JP4475458B2 - Dental article and method for producing the same - Google Patents

Description

  The present invention relates to a dental product that has both a function for satisfying aesthetics and other functions required for a dental product, and a manufacturing method thereof. More specifically, the present invention relates to an aesthetic property, durability, low The present invention relates to a dental product that satisfies both friction coefficients and a method for manufacturing the dental product.

  For example, as a dental material used for a dental article such as an orthodontic appliance, a metal material is generally used from the viewpoint of its function. For example, for orthodontic wires used in orthodontic appliances, cobalt-chromium alloy, stainless steel, titanium-nickel shape memory alloy, etc. are generally used as a base material or coating material (for example, , See Patent Document 1). These metal materials have sufficient elasticity by drawing or superelastic treatment, and the friction coefficient with the bracket used for mounting the wire is relatively small compared to other materials, and the correction effect is high. high.

  However, such orthodontic appliances usually attach a bracket to an unaligned tooth and a normal tooth with an adhesive, attach a wire to the bracket, and move the tooth over time by the elastic force of the wire. It is designed to correct the tooth alignment. For this reason, once the brackets and wires are mounted, they are mounted on the teeth over a long period of time while repeating the replacement of the wires about every month until the correction is completed.

  Therefore, in recent years, there has been a strong demand for improving esthetics so that it is not conspicuous that correction of teeth is in progress, mainly from women, from the viewpoint of beauty.

  However, there are no white and hard metal wires or brackets that meet these requirements. For this reason, as an orthodontic appliance currently marketed in order to satisfy the said request | requirement, the thing which coat | covered the base-material surface with the white coating material, for example using a metal wire as a base material is common.

Orthodontic wires currently in use are roughly divided into two types. One is a wire obtained by coating a metal wire base material with a white plastic such as Teflon (registered trademark). The other is a metal wire base material coated with the same white alumina ceramic as the ceramic material.
Japanese Patent Laid-Open No. 10-066701 (Publication date: March 10, 1998)

  The necessary properties of the coating material are as follows: (1) The color tone is close to the color of human teeth, (2) The coefficient of friction between the wire and the bracket is small, and the correction effect is high, (3) Durability It is mentioned that there is.

  However, although the wire using plastic as the coating material can adjust the color tone according to the color of human teeth, it is in use (during the treatment period), for example, it may be peeled off or discolored in about one month. Has a point. Moreover, since the coefficient of friction with the bracket is large, slippage hardly occurs between the bracket and the wire, and the correction effect is inferior.

  On the other hand, although the wire using white alumina ceramic as the coating material has a low friction coefficient, there is a fatal defect that when the wire is bent, the coating easily cracks and peels off. The orthodontic wire is used by using a special tool to bend the wire together with the teeth, or bend the end of the wire so as not to damage the mouth. The film is cracked at the bent portion, and peeling is likely to occur from here.

  Furthermore, since many recent toothpaste pastes contain fine abrasives, the surface of the coating must be hard enough to withstand wear and must be durable.

  However, orthodontic wires capable of overcoming such problems have not been developed yet. In addition to orthodontic wires, various dental products such as brackets, artificial tooth materials such as dentures and dentures, crowns, dental prosthesis clasps, etc. Providing a dental product that has both functions can be very effective in reducing the patient's psychological resistance.

  The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a dental product that has both a function for satisfying aesthetics and other functions required for a dental product, and its manufacture. It is to provide a method.

  In order to solve the above problems, a dental article according to the present invention includes a first functional layer and a second functional layer having different functions, and the first functional layer exhibits a desired color, The second functional layer is a skin layer that covers the first functional layer, and is characterized in that the first functional layer can be seen through.

  According to said structure, the said 1st functional layer exhibits a desired color, the said 2nd functional layer is a skin layer which covers the said 1st functional layer, and can see through the said 1st functional layer By providing the functions for satisfying aesthetics and other functions required for dental products, the first functional layer and the second function are not a single layer as in the prior art. Since it can be assigned to each layer separately, it is possible to provide a dental product having both a function for satisfying aesthetics and other functions.

  The dental article includes an orthodontic wire and a bracket for holding the wire, and at least one of the wire and the bracket includes the first functional layer and the second functional layer, and the second The functional layer preferably has a smaller coefficient of friction due to the friction between the wire and the bracket than the first functional layer.

  The second functional layer has a smaller coefficient of friction due to friction between the wire and the bracket than the first functional layer, so that the orthodontic effect is not hindered to satisfy aesthetics, There is an effect that it is possible to provide a dental product having an excellent orthodontic effect as compared with the conventional art.

  In the dental article, the first functional layer is preferably a kind selected from white metals and alloys thereof. The first functional layer is preferably one type selected from the group consisting of silver, aluminum, nickel, stainless steel, platinum, and a silver-titanium alloy.

  On the other hand, the second functional layer is preferably made of a transparent or translucent amorphous ceramic. The second functional layer is preferably made of titanium oxide or aluminum oxide.

  According to each of the above configurations, there is an effect that it is possible to provide a dental product that can satisfy all of the characteristics required for the dental product, such as aesthetics, low friction, and durability.

  In this case, as the first functional layer and the second functional layer, it is particularly preferable that the first functional layer is made of a silver-titanium alloy and the second functional layer is made of aluminum oxide.

  Further, the dental article has a configuration in which an antioxidant layer for preventing oxidation of the first functional layer is further provided between the first functional layer and the second functional layer. Also good.

  An anti-oxidation layer that prevents oxidation of the first functional layer is further provided between the first functional layer and the second functional layer, thereby protecting the first functional layer from oxidation. Thus, the first functional layer can be prevented from being damaged by oxidation.

  Further, it is desirable that the first functional layer has a different film forming state between the lower layer portion and the upper layer portion. Since the first functional layer has different film formation states between the lower layer portion and the upper layer portion, different functions can be imparted to the first functional layer itself between the lower layer portion and the upper layer portion. . Thereby, for example, the lower layer portion of the first functional layer has high adhesiveness with the base material, and the color tone obtained by seeing through the second functional layer at the upper layer portion of the first functional layer is obtained. There is an effect that adjustment can be performed.

  Moreover, in order to solve the said subject, the manufacturing method of the dental material concerning this invention comprises the process of forming the 1st functional layer and 2nd functional layer which have a mutually different function, The said 1st function And a second functional layer, the second functional layer being a skin layer covering the first functional layer, the first functional layer exhibiting a desired color, and the second functional layer Is characterized in that the first functional layer can be seen through.

  According to the above configuration, the first functional layer and the second functional layer are the skin layer in which the second functional layer covers the first functional layer, and the first functional layer is desired. And the second functional layer is formed so that the first functional layer can be seen through, so that a function for satisfying aesthetics required for a dental article and other functions can be obtained. Since it can be assigned to the first functional layer and the second functional layer separately instead of a single layer as in the prior art, it has both a function for satisfying aesthetics and other functions. There is an effect that a dental article can be manufactured.

  Further, in the method for manufacturing a dental article, the surface property of the first functional layer can be changed by using bias sputtering for forming the first functional layer. The color tone, and thus the color tone obtained through the second functional layer, can be easily adjusted by the bias sputtering. Furthermore, by using bias sputtering for the formation of the first functional layer, there is also an effect that the adhesion of the first functional layer to the stacked body (for example, a base material) can be improved.

  In the method for manufacturing a dental article, when bias sputtering is used to form the first functional layer, application of a bias voltage is stopped during the formation of the first functional layer, or the first functional layer is formed. The bias voltage applied in the latter half of the forming process is made lower than the bias voltage applied in the first half of the first functional layer forming process, for example, the lower layer portion and the upper layer portion of the first functional layer, Thus, the film forming state can be changed, and different functions can be imparted to the first functional layer itself in the lower layer portion and the upper layer portion. Accordingly, for example, the lower layer portion of the first functional layer is provided with high adhesiveness with a stacked body (for example, a base material), and the second functional layer is seen through the upper layer portion of the first functional layer. The color tone obtained in this way can be adjusted.

  As described above, the dental article according to the present invention is a skin layer in which the first functional layer exhibits a desired color, and the second functional layer covers the first functional layer. By providing the functional layer so that it can be seen through, the function for satisfying aesthetics and other functions required for dental products are not the single layer as in the prior art, but the first function. Since the layer and the second functional layer can be assigned separately, there is an effect that it is possible to provide a dental product that has both a function for satisfying aesthetics and other functions.

  In addition, as described above, the method for manufacturing a dental article according to the present invention includes the first functional layer and the second functional layer, and the skin layer in which the second functional layer covers the first functional layer. The first functional layer exhibits a desired color, and the second functional layer is formed so that the first functional layer can be seen through, thereby satisfying aesthetics required for a dental product. In order to satisfy aesthetics, the first function layer and the second function layer can be separately assigned to the first function layer and the second function layer instead of a single layer as in the prior art. There is an effect that it is possible to manufacture a dental product having both the above functions and other functions.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 13 as follows.

  In the present embodiment, an orthodontic appliance provided with an orthodontic wire and a bracket will be described as an example of a dental article according to the present invention. However, the present invention is limited to this. It is not a thing.

  Fig.2 (a) is a perspective view which shows schematic structure of the orthodontic appliance concerning this Embodiment, FIG.2 (b) is a disassembled perspective view of the principal part of the orthodontic appliance shown in Fig.2 (a). It is.

  As shown in FIG. 2A, the orthodontic appliance 11 according to the present embodiment includes an orthodontic wire 12 and a bracket 13 as a holding member that holds the wire 12.

  The orthodontic appliance 11 adheres (fixes) the bracket 13 to an unaligned tooth and a normal tooth with an adhesive (not shown) or the like, and as shown in FIG. The wire 12 is attached to the concave portion 14a provided in the wire attachment portion 14 (hook), and the teeth are moved over time by the elastic force of the wire 12 to correct the tooth arrangement.

  The orthodontic appliance 11, that is, the wire 12 and the bracket 13 have a configuration in which a first functional layer and a second functional layer having different functions are provided on a base material. In the following, each functional layer of the orthodontic appliance 11 will be described by taking as an example a wire 12 that is exposed to the most severe mechanical or chemical conditions in the orthodontic appliance 11.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the wire 12 according to the present embodiment.

  As shown in FIG. 1, the orthodontic wire 12 according to the present embodiment has a first functional layer (function) on a wire base material 1 (base material, laminated body) as shown in FIG. The base layer 2 as a film) and the skin layer 3 as a second functional layer (functional film) are stacked in this order. That is, the wire 12 according to the present embodiment performs the function sharing by providing a two-layer film as a coating layer on the wire base material 2.

  The said wire base material 1 is a base material which has a wire shape, and can use the well-known wire conventionally used for orthodontics. Specific examples of the wire substrate 1 include a cobalt-chromium (Co-Cr) alloy, stainless steel (Cr-based, Ni-Cr-based), and titanium-nickel (Ti-Ni) shape memory alloy. Although the wire which consists of metals is mentioned, it is not specifically limited.

  In addition, it is desirable that the wire base material 1 has sufficient elasticity by being subjected to a drawing process, a superelastic process, or the like.

  The wire 12 can be easily obtained by coating the surface of the wire base 1 with the base layer 2 and the skin layer 3.

  Properties required for orthodontic wires include (1) color tone close to human teeth color, (2) low coefficient of friction between wire and bracket, high orthodontic effect, (3) In particular, it is desirable that the color tone can be adjusted in accordance with the color of the individual teeth. As (3) above, first, the surface is hard and durable, and second, even if the wire is bent during the straightening operation, the coating coated on the wire base material is cracked or peeled off. Third, it is desirable that the coating does not wear or peel even if it is placed in the oral cavity for a long period of time.

  The wire 12 according to the present embodiment is coated twice on the wire base material 1 using a coating material having different characteristics instead of the conventional single layer coating, By providing two layers of functional layers with different functions and assigning each layer the functions necessary for dental supplies, it is possible to achieve pseudo-characteristics (color tone adjustment capability) for natural teeth that could not be compatible with each other. Thus, it is possible to satisfy both a high correction effect (low friction coefficient) and durability.

  In the present embodiment, the base layer 2 is a color layer (base layer, shielding layer) that shields the color of the wire base material 1 and exhibits a desired color, so that the wire 12 resembles a natural tooth. , And functions as a color tone adjustment layer for adjusting the color tone of the wire 12.

  The base layer 2 may itself exhibit a color resembling natural teeth, such that the color seen through the skin layer 3 is close to natural teeth, or a combination with the skin layer 3 May exhibit a color close to that of natural teeth. The underlayer 2 desirably completely shields the color of the wire base material 1 in order to enhance the aesthetics of the wire 12, but the color of the wire base material 1 is within a range that does not impede the purpose. You may be able to visually recognize.

  According to the present embodiment, the base layer 2 shields the color of the wire base material 1 so that the color of the metal wire base material 1 can be white that is close to the color of human teeth, A highly aesthetic wire 12 can be provided.

  Although it depends on the color of the skin layer 3 as the base layer 2, it is desirable to use a white or yellow material, and it is easier to adjust the color finally seen through fluoroscopy. It is more preferable to use a white material, and it is particularly preferable that the white material itself has a color close to that of natural teeth, and further exhibits the color of natural teeth. Moreover, it is desirable that the base layer 2 is excellent in adhesion with the wire base material 1.

  Specific examples of the material for the underlayer 2 include white metals such as silver (Ag), aluminum (Al), platinum (Pt), and nickel (Ni), stainless steel, and Ag-Ti alloys. , Ag-Ni alloys, and the like, which are alloys obtained by adding another element to the white metal.

  Among the materials exemplified above, Ag is white and rich in ductility, has high safety for medical use, and has excellent adhesion to the wire base material 1. For this reason, among the materials exemplified above, Ag and an alloy containing Ag (that is, an alloy formed by adding another metal such as Ti to Ag) are preferable as the material of the base layer 2. An Ag—Ti alloy and an Ag—Ni alloy are more preferable, and an Ag—Ti alloy is particularly preferable.

  The metal used for the base layer 2 is rich in ductility, and is preferably one that does not crack or peel even when the wire 12 is bent, for example, when correcting the back teeth, and the wire 12 is completely bent. Those which do not crack or peel off are particularly suitable. The radius of curvature when the wire 12 is completely bent is substantially equal to the thickness of the wire 12. Therefore, in other words, it is preferable that the metal used for the underlayer 2 has a bending radius of curvature that causes cracking or peeling of the underlayer 12 as small as possible, and the wire 12 has a radius of curvature that is equal to the thickness of the wire 12. Particularly suitable are those that do not crack or peel even when bent to equality. In addition, it shows that curvature is so gentle that a curvature radius is large. For example, in the specific example described later, it is particularly preferable that the wire 12 is not cracked or peeled even when the wire 12 is bent to a curvature radius of 0.4 mm. However, in consideration of actual use, it is desirable that the underlayer 2 does not crack or peel even if the wire 12 is bent to a curvature radius of 1.5 mm. It is more desirable not to.

  The layer thickness (film thickness) of the underlayer 2 is preferably 3 μm or more because it is difficult to peel off, although it depends on the type of coating thin film material for forming the underlayer 2. In some cases, it is more preferably in the range of 5 μm to 9 μm, and more preferably in the range of 3 μm to 5 μm in the case of an Ag-1 wt% Ti alloy (hereinafter sometimes referred to as “Ag + 1% Ti”).

  In the present embodiment, the skin layer 3 is a protective layer that covers and protects the base layer 3 as the outermost layer, has excellent physical properties such as durability, wear resistance, and corrosion resistance, and is used as the dental article. In the case of manufacturing an orthodontic appliance as shown in the present embodiment, it is desirable that the friction coefficient is small and the orthodontic effect is high.

  In the present embodiment, as described above, the wire layer 1 is shielded so as to resemble the color tone of the natural tooth, and the ground layer 2 as a color layer that exhibits a desired color tone is referred to as the skin layer 3 described above. Since the skin layer 3 is provided separately, the skin layer 3 is transparent or semi-transparent so that the base layer 2 as a coloring layer and a color tone adjusting layer can be seen through (that is, the color of the base layer 2 can be seen through). It is necessary to be.

  That is, in the present embodiment, the skin layer 3 has physical properties required for the outermost layer (surface layer) among various physical properties required for the dental article, and the skin layer 3 is insufficient. The undercoat layer 2 has a color tone adjustment function (a pseudo characteristic with respect to the color of natural teeth) including a shielding ability for the wire base material 1 and a coloring ability enabling a desired coloration, particularly the shielding ability and the coloring ability. Therefore, a material having a lower friction coefficient and higher transparency than that of the base layer 2 is used for the skin layer 3. That is, the skin layer 3 also functions as a friction coefficient adjusting layer. In other words, the skin layer 3 supplements physical properties that are insufficient for the base layer 2.

  Examples of the material of the skin layer 3 include transparent or translucent amorphous ceramics. More specifically, examples include aluminum oxide (alumina) and titanium oxide (titania). Amorphous ceramics are suitable as a protective film for the underlayer 2 because they are hard and wear resistant. In the present invention, since the wire 12 is used in the oral cavity as a dental product, it goes without saying that it is preferable to select and use a material that does not adversely affect the human body.

And among the ceramics having an oxide and an amorphous structure as shown in the above exemplified materials, titania (TiO ₂ ) and alumina (Al ₂ O ₃ ) are hard and have a small coefficient of friction, and orthodontic hardening is possible. It is preferable because it is high and transparent.

In addition, TiO ₂ has an antifouling / sterilizing effect due to a photocatalytic reaction, and can obtain an antifouling / sterilizing effect in the gap near the orthodontic appliance 11 that cannot be cleaned with a toothbrush during the correction period. It is effective for holding.

Al ₂ O ₃ is preferable because it has excellent adhesion to the base layer 2 and is difficult to peel off.

  Ordinary sintered alumina is white as it is in ceramics, but is brittle. On the other hand, oxide ceramics formed by sputtering, for example, are amorphous and transparent, and have high toughness. For this reason, even if it receives a big bending, it does not break.

  As described above, the skin layer 3 needs to be transparent or translucent in order to maintain the color tone of the base layer 2, and at the same time, must be hard to prevent abrasion due to brushing. A low coefficient of friction is required when used for a corrector.

As described above, ceramics having an amorphous structure with oxides such as Al ₂ O ₃ and TiO ₂ , in particular, oxide-based ceramics prepared by sputtering, serve to protect the base without changing the color tone, The coefficient of friction is small, and it is rich in wear resistance and corrosion resistance.

  When the above-described amorphous ceramic is used for the skin layer 3 in the wire 12, for example, the coefficient of static friction with stainless steel, which is a typical bracket material, is 0.26 in the combination of stainless steel and an alumina thin film. Because the friction coefficient between the conventional stainless steel and stainless steel (wire) is considerably smaller than 0.34, rather than the combination of metal bracket and metal wire, which is inferior in aesthetics but has a high correction effect, It is an excellent combination with a great correction effect.

  In order to provide the orthodontic appliance 11 having both aesthetics and a low friction coefficient, the friction coefficient between the wire 12 and the bracket 13 increases the friction coefficient more than before. In order to improve the aesthetics without any problems, it is preferable that the aesthetics are equal to or less than the conventional one. Specifically, the friction coefficient is preferably 0.34 or less, more preferably 0.3 or less, and even more preferably 0.2 or less. According to the present embodiment, as described above, the orthodontic appliance 11 that not only increases the coefficient of friction but also can reduce the coefficient of friction as compared with the prior art and has improved aesthetics compared to the prior art is provided. be able to.

The layer thickness (film thickness) of the skin layer 3 is not particularly limited as long as it covers the base layer 2 and allows the base layer 2 to be seen through. For example, the skin layer 3 has the film thickness. It is possible to make various changes in order to finely adjust the color tone so that the color seen through it becomes a color close to natural teeth, but the type of coating thin film material for forming the skin layer 3 and the base film 2 Depending on the combination and the like, if the skin layer 3 becomes too thick, the skin layer 3 may peel off naturally. Therefore, thickness of the skin layer 3 is preferably formed to the extent that the separation does not occur, for example, is preferably in the range of 1μm~2μm in Al ₂ O _3.

  Next, a method for producing the base layer 2 and the skin layer 3 will be described below.

  The base layer 2 can be easily obtained by coating the material of the base layer 2 on the wire base material 1 that has been subjected to a base treatment such as a polishing treatment if necessary.

  The skin layer 3 can be easily obtained by coating the material of the skin layer 3 on the base layer 2.

  As the coating method, for example, sputtering can be used as described above. When sputtering is used as the coating method, when the base layer 2 is made of Ag, it can be sputter-coated by ordinary DC bipolar sputtering or high-frequency sputtering. When the adhesion between the wire base material 1 and the wire base material 1 decreases, sputtering is performed while applying a bias voltage to perform sputtering and applying a controlled potential to the base material side to control ion bombardment to the base material. It is desirable to use bias sputtering for performing the above.

  The color tone of the wire 12 visually recognized through the skin layer 3 is not only the color of the coating material used for the base layer 2 and the skin layer 3, that is, the color unique to the material metal, for example, Depending on the reflection of light due to unevenness on the surface, it varies depending on the amount of alloy elements even in the same sputtering method, and also varies depending on the bias voltage even in the same alloy. That is, for example, the color of the base layer 2 is adjusted to be a white color close to human teeth by the film thickness, fine surface shape, light absorption / reflection, etc. in addition to the original color of the material (raw material) can do.

For example, when the TiO ₂ thin film is sputter coated on the skin layer 3 by reactive sputtering or the like, if the TiO ₂ thin film or the Al ₂ O ₃ thin film is thickened, it may be slightly colored yellow according to the film thickness. It changes from transparent to milky white. Therefore, the wire 12, as the thickness of TiO ₂ film, _Al 2 _{O 3,} or _the thin film is thick, becomes darker shades. Therefore, according to this Embodiment, the color tone of the said wire 12 visually recognized through the said skin layer 3 can be easily changed by changing the film thickness of the said skin layer 3, for example.

  As described above, the film thickness of the skin layer 3 is within a range in which the skin layer 3 does not peel naturally so that the color tone of the wire 12 visually recognized through the skin layer 3 has a desired color tone. The setting is not particularly limited.

  The color tone of the wire 12 visually recognized through the skin layer 3 can be adjusted by mixing the base layer 2 with an alloy and coloring it.

As described above, according to the present embodiment, by using the TiO ₂ or Al ₂ O ₃ for the skin layer 3, the wire 12 having a color very close to natural teeth can be obtained in combination with the base layer 2. Obtainable.

  Further, according to the present embodiment, by performing bias sputtering, the surface properties, specifically, the unevenness of the surface of each layer can be changed. More specifically, according to the present embodiment, by performing bias sputtering, the surface of the obtained layer can be smoothed and gloss can be imparted to the layer. Therefore, according to the present embodiment, for example, by using a sputtering bias for forming the underlayer 2, the color tone of the underlayer 2 is changed to that of the coating material (underground metal) used for the underlayer 2. The adhesive component (adhesiveness) between the base layer 2 and the wire substrate 1 is increased by adjusting the alloy component and the bias voltage (difference in reflection of light due to surface irregularities) and simultaneously applying the bias. be able to.

  Further, the underlying layer 2 and the skin layer 3 can also be adjusted in color tone by adjusting the fine shape of the surface and the absorption / reflection of light, etc. by polishing the surface.

  Moreover, the adhesiveness of the said wire base material 1 and the base layer 2 can also be improved by performing grinding | polishing processing etc. on the said wire base material 1 surface.

  The base layer 2 and the skin layer 3 are used by appropriately combining the thin film materials constituting the base layer 2 and the skin layer 3 so as to have a color tone different from natural teeth. In this case, each layer is desirably provided so as not to hinder the function of each layer.

  As shown in the present embodiment, when the base layer 2 is laminated on a base material such as the wire base material 1, the functions of the base layer 2 include shielding / coloring and color tone adjustment as described above. In addition to the above, it is required that the base layer 2 does not peel off even if the wire 12 is bent during the straightening operation.

As a suitable combination of the base layer 2 and the skin layer 3 (hereinafter referred to as base layer 2 / skin layer 3), for example, Al (target Al, sputtering gas Ar, white) / Al ₂ O ₃ (target Al, sputtering gas O ₂ , transparent); Ag (target Ag, sputtering gas Ar, white) / TiO ₂ (target Ti, sputtering gas O ₂ , yellow); Ag—Ti alloy (target AgTi, sputtering gas Ar, bias ( White) to bias stop (milky white)) / Al ₂ O ₃ (target Al, sputtering gas O ₂ gas, milky white), etc., but the above combinations are only examples, and are not limited to the above combinations. .

  Below, the film forming conditions of each thin film, the coating method, and the relationship between the various physical properties of the base layer 2 and the skin layer 3 for obtaining the above-described functions will be specifically described.

  In the following specific examples, a high frequency magnetron sputtering apparatus was used for coating each thin film. In addition, as a wire base material (adhesion evaluation), a 0.4 mm × 0.5 mm × 30 mm wire made of a Co—Cr alloy is used as the base material of each sample used in the following specific examples. As a base material (color tone comparison), a stainless steel plate “SUS304” of 20 mm × 10 mm × 1 mm was used. Two types of stainless steel plates having different surface roughness were used as the stainless steel plate. One is as-polished (untreated) and the other is sand shot blasted to roughen the surface. The original color of the thin film was confirmed using a glass substrate. As the glass substrate, soda glass of 20 mm × 26 mm × 1.5 mm was used. All the substrates were ultrasonically cleaned in acetone for 10 minutes before the experiment.

  Moreover, the film thickness, adhesiveness, and color tone of each thin film were evaluated (measured) by the following methods. The adhesion of each thin film was evaluated by the following bending test and corrosion test.

[Film thickness measurement]
The thickness of the thin film is measured with a stylus type surface roughness meter “SJ-201P” (trade name) manufactured by Mitutoyo Corporation. Was determined by

[Bending test]
After the thin film coating is applied to the wire base material, the obtained wire is sandwiched between simple bending jigs, and the wire is bent by turning a screw. A stereomicroscope “STZ-40TBITa” manufactured by Shimadzu Rika Co., Ltd. (trade name) The thin film was observed, and photographs of its surface and side surfaces were taken, and the radius of curvature of the wire at the time when the thin film was cracked or peeled was determined as an evaluation value for adhesion.

[Corrosion test (peeling characteristics)]
After the thin film coating is applied to the wire base material, the obtained wire is bent to a predetermined bending radius by a simple bending jig used in the bending test and fixed at both ends thereof, whereby the bending curvature radius (mm ) Was changed to obtain a thin film wire test piece. Next, the thin-film wire test piece is bent and immersed in a 3% NaCl aqueous solution, and the surface of the thin-film wire test piece is observed every predetermined time to check for cracks and peeling. The time when peeling occurred was examined.

[Color tone]
The color tone of the produced thin film was confirmed by comparing with a dental standard color sample (Vita Pan Shade Shade Guide manufactured by Vita Company), which is a sample of the color tone of teeth. The original color of the thin film was confirmed by performing thin film coating on the glass substrate.

First, in order to obtain the film forming conditions, the coating method, and the functions described above, using an Ag thin film as the base layer 2 and a TiO ₂ thin film as the skin layer 3 as an example. The relationship between various properties of the base layer 2 and the skin layer 3 will be specifically described.

[Formation of Ag thin film]
The Ag thin film was formed by directly coating Ag on the base material by performing sputtering or bias sputtering using Ag (99.98%) as a target (metal target). The conditions used for the normal sputtering and bias sputtering are: target Ag, sputtering gas Ar (99.999%), sputtering vacuum degree 4 × 10 ⁻³ Torr (≈0.5 Pa), high frequency output 300 W, sputtering time 3 to 10 The ultimate vacuum was 1 × 10 ⁻⁶ Torr (≈1.3 × 10 ⁻⁴ Pa, 2 hours).

When performing the sputtering and bias sputtering, the vacuum chamber is evacuated to 2 × 10 ⁻⁵ Torr (≈2.6 × 10 ⁻³ Pa) to clean the substrate surface, and then Ar gas ( The sample surface was sputter etched for 10 minutes, the target surface was cleaned by pre-sputtering, and sputtering was started.

  Here, the present inventors examined the relationship between the formation time and the film thickness of an Ag thin film formed by normal sputtering (hereinafter referred to as normal sputtering). As a result, the inventors of the present application find that the thin film formation speed increases as the sputtering output power increases, and when the sputter power is increased from 200 W to 300 W, the thin film formation speed is greatly improved. It has been found that even when the sputter power is increased from 300 W to 400 W, the rate of improvement is small, and when the sputter power is 300 W, the formation efficiency of the Ag thin film is high.

[Comparison of adhesion of Ag film by surface treatment]
In addition, in order to investigate the influence of the substrate surface roughness on the adhesion of the thin film, the substrate surface was polished with emery paper, and a stylus type surface roughness meter “SJ-201P” (trade name) manufactured by Mitutoyo Corporation. Was used to measure the surface roughness of the substrate. The wire substrate was used as the substrate. The results are shown in Table 1.

  As shown in Table 1, the surface roughness of the non-polished commercial wire substrate was an intermediate roughness between samples polished with 100 # or 500 # emery paper.

[Influence of substrate surface roughness and film thickness on bending radius of curvature]
The relationship between the bending radius of curvature (mm) of the wire when cracks occurred in the Ag thin film and the surface roughness and film thickness (μm) of the wire substrate was examined. The Ag thin films were prepared with a sputtering output of 300 W, a sputtering time of 5 minutes (film thickness 2.5 μm), and 10 minutes (film thickness 6 μm), respectively. The results are shown in Table 2 and FIG.

  From the results shown in Table 2 and FIG. 3, it can be seen that, regardless of the film thickness, the bending curvature radius at the time of occurrence of cracking is the smallest when buffed, and the smoother surface the Ag film is less likely to break. It can also be seen that even with a wire base material having the same surface roughness, the thicker the Ag thin film, the smaller the bending curvature radius when crack cracking occurs. Further, it can be seen that when the Ag thin film reaches a certain film thickness (about 6 μm), the bending radius of curvature at the time of cracking becomes almost constant regardless of the base treatment.

[Effects of sputtering output power and film thickness on the bending radius of curvature when cracks occur]
Using a high frequency sputtering method, when the sputtering output is 200 W, 300 W, or 400 W, the sputtering time is changed to 5 minutes, 10 minutes, or 15 minutes, and Ag films having different thicknesses (mm) are formed on the wire base material. The relationship between the bending radius of curvature (mm), the power (W) of the sputter output, and the film thickness (μm) was examined by a bending test. The results are shown in Table 3 and FIG.

  From the results shown in Table 3 and FIG. 4, when the film thickness of the Ag film is 3 μm or less, the bending radius of curvature at the time of cracking is the smallest when the sputtering output is 400 W, and the film thickness of the Ag film is relatively thin ( For film thicknesses of 3 μm or less, it is desirable to increase the sputter output to increase the thin film formation speed. However, when the film thickness is relatively thick (film thickness 5 μm to 9 μm), the radius of curvature at the time of cracking is It can be seen that a stable product can be obtained without depending much on the output. In addition, from the influence of the output on the formation rate of the Ag film and the influence of the output and the film thickness on the bending radius of curvature when the crack is generated, it was found that the film formation process of 300 W for 10 minutes is optimal. It was.

[Peeling characteristics of Ag thin film in 3% NaCl aqueous solution]
The corrosion test was performed using an Ag thin film wire test piece (film thickness: 5 μm) obtained by coating a wire base material with Ag by a high frequency sputtering method.

  FIG. 5 shows the relationship between the retention time in the 3% NaCl aqueous solution of the Ag thin film coated on the wire by the high frequency sputtering method, cracking / peeling generation strain, and the radius of curvature. As shown in FIG. 5, if the curvature radius is 1 mm or more, the Ag thin film wire test piece with the bending curvature radius (mm) changed can be cracked and peeled even after 2000 hours in the above 3% NaCl aqueous solution. Did not occur.

  However, although the Ag thin film is white and can block the color of the base material, it is inferior in aesthetics as it is unlike the color of human teeth. Furthermore, in order to use the wire formed by coating the Ag thin film as an orthodontic wire, it is necessary that its surface is hard and the friction coefficient is small.

As a result of intensive studies by the inventors of the present application, by coating, for example, a TiO ₂ thin film on the white Ag thin film, the color of the thin film becomes slightly yellow, which is close to the color of human teeth, and the above TiO 2 ₂ It is understood that the wire 12 can be adjusted to various milky white colors close to the color of human teeth by simply changing the thickness of the thin film, and the wire 12 satisfying the various physical properties described above can be obtained. It was.

However, when a white TiO ₂ thin film is directly sputter coated on the white Ag thin film by normal sputtering, cracking is likely to occur with a larger radius of curvature than when a single-layer Ag thin film is formed on the wire substrate. This tendency becomes more prominent as the TiO ₂ film becomes thicker, and although peeling does not occur at the interface between the Ag thin film and the TiO ₂ thin film, the Ag thin film may peel off from the interface of the wire base material. is there.

However, the above-mentioned wire base material is subjected to a ground treatment as described above, or by applying a bias voltage load during sputter coating, thereby making it possible to adhere the wire base material and Ag, and thus the Ag / TiO ₂ bilayer. The adhesion of the whole thin film is improved.

  First, regarding the adhesion between the wire substrate and the Ag thin film, a case where normal sputtering (that is, no bias) is performed and a case where bias sputtering is performed are compared.

[Bending test of Ag thin film by bias sputtering]
The influence of the bias voltage on the adhesion of the Ag thin film in the Ag thin film wire test piece obtained by coating the wire base material with Ag by the bias sputtering method was examined by the bending test. The thickness of the produced Ag thin film was 5 μm to 6 μm. Table 4 shows the bending test results of the Ag thin film by the bias sputtering. In Table 4, the underline indicates that the Ag thin film was cracked.

  From the results shown in Table 4, it can be seen that the adhesion of the Ag thin film to the wire substrate increases when a bias voltage is applied. It was also found that when the bias voltage was 200 V or higher, no cracking occurred in the Ag thin film even with a curvature radius of 0.3 mm. In any of the above measurements, the Ag thin film did not peel off even when a crack was generated by bending.

  Next, the influence of the film thickness on the adhesion of the Ag thin film in the Ag thin film wire test piece was examined when a bias DC voltage of 200 V was applied to the same wire substrate as described above and the sputtering time was changed. Table 5 shows the bending test result of the Ag thin film by the bias sputtering at this time. In Table 5 below, the underline indicates that the Ag thin film was cracked.

  As shown in Table 5, when the sputtering time is 1 minute, the Ag thin film breaks and peels off from the surface of the wire base material, but by performing sputtering for 3 minutes or longer, the Ag thin film can be prevented from cracking. I understand.

[Surface morphology and microhardness of bias sputtered Ag thin film]
The surface of the bias sputtered Ag thin film was observed with an optical microscope, and the surface hardness was measured with an ultra-micro hardness meter, and compared with a thin film not subjected to bias sputtering. As a result, it was found that the surface of the bias sputtered Ag thin film was flatter than that without bias. Further, the hardness of the surface of the Ag thin film is HUT [68] 130 to 160 when bias sputtering is performed, and HUT [68] 110 to 120 when no bias is applied, and when bias sputtering is performed, It was found that the hardness increased.

  From the above, it was found that the adhesion, surface roughness and surface hardness of the Ag thin film can be improved by performing bias sputtering.

  From the above, it can be seen that bias sputtering is very effective in improving the adhesion of the Ag thin film. According to the measurement by the inventors of the present application, the Ag thin film bias-sputtered with a DC bias voltage of 200V has a bending radius of about 0.6 mm when the sputtering time is 1 minute, and the bending radius of curvature is about 0.1 when the sputtering time is 3 minutes or more. There was no cracking or peeling to 3 mm.

Then, the result of evaluating the adhesion of the two-layer thin film by a bending test when a TiO ₂ thin film is formed on a normal sputtered (no bias) and bias sputtered Ag thin film (no bias) is shown below.

[Preparation of Ag / TiO ₂ bilayer thin film]
The Ag / TiO ₂ bilayer thin film used for the following measurements was prepared as follows.

On the white Ag thin film sputtered on the above-mentioned wire base material without bias or with a biased condition, pure Ti is used as a target (metal target) and a mixed gas of Ar and O ₂ is used to form a TiO ₂ thin film. Was sputter coated. The oxygen partial pressure of the sputtering gas in the TiO ₂ sputtering is 20%, the sputtering vacuum degree is 0.5 Pa (4 × 10 ⁻³ Torr), the high frequency output is 300 W, the sputtering time is 1 to 4 hours, and the ultimate vacuum is 1.3 × 10. ⁻⁴ Pa (1 × 10 ⁻⁶ Torr, 2 hours). The thickness of the Ag thin film was 5 μm.

Table 6 shows the bending test results of the TiO ₂ thin film formed on the Ag film by normal sputtering. Table 7 shows the bending test results of the TiO ₂ thin film formed on the bias sputtered Ag film. Furthermore, the relationship between the sputtering time and the bending curvature radius of the TiO ₂ thin film shown in Table 6 and Table 7 is shown together in FIG. The bending test was performed using the method described above. In FIG. 6, “Δ” indicates the case where the Ag film is broken.

As is apparent from Tables 6 and 7 and FIG. 6, when the Ag thin film is formed by bias sputtering, the Ag thin film and the substrate are in close contact with each other as compared with the case where the Ag thin film is formed by normal sputtering. It can be seen that the adhesiveness of the Ag / TiO ₂ bilayer thin film as a whole is improved. The sample with a sputtering time of 1 hour and the sample with 2 hours of TiO ₂ were not cracked even when bent with a bending test jig smaller than the complete bending. Further, in the sample of the sputtering time of the TiO ₂ is 3 hours cracks one of the three, although sputtering time of TiO ₂ are two is broken in samples of 4-hour, delamination do not have occurred, cracking is short, Moreover, in all the bias sputter samples, the bending radius of curvature at the time of occurrence of cracking was smaller than that without bias.

[Peeling behavior of Ag / TiO ₂ bilayer thin film specimen in 3% NaCl aqueous solution]
FIG. 7 shows the delamination behavior in a 3% NaCl aqueous solution of an Ag / TiO ₂ bilayer thin film specimen when the underlying Ag thin film was sputtered without bias. Further, FIG. 8 shows the peeling behavior in a 3% NaCl aqueous solution of an Ag / TiO ₂ bilayer thin film test piece when the underlying Ag thin film is bias-sputtered. From the results shown in FIG. 7 and FIG. 8, the adhesiveness between the Ag thin film and the substrate, and thus the overall Ag / TiO ₂ bilayer thin film, is improved by bias sputtering of the underlying Ag thin film. I understand.

  As described above, according to the present embodiment, it is understood that the bias sputtering method is suitable for improving the adhesion between the Ag thin film and the wire base material 1.

In the above-described specific examples, the case where the Ag thin film is formed by bias sputtering is described as an example in order to improve the adhesion between the Ag thin film and the wire base material 1, but the present invention is not limited to this. When the Ag / TiO ₂ thin film is provided as the base layer 2 and the skin layer 3 on the wire base material 1 as described above, the peel strength of the Ag thin film is improved, and the Ag thin film and the TiO ₂ are added. In order to improve the adhesion of the thin film, as shown in FIG. 13, as the intermediate layer 4 between the base layer 2 and the skin layer 3, for example, the white color of Ag of the base layer 2 is not changed. A titanium sputtered thin film having an extremely thin film thickness may be provided.

When the TiO ₂ thin film is directly sputter coated on the Ag thin film, the Ag thin film serving as the underlayer 2 is oxidized by mixing oxygen with the sputtering gas for forming the TiO ₂ thin film. It is considered that the adhesion between the Ag thin film and the wire base material 1 is lower than that of the layer. Therefore, by using an inert gas such as Ar gas between the Ag thin film and the TiO ₂ thin film and performing the thin film coating without using the oxygen gas, the Ag thin film is peeled off from the wire substrate 1. Can be prevented. In the case where the intermediate layer 4 is formed between the Ag thin film and the TiO ₂ thin film, when the Ti thin film is formed as the intermediate layer 4, if the Ti thin film is thick, the TiO ₂ thin film is formed. Since the color seen through is changed, it is desirable that the intermediate layer 4 be formed thin enough to prevent oxidation of the Ag thin film and keep the white color of the underlying Ag thin film. Further, when forming a TiO ₂ thin film on the Ag thin film via the intermediate layer 4, in order to prevent oxidation of the Ag thin film and further improve the adhesion between the Ag thin film and the wire substrate 1, for example, It is desirable to protect the side surface of the Ag thin film from oxidation of the Ag thin film by causing the Ti atoms to wrap around the side surface of the Ag thin film.

  However, even when the intermediate layer 4 is formed, the base layer 2 may be formed by bias sputtering or the base treatment described above may be applied to the wire base 1 in order to further improve adhesion or adjust the color tone. You may give it.

  As described above, as a method for increasing the adhesion between the Ag thin film and the wire base material 1, for example, the base treatment of the wire base material 1 is performed, or a bias voltage load is applied to the formation of the Ag thin film. The adhesion between the Ag thin film and the wire base material 1 can be improved by various methods such as applying the intermediate layer 4 between the base layer 2 and the skin layer 3.

  In addition, according to the present embodiment, by changing the combination of the base layer 2 and the skin layer 3, the adhesion between the base layer 2 and the wire base material 1 and the durability of the wire 12 can be improved. Can be improved.

For example, by using an Ag—Ti alloy thin film instead of an Ag thin film and using an Al ₂ O ₃ thin film instead of a TiO ₂ thin film, a dental product that is more excellent in the above-described characteristics required for a dental product can be obtained. Obtainable.

[Preparation of Ag-Ti alloy thin film]
The solid solubility limit of Ti in the Ag—Ti binary alloy is about 1% by weight at room temperature. In the following specific examples, an Ag—Ti alloy target having a Ti content of 1% by weight, 5% by weight, and 10% by weight, respectively, was prepared by a spark sintering method, and the degree of sputtering vacuum was 4 × 10 ^{− 3} Torr (≈0.5 Pa), high frequency output 300 W, sputtering time 3 minutes to 60 minutes, ultimate vacuum 1 × 10 ⁻⁶ Torr (≈1.3 × 10 ⁻⁴ Pa, 2 hours).

[Color and adhesion of Ag-Ti alloy thin film]
When each of the above samples was coated with an Ag-10 wt% Ti alloy thin film, an Ag-5 wt% Ti alloy thin film, and an Ag-1 wt% Ti alloy thin film using the above targets, Table 8 summarizes the results of the bending test and the color tone measurement results. In Table 8, “◯” indicates that the color tone measured by the above-described color tone measurement method is within the color range of the dental standard color sample, and “Δ” indicates that the color tone is the above-described dental tone. “X” indicates that the color tone is slightly out of the color range of the dental standard color sample. In addition, as a result of the bending test described above, the case where the thin film does not crack or peel even when the bending curvature radius is 0.3 mm is “A”, and when the bending curvature radius is 0.3 mm, the thin film is cracked. The case where the material did not peel was “B”, and the case where the thin film was observed to peel when bent to a radius of curvature of 0.3 mm was designated “C”.

  As shown in Table 8, when the Ti content in the Ag-Ti alloy thin film is 10% by weight or 5% by weight, the color of the thin film is poor, and the adhesion is poor in normal normal sputtering. On the other hand, when the Ti content was 1% by weight, the color of the thin film formed by normal sputtering was very close to the tooth color, but the adhesion was not good. On the other hand, the Ag-Ti alloy thin film formed by bias sputtering is white and slightly different from the tooth color. However, as a result of the bending test, the thin film is broken or peeled up to a bending curvature radius of 0.3 mm. It has excellent adhesion. Therefore, in order to achieve both the color and adhesion of the thin film, as shown in Table 8, for example, first, bias sputtering is performed for 5 minutes to perform adhesion between the Ag-Ti alloy thin film and the wire substrate. After improving the above, it is desirable to adjust the color by performing normal sputtering for 5 minutes with the bias voltage set to 0.

  According to the study by the inventors of the present application, the color of the Ag-Ti alloy thin film can be adjusted by changing the bias voltage. Moreover, the color of the said Ag-Ti alloy thin film can be adjusted also by Ti content. In addition, as shown also in Table 8, it is preferable that Ti content of an Ag-Ti alloy thin film is 1 weight% or less.

[Observation of surface condition of Ag-1 wt% Ti alloy thin film]
The surface of the Ag-1 wt% Ti alloy thin film was observed using an electron beam probe microanalyzer (EPMA). FIGS. 10A and 10B are views showing the state of the surface of an Ag-1 wt% Ti alloy thin film formed by normal sputtering, and FIGS. 11A and 11B show Ag formed by bias sputtering. It is a figure which shows the state of -1 weight% Ti alloy thin film surface. 10 (a) and 10 (b), and FIG. 11 (a) and FIG. 11 (b) each change the imaging magnification of the surface.

  As can be seen from FIGS. 10A and 10B and FIGS. 11A and 11B, when bias sputtering is performed, the crystal grains of the thin film are made finer than when normal sputtering is performed. Microscopic irregularities are increasing. Therefore, it is considered that such a change in surface properties is a cause of a difference in color tone between when bias sputtering is performed and when normal sputtering is performed.

  In addition, the line analysis result of the cross section of the Ag-1 weight% Ti alloy thin film by said EPMA is shown in FIG. According to this, almost no diffusion was observed between the base material and the Ag-1 wt% Ti alloy thin film, and a brittle intermetallic compound causing peeling was not formed.

  As described above, by performing bias sputtering, the adhesion of the Ag—Ti alloy thin film is improved in the same manner as the Ag thin film. Moreover, the color of the Ag-1 wt% Ti alloy thin film is milky white and is close to the color of human teeth. Therefore, it is possible to achieve both adhesion and aesthetics by turning off the bias power supply during the bias sputtering and continuing the sputtering, or changing the bias voltage over time.

  The voltage in the bias sputtering may be appropriately changed according to the type of the thin film material to be coated, and is not particularly limited. However, in order to improve adhesion with the substrate and improve aesthetics. In the initial coating stage, it is more desirable to set the bias voltage relatively high and to decrease the bias voltage stepwise or over time until the end of coating. That is, the base layer 2 is coated by bias sputtering at a higher bias voltage in the initial coating stage (first half of the base layer 2 forming process) than in the latter coating stage (second half of the base layer forming process). It is desirable to be done. As a result, it is possible to obtain the base layer 2 having different film forming states (surface properties) between the lower layer part and the upper layer part in the contact surface side and the skin layer side with the base material, that is, in the layer made of the same material. The change (control) of the bias voltage can be observed based on the properties of the cut surface or side surface of the wire 12.

Preparation of Ag-Ti alloy / _Al 2 _{O 3} two-layer film]
The color of the Ag-1 wt% Ti alloy thin film is close to the color of human teeth, but the thin film itself is soft, has low wear resistance, and has a high coefficient of friction. Therefore, it is necessary to coat the surface with a hard transparent thin film. However, the Ag-1 wt% Ti on the alloy thin film, a mixed gas of Ar and O _2, and the Ti to the target, when coated directly TiO ₂ thin film by reactive sputtering, discoloration during sputtering and cracking occurred Problems such as variations in the radius of curvature of bending occur.

Therefore, in this specific example, a ceramic target is sputtered directly with Ar gas to form a transparent ceramic thin film on the Ag-1 wt% Ti alloy thin film. In this specific example, Al ₂ O ₃ is used as a target, sputtering gas Ar (99.999%), sputtering vacuum degree 4 × 10 ⁻³ Torr (≈0.5 Pa), high frequency output 300 W, sputtering time 0.5 Al ₂ O ₃ is applied onto the Ag-1 wt% Ti alloy thin film with a protective film (skin) at an ultimate vacuum of 1 × 10 ⁻⁶ Torr (≈1.3 × 10 ⁻⁴ Pa, 2 hours) for ˜2 hours. Direct coating as layer 3).

[Ag-Ti alloy / _Al 2 adhesion _{O 3} bilayer films]
An Al ₂ O ₃ thin film was formed on a white Ag-1 wt% Ti alloy thin film (bias sputtering) and a milky white Ag-1 wt% Ti alloy thin film (first half: bias sputtering, second half: normal sputtering), and subjected to a bending test. The adhesion was evaluated. The results are shown in Table 9.

The Al ₂ O ₃ thin film was not cracked even when it was bent smaller than a complete bend in a bending test at a sputtering time of 1 hour. On the other hand, when the sputtering time was 2 hours, the film thickness was thick and only one of the three samples was cracked, but the other two were not cracked. Further, the adhesion between the Al ₂ O ₃ thin film and the Ag-1 wt% Ti alloy thin film and the adhesion between the Ag-1 wt% Ti alloy thin film and the substrate were both large.

[Ag-Ti alloy / _Al 2 _{O 3} two-layer color tone of films]
An Al ₂ O ₃ thin film is formed on an Ag thin film (white), a white Ag-1 wt% Ti alloy thin film (bias sputtering) and a milky white Ag-1 wt% Ti alloy thin film (first half: bias sputtering, second half: normal sputtering). The color tone of the AgTi—Al ₂ O ₃ bilayer thin film when the coating was performed at a sputtering time of 30 minutes, 60 minutes, and 120 minutes was examined. The results are shown in Table 10. In Table 10, “◯” indicates that the color tone measured by the color tone measurement method is within the color range of the dental standard color sample, and “Δ” indicates that the color tone is the dental color. “X” indicates that the color tone is slightly out of the color range of the dental standard color sample.

The color when Al ₂ O ₃ was coated on the Ag thin film was basically close to the white color of the underlying Ag thin film and was different from the tooth color. In addition, the Al ₂ O ₃ thin film sputtered for 30 minutes was thin, and interference light was observed.

Further, when an Al ₂ O ₃ thin film was sputtered onto a milky white Ag-1 wt% Ti alloy thin film (normal sputtering after bias sputtering), the milky white color became slightly dark regardless of the sputtering time. Moreover, when the Al ₂ O ₃ thin film was coated on the white Ag-1 wt% Ti alloy thin film, the color of the thin film was slightly yellow, and a color close to the color of the teeth was obtained. The Al ₂ O ₃ thin film is transparent, and the color does not change much even when the thickness of the Al ₂ O ₃ thin film changes. Thus, the color of the Ag-1 wt% Ti alloy thin film as a base layer 2 as seen through _Al 2 _{O 3} thin _film, but is not clear why the change by the coating of Al 2 _{O 3} thin film, as an underlying layer 2 This is probably because Al ₂ O ₃ entered the unevenness of the Ag-1 wt% Ti alloy thin film, resulting in a difference in light reflection.

[Ag-Ti alloy / _Al 2 adhesion _{O 3} bilayer films]
According to the present embodiment, a wire (double-layer film wire) obtained by coating an AgTi alloy as the underlayer 2 on the above-described wire base material and then coating Al ₂ O ₃ as the skin layer 3 on the AgTi alloy underlayer. ) Was bent in the atmosphere, and no cracking or peeling occurred even at a curvature radius of 0.35 mm (not so severely bent in actual use).

[Peeling life of AgTi / Al ₂ O ₃ bilayer thin film in 3% NaCl aqueous solution]
FIG. 9 shows the delamination behavior of the Ag—Ti / Al ₂ O ₃ bilayer thin film specimen in a 3% NaCl aqueous solution when an Ag—Ti alloy thin film is formed by bias sputtering. When an Ag-Ti alloy / Al ₂ O ₃ bilayer thin film specimen is used as a sample, cracks do not occur even after 450 hours at a curvature radius of 1.5 mm or more, and durability is maintained even in such a severe corrosive environment. I know that there is. Although the corrosive environment in the mouth is not so severe, there are contact with the skin and contact with the brush when brushing teeth. However, when a dental clinical test using an orthodontic appliance in which an Ag—Ti alloy / Al ₂ O ₃ bilayer thin film was formed, the above thin film did not peel for one month, which was about three times that of the conventional product. It was found to have the above durability. The interface where peeling occurs is mainly the interface between the base layer 2 and the wire base material 1, and the adhesion between the skin layer 3 and the base layer 2 is high.

Further, as apparent from FIGS. 7 to 9, the Ag—Ti alloy / Al ₂ O ₃ bilayer thin film has a longer peel life in a 3% NaCl aqueous solution than the Ag / TiO ₂ bilayer thin film, It turns out that it is excellent in durability.

As described above, the Al ₂ O ₃ thin film is a transparent film, and the color of the Ag—Ti alloy / Al ₂ O ₃ bilayer thin film can be controlled by the color of the underlying Ag—Ti alloy thin film. The color of the Ag—Ti alloy thin film as the underlayer 2 can be adjusted by the Ti content in the Ag—Ti target or the magnitude of the bias voltage during sputtering.

Furthermore, the adhesion of the Al ₂ O ₃ thin film is sufficient by sputtering for 2 hours or less, and the formation process of the Ag—Ti alloy / Al ₂ O ₃ bilayer thin film is simple and easy to control. It also has the advantage of being easy to automate.

In the above specific example, the case where the Al ₂ O ₃ thin film is coated on the Ag-1 wt% Ti alloy thin film instead of the TiO ₂ thin film has been described as an example. The TiO ₂ thin film may be formed on the Ag-1 wt% Ti alloy thin film by performing bias sputtering, base treatment, formation of the intermediate layer 4 and the like.

As described above, Al ₂ O ₃ and TiO ₂ cannot be made to resemble the color of natural teeth by itself, but when combined with the underlayer 2, they can resemble the color of natural teeth. Fine color adjustment can also be performed using a change in color tone by adjusting the film thickness of the skin layer 3.

  In the present embodiment, the case where the coating layer is formed by two layers or three layers has been described as an example. However, the present invention is not limited to this, and the coating layer is formed by each layer. What is necessary is just to set it as the structure formed from several layers according to the objective. In the present embodiment, the case where the base layer 2 and the skin layer 3 are formed on the wire base material 1 has been described as an example. However, the base material is limited to the wire base material. It is not a thing and the base material of various shapes and materials can be used according to a use. Moreover, the said base material is not necessarily required depending on the use, The said base layer 2 may have the structure which serves as a base material.

  In the present embodiment, the method for coating the underlayer 2 and the skin layer 3 has been described by taking, for example, sputtering and bias sputtering as examples. However, the present invention is not limited to this, and various conventionally known various methods are known. The coating method can be adopted.

  Specific examples of the coating method for the base layer 2 other than sputtering and bias sputtering include coating methods such as PVD (physical vapor deposition); CVD (chemical vapor deposition); plating; It is done. Moreover, as a coating method of the said skin layer 3, conventionally well-known various coating methods, such as coating of the transparent oxide by a sol-gel method, CVD method, etc., are employable, for example.

  As described above, according to the present embodiment, the multi-layer coating film has excellent aesthetics, correction effects, and durability compared with conventional single-layer coatings, and is white and has a large correction effect. An orthodontic appliance in which the coating film does not peel can be provided. In particular, orthodontic correction has the effect of facilitating brushing and preventing periodontal disease. Also, in elderly people, chewing objects with their own teeth, rather than dentures, suppresses the decline in thinking ability and greatly contributes to digestion and health maintenance. Therefore, in addition to shortening the correction period of the tooth arrangement, the present invention can exert a great effect in reducing the psychological resistance of the person who desires the correction of the tooth arrangement from an aesthetic aspect.

  In the present embodiment, as described above, as the dental article according to the present invention, the orthodontic appliance 11, particularly, the wire 12 exposed to the most severe conditions mechanically or chemically in the orthodontic appliance 11 is used. As described above by way of example, it is obvious that if the coating of the wire 12 is completed, it can be easily applied to the bracket 13 and the crown with a small applied force.

  In the orthodontic appliance 11, it is desirable that both the wire 12 and the bracket 13 include the base layer 2 and the skin layer 3. For example, depending on the size and shape of the bracket 13, any of the wire 12 and the bracket 13 may be used. Only one of them, for example, at least the wire 12 may include the multilayer coating film, that is, the base layer 2 and the skin layer 3. For example, since the bracket 13 is less used than the wire 12 in use, the size and shape of the bracket 13 such as when the exposed area of the bracket 13 is small when the wire 12 and the bracket 13 are engaged, Furthermore, depending on the material and surface properties of the contact portion with the wire 12 (for example, the concave portion 14a), it is possible to prioritize aesthetics for the exposed portion of the bracket 13 and adjust the friction coefficient with the wire 12. There may be a configuration in which only the wire 12 includes the base layer 2 and the skin layer 3.

  In the orthodontic appliance 11, it is desirable that at least the exposed portion of the wire 12 and / or the bracket 13 in a state where the wire 12 and the bracket 13 are engaged is coated with the multilayer coating described above. It is more preferable that the above-mentioned multilayer coating is also applied to the part, as described above, in order to reduce the friction coefficient and increase the orthodontic effect.

  As described above, the dental article provided with the multilayer coating film according to the present embodiment is excellent in aesthetics and durability, and has a wire (linear: cross-sectional rectangle and circle, curved: superelastic alloy wire) and Suitable for various dental products such as artificial teeth materials such as indentations and dentures, crowns (coating on the front surface of crowns), and dental prosthesis clasps, as well as brackets that bond directly to teeth and fix wires can do.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims, and the embodiments can be obtained by appropriately combining technical means disclosed in different embodiments. The form is also included in the technical scope of the present invention.

  Since the dental product according to the present invention has both the function for satisfying the aesthetics required for the dental product and other functions, the orthodontic appliance such as the wire and the bracket, the artificial tooth such as the denture and the denture, etc. It can be suitably used for applications such as tooth materials, crowns (coating on the front surface of crowns), and dental prosthesis clasps.

It is sectional drawing which shows typically the structure of the wire for orthodontics concerning one Embodiment of this invention. (A) is a perspective view which shows schematic structure of the orthodontic appliance concerning one Embodiment of this invention, (b) is a disassembled perspective view of the principal part of the orthodontic appliance shown to (a). It is a graph which shows the relationship between the bending curvature radius of a wire when a crack generate | occur | produces in an Ag thin film, the surface roughness of a wire base material, and a film thickness. It is a graph which shows the relationship between the bending curvature radius when a crack generate | occur | produces in an Ag thin film by a bending test, the power of sputtering output, and a film thickness. It is a graph which shows the relationship between the retention time in the 3% NaCl aqueous solution of the Ag thin film coated on the wire by the high frequency sputtering method, cracking / peeling generation strain and the radius of curvature. It is a graph showing the relationship between a normal sputtering or bias sputtering the Ag film to form the TiO ₂ thin film sputtering time and bending radius of curvature. Is a graph showing time and retention of 3% NaCl aqueous solution of Ag / TiO ₂ bilayer thin film specimen in the case of the Ag thin film underlayer sputtered without bias, the relationship between the crack and peeling occurred distortion and curvature radius. Is a graph showing time and retention of 3% NaCl aqueous solution of Ag / TiO ₂ bilayer thin film specimen in the case of the Ag film of the base bias sputtering, the relationship between the crack and peeling occurred distortion and curvature radius. The relationship between the holding time in the 3% NaCl aqueous solution of the Ag-Ti / Al ₂ O ₃ bilayer thin film specimen, the cracking / peeling strain and the radius of curvature when an Ag-Ti alloy thin film is formed by bias sputtering is shown. It is a graph. (A) * (b) is a figure which shows the state of the Ag-1 weight% Ti alloy thin film surface formed by normal sputtering. (A) * (b) is a figure which shows the state of the Ag-1 weight% Ti alloy thin film surface formed by bias sputtering. It is a figure which shows the line analysis result of the cross section of the Ag-1 weight% Ti alloy thin film by an electron beam probe microanalyzer. It is sectional drawing which shows typically the structure of the wire for other orthodontics concerning one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wire base material 2 Underlayer (1st functional layer)
3 skin layer (second functional layer)
4 Middle layer 11 orthodontic appliance (dental supplies)
12 Wire (Dental Supplies)
13 Bracket (Dental Supplies)
14 Wire mounting part 14a Concave part

Claims (13)

A first functional layer and a second functional layer having different functions, the first functional layer exhibiting a desired color, and the second functional layer is a skin layer covering the first functional layer In the dental article provided so that the first functional layer can be seen through,
The first functional layer is a dental article, wherein the lower layer portion and the upper layer portion have different smoothness due to surface irregularities. An orthodontic wire and a bracket for holding the wire;
At least one of the wire and the bracket includes the first functional layer and the second functional layer, and a friction between the wire and the bracket results in a second functional layer provided on one of the wire and the bracket. the coefficient of friction between the other of the wire and bracket, claims, characterized in that less than the coefficient of friction between the wire and the bracket when using the first functional layer to the skin layer of the wire and the bracket The dental article according to 1 .   The dental product according to claim 1 or 2, wherein the first functional layer is a kind selected from white metals and alloys thereof.   4. The dental article according to claim 3, wherein the first functional layer is a kind selected from the group consisting of silver, aluminum, nickel, stainless steel, platinum, and a silver-titanium alloy.   The dental product according to any one of claims 1 to 4, wherein the second functional layer is made of a transparent or translucent amorphous ceramic.   The dental product according to any one of claims 1 to 5, wherein the second functional layer is made of titanium oxide or aluminum oxide.   The dental article according to claim 1 or 2, wherein the first functional layer is made of a silver-titanium alloy, and the second functional layer is made of aluminum oxide.   The dental layer according to claim 1 or 2, wherein an antioxidant layer for preventing oxidation of the first functional layer is further provided between the first functional layer and the second functional layer. Supplies. A first functional layer and a second functional layer having different functions, the first functional layer exhibiting a desired color, and the second functional layer is a skin layer covering the first functional layer In the dental article provided so that the first functional layer can be seen through,
A dental article, further comprising an antioxidant layer for preventing oxidation of the first functional layer between the first functional layer and the second functional layer. A method of manufacturing a dental article according to claim 1,
Forming a first functional layer;
Forming a second functional layer having a function different from that of the first functional layer,
The first functional layer and the second functional layer, the second functional layer is a skin layer that covers the first functional layer, the first functional layer exhibits a desired color, and the above The second functional layer is formed so that the first functional layer can be seen through,
A method for producing a dental article, wherein bias sputtering is used to form the first functional layer. 11. The method for manufacturing a dental article according to claim 10, wherein the application of the bias voltage is stopped during the formation of the first functional layer. 11. The dental article according to claim 10 , wherein a bias voltage applied in the latter half of the first functional layer forming step is made lower than a bias voltage applied in the first half of the first functional layer forming step. Method. Between the first functional layer and the second functional layer, claim, characterized by further comprising a step of forming an anti-oxidation layer for preventing oxidation of the first functional layer 10-12 The manufacturing method of the dental article of any one of these.

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