This application claims the benefit of priority to Japanese Patent Application No. 2020-213566 filed on Dec. 23, 2020. The entire contents of this application are hereby incorporated by reference herein.
The present invention relates to a method for producing a dental prosthesis.
Conventionally, a dental prosthesis production device processes a processing target made of a dental ceramic material, a dental resin material or the like into a desired shape to produce a dental prosthesis (for example, an artificial tooth, an artificial dental crown or the like). For example, Japanese Laid-Open Patent Publication No. 2020-183007 discloses a dental prosthesis production device that processes, for example, cuts and polishes, a processing target by use of a processing tool to produce a dental prosthesis.
In the case where a processing tool is used to cut a processing target as described in Japanese Laid-Open Patent Publication No. 2020-183007, the processing target having a certain shape (typically, a parallelepiped shape) needs to be cut into the shape of a dental prosthesis. Specifically, a portion of the processing target excluding the dental prosthesis needs to be cut away. This tends to cause the processing time to be extended.
Preferred embodiments of the present invention provide methods for producing a dental prosthesis in a shorter time period.
A preferred embodiment of the present invention provides a method for producing a dental prosthesis including preparing three-dimensional data on the dental prosthesis, preparing a processing target that transmits laser light, setting processing points representing an outer shape of the dental prosthesis based on the three-dimensional data, setting a to-be-cut plane extending from a surface of the processing target to the processing points, creating the processing points in the processing target by irradiating the processing target with the laser light, and cutting a portion of the processing target that is outward of the dental prosthesis with an internal stress by irradiating the processing target with the laser light along the to-be-cut plane.
According to the method according to the above-described preferred embodiment of the present invention, it is not necessary to cut and remove the entirety of a region of the processing target extending from the surface thereof to an outer circumference of a dental prosthesis. Therefore, the dental prosthesis may be produced in a shorter time period.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
Hereinafter, methods for producing a dental prosthesis according to preferred embodiments of the present invention will be described with reference to the drawings. The preferred embodiments described herein are not intended to specifically limit the present invention. Elements, portions and steps that have the same functions will bear the same reference signs, and overlapping descriptions will be omitted or simplified. In the drawings, letters F, Rr, L, R, U and D respectively represent front, rear, left, right, up and down. These directions are merely set for the sake of convenience, and are not to be interpreted as limiting the preferred embodiments in any way.
First, in the three-dimensional data preparation step (step S10), three-dimensional data on a dental prosthesis is prepared. The three-dimensional data is, for example, STL (Standard Triangulated Language) data. The three-dimensional data on the dental prosthesis includes three-dimensional data representing an outer shape of the dental prosthesis, three-dimensional data representing an outer shape of a processing target, three-dimensional data representing processing points, and three-dimensional data representing processing planes. This step includes a preparation step (step S11) of preparing the three-dimensional data representing the outer shape of the dental prosthesis, a positioning step (step S12) of determining a position of the dental prosthesis with respect to the processing target, a first generation step (step S13) of generating the processing points, and a second generation step (step S14) of generating the processing planes. The three-dimensional data on the dental prosthesis is created by, for example, a computer-aided design device (CAD device). The CAD device may be realized in the form of software or hardware.
In step S11, the three-dimensional data representing the outer shape of the dental prosthesis is prepared. The three-dimensional data representing the outer shape of the dental prosthesis is used in the positioning step (step S12), the first generation step (step S13) and the second generation step (step S14).
In step S12, the position of the dental prosthesis 10 with respect to a processing target 5 is determined. First, the processing target 5 to be used is determined. Next, the position of the dental prosthesis 10 is determined such that the dental prosthesis 10 to be produced is accommodated in the processing target 5. The position of the dental prosthesis 10 may be automatically determined by the determination on the processing target 5 to be used.
In step S13, the three-dimensional data representing the outer shape of the dental prosthesis 10 is used to create data on a plurality of processing points 6 (see
In step S14, the three-dimensional data representing the outer shape of the dental prosthesis 10 and the data on the processing points 6 are used to set a to-be-cut plane 7 or to-be-cut planes (see
Next, in the processing target preparation step (step S20), the processing target 5 (see
Next, in the processing point creation step (step S30), as shown in
Next, in the cutting step (step S40), as shown in
As shown in
Next, in the retrieval step (step S50), an external force is applied to the processing target 5 to retrieve the dental prosthesis 10 cut from the processing target 5. For example, the processing target 5 is vibrated after the cutting step (step S40) to be completely cut. As a result, as shown in
Next, in the polishing step (step S60), a surface of the dental prosthesis 10 is irradiated with the laser light LA to be polished. In this preferred embodiment, an unnecessary portion at the surface of the dental prosthesis 10 is removed by irradiation with the laser light. The same effect is obtained as in the case where the surface is polished by use of a common processing tool. In this step, for example, the dental prosthesis 10 is irradiated with the laser light LA while being held by a holding member (not shown). The laser irradiator 52 described above may be provided with the holding member, or a tool different from the laser irradiator 52 may be used, to direct the laser light LA toward the dental prosthesis 10.
Next, in the baking step (step S70), the dental prosthesis 10 is irradiated with the laser light LA to be baked. In this step, for example, the dental prosthesis 10 is irradiated with the laser light LA while being held by the holding member (not shown) described above. The laser irradiator 52 described above may be provided with the holding member, or a tool different from the laser irradiator 52 may be used, to direct the laser light LA toward the dental prosthesis 10. The same tool as that used in step S60 may be used.
As described above, according to the method in this preferred embodiment, in the processing point creation step (step S30), the processing target 5 is irradiated with the laser light LA based on the three-dimensional data, so that the plurality of processing points 6 representing the outer shape of the dental prosthesis 10 are created in the processing target 5. As a result, the dental prosthesis 10 is formed in the processing target 5. In the case where a processing tool is used to cut a processing target, it is necessary to cut and remove the entirety of a region of the processing target that extends from a surface thereof to an outer circumference of the dental prosthesis, in order to form the outer shape of the dental prosthesis. According to the method in this preferred embodiment, the processing target 5 transmitting the laser light LA is used. Therefore, the outer shape of the dental prosthesis 10 may be formed in the processing target 5 in a shorter time period with no removal of such a region. After this, in the cutting step (step S40), the processing target 5 is irradiated with the laser light LA along the to-be-cut plane 7 extending from the surface of the processing target 5 to the processing points 6, so that a portion of the processing target 5 that is outward of the dental prosthesis 10 is cut with an internal stress. The processing target 5 is irradiated with the laser light LA along the to-be-cut plane 7 in this manner. As a result, the processing target 5 is cut, and the dental prosthesis 10 formed in the processing target 5 may be retrieved. Since the processing target 5 may be cut by merely irradiating the processing target 5 with the laser light LA along the to-be-cut plane 7 in this preferred embodiment, the processing may be finished in a relatively short time period. The processing target made of a dental ceramic material, a dental resin material or the like is highly hard and highly brittle. Therefore, in the case where a processing tool is used to cut the processing target, the processing tool is abraded as a result of cutting the processing target, and thus tends to have a shorter life. Since the processing tool is exchanged more frequently, the production cost of the dental prosthesis may undesirably be raised. According to the method in this preferred embodiment, the processing target 5 is irradiated with the laser light LA to be processed. Therefore, there is no such problem that the processing tool is abraded as a result of contacting the processing target 5. This allows the dental prosthesis 10 to be produced more economically.
According to the method in this preferred embodiment, in the cutting step (step S40), the processing target 5 is irradiated with the laser light LA, so that the plurality of processing planes 8 are created on the to-be-cut plane 7 so as to extend from the surface of the processing target 5 toward the processing points 6. In this manner, the laser light LA is directed locally toward the to-be-cut plane 7 to create the plurality of processing planes 8. Therefore, the processing time period is shortened as compared with the case where an unnecessary portion of the processing target 5 is entirely removed. Since the processing planes 8 to be formed as a result of the processing have a smaller total area than that of the to-be-cut plane 7, the processing time period is shortened to a greater extent.
According to the method in this preferred embodiment, the processing planes 8 extend in a direction crossing the to-be-cut plane 7. Therefore, a portion of the processing target 5 that is located between each two processing planes 8 adjacent to each other is effectively cut with an internal stress.
According to the method in this preferred embodiment, the processing planes 8 are located at an interval that is wider than the interval between the processing points 6. Unlike the outer shape of the dental prosthesis 10, a cutting plane formed by the to-be-cut plane 7 does not need to be created highly precisely. Therefore, the laser light LA may be directed at a relatively long interval, as long as the processing target 5 may be cut. This allow the processing time period to be shortened.
According to the method in this preferred embodiment, the processing planes 8 may each be formed by irradiating the processing target 5 with the laser light LA spirally. Therefore, the processing target 5 is cut along the to-be-cut plane 7 with more certainty.
According to the method in this preferred embodiment, the processing planes 8 may each be formed by irradiating the processing target 5 with the laser light LA concentrically. Therefore, the processing target 5 is cut along the to-be-cut plane 7 with more certainty.
According to the method in this preferred embodiment, the processing planes 8 may each be formed by irradiating the processing target 5 with the laser light LA like a scanning line. Therefore, the processing target 5 is cut along the to-be-cut plane 7 with more certainty.
According to the method in this preferred embodiment, in1 the processing point creation step (step S30), the plurality of processing points 6 are formed at such an interval that the laser light LA has an equal energy level per predetermined surface area among the plurality of processing points 6. Therefore, during the formation of the outer shape of the dental prosthesis 10 in the processing target 5, the energy of the laser light LA is prevented from being locally concentrated due to the shape or the radius of curvature of the surface of the dental prosthesis 10. This reduces or prevents cracks in the dental prosthesis 10, for example.
The method in this preferred embodiment further includes the retrieval step (step S50) of, after the cutting step (step S40), applying an external force to the processing target 5 to retrieve the dental prosthesis 10 cut from the processing target 5. After the processing target 5 is cut in the cutting step (step S40), the dental prosthesis 10 is usually retrieved spontaneously. In the case where the dental prosthesis 10 has a certain shape or in the case where the processing target 5 is made of a certain material, it may occur that the dental prosthesis 10 cannot be retrieved immediately after the processing target 5 is cut. Even in such a case, the dental prosthesis 10 may easily be retrieved from the processing target 5 by applying an external force to the processing target 5 (for example, by vibrating the processing target 5).
According to the method in this preferred embodiment, the laser light LA has a pulse width on the order of nanoseconds, picoseconds or femtoseconds. In the case where the processing target 5 needs to be processed highly precisely, it is preferred that the laser light LA is ultrashort pulse laser light. With such laser light LA, the dental prosthesis 10 may be produced highly precisely in the processing target 5, and the processing target 5 may be cut highly precisely. The laser light LA may be short pulse laser light. In the case where the processing target 5 is made of a certain material, the processing time period of the processing target 5 may be shortened with such laser light LA.
The method in this preferred embodiment further includes the polishing step (step S60) of, after the cutting step (step S40), irradiating the surface of the dental prosthesis 10 with the laser light LA to polish the dental prosthesis 10. In the case where, for example, a processing tool is used, both of a processing tool for cutting and a processing tool for polishing need to be prepared. In this preferred embodiment, the laser light LA is used to polish the dental prosthesis 10. Therefore, no additional tool or the like is needed to polish the dental prosthesis 10.
The method in this preferred embodiment further includes the baking step (step S70) of, after the polishing step (step S60), irradiating the dental prosthesis 10 with the laser light LA to bake the dental prosthesis 10. In the case where a processing tool is used to produce the dental prosthesis 10, the dental prosthesis 10 needs to be baked by another baking device. In this preferred embodiment, heat of the laser light LA may be applied. Therefore, no baking device is needed to bake the dental prosthesis 10.
Some preferred embodiments of the present invention are described above. The above-described preferred embodiments are mere examples, and the present invention may be carried out in any of various other preferred embodiments.
In the above-described preferred embodiments, the baking step (step S70) is performed after the polishing step (step S60). The method may further include a quality modification step of modifying the quality of the dental prosthesis 10 between the polishing step (step S60) and the baking step (step S70) or between the processing point creation step (step S30) and the cutting step (step S40). In the quality modification step, the dental prosthesis 10 is irradiated with the laser light LA, and thus may be improved in, for example, the color development quality or the light transmission quality.
In the above-described preferred embodiments, the processing planes 8 are formed to be generally circular, for example. The processing planes 8 are not limited to being generally circular. The processing planes 8 may have any shape that has a certain area size, for example, may be rectangular or triangular.
The terms and expressions used herein are for description only and are not to be interpreted in a limited sense. These terms and expressions should be recognized as not excluding any equivalents to the elements shown and described herein and as allowing any modification encompassed in the scope of the claims. The present invention may be embodied in many various forms. This disclosure should be regarded as providing preferred embodiments of the principles of the present invention. These preferred embodiments are provided with the understanding that they are not intended to limit the present invention to the preferred embodiments described in the specification and/or shown in the drawings. The present invention is not limited to the preferred embodiments described herein. The present invention encompasses any of preferred embodiments including equivalent elements, modifications, deletions, combinations, improvements and/or alterations which can be recognized by a person of ordinary skill in the art based on the disclosure. The elements of each claim should be interpreted broadly based on the terms used in the claim, and should not be limited to any of the preferred embodiments described in this specification or referred to during the prosecution of the present application.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
Number | Date | Country | Kind |
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2020-213566 | Dec 2020 | JP | national |