JP4421395B2 - Manufacturing method for ceramic dental restoration - Google Patents

Description

  The present invention relates to a method for producing a novel ceramic dental restoration. More particularly, the present invention relates to a method for producing a full ceramic dental restoration that can produce a full ceramic coping having high strength and good compatibility by a simple method.

  As a material used for restoration of a tooth partially lost due to caries or the like, a composite material composed of an inorganic substance and an organic substance called a composite resin, a metal, or ceramics is used. Metals and ceramics are used for bridges that require particularly high strength, i.e., irremovable prostheses that supplement missing teeth. In recent years, restoration without using metal in the oral cavity has been desired due to problems such as aesthetic demands of patients and metal allergy.

  In such a restoration, first, the tooth (abutment tooth) on which the restoration is to be mounted is ground by an air turbine or the like to obtain a shape necessary for holding the restoration. Next, the abutment tooth and its peripheral part are molded with an impression material, and a gypsum model having the same shape as the abutment tooth is created from the impression mold. Thereafter, a restoration is formed from the gypsum model using a working abutment tooth model. At this time, instead of suddenly forming a restoration having a complete tooth shape, a thin cover-like material covering the abutment tooth (also called a frame or a cap) called a coping is manufactured, and this coping is placed on the coping. In general, a method of building up and curing a composite material composed of an inorganic material and an organic material called a composite resin as an upper structure and a method of building up and firing ceramics such as porcelain are generally used.

  The method for producing the coping is a method in which glass or glass ceramics is formed by centrifugal casting using the lost wax method, as in the case of the metal casting crown, or by crystallization, which is called ceraming, if necessary. A method of sintering ceramic powder has been taken. Particularly, oxide-based ceramics having high strength have a high melting point, making it difficult to use centrifugal casting and heat-pressure injection methods, and industrially, a method of sintering powder is generally used.

  In the manufacturing method of such ceramic coping in dentistry, conventionally, a method of immersing the abutment tooth model in a slurry made of ceramic powder and a solvent, or laminating the slurry on the abutment tooth model with a brush or the like and sintering. Methods have been taken generally.

  In recent years, several methods for manufacturing a crown restoration made of all ceramics using an electrophoretic molding method have been proposed (see, for example, Patent Documents 1 and 2).

  The electrophoretic molding method is a method in which ceramic particles are dispersed and charged in a polar solvent, and a current is passed through the solvent to deposit the charged ceramic particles on an electrode by electrophoresis. According to this method, it is possible to produce a relatively dense thick film even without pressure, and a molding density comparable to that of normal pressure molding can be obtained. And by controlling the raw material powder species in the liquid in the course of the deposition process, it is possible to control the microstructure such as lamination and tilting (for example, non-patent Reference 1).

  Therefore, a high-strength ceramic restoration is obtained by forming a conductive layer on the abutment model, using this as one electrode, depositing the ceramic using the electrophoretic molding method, and firing the ceramic. Is possible.

WO99 / 50480 pamphlet International Publication No. 02/30362 pamphlet, abstract Tetsuro Uchikoshi, “Molding and Laminating of Ceramics by Electrophoresis”, Material Integration, T.I.C., October 25, 2000, No. 13, No. 11, p. 18-24

  As described above, in the restoration of full ceramics that does not use metal, the coping needs to be made of ceramics instead of metal, but the conventional ceramics that use the slurry composed of ceramic powder and solvent are used. The coping manufacturing method has the following problems. That is, since such a slurry requires a certain degree of applicability, it is difficult to increase the proportion of ceramic particles, and therefore, the polymerization shrinkage is large during sintering, and the shape tends to change. There is also a problem in mechanical strength because the density of is low. Furthermore, uneven coating and dry unevenness are likely to occur depending on the arm of the operator, and the resulting coping will not be uniform in thickness or density. For this reason, the sintered body obtained after firing becomes uneven, and sufficient mechanical strength cannot be obtained in this respect. Also, depending on the surrounding conditions of the tooth to be repaired, if the coping is too thick, the ceramic layer laminated on it must be thinned, and there is a problem with the compatibility with the color of the surrounding teeth. It may occur or it may be difficult to attach the crown restoration manufactured using the coping to the abutment tooth.

  Furthermore, in impression collection, when the impression material is taken out from the oral cavity, the impression material may be plastically deformed. For this reason, an abutment tooth model having the same shape as the abutment tooth is rarely obtained. Therefore, when a coping that is perfectly matched to the abutment tooth model is manufactured, such a coping is often not compatible with the abutment tooth. In addition, normal crown restorations need to have strong abutment with the abutment tooth using an adhesive such as dental cement, but the space for these adhesives (the margin) is the restoration ( It is necessary between the coping) and the abutment tooth. Therefore, before applying the ceramic slurry as described above onto the abutment tooth model, apply a spacer material, or make the abutment tooth model smaller than the collected impression, or such a coping. It was necessary to grind the abutment tooth again before mounting the crown restoration made using In the method of applying a material to be a spacer, a material that is removed by incineration when the ceramic is sintered is adopted as the spacer material. Although depending on the spacer material and the arm of the surgeon, when the ceramic slurry is applied, mechanical stress by a brush or the like is applied, and the spacer material and the ceramic slurry may be mixed. In this case, at the time of sintering, this spacer substance is mixed, and the portion that is removed by incineration thereafter becomes empty. Also from this point, a problem arises in the strength of the ceramic coping obtained.

  Therefore, a simple ceramic coping that has a high mechanical strength with a good reproducibility, an appropriate thickness, and a crown restoration using the ceramic coping has good compatibility with the abutment tooth. There was a need for a manufacturing method.

  On the other hand, conventional methods for producing dental restorations made of ceramics using electrophoretic formation have problems such as large deformation of the restoration or difficulty in removal from the abutment tooth model after firing. Was.

  As a result of intensive studies to solve the above problems, the inventors of the present invention pay attention to the fact that the ceramic forming method by the electrophoretic forming method can form a ceramic with good reproducibility even with a relatively complicated shape. Focusing on the fact that a removable spacer is often required in the manufacture of dental copings, the present invention was completed as a result of further investigation.

  That is, the present invention provides a restoration material made of ceramics used for repairing a tooth defect part by depositing ceramics and / or its precursor particles by an electrophoretic molding method to obtain a restoration material precursor, and then the restoration material. In the method of sintering ceramics and / or precursor particles thereof by heating the precursor, (1) as an electrode when depositing ceramics and / or precursor particles thereof by the electrophoresis molding method, Using an abutment tooth model having a conductive layer with a thickness of 0.005 to 0.5 mm formed of a combustible conductive material, and (2) ceramics and / or precursor particles thereof by heating a restoration precursor Is a ceramic dental restoration, wherein the restoration precursor is not removed from the abutment tooth model.

  Using the above manufacturing method of the present invention, a dental restoration made of ceramics having a uniform thickness and high density deposited on an abutment tooth model, less shrinkage after firing, high mechanical strength, and excellent compatibility. It can be obtained with good reproducibility. Moreover, the removal from an abutment tooth model is also easy. Furthermore, it is possible to obtain a restoration having a desired thickness by changing the current, voltage, deposition time, and the like.

  The abutment tooth model used in the present invention may be manufactured by a publicly known method in a dental technician, and the manufacturing method, material, and the like are not particularly limited. Generally, a gypsum model made by pouring gypsum into an impression taken in the oral cavity is re-impressed, a casting mold material is poured into it, and a dentition replica is produced. The material used for the abutment tooth model here is preferably a material called a refractory model material or a material called a phosphate-based investment material.

  In particular, when making a bridge, if the missing tooth part is assumed to be a hollow pontic cavity part with wax etc. in advance on the gypsum model after taking a double impression and making a double model, This is achieved by a method of depositing ceramic powder on the missing tooth portion.

  The abutment tooth model obtained in this way is trimmed to an appropriate size according to the prosthetic restoration part as necessary, and a predetermined part (part that reproduces the tooth quality) where a dental restoration is to be formed Is coated with a conductive and flammable substance to form a conductive layer. As will be described later, it is necessary to pass an electric current through the abutment tooth model having the conductive layer thus obtained, and therefore it is necessary to ensure electrical continuity with an external power source. In this case, the electrical connection from the external power source may be performed by connection of a metal wire or the like, or may be performed by a conductive layer formed integrally with a portion where the dental restoration is to be formed. That is, in the manufacturing method of the present invention, a conductive layer may be formed in addition to a predetermined portion where a dental restoration on the abutment tooth model is to be formed as necessary.

  When using a nonflammable material such as metal or ceramics as the conductive layer, in order to improve the compatibility with the abutment tooth, the preparation of the abutment tooth model, or Re-grinding of the abutment tooth is necessary, and it is not a simple method. Further, in the case of metal or the like, mixing into ceramics may occur during firing, and the strength and color tone may change. In addition, these metals and ceramics may be integrated with the dental restoration when the particles are sintered and cannot be removed from the abutment tooth model. On the other hand, ceramic particles, which will be described later, do not accumulate in a non-conductive substance, and eventually a dental restoration cannot be produced.

The conductive and flammable substances include artificial graphite, natural graphite, activated carbon, glassy carbon, fullerene, carbon nanotubes and other carbons; polyaniline, polydimethylaminostyrene doped with chloroanil, and polyvinyl doped with tetracyanoethylene Mesitylene, polyvinyl naphthalene doped with tetracyanoethylene, halogen doped polyvinyl anthracene, polyvinyl pyrene, polyvinyl carbazole, tetracyanoethylene, polyvinyl pyridine, tetracyanoethylene, doped polydiphenylamine, 7,7,8,8- Electronically conductive polymers such as polyvinyl imidazole doped with tetracyanoquinodimethane, polyacetylene doped with halogen, polythiophene doped with HClO ₄ , etc. Is mentioned.

  Among these, it is difficult to become a catalyst for an undesirable electrochemical reaction, and is itself electrochemically stable, excellent in conductivity, and easy to coat a predetermined portion on the abutment tooth model. In terms, carbon is preferable. Furthermore, graphite is more preferable because it is easy to form a uniform paste during coating, and artificial graphite is particularly preferable because impurities such as metals are difficult to mix.

  The shape of the conductive substance such as carbon is not particularly limited as long as it can cover a predetermined part on the abutment tooth model and form a conductive layer. ), Any flaky shape or fibrous shape, but it is easy to obtain, and is easy to form a conductive layer by applying the paste as described below. Is particularly preferred.

  The method for forming the conductive layer on the abutment model with such a flammable and conductive material is not particularly limited, but the conductive material is used as a solvent in that the operation is simple and no special equipment is required. A method of mixing and pasting and pasting the paste at a predetermined position with a brush or the like and drying is preferable.

  The method for adjusting the paste is not particularly limited, and may be in accordance with a known method for producing a conductive paste. Typically, the above-described minute amorphous carbon may be mixed with a volatile organic solvent such as ethyl acetate or a curable resin such as an acrylic resin to form a uniform paste. Moreover, you may use electrically conductive pastes, such as a commercially available carbon paste.

  The conductive paste thus prepared is applied to a predetermined position on the abutment tooth model, that is, a part where coping is to be formed, using a brush or the like as described above. Next, a conductive layer is formed on the abutment tooth model by drying or curing.

  In the present invention, the thickness of the conductive layer needs to be within a certain range. That is, if the conductive layer is too thick, the space generated after the conductive layer is removed by heating described later becomes too large. For this reason, the amount of shrinkage generated when the ceramics and / or precursor particles thereof are sintered increases, and it becomes difficult to obtain a dental restoration having excellent compatibility. On the other hand, if the conductive layer is too thin, it will not be possible to secure the margin necessary to ensure good compatibility with the abutment tooth, and the size of the abutment tooth model will be adjusted, or the abutment tooth will be reground. Therefore, it is not a simple method. In the present invention, the thickness of the conductive layer is 0.005 mm to 0.5 mm. Note that the conductive layer does not need to be uniform as long as it is in the above range, and there may be considerable coating unevenness (thickness unevenness). Therefore, compared to a method of applying a ceramic paste that similarly requires a paste application step, the application is much easier, and this is a simple manufacturing method.

  In addition, the conductive layer may be formed by a method such as vapor deposition as necessary. In this case, it is necessary to protect the conductive layer from being formed in areas other than a predetermined region, or unnecessary after the vapor deposition. It is necessary to remove the conductive layer portion.

  The abutment tooth model having the conductive layer thus obtained is used as an electrode, and ceramics and / or precursor particles thereof are deposited on the conductive layer by electrophoretic formation.

  The electrophoretic formation method may be performed according to a known method. Specifically, the abutment tooth model having the conductive layer is immersed in a solvent having ionic conductivity in which particles are dispersed, and this solvent is also used. A current may be passed using a counter electrode immersed in the inside.

  The ceramics and / or precursor particles thereof are components that are deposited on the conductive layer of the abutment tooth model to form a dental restoration, and the material may be appropriately selected depending on the intended coping material. In general, metal oxides are suitably used for such ceramic particles, but glass and glass ceramics, or precursors thereof such as metal oxide sols may be used.

  Examples of the metal oxide include zirconia, yttria-stabilized zirconia, magnesium-stabilized zirconia, calcia-stabilized zirconia, ceria-stabilized zirconia, alumina, spinel, and the like, and mixtures and composite oxides composed of two or more thereof. Moreover, silicon nitride etc. are mentioned as ceramic particles other than a metal oxide.

  Examples of the ceramic precursor particles include metal hydroxides, carbonates, alkoxides, and metal powders as described above.

  The shape of the ceramic particles and / or precursor particles thereof is not particularly limited, and may be any known shape such as a spherical shape or an indeterminate shape, and the particle diameter is not particularly limited, but can be easily dispersed in a solvent, Since the coping obtained due to good sinterability becomes excellent in mechanical strength, the average particle diameter is preferably about 10 nm to 10 μm, more preferably about 10 nm to 200 nm.

  In the present invention, a plurality of ceramics and / or precursor particles thereof having different materials, shapes, particle diameters and the like may be used in combination as necessary. For example, by using ceramic particles and ceramic precursor particles in combination, it is possible to improve the sinterability and to easily ensure the thickness. More specifically, the deposition thickness can be easily secured by using a mixture of alumina particles and metal aluminum powder.

  Such ceramics and / or precursor particles thereof are naturally charged by being dispersed in a solvent. Such charged ceramic particles are attracted to the electrode in accordance with the electric charge by passing electricity through the solvent using the electrode. In order to perform the charging more efficiently, it is preferable to adjust the pH of the solvent by adding an acid such as nitric acid, sulfuric acid and acetic acid, or an alkali such as tetramethylammonium hydroxide and ammonia. Although depending on the type of ceramic particles used, etc., it is generally possible to charge positively (+) efficiently by adjusting the pH to about 3 to 5 with an acid. Conversely, it can be negatively charged by making it basic.

  The solvent for dispersing the ceramic and / or its precursor particles is not particularly limited as long as the conductive layer formed on the particles or the abutment model is not completely dissolved. In view of the properties, difficulty of peeling the conductive layer from the abutment tooth model, ease of removal during firing, etc., a volatile polar solvent is preferable. Specific examples include water; alcohols such as ethanol, ethyl cellosolve, isopropyl alcohol, isobutyl alcohol, and ethoxyethanol; ketones such as methyl ethyl ketone and methyl butyl ketone; and carboxylic acids such as octylic acid and propionic acid. Moreover, these 2 or more types of mixed solvents may be sufficient. The amount of the ceramic and / or its precursor particles dispersed in these solvents is not particularly limited, but in general, the concentration of the ceramic and / or its precursor particles is about 1 to 30% by volume. .

  In addition, as the solvent used in the present invention, an acid or base for pH adjustment as described above may be blended, and further, in order to improve the prevention of crack generation and operability during the sintering of ceramics. A peptizer, a binder or the like may be added.

  Examples of peptizers are generally caustic soda, sodium silicate, water glass, sodium carbonate, soda ash, sodium phosphate, sodium aluminate, sodium oxalate, ammonium oxalate, lithium hydroxide, lithium carbonate, lithium aluminate, lithium citrate, Diethylamine, di-n-propylamine, monoamylamine, monoethylamine, mono-iso-butylamine, mono-n-butylamine, mono-n-propylamine, mono-sec-butylamine, triethylamine, pyridine, piperidine, ethylamine, water Tetramethylammonium oxide and polyvinylamine can be used.

  Examples of binders include starch, soluble starch, pregelatinized starch, dextrin, alginic acid, sodium alginate, gum arabic, tragacanth gum, gucci gum, casein, casein soda, glucose, gelatin, glue (impure gelatin), wheat flour, soy protein, Peptone, honey, Na-carboxyl methyl cellulose, methyl cellulose, methyl ethyl cellulose, cellulose acetate, sodium lignin sulfonate, calcium lignin sulfonate, Na-carboxyl methyl starch, hydroxyethyl starch, starch phosphate soda, glycerin, pulp waste liquor, polyvinyl alcohol , Polyvinyl methyl ether, polyacrylic acid amide, polyacrylic acid soda, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyethylene glycol, polyethylene Lene oxide, polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer, tannic acid, urea, shellac, rosin emulsion, animal and vegetable oils (soybean oil, fish oil, beef tallow, etc.), liquid paraffin, wax emulsion (carnauba wax, carbo Wax, earth wax, etc.), ceresin, heavy oil, machine oil, spindle oil, ethyl cellulose, acetyl cellulose, ester gum, polyvinyl acetate, chroman resin, petroleum resin, phenol resin, ethylene silicate, etc. It can be dispersed effectively. Such peptizer and binder can be added in an amount of 0.2 to 5 parts by weight with respect to 100 parts by weight of the ceramic. Some of these peptizers and binders also act as solvent pH adjusters.

  The abutment tooth model in which the conductive layer is formed is immersed in such a solvent in which ceramics and / or precursor particles thereof are dispersed. In order to pass a current through the solvent using the abutment tooth model as one electrode. In addition, a counter electrode that is electrically connected to the conductive layer in the abutment tooth model is also immersed in the solvent. The counter electrode is not particularly limited as long as it has conductivity, and various metals, alloys, carbon electrodes, or the like may be used.

  A solvent in which charged ceramics and / or precursor particles thereof are dispersed and in which an acid or a base, a peptizer, a binder and the like are mixed and dissolved as necessary exhibits ionic conductivity. Therefore, by passing an electric current using the conductive layer and the counter electrode in the abutment tooth model as electrodes, each component in the solvent is attracted to one of the electrodes according to the charge that the solvent has. At this time, the ceramic particles are deposited on the conductive layer by selecting the positive and negative polarities so that the ceramic and / or its precursor particles are attracted to the conductive layer side of the abutment tooth model. The deposited thickness may be appropriately determined in consideration of the size, shape, etc. of the crown restoration intended for production, and is generally 0.2 to 10 mm, particularly about 0.5 to 1 mm. Are often needed.

The applied voltage, current, and application time of this electrophoresis can be adjusted according to the desired film thickness, but are approximately 1 V to 300 V, 1 to 300 mA / cm ² , about 30 seconds to 6 hours, and are sufficiently uniform and have a deposition density. A high film is obtained. In addition, it is preferable that the applied voltage at this time is set to such an extent that the used solvent or the like is not electrolyzed. Conversely, when it is necessary to apply a high voltage, for example, when it is desired to deposit at a high speed, it is preferable to suppress the blending of components that cause electrolysis at the voltage as much as possible.

  The abutment tooth model in which ceramics and / or precursor particles thereof are thus deposited on the conductive layer is then pulled up from the solvent and dried to become a restoration precursor. In addition, if it is desired to change the thickness depending on the location, a conductive layer is first formed and deposited on a portion where the thickness is desired (for example, a pontic portion), and then a portion that may be thinner ( For example, it is also possible to employ a method in which a conductive layer is further formed on the abutment portion, and then immersed and energized again. Furthermore, if necessary, it is also possible to change a ceramic to be used and / or precursor particles thereof to obtain a dental restoration having a multilayer structure in which different ceramics and / or precursor particles thereof are laminated.

  Next, the restoration precursor is heated to sinter the ceramics and / or its precursor particles deposited on the conductive layer. In the present invention, the restoration precursor is used as the abutment tooth model in this heating. Must be done without removing from the top. When the restoration precursor is removed from the abutment tooth model and heated to sinter the ceramic and / or its precursor particles, the sintering will greatly shrink, resulting in a restoration with excellent compatibility. It becomes extremely difficult to obtain.

  The heating temperature may be equal to or higher than the temperature at which the used ceramic and / or precursor particles thereof are sintered, and known conditions may be adopted as appropriate. In general, the temperature of 1250 ° C. to 1600 ° C. is used for aluminia and zirconia. It densifies by baking for 2 to 8 hours in the range.

  The combustible conductive material burns and burns at a temperature much lower than the temperature at which the ceramics and / or precursor particles thereof are sintered. That is, by heating the restoration precursor, first, a conductive layer made of a combustible substance is incinerated and removed at a relatively low temperature portion. As a result, it can be easily removed from the abutment tooth model, and a ceramic dental restoration having a necessary margin portion already formed can be obtained. The temperature at this time is about 300 to 700 ° C. although it depends on the combustible material used. In addition, it is preferable that the combustible material is sufficiently incinerated and removed before the ceramics and / or precursor particles thereof in the next step are completely sintered, and generally, in an oxidizing atmosphere (in air) ) At the above temperature for about 30 minutes to 2 hours. Further, when a peptizer or a binder is blended, it is usually removed by incineration by holding in the range of 300 to 700 ° C. It should be noted that the sintering of the ceramic and / or its precursor particles proceeds to some extent even by such holding in the range of 300 ° C. to 700 ° C.

  In the production method of the present invention, heating for mainly removing the combustible material used for forming the conductive layer, and sintering and densification of the ceramic and / or its precursor particles are mainly used. Heating may be performed separately (it may be cooled once), but usually a method of successively raising the temperature is preferred.

  Moreover, although an electric furnace is mainly used for heating in this case, any electric furnace that can obtain a temperature of about 1600 ° C. may be used.

  The ceramic dental restoration thus obtained may then be used in the same manner as a dental restoration obtained by another method.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The materials and the evaluation methods used in the examples and comparative examples are as follows.

Preparation of Abutment Tooth Model A training jaw model 530 manufactured by Nissin Co., Ltd. was assumed to be a model assuming four bridges in the oral cavity. Cylindrical RTV-2K manufactured by GE Toshiba Silicone Co., Ltd. was used to make a double impression on cylindrical teeth of 6 mmΦ and 4 mmΦ, and 3 mm in height. Further, a double model was prepared using the Giesa Cosmotech 2 vest (manufactured by GC) for the double impression. This was trimmed to obtain an abutment tooth model.

Measurement of sintered ceramics density The weight-measured sample was immersed in kerosene and held in a desiccator under reduced pressure for 2 hours. At this point, it was confirmed that no bubbles were generated from the sample in kerosene. Furthermore, the weight (w2) in the kerosene of the sample which performed this kerosene immersion, the sample was taken out from kerosene, and the weight (w1) in the air was measured. From these w1 and w2, the weight (w) of the sample before immersion and the density ρ _{k of} kerosene, the density (ρ) was determined according to the following formula. Further, the density obtained as a percentage of the theoretical density was taken as the relative density.
ρ = wρ _k / (w1-w2)
w: Weight of sample before immersion: w
w1: Weight of sample after kerosene immersion: w1
w2: Weight of sample in kerosene: w2
ρ _k : Kerosene density Bending strength A sample having a size of 25 mm × 5 mm × 5 mm was formed as a measurement sample of bending strength using Gyera Cosmotech 2 vest (manufactured by GC). A conductive layer was formed on the bottom of the mold and ceramic powder was deposited by electrophoresis, or a ceramic paste was applied and dried. Thereafter, it was fired at a predetermined temperature to obtain a sample. This fired sample is ground and polished into a rectangular shape having a width of 4 mm, a thickness of 1.2 mm, and a length of 20 mm by using a rotary polishing machine (Malto Co., Ltd., diamond wrap), and a diamond slurry having a surface of 1 μm. To finish the mirror surface. A bending strength was obtained by performing a three-point bending test with a strength tester (manufactured by Shimadzu Corporation, Autograph) under the conditions of a crosshead speed of 1 mm / min and a span distance of 15 mm.

Example 1
After adding 30.25 g of yttria-stabilized zirconia (TZ-3YE, manufactured by Tosoh Corp.) to 95 ml of ethanol, the pH was adjusted to 4.5 using acetic acid, and then stirred for 2 hours. Meanwhile, 1.2 g of polyvinyl butyral 1200 (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed and dissolved in 98.8 g of ethanol to obtain a 1.2 wt% solution. 5 ml of this solution was added to the slurry.

  A carbon paste (Dotite XC-12, manufactured by Fujikura Kasei Co., Ltd.) is applied to the abutment tooth model so that the heat is 0.5 mm or less, and a copper lead wire is silver on the abutment tooth. The electrode was adhered with a paste (Doutite D-550, manufactured by Fujikura Kasei Co., Ltd.). The average thickness after drying the carbon paste was about 0.011 mm. An abutment tooth model on which a carbon paste was applied and a copper wire was installed and a stainless steel plate were immersed in the slurry, and a DC voltage of 100 V was applied for 15 minutes as a negative electrode and a positive electrode, respectively. The yttria-stabilized zirconia deposited at this time had a thickness of 2 mm. The coping precursor thus prepared is baked together with an abutment tooth model using an electric furnace (SUPER BURN, manufactured by Motoyama) at 500 ° C. for 1 hour and 1350 ° C. for 3 hours to obtain a coping made of yttria stabilized zirconia. It was. The relative density of the coping was 99%.

  Using a bending strength mold instead of the abutment tooth model, a bending strength test sample was prepared in the same manner as described above. As a result, the bending strength was 1200 MPa. In addition, the voltage application for ceramic particle deposition was performed for 60 minutes.

Example 2
19.75 g of alumina (TM-DAR, Daimei Chemical Industries) was added to 95 ml of ethanol and stirred for 2 hours, and then the pH was adjusted to 5 using acetic acid.

  0.1 g of carbon fiber (VGCF, Showa Denko KK, average fiber diameter of 0.15 μm) was dispersed in 12 g of ethyl acetate to obtain a paste. The said paste was apply | coated to the abutment tooth model similarly to Example 1, and it was set as the electrode by installing a copper wire. The average thickness after drying the carbon paste was about 0.023 mm. Using this, a DC voltage of 100 V was applied for 15 minutes. The thickness of the deposited alumina at this time was 1.7 mm. The coping precursor thus prepared was fired together with the abutment tooth model using an electric furnace (SUPER BURN, manufactured by Motoyama) at 500 ° C. for 1 hour and 1350 ° C. for 3 hours to obtain an aluminum coping. The relative density of the coping density was 97%.

  Using a bending strength mold instead of the abutment tooth model, a bending strength test sample was prepared in the same manner as described above. As a result, the bending strength was 700 MPa. In addition, the voltage application for ceramic particle deposition was performed for 90 minutes.

Example 3
22.0 g of yttria-stabilized zirconia (TZ-3YE, manufactured by Tosoh Corporation) and 5.5 g of alumina (TM-DAR, Daimei Chemical Co., Ltd.) were added to 95 ml of ethanol, stirred for 2 hours, and then adjusted to pH 5.5 using acetic acid. It was adjusted.

  0.1 g of carbon fiber (VGCF, manufactured by Showa Denko KK, average fiber diameter of 0.15 μm) was dispersed in 12 g of ethyl acetate to obtain a paste. The said paste was apply | coated to the abutment tooth model similarly to Example 1, and it was set as the electrode by installing a copper wire. The average thickness after drying the carbon paste was about 0.24 mm. Using this, a DC voltage of 100 V was applied for 15 minutes. At this time, the deposited zirconia-alumina had a thickness of 2.2 mm. The coping precursor thus prepared was calcined together with an abutment tooth model using an electric furnace (SUPER BURN, manufactured by Motoyama) at 500 ° C. for 1 hour and 1350 ° C. for 3 hours to obtain a zirconia-alumina coping. The relative density of the coping was 95%.

  Using a bending strength mold instead of the abutment tooth model, a bending strength test sample was prepared in the same manner as described above. As a result, the bending strength was 1500 MPa. The voltage application for depositing the ceramic particles was performed for 70 minutes.

Example 4
After adding 9.99 g of alumina (TM-DAR, Daimei Chemical Industries) and 6.66 g of aluminum (Wako Pure Chemical Industries) to 95 ml of ethanol and stirring for 2 hours, the pH was adjusted to 4.0 using acetic acid. Carbon paste (Dotite D-550, manufactured by Fujikura Kasei Co., Ltd.) was applied to the abutment tooth model in the same manner as in Example 1, and a copper wire was installed to obtain an electrode. The average thickness after drying the carbon paste was about 0.006 mm. Using this, a DC voltage of 100 V was applied for 10 minutes. The thickness of the deposited alumina at this time was 2.5 mm. The coping precursor thus produced was baked together with the abutment tooth model using an electric furnace (SUPER BURN, manufactured by Motoyama) at 500 ° C. for 1 hour and 1350 ° C. for 10 hours to obtain a coping by aluminum. The relative density of the coping was 94%.

  Using a bending strength mold instead of the abutment tooth model, a bending strength test sample was prepared in the same manner as described above. As a result, the bending strength was 650 MPa. Note that voltage application for depositing ceramic particles was performed for 40 minutes.

Example 5
19.75 g of alumina (TM-DAR, Daimei Chemical Industries) was added to 95 ml of ethanol and stirred for 2 hours, and then the pH was adjusted to 9 using an aqueous ammonia solution.

  Similarly to Example 1, carbon paste (Dotite XC-12) was applied to the abutment tooth model, and a copper wire was installed to obtain an electrode. The average thickness after drying the carbon paste was about 0.023 mm. Using this, a DC voltage of 100 V was applied for 15 minutes. At this time, the thickness of the deposited alumina was 2.3 mm. The coping precursor thus prepared together with the abutment tooth model was baked at 500 ° C. for 1 hour and 1350 ° C. for 3 hours using an electric furnace (SUPER BURN, manufactured by Motoyama) to obtain a coping by aluminum. The relative density of the coping was 96%.

  Using a bending strength mold instead of the abutment tooth model, a bending strength test sample was prepared in the same manner as described above. As a result, the bending strength was 660 MPa. Note that voltage application for depositing ceramic particles was performed for 60 minutes.

Comparative Example 1
After adding 30.25 g of yttria-stabilized zirconia (TZ-3YE, manufactured by Tosoh Corporation) to 95 ml of ethanol and stirring for 2 hours, the pH was adjusted to 4.0 using acetic acid. Conductivity was the same as in Example 1 except that silver paste (Dotite D-550, manufactured by Fujikura Kasei Co., Ltd.) was used instead of the carbon paste (coating thickness after drying 0.046 mm), and the voltage during deposition was 80 V. A layer was formed to deposit zirconia. At this time, the deposited zirconia had a thickness of 2.5 mm. The coping precursor thus prepared was baked together with an abutment tooth model using an electric furnace (SUPER BURN, manufactured by Motoyama) at 500 ° C. for 1 hour and 1350 ° C. for 3 hours. Also, the coping obtained was greyish.

Comparative Example 2
A slurry of ceramic powder prepared in the same manner as in Example 1 was applied to an abutment tooth model with a brush so as to have a thickness of about 2 mm, and then dried. Subsequently, when the abutment tooth model was baked at 500 ° C. for 1 hour and 1350 ° C. for 3 hours using an electric furnace (SUPER BURN, manufactured by Motoyama), the shape of the crown was not maintained due to shrinkage.

Comparative Example 3
The operation was performed in the same manner as in Example 1 except that ethyl cellulose was used in place of the carbon paste, but no ceramic was deposited on the abutment tooth model even when a voltage was applied.

Claims (1)

A ceramic restoration used to repair a tooth defect portion is obtained by depositing ceramics and / or its precursor particles by an electrophoretic molding method to obtain a restoration precursor, and then heating the restoration precursor. In the method for producing ceramics and / or precursor particles thereof by sintering, (1) combustible conductivity as an electrode when depositing ceramics and / or precursor particles thereof by the electrophoretic molding method Using an abutment tooth model having a conductive layer with a thickness of 0.005 to 0.5 mm formed of a substance, and (2) sintering ceramics and / or precursor particles thereof by heating a restoration precursor, A method for producing a dental restoration made of ceramics, which is performed without removing the restoration precursor from the abutment tooth model.