JP2019013756A - Rigidity improvement method of ceramic body, processing method of artificial tooth and ceramic mold processor - Google Patents

Abstract

To provide a method for improving the rigidity of a ceramic body.SOLUTION: A particle-containing liquid is injected to a ceramic body in an initial state having a fragility initiation part which is invisible by naked eyes on a surface layer part, a fragile part having higher fragility is formed by progressing the fragility of the fragility initiation part, a stress concentration of the fragile part is alleviated by further injecting the particle-containing liquid to the fragile part, and the ceramic body is brought into a state where rigidity is higher than that in the initial state.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for improving the strength of a ceramic body, a method for processing an artificial tooth, and a ceramic shaped body processing apparatus.

  Natural teeth naturally present in the oral cavity are the digestive organs that function first to absorb the nutrients of food delivered to the mouth, and have a very important role in chewing food. Yes.

  Therefore, when natural teeth are lost due to caries or accidents, it is necessary to place artificial teeth in the oral cavity to replace the lost teeth.

  Various materials have been proposed for artificial teeth based on the viewpoints of physical strength, aesthetics, price, etc., and patients undergoing dental treatment should select materials as needed unless they are contrary to the purpose of treatment. Artificial teeth can be formed.

JP-A-10-218721

  By the way, in recent years, ceramic materials are widely used as materials for artificial teeth, and those having a color closer to natural teeth have been proposed.

  However, although the conventional artificial teeth have been considered for aesthetics, when the artificial teeth actually installed in the oral cavity are observed by a third party, there is a slight discomfort different from natural teeth. I remembered it.

  In addition, many artificial teeth are formed by cutting an artificial tooth material, but fine defects generated in the cutting process often cause a loss accident, and there is still room for improvement.

  In addition, this problem is not limited to ceramic artificial teeth, but is also a strength viewpoint mainly in ceramic materials and shaped bodies (hereinafter also simply referred to as ceramic bodies) used in various fields. Improvement is desired.

  The present invention has been made in view of such circumstances, and provides a method for improving the strength of a ceramic body.

  In addition, the present invention provides a method for processing an artificial tooth that has an appearance close to that of natural teeth, improves the strength of the ceramic body, and suppresses a loss accident.

  Furthermore, the present invention also provides a processing apparatus capable of improving the strength of the ceramic shaped body.

  In order to solve the above-described conventional problems, in the method for improving the strength of a ceramic body according to the present invention, (1) particles are contained in an initial state ceramic body having a brittleness-inducing portion that cannot be visually observed with the naked eye on the surface layer portion. By spraying the liquid, the vulnerability of the vulnerability-inducing part is advanced to form a weaker weak part, and by further injecting the particle-containing liquid into the weak part, the stress concentration of the weak part is reduced. Thus, the ceramic body is in a state of higher strength than the initial state.

  In the method for improving the strength of the ceramic body according to the present invention, (2) the brittleness-inducing portion is different from or is the same as the base material composition of the ceramic body. It is also characterized in that it is one of a heat-denatured part that is different from the base material composition generated by the molding process of the body, a stripped part existing on the surface layer of the ceramic body, or a combination thereof.

  In the artificial tooth machining method according to the present invention, (3) the artificial tooth machining method for machining by the ceramic body strength improving method according to (1) or (2) above, wherein the ceramic in the initial state is used. The body is an artificial tooth having a desired tooth shape by cutting an artificial tooth material, and at least the upper gingival margin region of the artificial tooth is surface roughness Sa0 with a plurality of collision marks by particles contained in the particle-containing liquid. The rough surface was 7 to 0.8.

  Further, in the ceramic shaped body processing apparatus according to the present invention, (4) the holding part capable of holding the ceramic shaped body, the injection nozzle for injecting the particle-containing liquid, the X axis direction which is the front-rear direction, and the left-right direction. Positions of the injection nozzle and the holding portion in five directions including a three-axis direction of the Y-axis direction and the Z-axis direction that is the vertical direction and at least a direction around the X-axis and the Y-axis among the three axes. A posture displacement mechanism for relatively displacing the relationship, a storage unit storing the outer shape data of the ceramic model, and a control unit, the control unit refer to the outer shape data stored in the storage unit However, rough surface formation execution means for controlling the posture displacement mechanism is provided so that the surface target region of the ceramic shaped body uniformly faces the jet of the particle-containing liquid ejected from the ejection nozzle.

The ceramic shaped body processing apparatus according to the present invention is also characterized by the following points.
(5) The apparatus further includes a cutting unit that cuts the ceramic modeling material held by the holding unit, and the posture displacement mechanism can relatively displace the positional relationship between the cutting unit and the holding unit in the five directions. And the control unit controls the posture displacement mechanism so that the ceramic modeling material is cut into a target ceramic modeling body shape by referring to the external shape data stored in the storage unit. Provide cutting execution means.
(6) The rough surface forming execution means is executed after execution of the cutting execution means.
(7) The ceramic shaped body is an artificial tooth, and the surface target region is at least the gingival margin region of the artificial tooth.

  According to the method for improving the strength of a ceramic body according to the present invention, the particle-containing liquid is sprayed onto the ceramic body in an initial state having a brittleness-inducing portion that is invisible on the naked eye on the surface layer portion. The fragile portion is developed to form a more fragile fragile portion, and by further injecting a particle-containing liquid into the fragile portion, the stress concentration of the fragile portion is relaxed, and the ceramic body is moved from the initial state. Since the strength is high, the strength of the ceramic body can be improved.

  Further, the brittleness-inducing part is a base material embedded part of a granular material having a grain boundary that is different or the same as the base material composition of the ceramic body, and a base material composition that is generated by the processing of the ceramic body. If it is a heterogeneous heat-denatured part, a stripped part existing on the surface layer of the ceramic body, or a combination part thereof, the strength reduction caused by the base material embedded part of the granule, the heat-denatured part, or the stripped part Can be effectively suppressed.

  Further, according to the artificial tooth machining method of the present invention, the artificial tooth machining method for machining by the method for improving the strength of the ceramic body according to (1) or (2) above, wherein the ceramic body in the initial state is used. Is an artificial tooth having a desired tooth shape by cutting the artificial tooth material, and at least the upper gingival margin region of the artificial tooth with a plurality of collision marks due to particles contained in the particle-containing liquid and surface roughness Sa0.7 Since it was set to the rough surface of -0.8, the artificial tooth can be processed with an appearance close to that of a natural tooth and a loss accident can be suppressed.

  Moreover, according to the ceramic molded object processing apparatus which concerns on this invention, the holding | maintenance part which can hold | maintain a ceramic molded object, the injection nozzle which injects a particle-containing liquid, the X-axis direction which is the front-back direction, and Y which is the left-right direction The positional relationship between the injection nozzle and the holding unit in five directions, ie, the three axial directions of the axial direction and the Z-axis direction that is the vertical direction, and at least the X-axis and Y-axis rotation directions of the three axes. A posture displacement mechanism for relatively displacing the ceramic body, a storage unit storing the outer shape data of the ceramic model, and a control unit, the control unit referencing the outer shape data stored in the storage unit However, since the surface target area of the ceramic shaped body is provided with rough surface forming execution means for controlling the posture displacement mechanism so as to uniformly face the jet of the particle-containing liquid ejected from the ejection nozzle, Suppressing strength reduction derived from the vulnerability caused portions present on the surface target region of box shaped bodies, it is possible to improve the strength of the ceramic shaped bodies.

  Moreover, it further includes a cutting unit that cuts the ceramic modeling material held by the holding unit, and the posture displacement mechanism can relatively displace the positional relationship between the cutting unit and the holding unit in the five directions. The control unit controls cutting of the posture displacement mechanism so that the ceramic model material is cut into a target ceramic model shape by referring to the outer shape data stored in the storage unit. If the execution means is provided, it is possible to provide a machining apparatus capable of cutting the ceramic shaped body from the ceramic shaped material as well as the ceramic shaped body can be subjected to the strength improvement processing. .

  Further, if the rough surface formation execution means is executed after the execution of the cutting execution means, it is a weakness that continues to exist in the surface target area of the ceramic shaped body with respect to the ceramic shaped body formed by cutting the ceramic shaped material. The processing which suppresses the strength reduction originating in the sex-induced part can be performed.

  Further, if the ceramic shaped body is an artificial tooth and the surface target region is at least the gingival margin region of the artificial tooth, it has an appearance close to that of a natural tooth, and the strength of the ceramic body is improved. In addition, it is possible to provide an apparatus capable of processing an artificial tooth in which a loss accident is suppressed. In particular, the above-described effects can be enjoyed with respect to the gingival margin region where a large force is applied and strength is required.

It is explanatory drawing which showed the state of the vulnerability inducement part. It is explanatory drawing which showed the process of the process with respect to a surface target area | region. It is explanatory drawing which showed the process of the process with respect to a surface target area | region. It is explanatory drawing which showed the process of the process with respect to a surface target area | region. It is explanatory drawing which showed the change of the surface state of a ceramic modeling body. It is explanatory drawing which showed the change of the surface state of a ceramic modeling body. It is explanatory drawing which showed the result of the intensity | strength confirmation test. It is explanatory drawing which showed the structure of the artificial tooth processing apparatus which concerns on this embodiment. It is the block diagram which showed the electrical structure of the artificial tooth processing apparatus. It is the flow which showed the process performed with an artificial tooth processing apparatus. It is explanatory drawing which showed operation | movement of the artificial tooth processing apparatus. It is explanatory drawing which shows the surface state of the artificial tooth and the artificial tooth for a comparison.

  The present invention provides a method for improving the strength of a ceramic body, and in particular, a ceramic body (hereinafter also referred to as an initial ceramic body) having a brittleness-inducing portion that cannot be visually observed with the naked eye. The method of improving the intensity | strength of is provided.

Here, the ceramic constituting the ceramic body is not particularly limited. For example, oxide ceramics such as alumina (Al ₂ O ₃ ), zirconia, barium titanate (BaO ₃ Ti), and hydroxyapatite Hydroxide ceramics such as, carbide ceramics such as silicon carbide (SiC), carbonate ceramics, nitride ceramics such as silicon nitride (Si ₃ N ₄ ), halide ceramics such as fluorite, phosphoric acid Examples thereof include salt-based ceramics or composite ceramics thereof.

  Further, in this specification, the vulnerability-inducing part is a small part that cannot be visually observed with the naked eye (approximately 10 to 300 μm square). For example, in a state before use of the ceramic molded body, Although it is not, it is a site where stress is applied during use or a change in temperature can be triggered in the future to cause weakness by triggering a change in temperature.

  Such a weakness-inducing part is not particularly limited as long as it is a part as described above. However, if a specific example is provided for understanding of the present invention, for example, a microcrack, a heat-denatured part, a peeled part And a base material embedding part of particles.

  As shown in FIG. 1A, the microcrack 52 is a fragility-inducing portion 53 formed of a very small crack formed in the surface layer portion 51 of the base material 50. Such micro cracks 52 may occur during firing of the ceramic body or subsequent cooling process.

  When the microcracks 52 are present on the surface of the base material 50, for example, when stress is applied to the base material 50 by using a ceramic body, as shown in the left diagram of FIG. Propagates to the inside of the base material 50 and becomes a crack 54 to form a fragile portion 55, leading to breakage of the base material 50, that is, breakage of the ceramic body.

  The heat-denaturing part is a vulnerability-inducing part including a part that has been changed to a property different from that of the base material 50 due to heat during processing, for example.

  As an example, when a base material originally having a predetermined strength is cut, frictional heat is applied, and the part changes to a molecular bonding state different from that of the base material so that the original strength cannot be exhibited. Is mentioned.

  Such a heat-denatured part is difficult to visually check with the naked eye because it is a molecular structure change, and when stress is applied to the ceramic molded body after processing, Due to the difference in strength between the heat-denatured portion and the base material, the heat-denatured portion is destroyed, leading to breakage of the ceramic body.

  As shown in FIG. 1B, the peeled portion 56 is a bristle-like (overhang-like) vulnerability-inducing portion 53 formed by, for example, the microcrack 52 extending in a substantially horizontal direction in the base material surface layer portion. is there.

  When the peeled portion 56 exists in the surface layer portion 51, when stress due to warpage or the like is applied to the base material 50, the stress concentrates on the tip of the microcrack 52 (near the base portion of the peeled portion 56), The microcrack 52 further develops to become a fragile portion 55, and a peeling piece 57 as shown in the left figure is generated, leading to peeling of a small piece from the ceramic molded body and a chipping of the ceramic molded body.

  As shown in FIG. 1 (c), the base material embedded portion 58 has the surface layer portion 51 of the base material 50 in which a granule 59 having a grain boundary 60 that is different from or the same as the base material 50 and embedded in the base material 50 is embedded. This is the state vulnerability inducing unit 53. In such a grain 59, for example, a part that should originally be sintered integrally at the time of firing the ceramic body is not sintered due to some cause such as temperature unevenness, and a grain boundary 60 is formed or is essentially uniform. It may appear when the ceramic powder raw material is partially biased. Note that the grain boundary 60 is, for example, a heterogeneous interface, a boundary where the sintered state is not continuous but non-uniform and the continuity of mechanical strength is lost even if it is homogeneous, or internal residual stress. It is a concept including a boundary where cracks may occur due to unevenness of the material, and cracks, etc., and means the boundary of the property that the particles can fall off from the base material.

  In the case where the base material embedded portion 58 exists in the surface layer portion 51, when a predetermined stress is applied to the base material 50 due to the use of a ceramic molded body or the like, the granules 59 fall off from the base material 50 and the surface layer portion 51. In this case, a drop mark 61 is formed to become a fragile portion 55, and stress concentrates on the drop mark 61, causing breakage of the ceramic molded body.

  It is known that when a stress concentration part due to a defect or the like exists on the surface of a ceramic material, the original strength is weakened. Any surface defect portion such as the fragile portion 55 typified by the above-described specific example indicates that stress concentration occurs. By appropriately removing the defective portion, the stress concentration portion disappears, and the overall strength of the ceramic molded body and parts is improved compared to before the treatment.

  That is, in the method for improving the strength of the ceramic body according to the present embodiment, the weakness-inducing portion, which is a weak portion, is first removed preferentially from the surface of the ceramic body in the initial state having such a weakness-inducing portion. Then, a process for finishing to a smooth surface shape as a shape that does not cause stress concentration is performed.

  The step of preferentially removing the fragility-inducing portion (hereinafter referred to as the first step) is to inject the particle-containing liquid onto the ceramic body in the initial state to convert the fragility-inducing portion into the fragile portion. Do.

  Moreover, the process (henceforth a 2nd process) which finishes in the smooth look-up shape which does not raise | generate a stress concentration further injects a particle-containing liquid with respect to the weak part formed intentionally by the 1st process. The stress concentration of the fragile portion is relaxed to obtain a ceramic body having a higher strength than the initial state described above.

  Specifically, for example, in the case of a ceramic body having a microcrack 52 in the surface layer portion 51, as shown in FIG. 2A, the surface target region including the vulnerability-inducing portion 53 of the ceramic shaped body surface layer portion 51. While the particle-containing liquid W is being ejected from the ejection nozzle 18, the surface target region is scanned with the particle-containing liquid W (ejection nozzle 18).

  Then, the opening of the microcrack 52 is expanded by the particle-containing liquid W that is press-fitted into the microcrack 52, and the microcrack 52 is once changed to the mode of the fragile portion 55. By removing the entire original surface layer portion 51, the stress concentration is relaxed as shown in FIG. 2B, or it is derived from the microcrack 52 as shown in FIG. 2C. Even though it is a remaining concave portion, the crack tip is rounded to form a scar portion 62 in which stress concentration is relaxed.

  Therefore, the ceramic body can be in a higher strength state than the ceramic body in the initial state where the fragile portion appears after the fragility-inducing portion and causes damage or fracture.

  In addition, the injection of the particle-containing liquid with respect to the vulnerability-inducing part may be performed separately in the first step and the second step, and the first step and the second step are continuously performed. You can go.

  That is, after the brittleness-inducing part is scanned once with the particle-containing liquid W (injection nozzle 18) and changed into the brittle part, the stress concentration of the brittle part may be relaxed by the second scanning. The stress concentration may be alleviated for the fragile portion generated while changing to the fragile portion only by scanning.

  Moreover, the frequency | count of implementing a 1st process and a 2nd process is not specifically limited, For example, you may carry out only once and may carry out several times about either one or both.

  Similarly, when the brittleness-inducing part is the stripped part 56 as shown in FIG. 3A, the particle-containing liquid W is jetted onto the surface target region including the brittleness-inducing part 53 of the ceramic shaped body surface layer part 51. While ejecting from the nozzle 18, the surface target area is scanned with the particle-containing liquid W (ejection nozzle 18).

  Then, the peeling piece part 56 is once changed into the mode of the weak part 55 because the peeling piece 57 peels off by the particle-containing liquid W and the peeling mark 63 is formed.

  Next, by scanning the peeling marks 63 with the particle-containing liquid W as a second step, the bottom and corners (corners) were rounded while the remaining recesses originated from the peeling marks 63, and the stress concentration was alleviated. It becomes a scar part 62. Although illustration is omitted, as shown in FIG. 2B, it is a matter of course that the original surface layer portion 51 as a whole may be removed so that the stress concentration is relaxed to be in a substantially smooth state.

  Further, as shown in FIG. 4 (a), the surface target region including the vulnerability-inducing portion 53 of the surface layer portion 51 of the ceramic shaped body is also obtained when the vulnerability-inducing portion is the base material embedded portion 65 of the particles 64. In contrast, the particle-containing liquid W (jet nozzle 18) is scanned on the surface target area while the particle-containing liquid W is jetted from the jet nozzle 18.

  Then, as shown in FIG. 4B, the particle 64 is dropped from the base material embedding portion 65 and the drop mark 66 is formed by the particle-containing liquid W, so that it is once changed to the mode of the fragile portion 55. .

  Next, by scanning the peeling marks 63 with the particle-containing liquid W as the second step, the entire surface layer portion 51 as a whole is removed and the stress concentration is relaxed as shown in FIG. Alternatively, as shown in FIG. 4 (d), it is possible to obtain a scar portion 62 in which the bottom and corners (corner portions) are rounded and the stress concentration is relaxed even though it is a remaining concave portion derived from the drop mark 66.

  As described above, in the method for improving the strength of the ceramic body according to the present embodiment, the particle-containing liquid is jetted onto the ceramic body in the initial state having the brittleness-inducing portion that cannot be visually observed with the naked eye on the surface layer portion, The fragility of the triggering part is developed to form a more fragile fragile part, and the concentration of stress in the fragile part is relieved by injecting a particle-containing liquid further into the fragile part, whereby the ceramic body is By making the strength higher than the state, the strength of the ceramic body can be improved. In addition, the particle containing liquid to inject is the same as the particle containing liquid used in the process of the artificial tooth mentioned later, The detail is demonstrated later.

  In other words, the method for improving the strength of the ceramic body according to the present embodiment is such that the particle-containing liquid is sprayed onto the fragility-inducing portion, and the stress concentration portion is temporarily changed to the fragile portion, and then the stress is increased. It can be said that the stress concentration of the fragile portion is relaxed by press-fitting a jet of the particle-containing liquid into the concentrated portion and concentrating and wearing the stress concentrated portion.

  That is, the technical concept of the method for improving the strength of the ceramic body according to the present embodiment is not the surface polishing or flattening that is also in the above-described prior art, but the defects and weaknesses such as the vulnerability-inducing part 53 described above. Smooth surface shape creation (including non-directionality) that does not cause part removal and stress concentration.

  The present invention also provides an artificial tooth having an appearance close to that of a natural tooth when the ceramic molded body is, for example, an artificial tooth, and a method for processing the same, and a method for processing the artificial tooth. It is characterized in that a rough surface having a surface roughness Sa (arithmetic mean surface roughness) of 0.7 to 0.8 is formed at least over the entire gingival margin region.

  The artificial tooth may be an implant denture attached to an abutment, a denture used for a crown bridge, or an artificial tooth arranged on a denture base formed of resin or the like. May be.

  The material used for the artificial tooth is not particularly limited.For example, lithium disilicate glass ceramic or yttria-stabilized tetragonal zirconia polycrystal ), Polymer-infiltrated ceramic network, Nano-ceramic resin composite, Zirconium oxide + A fluorapatite glass-ceramic, Shiroishi stone reinforced glass ceramic ( Leucite-reinforced glass-ceramic) and monochromatic feldspar ceramic blanks can be used.

  In the present specification, the supragingival region of the artificial tooth is a region corresponding to the supragingival portion of the natural tooth on the surface of the artificial tooth, that is, the portion hidden in the actual gingiva of the patient after the operation on the patient, It does not matter whether it has a subgingival margin. For example, in the case of a denture, an exposed portion of an artificial tooth formed by projecting from a simulated gingiva is considered as the supragingival region.

  As a feature of the artificial tooth and its processing method according to the present embodiment, this gingival margin region is a rough surface having a surface roughness Sa0.7 to 0.8 consisting of a plurality of collision marks.

  In general, an artificial tooth is not only formed by cutting a target artificial tooth shape from a predetermined ceramic modeling material (for example, artificial tooth material), but also an artificial tooth formed in a shape complementary to a predetermined formwork. Even for teeth, the surface is cut to make fine adjustments.

  At this time, a dentist or a dental technician who performs cutting makes the surface of the artificial tooth contact the surface of the artificial tooth with a so-called air turbine or engine. And scratch marks are formed.

  Then, due to heat generated by this friction (for example, heat of several hundreds of degrees Celsius), the surface composition of the artificial tooth changes from the originally intended artificial tooth composition, that is, the composition of the artificial tooth material to a different state, The desired function such as desired strength may not be exhibited.

  In addition, the frictional heat may change not only to the artificial tooth surface but also to the deep layer due to heat propagation.

  Furthermore, the surface layer that has been altered by the formation of scratch marks may peel off from the interface, and cracks may be generated from the peeled portion, causing a loss accident.

  In many cases, the scratch marks are formed in a streak shape along the rubbing direction, and when the scratch marks are exposed to light, a reflection different from that of natural teeth is made. You may feel uncomfortable.

  In this respect, since the artificial tooth according to the present embodiment has a non-directional rough surface formed of a collision mark instead of a scratch mark, there is no unevenness in reflection and the third party does not feel uncomfortable.

  In addition, collision objects that can form a rough surface of Sa 0.7 to 0.8 are high-speed fine particles, and the collision energy of each object forming one collision mark is extremely small, which may cause alteration of the artificial tooth material. In addition, the first and second steps described above are already substantially completed along with the formation of the rough surface, thereby suppressing the possibility of deteriorating the surface layer that has deteriorated during subsequent use and the accidental loss of artificial teeth. be able to.

  In particular, in this embodiment, in forming this rough surface, as a method for processing the artificial tooth, particles are formed in at least the gingival margin region of the artificial tooth as a ceramic shaped body having a target tooth shape by cutting the artificial tooth material. The contained liquid is sprayed evenly, and the above gingival margin region is made to be a rough surface having a surface roughness Sa0.7 to 0.8 by a plurality of collision marks caused by particles contained in the same particle-containing liquid.

  The particle-containing liquid is a liquid in which particles for colliding with artificial teeth are dispersed in a predetermined dispersion medium.

Particles form collision marks where the gingival margin region becomes a rough surface with a surface roughness of Sa0.7 to 0.8, based on the kinetic energy obtained from the relationship between the injection speed of the particles injected with the dispersion medium and the mass of the particles themselves. It is not particularly limited as long as it is possible, and it does not matter whether it is harder or softer than the hardness of the artificial tooth material. As an example of the particles, alumina particles having a mass of about 1.18 × 10 ^{−11 to} 5.44 × 10 ⁻¹¹ g (diameter of about 0.90 to 1.50 μm) can be used.

  The dispersion medium is not particularly limited as long as it does not alter the artificial teeth and can disperse the particles stably. For example, it can be water.

For example, when the particles are alumina particles having a mass of about 1.18 × 10 ^{−11 to} 5.44 × 10 ⁻¹¹ g and the dispersion medium is water, the particle-containing liquid is 3.0 g to 3.5 g in 100 g of the particle-containing liquid. It can contain about g alumina particles.

  The particle-containing liquid prepared in this way uses kinetic energy capable of executing the first and second steps and kinetic energy capable of forming a rough surface in the surface target region including the aforementioned weakness-inducing portion. The surface of the ceramic shaped body, for example, at least the region on the gingival margin of the artificial tooth is sprayed by a device that can be sprayed as much as possible. This spraying is performed on the ceramic shaped body processing apparatus according to the present embodiment. You may be made to do by.

  The ceramic model body processing apparatus according to the present embodiment includes a holding unit, an injection nozzle, a posture displacement mechanism, a storage unit, and a control unit, and by injecting a particle-containing liquid onto the ceramic model body, It is possible to suppress the strength reduction derived from the vulnerability-causing part existing in the surface target area and to improve the strength of the ceramic shaped body, and when the ceramic shaped body is an artificial tooth, there is a loss accident with an appearance close to natural teeth. It is possible to perform processing that is suppressed.

  Here, the holding part is a part for holding a ceramic shaped body (for example, artificial tooth) or a ceramic shaped material (for example, artificial tooth material) that is a raw material for cutting the ceramic shaped body.

  Further, the injection nozzle is a nozzle that injects the particle-containing liquid from a tank or the like provided in the ceramic shaped body processing apparatus by a liquid feed pump or compressed air, and the ceramic shaped body held by the holding unit, The particle-containing liquid is ejected at a speed at which the particles have kinetic energy capable of forming the rough surface.

  The posture displacement mechanism includes a three-axis direction (XYZ-axis direction) of an X-axis direction that is the front-rear direction, a Y-axis direction that is the left-right direction, and a Z-axis direction that is the vertical direction, and at least the X-axis and Y-axis among the three axes This is a mechanism for relatively displacing the positional relationship between the injection nozzle and the holding portion in five directions, ie, the direction around the axis. By this posture displacement mechanism, the ceramic shaped body held by the holding portion and the injection nozzle for injecting the above-described particle-containing liquid can be displaced freely in five directions.

  The posture displacement mechanism includes a moving system mechanism that can move in three directions orthogonal to each other, ie, an X-axis direction that is the front-rear direction, a Y-axis direction that is the left-right direction, and a Z-axis direction that is the vertical direction. It can be realized by including a rotation system mechanism capable of displacing relative positions around at least two of the axes (XYZ axes), preferably around the X and Y axes. Each component of the mechanism and the rotating system mechanism may be integrally formed as a single unit, or may be separately provided as necessary.

  In other words, the posture displacement mechanism is a mechanism for changing the surface of the ceramic body to be brought into contact with the jet of the particle-containing liquid ejected from the ejection nozzle by a combination of the operation of the rotation system mechanism and the operation of the movement system mechanism. It can be said.

  The storage unit is a part in which the external shape data of the ceramic model is stored in a format that can be referred to by the control unit. Specifically, the storage unit is an optical recording medium such as a ROM, a RAM (including a non-volatile memory), an optical disk, or a hard disk. This is realized by a magnetic recording medium or the like.

  Then, the control unit refers to the outer shape data stored in the storage unit, and in the case of an artificial tooth, a predetermined region of the ceramic shaped body, for example, at least the gingival margin region is jetted from the particle-containing liquid ejected from the ejection nozzle. Rough surface formation execution means for controlling the posture displacement mechanism so as to be evenly opposed is provided.

  That is, the control unit causes the rough surface formation execution means to face a predetermined region of the ceramic shaped body, for example, in the case of an artificial tooth, substantially the entire region including at least the gingival margin region to the particle-containing liquid sprayed from the spray nozzle, more preferably The rough surface is formed by causing the jet direction of the particle-containing liquid to face the processing target surface of the artificial tooth so as to be substantially vertical.

  Moreover, in the ceramic model body processing apparatus according to the present embodiment, the ceramic model body processing apparatus further includes a cutting unit that cuts the ceramic modeling material held by the holding unit, and the posture displacement mechanism has a positional relationship between the cutting unit and the holding unit in the five directions. The posture displacement mechanism is configured so that the ceramic shaped material is cut into the desired ceramic shaped body shape by referring to the outer shape data stored in the storage unit, and the ceramic shaped body is formed. It is good also as providing the cutting execution means which controls.

  By having such a configuration, it is possible to execute the first step and the second step on the ceramic model and to form a rough surface, as well as cutting the ceramic model. It can be set as the possible ceramic modeling object processing apparatus.

  Moreover, in the ceramic molded body processing apparatus according to the present embodiment, the rough surface forming execution unit may be executed after the cutting execution unit is executed.

  By adopting such a configuration, the ceramic shaped body formed by cutting the ceramic shaped material is subsequently subjected to processing that suppresses the strength reduction derived from the brittleness-inducing portion existing in the surface target region of the ceramic shaped body. Can do. Moreover, when the ceramic shaped body is an artificial tooth, it is possible to perform processing with an appearance close to that of a natural tooth and suppressing a loss accident.

  The ceramic body processing apparatus according to the present embodiment may have a structure in which the above-described components are integrally accommodated in a single housing, and the configuration relating to driving is accommodated in the housing, while the control is related to control. The structure may be constructed by, for example, using a personal computer and electrically connecting them together.

  Next, the method for improving the strength of the ceramic body according to the present embodiment will be described below with the result of observing the state change of the surface of the ceramic body actually used in the method.

  In this test, a ceramic model formed on the basis of a predetermined ceramic model material is subjected to the method for improving the strength of the ceramic body according to the present embodiment, and the state of the surface according to the number of scans by the injection of the particle-containing liquid is observed. It was.

  By using two types of ceramic molding materials, CERASMART270 (CERASMART is a registered trademark) and KZR-CAD Zr (KZR-CAD is a registered trademark), the material is molded into a plate shape of 14mm in length × 12mm in width × 2mm in thickness. Each was formed into a ceramic body and subjected to the test. In the following description, a ceramic model made by CERASMART270 is referred to as a ceramic model A1, and a ceramic model from KZR-CAD Zr is referred to as a ceramic model A2.

  First, FIG. 5 shows the state of the surface corresponding to the number of scans of the ceramic shaped body A1. 5 (a) to 5 (f) all show a microscopic enlarged photograph of the same sample and a cross-sectional curve of the white line portion shown on the same photograph, the particle-containing liquid injection processing apparatus and the microscopic imaging apparatus, In view of the repeated setting of the sample, the same field of view is not shown although it is almost the same place. The same applies to FIG. 6 described later.

  CERASMART270 is a zirconia ceramic material containing about 10% filler. However, as shown in FIG. 5A, the surface of the ceramic body A1 in the state before scanning is a convex portion due to the filler or the filler falling off. Concavities, polishing marks, and the like were observed. In addition, these unevenness | corrugations and grinding | polishing traces are the magnitude | sizes of the grade which are hard to observe with the naked eye.

  When three injection scans were performed on such a ceramic shaped body A1, as shown in FIG. 5 (b), further dropout of fillers and the like was promoted, and a more uneven state was observed. That is, the change of the vulnerability-induced part to the weak part due to the injection of the particle-containing liquid was observed.

  Next, when the ceramic scanning body A1 in which many fragile portions were formed was further subjected to jet scanning 6 times, 9 times 12 times, and 15 times, as shown in FIGS. 5 (c) to (f), The formation of new fragile parts due to changes in the fragility-causing part gradually decreases, while the previously formed fragile parts are worn by the jet of the injected particle-containing liquid and the stress concentration is relaxed. Observed.

  FIG. 6 shows the state of the surface of the ceramic body A2 according to the number of scans. As can be seen from the comparison with the surface state of the ceramic body A1 shown in FIG. 5A, KZR-CAD Zr, which is the material of the ceramic body A2, has a finer surface than CERASMART270. At first glance, it seems that the vulnerability-inducing region does not exist with the naked eye.

  When the ceramic scanning body A2 was subjected to jet scanning three times and six times, as shown in FIGS. 6 (b) and 6 (c), the latent vulnerability-inducing part was the weak part. It was observed that it changed and became obvious.

  Further, when the ninth injection scan was performed, formation of a larger fragile portion was also observed as shown in FIG.

  Next, when the ceramic shaped body A2 formed with many fragile portions was further subjected to jet scanning 12 times and 15 times, as shown in FIGS. 6 (e) and (f), the fragility inducing portion was shown. It was observed that the formation of new fragile portions due to the change in the diameter gradually decreased, while the previously formed fragile portions were worn by the jet of the injected particle-containing liquid and the stress concentration was relaxed.

  Next, using the ceramic model A1 as a representative example, a confirmation test by three-point bending was performed on the strength change before and after processing.

  In the test, a ceramic shaped body A1 is placed over a 3 mm diameter cylindrical support disposed at an interval of 1.2 cm, and a substantially central portion of the ceramic shaped body A1 is pressed from above by a cylindrical presser having a diameter of 3 mm. I went there. The test was performed three times for each of the sample before processing and the sample after processing. The result is shown in FIG.

  FIG. 7A and FIG. 7B are stress-strain curves before and after processing, respectively. As shown in FIG. 7 (a), the ceramic shaped body A1 before processing reaches fracture when the strain exceeds approximately 0.1%, and it can be seen that the stress at that time has a large variation of 80 to 120 MPa. .

  On the other hand, as shown in FIG.7 (b), the ceramic molded object A1 after a process reached | attained the fracture | rupture at about 0.14% of distortion, and the stress at that time was 130-150 MPa.

  Based on these results, as shown in FIG. 7C, the ceramic body provided for the method for improving the strength of the ceramic body according to the present embodiment is confirmed to have improved strength compared to the ceramic body in the initial state. It was done. Another characteristic is that the variation in stress at the time of fracture converges compared to the state before processing, and the method for improving the strength of the ceramic body according to this embodiment also improves the uniformity of the strength of the product. It was shown that it can contribute.

  Next, the ceramic body strength improving method, artificial tooth processing method, and ceramic shaped body processing apparatus according to the present embodiment will be described in detail with reference to the drawings. In the following description, the ceramic shaped body is an artificial tooth, the ceramic shaped material is an artificial tooth material, and the ceramic shaped body processing apparatus is an artificial tooth processing apparatus as a representative example. It should not be construed as being limited to the representative examples. However, this does not prevent the applicant from limiting the application to the aspect of the present embodiment.

[1. Structure of artificial tooth processing device)
First, the structure of an artificial tooth machining apparatus as a ceramic model body machining apparatus according to the present embodiment will be described. FIG. 8 is an explanatory view showing the entire structure of the artificial tooth machining apparatus A. FIG.

  As shown in FIG. 8, the artificial tooth machining apparatus A is composed of a personal computer system 10 that mainly controls a control system and an apparatus main body 11 that mainly controls an operation system.

  In addition to the computer main body 10a, the personal computer system 10 is connected with a display 12 as a display means, a mouse 13 and a keyboard 14 as input means, and is personally referred to information output from the personal computer system 10. Input to the computer system 10 is possible.

  The apparatus main body 11 includes a housing 15 formed in a substantially rectangular box shape, and an opening 15a for a user to access the inside of the housing 15 is formed at a front portion thereof. The door body 16 formed with a transparent portion that allows the inside of the housing 15 to be visually recognized is pivotally mounted so as to be openable and closable.

  An upper moving body 20 including a cutting drill 17 for cutting the artificial tooth material S held in a holding portion described later and an injection nozzle 18 for injecting the particle-containing liquid is disposed above the housing 15. It is installed.

  The upper moving body 20 incorporates an X-axis motor and a Z-axis motor (not shown) that are electrically connected to a control unit 40, which will be described later, and a left and right rail disposed in the housing 15 in the left-right direction. The upper moving body 20 itself can be moved in the left-right direction (X-axis direction) and the up-down direction (Z-axis direction) along 20a and the up-and-down rail 20b arranged in the up-down direction.

  A processing stage 21 is disposed below the inside of the housing 15. The processing stage 21 is configured by disposing an annular holding ring 21b that functions as a holding portion inside a rectangular stage frame 21a.

  The stage frame 21a is connected to a motor 22a around the Y axis disposed on the processing stage moving body 22 via a motor shaft 22b so that the processing stage 21 can be rotated in the direction around the Y axis.

  The holding ring 21b is connected to an X-axis motor (not shown) disposed on the side surface of the stage frame 21a via a motor shaft 23b penetrating the stage frame 21a. It can be rotated in the direction.

  Further, the processing stage moving body 22 is provided with a Y-axis motor 22c, and the processing stage moving body 22 is moved in the front-rear direction (Y-axis) along a front-rear rail 22d disposed in the front-rear direction at the lower part in the casing 15. Direction).

  That is, in the artificial tooth processing apparatus A, the X-axis motor and the Z-axis motor built in the upper moving body 20, the Y-axis motor 22c provided in the processing stage moving body 22, the left and right rails 20a, the upper and lower rails 20b, and the front and rear rails Each of the rails such as 22d constitutes a moving system mechanism, and a rotating system includes a Y-axis motor 22a disposed on the processing stage moving body 22 and an X-axis motor 23a disposed on the side surface of the stage frame 21a. The mechanism is configured, and a posture displacement mechanism is constructed by the moving system mechanism and the rotating system mechanism. The cutting drill 17 and the injection nozzle 18 provided in the upper moving body 20 and the artificial tooth held by the holding ring 21b. The positional relationship with the material and artificial teeth is configured to be displaceable in five directions.

  In addition, a slurry tank 24 and a cleaning liquid tank 25 are provided inside the housing 15.

  The slurry tank 24 is a tank for storing a particle-containing liquid, and the particle-containing liquid stored in the slurry tank 24 is sprayed together with compressed air or the like from the spray nozzle 18 when a rough surface of the artificial tooth is formed through a slurry supply pipe (not shown). Is done.

  The cleaning liquid tank 25 is a tank for storing the cleaning liquid, and the cleaning liquid stored in the cleaning liquid tank 25 is discharged from the injection nozzle 18 during the cleaning process after the rough surface of the artificial tooth is formed through a cleaning liquid supply pipe (not shown). Is done.

  Next, the electrical configuration of the artificial tooth machining apparatus A will be described with reference to FIG. FIG. 9 is a block diagram showing an electrical configuration of the artificial tooth machining apparatus A.

  The personal computer system 10 includes a CPU 31, a ROM 32, a RAM 33, and a hard disk 34, and is configured to execute a program necessary for the operation of the artificial tooth processing apparatus A.

  The ROM 32, the RAM 33, and the hard disk 34 are parts that function as the storage unit 41 of the artificial tooth processing apparatus A. The ROM 32, the RAM 33, and the hard disk 34 are programs executed by the CPU 31, artificial tooth data input by the user, for example, a template for creating artificial teeth. Data is stored.

  When the program is executed by the CPU 31, the processing result is displayed on the display 12, and the user inputs to the personal computer system 10 using the mouse 13 and the keyboard 14 while referring to the display result. Can do.

  On the other hand, the apparatus main body 11 includes a main body control unit 35, a posture displacement mechanism 36, a liquid feeding unit 37, and a cutting unit 38.

  The main body control unit 35 is a part that functions as the control unit 40 of the artificial tooth machining apparatus A as a whole in cooperation with the CPU 31 of the personal computer system 10, and mainly receives commands from the personal computer system 10 to change the posture. Drive control of the mechanism 36, the liquid feeding part 37, the cutting part 38, etc. is performed.

  That is, the main body control unit 35 executes a program or the like stored in the storage unit 41, so that at least the upper gingival margin region of the artificial tooth is referred to the external shape data of the artificial tooth or the like stored in the storage unit 41. It functions as a rough surface forming execution means for controlling the posture displacement mechanism 36 so as to evenly face the jet of the particle-containing liquid ejected from the ejection nozzle 18, and external data such as artificial teeth stored in the storage unit 41 is used. It functions as a cutting execution means for controlling the posture displacement mechanism 36 so that the artificial tooth material is cut into the target tooth shape while the artificial tooth material is being referred to and an artificial tooth is formed.

  The posture displacement mechanism 36 is a part constituted by the above-described moving system mechanism and rotating system mechanism, and each cutting motor provided by the upper moving body 20 is driven by each motor or the like based on a command from the main body control unit 35. 17 and the injection nozzle 18 and the positional relationship between the artificial tooth material and artificial teeth held by the holding ring 21b are displaced in five directions.

  The liquid feeding unit 37 is a part for feeding and stopping the particle-containing liquid in the slurry tank 24 and the cleaning liquid in the cleaning liquid tank 25 to the injection nozzle 18 based on a command from the main body control unit 35. The liquid feeding unit 37 also supplies and stops compressed air used for spraying the particle-containing liquid from the spray nozzle 18.

  The cutting part 38 is a part for cutting the artificial tooth material held by the holding ring 21b, and the main body control part 35 controls rotation of the cutting drill 17 by controlling a motor or the like provided in the cutting part 38. A stop will be made.

  Further, the personal computer system 10 and the apparatus main body 11 are each provided with an I / O port 39 for performing input / output, and can communicate with each other.

  As described above, the artificial tooth processing apparatus A according to the present embodiment includes the holding ring 21b as a holding portion that can hold the artificial teeth, the injection nozzle 18 that jets the particle-containing liquid, and the X-axis direction that is the front-rear direction. And the jet nozzle 18 in five directions including a three-axis direction including a Y-axis direction that is a left-right direction and a Z-axis direction that is a vertical direction, and a direction around at least an X-axis and a Y-axis among the three axes. A posture displacement mechanism 36 that relatively displaces the positional relationship with the holding ring 21b, a storage unit 41 that stores the external shape data of the artificial tooth, and a control unit 40. The coarse displacement control unit 36 controls the posture displacement mechanism 36 so that at least the upper gingival margin region of the artificial tooth uniformly faces the jet of the particle-containing liquid ejected from the ejection nozzle 18 while referring to the external shape data stored in the storage unit 41. Surface formation Comprises a row unit, at close to the natural tooth appearance, of course it is possible to perform the machining defect accident is suppressed, thereby enabling also the cutting of the artificial tooth itself.

[2. Processing with artificial tooth processing equipment)
Next, with reference to the operation of the artificial tooth processing apparatus A and the processing executed by the control unit 40, FIG. 10 and FIG. 11 are used for cutting the artificial tooth material and roughing the artificial tooth by the artificial tooth processing apparatus A. The description will be given with reference.

  When the user inserts a disc-shaped artificial tooth material S (made of lithium disilicate glass ceramic) into the holding ring 21b and starts up predetermined software in the personal computer system 10 to instruct the formation of artificial teeth, the CPU 31 Refers to the external shape data of the artificial tooth stored in the storage unit 41 (step S11), and sequentially performs communication and the like necessary for performing the cutting process with the main body control unit 35.

  Further, the main body control unit 35 instructs the posture displacement mechanism 36 to adjust the relative positional relationship between the cutting drill 17 and the holding ring 21b (or the artificial tooth material held by the holding ring 21b) based on an instruction from the CPU 31. At the same time, an instruction such as the cutting speed of the cutting drill 17 is given to the cutting unit 38 (step S12). At this time, as shown in FIG. 11A, the relative positions of the cutting drill 17 and the holding ring 21b are freely displaced by the posture displacement mechanism 36 based on the external shape data of the artificial tooth, and cutting for artificial tooth formation is performed. Executed.

  When this cutting process is completed, the control unit 40 then performs a rough surface forming process. In the rough surface property process, the CPU 31 forms an area (hereinafter also referred to as a rough surface formation area) in which a rough surface including at least the gingival margin area is included in the outline data of the artificial tooth stored in the storage unit 41. The corresponding outline data is referred to (step S13), and communication necessary for performing the rough surface forming process is sequentially performed with the main body control unit 35.

  Further, the main body control unit 35 makes the posture displacement mechanism 36 relative to the injection nozzle 18 and the holding ring 21b (or the artificial tooth formed on the artificial tooth material held on the holding ring 21b) based on an instruction from the CPU 31. While instructing the adjustment of the positional relationship, the liquid feeding unit 37 is instructed to feed the particle-containing liquid, supply compressed air, and the like (step S14). At this time, as shown in FIG. 11 (b), the relative position of the injection nozzle 18 and the holding ring 21b is freely displaced based on the external shape data of the artificial tooth by the posture displacement mechanism 36, and on the gingival margin of the artificial tooth surface. The rough surface is formed on the rough surface forming region including the region. In addition, in this process, it adjusted to the injection speed (particle kinetic energy) of the particle-containing liquid W from the injection nozzle 18 so that the rough surface of surface roughness Sa0.7-0.8 which consists of a some collision trace may be formed. .

  When the rough surface forming process is completed, the control unit 40 then performs a cleaning process. In the cleaning process, the CPU 31 refers to the contour data of the artificial tooth stored in the storage unit 41 (step S15), and sequentially performs communication and the like necessary for performing the cleaning process with the main body control unit 35.

  Further, the main body control unit 35 makes the posture displacement mechanism 36 relative to the injection nozzle 18 and the holding ring 21b (or the artificial tooth formed on the artificial tooth material held on the holding ring 21b) based on an instruction from the CPU 31. While instructing the adjustment of the positional relationship, the liquid feeding unit 37 is instructed about the liquid feeding speed of the cleaning liquid (step S16). At this time, the relative position of the injection nozzle 18 and the holding ring 21b is freely displaced by the posture displacement mechanism 36 based on the outline data of the artificial tooth, and the surface of the artificial tooth is cleaned.

  After finishing the cleaning process, the artificial tooth material S on which the artificial teeth were formed was removed from the holding ring 21b, and the artificial teeth were further removed from the artificial tooth material S to obtain an artificial tooth T1 according to this embodiment.

[3. Preparation of artificial tooth sample for comparison)
A comparative artificial tooth sample was prepared for comparison with the artificial tooth T1 according to the present embodiment. Specifically, [2. The processing is substantially the same as the processing by the artificial tooth processing apparatus], but the surface roughness of the rough surface formed in the rough surface forming step is Sa0.5 to 0.6 for comparison, and the surface roughness of the rough surface is the same. A grinding wheel mounted on an air turbine after performing a cutting process using a comparative artificial tooth T3 having a Sa of 0.9 to 1.0 and an artificial tooth processing apparatus A, and performing a cleaning process without performing a rough surface forming process. Then, a comparative artificial tooth T4 that was polished so that the surface roughness of the rough surface was Sa0.7 to 0.8 was prepared.

[4. (Rough surface check)
Next, the rough surface was observed and analyzed for the artificial tooth T1 and the comparative artificial teeth T2 to T4 according to the present embodiment. The result is shown in FIG.

  FIGS. 12A to 12D show the surface states of the artificial tooth T1 and the comparative artificial teeth T2 to T4, and show a three-dimensional analysis image and a two-dimensional (planar) image, respectively. As shown to Fig.12 (a), in the artificial tooth T1, it was confirmed that the rough surface which consists of a some collision trace is formed in the whole region of the gingival margin area | region at least. Further, when the surface roughness was measured with an Olympus laser microscope (LEXTOLS4000), it was confirmed that the surface roughness was Sa0.7 to 0.8.

  Further, as shown in FIGS. 12B and 12C, also in the comparative artificial tooth T2 and the comparative artificial tooth T3, a rough surface including a plurality of collision marks is formed at least in the entire region of the gingival margin. Has been confirmed. When the surface roughness was measured with a laser microscope, the surface roughness of the comparative artificial tooth T2 was Sa0.5 to 0.6, and the surface roughness of the comparative artificial tooth T3 was Sa0.9 to 1.0. It was confirmed.

  Further, as shown in FIG. 12 (d), it was confirmed that the rough surface of the comparative artificial tooth T4 was formed with innumerable scratch marks. Moreover, when surface roughness was measured with the laser microscope, it was confirmed that it was surface roughness Sa0.7-0.8 similarly to artificial tooth T1.

[4. (Examination of aesthetics)
Next, the aesthetics of the artificial tooth T1 and the comparative artificial teeth T2 to T4 according to the present embodiment were examined, specifically, which artificial tooth was closer to the natural tooth.

Five dental technicians evaluated the artificial tooth T1 and the comparative artificial teeth T2 to T4 by comparing them while referring to the natural teeth. Evaluation was made in 5 stages of 1 to 5, and the larger the value, the closer the impression was to natural teeth. The results are shown in Table 1.

  As can be seen from Table 1, among the artificial teeth T1 and the comparative artificial teeth T2 to T4, the artificial tooth closest to the natural tooth as viewed from a third party is the artificial tooth T1 according to this embodiment. It has been shown.

  Further, the comparative artificial tooth T2 and the comparative artificial tooth T3 are also artificial teeth with relatively little discomfort, and the comparative artificial tooth T3 having a slightly rough surface than the artificial tooth T1 is more than the artificial tooth T1. The result was less uncomfortable as compared to the comparative artificial tooth T2 having a fine rough surface.

  Further, like the conventional artificial tooth formation, the comparative artificial tooth T4 subjected to the rotary polishing has the same practical appearance as before, but the artificial tooth T1, the comparative artificial tooth T2, and the comparative artificial tooth. Compared to T3, the result was a strong sense of discomfort not found in natural teeth. This was considered to be caused by a subtle difference in reflection of light derived from scratches along the polishing direction by the rotating grindstone.

[5. (Examination of strength)
Next, the strength of the artificial tooth T1 and the comparative artificial teeth T2 to T4 according to the present embodiment was examined.

  Specifically, the artificial teeth T1 and comparative artificial teeth T2 to T4 according to the present embodiment having the shape of a corresponding pair of upper and lower molars are provided to a testing machine, and the occlusion of the upper and lower molars is mechanically repeated. We went and examined its durability.

  As a result, regarding the artificial tooth T4 for comparison, chipping and flaking of the flakes were confirmed when 3500 hours passed after the start of the test.

  On the other hand, with respect to the artificial tooth T1 and the comparative artificial teeth T2 and T3 according to the present embodiment, no chipping or flaking of the flakes was confirmed even after 3500 hours.

  As described above, according to the method for improving the strength of the ceramic body according to the present embodiment, the particle-containing liquid is sprayed onto the ceramic body in an initial state having a brittleness-inducing portion that is invisible on the naked eye on the surface layer portion. The weakness-inducing portion is developed to form a weaker weakening portion, and the particle-containing liquid is further injected into the weakening portion to relieve the stress concentration of the weakening portion. Since the body is in a state of higher strength than the initial state, the strength of the ceramic body can be improved.

  In addition, according to the artificial tooth according to the present embodiment, the rough surface having a surface roughness Sa0.7 to 0.8 consisting of a plurality of collision marks is formed at least over the entire region of the gingival margin, so that the appearance close to natural teeth Furthermore, it is possible to provide an artificial tooth in which loss accidents are suppressed.

  Finally, the description of each embodiment described above is an example of the present invention, and the present invention is not limited to the above-described embodiment. For this reason, it is a matter of course that various modifications can be made in accordance with the design and the like as long as they do not depart from the technical idea according to the present invention other than the embodiments described above.

DESCRIPTION OF SYMBOLS 17 Cutting drill 18 Injection nozzle 20 Upper moving body 21 Processing stage 21b Holding ring 24 Slurry tank 25 Cleaning liquid tank 36 Posture displacement mechanism 37 Liquid feeding part 38 Cutting part 40 Control part 41 Memory | storage part A Artificial tooth processing apparatus S Artificial tooth material T1 Artificial material Teeth W Particle-containing liquid

Claims (7)

  A particle-containing liquid is sprayed onto a ceramic body in an initial state having a weakness-inducing portion that cannot be seen with the naked eye on the surface layer portion, and the vulnerability of the weakness-inducing portion is advanced to form a weaker weakness portion. A method for improving the strength of a ceramic body, which further reduces the stress concentration of the fragile portion by spraying a particle-containing liquid onto the fragile portion, thereby bringing the ceramic body into a higher strength than the initial state.   The brittleness inducing portion is different from the base material composition of the ceramic body, which is different from the base material composition of the ceramic body, or is different from the base material composition of the base body embedded in the ceramic body with a grain boundary. 2. The method for improving the strength of a ceramic body according to claim 1, wherein the heat denaturing portion, a strip portion existing on the surface layer of the ceramic body, or a combination thereof is used.   An artificial tooth machining method according to claim 1 or 2, wherein the ceramic body in the initial state is formed into a target tooth shape by cutting an artificial tooth material. A method for processing an artificial tooth, wherein at least the upper gingival margin region of the artificial tooth is a rough surface having a surface roughness of Sa0.7 to 0.8 with a plurality of collision marks formed by particles contained in the particle-containing liquid. A holding part capable of holding a ceramic shaped body;
An injection nozzle for injecting the particle-containing liquid;
Five directions including an X-axis direction that is the front-rear direction, a Y-axis direction that is the left-right direction, and a Z-axis direction that is the up-down direction, and at least the X-axis and Y-axis rotation directions of the three axes. A posture displacement mechanism for relatively displacing a positional relationship between the injection nozzle and the holding unit;
A storage unit storing external shape data of the ceramic body;
A control unit,
The control unit controls the posture displacement mechanism so that the surface target area of the ceramic shaped body uniformly faces the jet of the particle-containing liquid ejected from the ejection nozzle while referring to the external shape data stored in the storage unit. A ceramic body processing apparatus comprising rough surface forming execution means for performing the processing. A cutting part for cutting the ceramic modeling material held in the holding part;
The posture displacement mechanism is capable of relatively displacing the positional relationship between the cutting unit and the holding unit in the five directions.
The controller executes cutting execution to control the posture displacement mechanism so that the ceramic shaped material is cut into a target ceramic shaped body shape by referring to the outer shape data stored in the storage unit. The ceramic shaped body processing apparatus according to claim 4, comprising means.   6. The ceramic shaped body processing apparatus according to claim 5, wherein the rough surface forming execution unit is executed after the cutting execution unit is executed.   The ceramic shaped body processing apparatus according to any one of claims 4 to 6, wherein the ceramic shaped body is an artificial tooth, and the surface target region is at least a region on the gingival margin of the artificial tooth.