each bracket 1 are not limited to the same width, and may have different sizes.

In the present invention, for any purpose,
There may be a pre-step of the step [1A], an intermediate step existing between the steps [1A] to [3A], or a post-step of the step [3A]. In this case, as a post-process (post-treatment),
For example, surface treatments such as deburring, cleaning and polishing, various other mechanical processings, chemical treatments and the like can be mentioned.

When the long sintered body 10 has Ti as a basic component, that is, when it is made of Ti or a Ti-based alloy (hereinafter referred to as "Ti-based metal material"), the long sintered body 10 is used. Is C: 0.01-0.5 wt%, O: 0.02-
It preferably contains 0.8 wt% and N: 0.005 to 0.6 wt%.

The Ti-based metallic material is lightweight and has high strength, is less likely to be deformed or damaged, has excellent durability and corrosion resistance, has very little elution of metallic components, and suppresses the development of metallic allergies. It has excellent biocompatibility. Further, since the Ti-based metal material has less metallic luster than stainless steel, it has an advantage of not impairing aesthetics when the bracket 1 is mounted.

C, O and N are present in the Ti-based metal material constituting the long sintered body 10 in the form of forming a compound with Ti, for example. By containing an appropriate amount in the material, it is possible to maintain physical properties such as strength, hardness, ductility (toughness), and elasticity suitable for an orthodontic member (dental device).

The content of C in the Ti-based metal material is preferably about 0.01 to 0.5 wt%, more preferably about 0.03 to 0.25 wt%, and further preferably 0.0.
It is set to about 3 to 0.15 wt%. C content is 0.01
If it is less than wt%, the strength of the material may be lowered when the contents of O and N are small, and if it exceeds 0.5 wt%, the ductility of the material may be lowered.

The content of O in the Ti-based metal material is preferably about 0.02 to 0.8 wt%, more preferably about 0.06 to 0.6 wt%, and further preferably 0.06.
Approximately 0.4 wt%. O content is 0.02wt%
If it is less than 0.8% by weight, the material strength may decrease, and if it exceeds 0.8% by weight, the ductility of the material may decrease.

The content of N in the Ti-based metal material is preferably about 0.005 to 0.6 wt%, more preferably about 0.01 to 0.18 wt%, and even more preferably about 0.1.
It is set to about 01 to 0.09 wt%. N content is 0.0
If it is less than 5 wt%, the strength of the material may be lowered when the C and O contents are small, and if it exceeds 0.6 wt%, the ductility of the material may be lowered.

C, O and N in the Ti-based metal material
Is preferably about 0.035 to 1.2 wt%, more preferably about 0.08 to 0.95 wt%, and even more preferably about 0.08 to 0.6 wt%. More preferable. If this total content is less than 0.035 wt%, the material strength will decrease, and if it exceeds 1.2 wt%,
The ductility of the material may decrease.

In the Ti-based metallic material, for example, F
Other elements such as e, Ni, Cr, Pd, Co, Zr, Al, V, and Mo may be contained inevitably or positively in a range that does not cause harmful effects such as metal allergy. Addition of these elements contributes to the increase in strength of the metal material.
These elements are preferably present in the form of forming an alloy with Ti or an intermetallic compound.

[0080]

EXAMPLES Next, specific examples of the method for producing a long sintered body for an orthodontic member according to the present invention will be described.

Example 1 As the metal powder, Ti powder having an average particle size of 20 μm manufactured by the gas atomizing method was prepared.

This metal powder: 91 wt%, polystyrene (PS): 2.7 wt%, ethylene-vinyl acetate copolymer (EVA): 2.7 wt% and paraffin wax:
A binder composed of 2.3 wt% and dibutyl phthalate (plasticizer): 1.3 wt% were mixed, and these were kneaded by a kneader at 100 ° C. for 60 minutes.

Next, using this kneaded material (compound), a long molding having an irregular cross section (for bracket: cross-sectional area = 3.5 mm ² ) shown in FIG. 2 was extruded by an extrusion molding machine. The molding conditions during extrusion molding were a cylinder temperature of 140 ° C., a molding die (outlet portion) temperature of 70 ° C., an extrusion pressure of 120 kgf / cm ² , and an extrusion speed of 10 mm / sec. The content of the metal powder in the obtained long shaped body was about 91 wt%.

Next, a degreasing treatment was applied to this long shaped body using a degreasing furnace. The degreasing condition is 1 × 10 ⁻³ Torr
The pressure was reduced to 500 ° C. for 60 minutes.

Next, for the degreased long degreased body,
Sintering was performed using a sintering furnace to obtain a long sintered body having a length of about 240 mm. The sintering conditions were 1200 ° C. × 180 minutes under a reduced pressure of 1 × 10 ⁻³ Torr.

This long sintered body is made of a Ti-based metal material, and is made of LECO's EC-12 type (carbon analyzer), RO-116 type (oxygen analyzer), TN-114.
As a result of elemental analysis by each analyzer of the type (nitrogen analyzer), the amounts of C, O and N contained were C:
It was 0.05 wt%, O: 0.40 wt%, N: 0.02 wt%.

The porosity of the long sintered body (measured by Archimedes method) was 3 vol%.

Example 2 In the sintering step, as primary sintering, 1050 ° C. × 8 was performed under a reduced pressure of 1 × 10 ⁻³ Torr.
A long sintered body was manufactured in the same manner as in Example 1 except that the secondary sintering was performed for 0 minutes in the argon gas atmosphere of 10 Torr at 1200 ° C. for 90 minutes.

This long sintered body is composed of a Ti-based metal material, and as a result of elemental analysis by the above-mentioned analyzer, the amounts of C, O and N contained are C: 0.06 wt.
%, O: 0.35 wt%, N: 0.02 wt%.

The porosity of the long sintered body (measured by Archimedes method) was 3.5 vol%.

(Example 3) As a metal powder, Ti-6wt produced by a gas atomization method and having an average particle size of 20µm was used.
% Al-4 wt% V Ti-based alloy powder was prepared.

This metal powder: 90 wt%, polystyrene (PS): 3.0 wt%, ethylene-vinyl acetate copolymer (EVA): 3.0 wt% and paraffin wax:
A binder composed of 2.4 wt% and dibutyl phthalate (plasticizer): 1.6 wt% were mixed, and these were kneaded by a kneader at 100 ° C. for 60 minutes.

Next, using this kneaded material (compound), a long molding having an irregular cross section (for bracket: cross-sectional area = 3.5 mm ² ) shown in FIG. 2 was extruded by an extrusion molding machine. The molding conditions during extrusion molding were a cylinder temperature of 140 ° C., a molding die (outlet portion) temperature of 70 ° C., an extrusion pressure of 120 kgf / cm ² , and an extrusion speed of 10 mm / sec. The content of the metal powder in the obtained long shaped body was about 90 wt%.

Next, a degreasing process was performed on the long molded body using a degreasing furnace. The degreasing condition is 1 × 10 ⁻³ Torr
The pressure was reduced to 520 ° C. for 60 minutes.

Next, for the degreased long degreased body,
Sintering was performed using a sintering furnace to obtain a long sintered body having a length of about 240 mm. The sintering conditions were 1250 ° C. and 180 minutes under an argon gas atmosphere of 1 × 10 ^-1 Torr.

This long sintered body is composed of a Ti-based metal material, and as a result of the elemental analysis by the above-mentioned analyzer, the contained amounts of C, O and N are C: 0.06 wt.
%, O: 0.45 wt%, N: 0.02 wt%.

The porosity of the long sintered body (measured by Archimedes method) was 3 vol%.

(Example 4) As a metal powder, stainless steel having a mean particle size of 15 μm produced by a gas atomization method (composition: Fe-12 wt%, Ni-17 wt%, Cr-
2.5 wt%, Mo alloy) powder, sintering conditions 10 To
A long sintered body was manufactured in the same manner as in Example 1 except that the temperature was 1,350 ° C. × 180 minutes under an argon gas atmosphere of rr. The porosity of the long sintered body (measured by Archimedes method) was 2 vol%.

Example 5 As a raw material powder, a yttria partially stabilized zirconia (ZrO ₂ -5.5Y ₂ O ₃ ) powder having an average particle size of 1 μm, which was produced by a spray pyrolysis method, was prepared.

A binder composed of 80 wt% of this ceramic powder, 6.0 wt% of polystyrene (PS), 6.0 wt% of ethylene-vinyl acetate copolymer (EVA) and 4.8 wt% of paraffin wax. And dibutyl phthalate (plasticizer): 3.2 wt% were mixed, and these were kneaded in a kneader at 100 ° C. for 60 minutes.

Next, using this kneaded material (compound), a long molded body having a modified cross section (for bracket: cross-sectional area = 5.2 mm ² ) shown in FIG. 2 was extruded by an extrusion molding machine. The molding conditions during extrusion molding were a cylinder temperature of 130 ° C., a molding die (outlet portion) temperature of 70 ° C., an extrusion pressure of 120 kgf / cm ² , and an extrusion speed of 3 mm / sec. The content of the raw material powder in the obtained long shaped body was about 80 wt%.

Next, a degreasing treatment was performed on this long shaped body using a degreasing furnace. The degreasing condition is 1 × 10 ⁻³ Torr
The pressure was reduced to 450 ° C. for 60 minutes.

Next, for the degreased long degreased body,
Sintering was performed using a sintering furnace to obtain a long sintered body having a length of about 240 mm. The sintering conditions were 1450 ° C. × 180 minutes under a reduced pressure of 1 × 10 ⁻³ Torr. The porosity (measured by Archimedes method) of the long sintered body was 1 vol%.

<Manufacture of Bracket> Each long sintered body of Examples 1 to 5 was cut into a predetermined length, and then,
Slot 5 by machining for each cut piece
Was formed to obtain a bracket having the shape shown in FIG. In each of the examples, about 50 brackets were obtained from one long sintered body. Also, from one long sintered body, three types of brackets having different lengths in the longitudinal direction of 3 mm, 4 mm and 6 mm were obtained.

<Evaluation of Quality / Characteristics> 1. The brackets obtained from the long sintered bodies of Quality Examples 1 to 5 were cut in multiple directions, and the cut end faces thereof were visually observed to check for the presence of sintering defects. As a result, each of the brackets according to Examples 1 to 5 was of good quality with no sintering defects.

2. Dimensional error Bracket 1 obtained from each long sintered body of Examples 1 to 5
The maximum width of the engaging portion 3 and the slot 4 for each 0
When the dimension of the width was measured and the dimension error (variation in dimension) was examined, the dimension error was ± 0.5% or less in all cases. From this, it was confirmed that all of Examples 1 to 5 had high dimensional accuracy.

3. Mechanical Strength (Bending Strength) Japan Powder Metallurgy Association Standard JPMA M09-1992
Based on the above, the transverse rupture strength was measured with the transverse rupture strength test pieces of the sintered bodies of Examples 1 to 5.

4. Hardness Based on JIS Z 2244, the Vickers hardness Hv of the surface of the engaging portion 3 in the sintered bodies of Examples 1 to 5 was measured (load 500 g).

5. Metal component elution amount (biocompatibility) Each bracket of Examples 1 to 5 was added to a 0.05% hydrochloric acid solution to give 1
After soaking for 00 days, the concentration of metal ions in this solution was analyzed and quantified by a plasma emission spectrometer. The smaller the elution amount, the better the biocompatibility.

6. The degree of gloss of the aesthetic surface and the difference with the color tone of the tooth were visually determined. It was evaluated in four grades of ⊚, ◯, Δ, and × in the order of decreasing gloss (= great aesthetics). In addition, those with little difference from the color of the tooth were evaluated as aesthetic.

Table 1 below shows the results of the mechanical strength (flexural strength), hardness, elution amount of metal components (biocompatibility) and aesthetics.

[0112]

[Table 1]

As shown in Table 1, each of the brackets obtained from the long sintered bodies of Examples 1 to 5 has high mechanical strength (flexural strength) and surface hardness. Particularly, the brackets obtained from the long sintered bodies of Examples 1, 2, 3 and 5 are excellent in biocompatibility and aesthetics.

[0114]

As described above, according to the present invention, it is possible to easily manufacture even a complicated shape and to have high dimensional accuracy and high density (low porosity) long-sintering for orthodontic members. body,
That is, an orthodontic member can be obtained. Since it is formed by extrusion, it has high productivity and is suitable for mass production of orthodontic members.

Further, it is possible to manufacture a long sintered body for an orthodontic member using a hard material or the like which has been difficult to process in the past, and the function and shape (design) of the orthodontic member can be manufactured. ) Can be expanded.

Also, since various kinds of orthodontic members can be easily manufactured by adjusting the cutting length, it is possible to supply the orthodontic members with excellent productivity and at low cost.

Further, in the case of using a Ti-based metal material, the contents of C, O and N in the sintered body can be reduced, so that an orthodontic member with high ductility (toughness) can be obtained. To be

[Brief description of drawings]

FIG. 1 is a process chart showing an embodiment of a method for producing a long sintered body for an orthodontic member according to the present invention.

FIG. 2 is a perspective view showing an example of a long sintered body for an orthodontic member manufactured by the method for manufacturing a long sintered body for an orthodontic member of the present invention.

FIG. 3 is a perspective view showing a configuration example of an orthodontic member (bracket) obtained from a long sintered body for an orthodontic member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Orthodontic bracket, 10 ... Long sintered body for orthodontic members, 2 ... Base part, 3 ... Engagement part (tie wing), 31
... 34 ... protrusions, 35, 36 ... ridges, 4, 5 ... slots (grooves), 6 ... bottom surface (back surface), 7, 8 ... grooves, 1A to 3A ...
Process

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaaki Sakata             18-18 12 Kogishi-dori, Suwa City, Nagano Prefecture             In ceremony company Ingex F-term (reference) 4C052 AA20 JJ02 JJ03 JJ09                 4K018 BA11 CA31 DA03 DA11 HA10                       KA63

Claims (10)

[Claims] 1. Using a compound containing raw material powder,
A step of obtaining a long molded body having a cross-sectional shape corresponding to the cross-sectional shape of the orthodontic member by extrusion molding, a step of degreasing the long molded body, and a degreased body that has been degreased. And a step of obtaining a long sintered body by sintering the method for producing a long sintered body for an orthodontic member. 2. The method for producing a long sintered body for an orthodontic member according to claim 1, wherein at least one groove is formed in the finally obtained long sintered body. 3. The elongated sintered body for an orthodontic member according to claim 1, wherein at least one ridge is formed on the finally obtained elongated sintered body. Production method. 4. The method for producing a long sintered body for an orthodontic member according to claim 1, wherein the raw material powder is a metal powder or a ceramic powder. 5. The method for producing a long sintered body for an orthodontic member according to claim 1, wherein the raw material powder is a powder of Ti or a Ti-based alloy. 6. The finally obtained long sintered body is C:
0.01-0.5 wt%, O: 0.02-0.8 wt%,
N: 0.005-0.6 wt% is included.
A method for producing a long sintered body for an orthodontic member according to. 7. The total content of C, O and N is 0.0.
The method for producing a long sintered body for an orthodontic member according to claim 6, wherein the content is 35 to 1.2 wt%. 8. The method for manufacturing a long sintered body for an orthodontic member according to claim 1, wherein the raw material powder is a powder of stainless steel. 9. The method for producing a long sintered body for an orthodontic member according to claim 1, wherein the porosity of the finally obtained long sintered body is 7 vol% or less. . 10. The method for producing a long sintered body for an orthodontic member according to claim 1, wherein the orthodontic member is a bracket.