Patent Description:
When a loss of a tooth occurs by a tooth fracture, or by damaging or defecting of a tooth caused by a cavity, or the like, a procedure of manufacturing a dental restoration or a dental prosthesis is performed. The procedure of manufacturing a dental prosthesis refers to all procedures that produce an artificial tooth that is to be the most similar to a natural tooth and affixes or crowns the artificial tooth after removing a part or entire of a tooth. In a dental prosthesis, when a tooth shape is reproduced by pouring a plaster to a tooth form of a patient reproduced by an impression procedure or the tooth shape is obtained through an intra oral scanning procedure, a desired tooth can be designed on a screen through a computer-aided design (CAD) process and the dental prosthesis is processed automatically at a processing apparatus using a computer-aided design (CAD)/ a computer-aided manufacturing (CAM).

In general, as illustrated in <FIG>, the processing apparatus using CAD/CAM produces the dental prosthesis by processing a workpiece <NUM> with a processing tool <NUM> after fixing the workpiece <NUM> to a jig <NUM> by fastening a fixing table <NUM> to a seating table <NUM> by bolts <NUM> while the workpiece <NUM> having a disc shape is inserted in the seating table <NUM>.

Since the workpiece <NUM> in the conventional art has a disc shape, among regions of the workpiece <NUM> to be processed, a peripheral region of a portion in contact with the fixing table <NUM> or the seating table <NUM> has to be defined as a region in which processing is impossible in order for performing a cutting movement of a tool of the processing tool <NUM> without being interfered by the fixing table <NUM> or the seating table <NUM>. Therefore, the workpiece <NUM> inevitably includes a dead space that is a space impossible to be processed to be the dental prosthesis, so that there is a problem in that productivity of a dental prosthesis is low.

In addition, the workpiece <NUM> is fixed to the jig <NUM> with being in contact directly with the seating table <NUM> or the fixing table <NUM> over a wide area along the circumference thereof. That is, the workpiece <NUM> is in surface contact directly with the seating table <NUM> or the fixing table <NUM> that are solid, and there may be a problem in that the workpiece <NUM> may be broken by an instantaneously concentrated stress when the tool of the processing tool <NUM> contacts the workpiece <NUM>.

(Patent Document <NUM>) <CIT> (Patent Document <NUM>) <CIT>.

Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and an objective of the present disclosure is to provide a dental blank capable of minimizing a dead space by using a material portion having a polygonal shape and capable of increasing production efficiency of a dental prosthesis.

In addition, another objective of the present disclosure is to provide a dental blank capable of reducing the consumption of a material portion caused by a crack by protecting the material portion from an external force by using a guard portion such that the material portion does not directly contact with a seating portion or a fixing portion.

According to an embodiment of the present disclosure, the dental blank may include: a seating portion provided in an artificial tooth processing apparatus; and a material portion configured to be inserted into the seating portion, wherein the material portion may include a plurality of outer contacting portions in contact with an inner side of the seating portion, and has a polygonal shape in a cross-section. According to an embodiment of the present disclosure, the outer contacting portions may be in linear contact with an inner side surface of the seating portion along an insertion direction that the material portion is inserted into the seating groove.

According to an embodiment of the present disclosure, the material portion may include a guard portion in contact with a side portion of the material portion and configured to protect the material portion. According to an embodiment of the present disclosure, the guard portion may be positioned to surround a side surface of the material portion. According to an embodiment of the present disclosure, the guard portion may have a polygonal shape in a cross-section. According to an embodiment of the present disclosure, the guard portion may be positioned at an upper portion or a lower portion of the material portion. According to an embodiment of the present disclosure, the seating portion may include a seating groove in which the material portion is seated, the seating groove having a circular shape in a cross-section. According to an embodiment of the present disclosure, a dental prosthesis processed by the artificial tooth processing apparatus may be formed at the material portion.

According to the dental blank of the present disclosure, spreading of an external force applied to the material portion may be prevented by the material portion having a polygonal shape, and the consumption of the material portion caused by a crack may be reduced.

In addition, according to the dental blank of the present disclosure, an abrasion of a processing tool may be reduced by reducing an inserting load by forming tool entrance portions, and a border region of the material portion may be processed, so that the dead space of the material portion may be reduced and production efficiency of the dental prosthesis may increase.

In addition, according to the dental blank of the present disclosure, a stress, an impact, etc., that are transferred from the processing apparatus may be relieved by the guard portion, so that a breakage of the material portion may be prevented.

Advantages and features of the present disclosure, and a method of achieving them will become apparent with reference to the exemplary embodiments described below in detail together with the accompanying drawings.

However, the present disclosure is not limited to the exemplary embodiments disclosed below, but will be implemented in a variety of different forms. These exemplary embodiments are provided only to complete the disclosure of the present disclosure and to completely inform the scope of the present disclosure to those skilled in the art to which the present disclosure pertains, and the present disclosure is only defined by the scope of the claims.

Hereinafter, a dental blank according to an embodiment of the present disclosure will be described in detail with reference to <FIG>. In describing the present disclosure, detailed descriptions of related known functions or configurations are omitted so as not to obscure the subject matter of the present disclosure.

<FIG> is a view schematically illustrating an application example of a dental blank according to an embodiment of the present disclosure, <FIG> is an exploded perspective view schematically illustrating the dental blank according to an embodiment of the present disclosure, <FIG> is a perspective view schematically illustrating a material portion of the dental blank according to an embodiment of the present disclosure, <FIG> is a plan view schematically illustrating the material portion and a seating groove of the dental blank according to an embodiment of the present disclosure, <FIG> is a cross-sectional view schematically illustrating the material portion and the seating groove of the dental blank according to an embodiment of the present disclosure, <FIG> and <FIG> are plan views schematically illustrating the material portion, a guard portion, and the seating groove of the dental blank according to an embodiment of the present disclosure, <FIG> is a cross-sectional view schematically illustrating the material portion, the guard portion, and the seating groove of the dental blank according to an embodiment of the present disclosure, <FIG> is a plan view schematically illustrating the material portion and the guard portion of the dental blank according to an embodiment of the present disclosure, and <FIG> are cross-sectional views schematically illustrating the material portion and the guard portion of the dental blank according to an embodiment of the present disclosure.

As illustrated in <FIG>, a dental blank <NUM> may be applied to an artificial tooth processing apparatus. For example, the artificial tooth processing apparatus may be a processing apparatus <NUM> using a computer-aided design (CAD)/ a computer-aided manufacturing (CAM). The processing apparatus <NUM> using CAD/CAM may process the dental blank <NUM> by grinding, milling, cutting, etc. The dental blank <NUM> may include a material portion <NUM>, a seating portion <NUM>, and a fixing portion <NUM>.

The material portion <NUM> may be formed of at least one material selected from glass or glass-ceramic, polymer infiltrated glass, composite resin or hybrid material, unsintered or a partially sintered or a densely-sintered ceramic, and a metal or a metal alloy. The material portion <NUM> has characteristics such as high strength, thermal stability, and high corrosion resistance. Further, the material portion <NUM> with white or colored may be used alone or the material portion <NUM> with a mixture of white and colored may be used.

The material portion <NUM> may be processed to be a dental prosthesis <NUM> by the processing apparatus <NUM> using CAD/CAM. For example, when the dental blank <NUM> is mounted at the processing apparatus <NUM> using CAD/CAM, a processing tool <NUM> of the processing apparatus <NUM> is operated based on data converted through an outer surface coordinate of a tooth model obtained by scanning, and the material portion <NUM> of the dental blank <NUM> is cut such that the material portion <NUM> is processed to be the dental prosthesis <NUM>.

Here, the dental prosthesis <NUM> may refer to a dental restoration, a dental filler, or a dental cast that may be used in restoring a part of a tooth or may be used in replacing a lost tooth when a loss of a tooth occurs by a tooth fracture, or by damaging or defecting of a tooth caused by a cavity, or the like. For example, the dental prosthesis <NUM> may be a crown, an inlay, an onlay, a veneer, a coping, a pontic, or a laminate that have various tooth forms.

In the material portion <NUM>, a connection bar <NUM> that is connected to the dental prosthesis <NUM> may be additionally processed. The connection bar <NUM> may interconnect an inside of the material portion <NUM> and the dental prosthesis <NUM> that is processed, and the connection bar <NUM> may perform a function that allows the dental prosthesis <NUM> to be easily separated from the material portion <NUM>. The material portion <NUM> may refer to a body that is machined by the processing apparatus <NUM> using CAD/CAM, or may refer to a body that is in a state in which the dental prosthesis <NUM> that is processed is included.

The seating portion <NUM> is connected with the processing apparatus <NUM> using CAD/CAM, and may include a seating groove <NUM>, a coupling groove <NUM>, and coupling holes <NUM>. The seating groove <NUM> may have a circular groove shape that is recessed toward an inside of the seating portion <NUM>. The seating groove <NUM> may be a space in which the material portion <NUM> is seated. When the material portion <NUM> is positioned at the seating groove <NUM>, a circumference of an inner side surface of the seating groove <NUM> may be in contact with outer side angles of the material portion <NUM>.

The coupling groove <NUM> may have a circular groove shape that is recessed toward the inside of the seating portion <NUM>. The coupling groove <NUM> may be a space in which the fixing portion <NUM> is seated. The coupling holes <NUM> may have a hole shape that is formed toward the inside of the seating portion <NUM>.

The fixing portion <NUM> may include fasteners <NUM> and fastening holes <NUM>. The fasteners <NUM> are fastening devices such as a bolt and so on, and may be connected to the coupling holes <NUM> with being in a state in which the fasteners <NUM> are inserted in the fastening holes <NUM> that penetrate the fixing portion <NUM>.

When the material portion <NUM> and the fixing portion <NUM> are respectively seated in the seating groove <NUM> and the coupling groove <NUM>, the fasteners <NUM> may be coupled to the coupling holes <NUM> by passing through the fastening holes <NUM>. That is, since the fasteners <NUM> are fastened to the coupling holes <NUM> by bolting when the fixing portion <NUM> is in a state in which the fixing portion <NUM> is in contact with a portion of the material portion <NUM>, the fixing portion <NUM> may fix the material portion <NUM> to the seating portion <NUM>.

Hereinafter, a structure of the material portion <NUM> of the dental blank <NUM> will be described in detail with reference to <FIG> and <FIG>.

As illustrated in <FIG> and <FIG>, the material portion <NUM> has a polygonal shape in a cross-section, and may include a plurality of outer contacting portions <NUM> that are positioned around an edge of the material portion <NUM>. The outer contacting portions <NUM> may be formed to correspond to the polygonal shape of the material portion <NUM>. For example, when the material portion <NUM> is formed in an octagonal shape, eight outer contacting portions <NUM> may be formed at the material portion <NUM>.

When the material portion <NUM> is accommodated in the seating groove <NUM>, each of the outer contacting portions 13a, 13b, 13c, and 13d may be in contact with an inner side of the seating groove <NUM>. Since the material portion <NUM> has the polygonal shape, each of the outer contacting portions 13a, 13b, 13c, and 13d may be in linear contact with an inner side surface of the seating groove <NUM> along an insertion direction that the material portion <NUM> is inserted into the seating groove <NUM>. In other words, when the material portion <NUM> is inserted into the seating groove <NUM>, as illustrated in the expanded circle in <FIG>, linear contacting portions <NUM> that are in linear contact along a z-axis direction may be formed between the inner surface of the seating groove <NUM> and the outer contacting portions 13a.

A conventional workpiece is formed in a disc shape, and when the conventional workpiece is accommodated in a seating table, the entire of circular perimeter of the workpiece is in surface contact with and fixed to an inner surface of the seating table. In this state, when an external force is applied to the workpiece, the external force is spread to the entire of the workpiece along a wide surface contacting area between the workpiece and the seating table that is solid, so that the entire region of the workpiece may be broken.

However, since the material portion <NUM> of the present invention is formed in the polygonal shape, the outer contacting portions <NUM> and the seating groove <NUM> are in linear contact with each other when the material portion <NUM> is accommodated in the seating groove <NUM>. That is, the linear contacting portions <NUM> that are relatively narrow are formed between the material portion <NUM> and the seating groove <NUM>, so that an external force does not spread to the entire of the material portion <NUM> even if the external force is applied to the material portion <NUM>. Therefore, the material portion <NUM> of the present invention is prevented from being entirely broken, so that the consumption of the material portion <NUM> caused by a crack may be reduced.

Meanwhile, when the material portion <NUM> is accommodated in the seating groove <NUM>, tool entrance portions <NUM> may be formed between a space of the seating groove <NUM> and the outer contacting portions <NUM>. The tool entrance portions <NUM> are separation spaces between the material portion <NUM> that is formed in the polygonal shape and the seating groove <NUM> that is formed in a circular shape. For example, the tool entrance portions <NUM> may be spaces having a circular arc formed between a pair of outer contacting portions 13a and 13b and the inner surface of the seating groove <NUM>. When the material portion <NUM> is formed in an octagonal shape, eight tool entrance portions <NUM> may be formed. The tool entrance portions <NUM> may be spaces in which the processing tool <NUM> of the processing apparatus <NUM> enters, or may be spaces in which the processing tool <NUM> is accommodated.

In the conventional workpiece formed in the disc shape, since the conventional workpiece is in close contact with the seating table that is formed in the circular shape, a separation space cannot be formed, so that a processing tool begins processing the workpiece from a top portion of the workpiece. Therefore, when the processing tool begins in contact with the top surface of the workpiece, the workpiece may be broken since a stress is concentrated on a contact surface instantaneously. In addition, conventionally, a region where the workpiece is in close contact with the seating table or with a fixing table and a surrounding region are defined as a dead space that is a space impossible to process, so that a productivity of manufacturing a dental prosthesis is low.

However, in the dental blank <NUM> proposed in the present disclosure, by forming the tool entrance portions <NUM> between the material portion <NUM> that is formed in the polygonal shape and the seating groove <NUM> that is formed in the circular shape, since a process begins in a state in which the processing tool <NUM> enters into a side surface of the material portion <NUM>, an inserting load of the processing tool <NUM> is low and a stress concentration phenomenon may be prevented. In addition, when the processing tool <NUM> begins processing from the tool entrance portions <NUM>, a border region of the material portion <NUM> may be processed, so that the dead space of the material portion <NUM> may be reduced and production efficiency of the dental prosthesis <NUM> may increase. Moreover, when the dental prosthesis <NUM> is processed at the edge of the material portion <NUM>, since an amount of resistance applied to the processing tool <NUM> is lower than that of when the dental prosthesis <NUM> is formed at the center portion of the material portion <NUM>, an abrasion of the processing tool <NUM> may be reduced and a manufacturing speed of the dental prosthesis <NUM> may increase.

The material portion <NUM> may be a polygonal shape having four angles to <NUM> angles in a cross-section, and may preferably have an octagonal shape. Here, the octagonal shape is not a mathematically perfect octagonal shape and should be understood to mean the octagonal shape when viewed in its entirety at a glance. In the present disclosure, the term "octagonal shape" may be understood to include the former and the latter.

A diameter of the material portion <NUM> that is the longest diameter of the octagonal in a cross-section of the material portion <NUM> may be <NUM> or more, and may preferably be <NUM> to <NUM>. A thickness of the material portion <NUM>, i.e., a height of the material portion <NUM> in the z-axis direction may be <NUM> or more. The thickness of the material portion <NUM> may be smaller than the diameter of the material portion <NUM>.

As illustrated in <FIG>, the material portion <NUM> may include a guard portion <NUM>. The guard portion <NUM> may be positioned to be in contact with a side portion of the material portion <NUM>. The guard portion <NUM> is manufactured of a material such as plastic, rubber, silicone, and so on, so that the guard portion <NUM> may relieve a stress, an impact, etc., that are transferred from the processing apparatus <NUM>, thereby allowing the material portion <NUM> to be protected. The guard portion <NUM> may be attachable to and detachable from the material portion <NUM>, and may be reused.

The guard portion <NUM> may have an opening portion <NUM> at a side portion thereof. Since the opening portion <NUM> may be positioned to face the tool entrance portions <NUM>, the material portion <NUM> may be processed directly through the opening portion <NUM> even if the processing tool <NUM> begins processing during in a state in which the processing tool <NUM> is positioned at the tool entrance portions <NUM>.

As illustrated in <FIG>, the guard portion <NUM> is formed in a circular shape, and may be positioned between the seating groove <NUM> and the material portion <NUM> by surrounding the side surface of the material portion <NUM>. An outer side of the guard portion <NUM> may be in surface contact with the seating groove <NUM>, and an inner side of the guard portion <NUM> may be in linear contact with the polygonal shape of the material portion <NUM>. In this case, the guard portion <NUM> may protect the material portion <NUM> from an external force transferred from the processing apparatus <NUM>.

As illustrated in <FIG>, the guard portion <NUM> may be formed in a shape that correspond to the polygonal shape of the material portion <NUM>. For example, when the material portion <NUM> is formed in an octagonal shape, a cross-section of the guard portion <NUM> may be an octagonal shape. In this case, since the guard portion <NUM> is positioned to surround the side surface of the material portion <NUM>, a processing vibration generated while the material portion <NUM> is processed may be attenuated, and it is possible to prevent the processing vibration from spreading to the processing apparatus <NUM>.

As illustrated in <FIG>, the guard portion <NUM> may be positioned to surround a portion of the side surface of the material portion <NUM>. That is, a thickness of the guard portion <NUM>, i.e., a height of the guard portion <NUM> in the z-axis direction may be smaller than the thickness of the material portion <NUM>. In this case, when a cutting movement of the processing tool <NUM> is performed on the material portion <NUM>, interference that occurs between the guard portion <NUM> and the processing tool <NUM> may be prevented.

As illustrated in <FIG> and <FIG>, the guard portion <NUM> may be positioned at an upper portion of the material portion <NUM>. In this case, the guard portion <NUM> is positioned between the material portion <NUM> and the fixing portion <NUM>, and the material portion <NUM> may be protected from a fastening pressure that may be generated when the fixing portion <NUM> is fastened to the seating portion <NUM> by bolting.

As illustrated in <FIG>, the guard portion <NUM> may be positioned at a lower portion of the material portion <NUM>. In this case, by the guard portion <NUM> positioned between the material portion <NUM> and the seating portion <NUM>, the guard portion <NUM> absorbs a stress generated when the processing tool <NUM> processes the material portion <NUM>, so that the guard portion <NUM> may provide a cushioning effect to the material portion <NUM>.

In summary, the guard portion <NUM> may protect the material portion <NUM> by being in contact with the side portion of the material portion <NUM>, and the guard portion <NUM> may be positioned at the side surface, the lower portion, or the upper portion of the material portion <NUM>. By the dental blank <NUM> according to the present disclosure including the guard portion <NUM>, the material portion <NUM> does not directly contact the seating portion <NUM> or the fixing portion <NUM>, so that the material portion <NUM> may be protected from an external force, thereby being capable of preventing the material portion <NUM> from breakage.

Claim 1:
A dental blank comprising:
a material portion (<NUM>) inserted into a seating portion (<NUM>) that comprises a seating groove (<NUM>) having a circular shape in a cross-section, the material portion (<NUM>) comprising a plurality of outer contacting portions (<NUM>) in contact with an inner side of the seating portion (<NUM>), and the material portion (<NUM>) having a polygonal shape in a cross-section in which the polygonal shape distinct from the circular shape,
wherein the plurality of outer contacting portions (<NUM>) is in linear contact with an inner side surface of the seating portion (<NUM>) along an insertion direction where the material portion (<NUM>) is inserted into the seating groove (<NUM>), and a tool entrance portion (<NUM>) that is a separation space between the seating groove (<NUM>) and the material portion (<NUM>) is formed due to a difference in shape between the circular shape of the seating groove (<NUM>) and the polygonal shape of the material portion (<NUM>).