Title of Invention: BUR UNIT FOR MANUFACTURING DENTAL

WORKPIECE

Technical Field

[I] Embodiments relate to a bur unit for manufacturing a dental workpiece, and more particularly, to a bur unit for manufacturing a dental workpiece, which is configured to mill a blank material containing zirconia to a desired size to copy or imitate the upper structure of a tooth or dental implant.

Background Art

[2] Copy milling devices, for manufacturing a complicated three-dimensional workpiece, are well known in the art.

[3] As demand for the beauty of teeth increases, research has been conducted on ways to restore a tooth using the same color and shape as the natural tooth.

[4] A ceramic-metal restoration, widely used in a restoring process, forms a black line due to metal coping and low light transmittance.

[5] Thus, all-ceramic restorations are being developed and used to address this limitation.

[6] Zirconia is regarded with much interest as a material for all-ceramic restorations.

[7] A denture or artificial tooth is a prosthetic device replacing a lost natural tooth.

[8] It is difficult to process an artificial tooth containing zirconia. According to a method of manufacturing an artificial tooth containing zirconia, a sample tooth is manufactured, then, a zirconia block is cut and milled for surface grinding on the basis of the sample tooth before a sintering process, and then, the sintering process is performed at about 1500 ⁰ C to obtain a stabilized workpiece.

[9] Since the size of zirconia is reduced by about 20% to 30% after a sintering process, a milling process should be performed such that the size of zirconia is about 20% to 30% greater than the final desired size.

[10] This is difficult even for a skilled operator. In addition, it takes a long time to manufacture an artificial tooth containing zirconia, and it is substantially difficult to obtain a precise profile.

[I I] Thus, since even a minute difference of an artificial tooth may provide an uncomfortable fit for a patient or user, a precise profile is important.

[12] Since related art computer aided design/computer aided manufacturing (CAD/CAM) systems use a scanning machine controlled by a computer to perform a laser scan process on a manufactured model, skilled operating of software and an accurate prep design are required. Furthermore, expensive equipment such as CAD/CAM systems is a financial burden on an individual dental researcher or dentist.

[13] To address these limitations, a manually aided design-manually aided manufacturing

(MAD-MAM) system has been developed.

[14] Such a MAD-MAM system does not require complicated operation of software and has fewer limitations in prep design than a CAD/CAM system, and an install cost is reduced.

[15] A MAD-MAM system having the effects as described above is pivotable about a horizontal axis substantially perpendicular to a carrier plate for a blank and a model body and in a longitudinal direction of the MAD-MAM system. Such a MAD-MAM system includes a driving arm that is configured to movably connect a tracking device of a model part to a motor driven machining tool cutting a blank to form a workpiece such that the tracking device is mechanically synchronized with the machining tool.

[16] In this case, the tracking device corresponding to a guide part disposed at the carrier plate accommodating a model body and a blank precisely tracks the profile of a model body, and the machining tool corresponding to a milling unit mills the blank.

[17] At this point, burs simultaneously process the outer and inner surfaces of the blank.

The burs are respectively installed on the tracking device and the machining tool to directly process a blank material and are variously provided according to the dimensions of outer and inner surfaces of a blank material.

[18] However, since various burs classified by size are required to process the inner surface of a blank material, a process time is increased.

[19] That is, a tool is required for processing the inner surface of a blank material in a single process to have desired dimensions. Disclosure of Invention

Technical Problem

[20] Embodiments are directed to a bur unit for manufacturing a dental piece, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.

[21] It is therefore a feature of an embodiment to provide a discrete and dedicated bur unit installed on a tracking device and a machining tool to directly process a blank material, which easily tracks the inner surface of a model body and mills the inner surface of the blank material. Solution to Problem

[22] At least one of the above and other features and advantages may be realized by providing a bur unit for manufacturing a dental workpiece and including a plurality of burs respectively fixed to a tracking device (410) and a machining tool (400) for corresponding to a model body (500) and a blank (510) to be cut for copying the model body (500), the bur unit including: a guide tool (10) installed on the tracking device (410) and having a diameter corresponding to an abutment that is coupled to an inner surface of the model body (500); and a milling tool (20) installed on the machining tool (400) to cut an inner surface of the blank (510) expanded through a primary sintering process, the milling tool (20) having a diameter that is greater than that of the guide tool (10) by a shrinkage rate of the blank (510) after a secondary sintering process.

[23] The guide tool (10) may include a cylinder part (11) having a cylindrical outer surface to track the inner surface of the model body (500).

[24] The milling tool (20) may include a blade part (21) on an outer surface such that the blade part (21) rotates to cut the inner surface of the blank (510).

[25] The guide tool (10) may have the same size as an abutment coupling surface.

Advantageous Effects of Invention

[26] As described above, a bur unit for manufacturing a dental workpiece in accordance with the embodiments is configured to easily track the inner surface of a model body and simply and quickly cut the inner surface (abutment coupling surface) of a blank in a single milling process. [27] In addition, a standardized single bur is used to achieve cost reduction.

Brief Description of Drawings [28] The above and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings, in which: [29] FIG. 1 illustrates a perspective view of a copy milling device for manufacturing a dental workpiece, according to an embodiment; [30] FIG. 2 illustrates a cross-sectional view of a carrier plate on which a model body and a blank of a copy milling device for manufacturing a dental workpiece are installed, according to an embodiment; [31] FIGS. 3 and 4 illustrate a perspective view and a side view of a guide tool of a bur unit for manufacturing a dental workpiece, according to an embodiment; and [32] FIGS. 5 and 6 illustrate a perspective view and a side view of a milling tool of a bur unit for manufacturing a dental workpiece, according to an embodiment.

Mode for the Invention [33] Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. [34] FIG. 1 illustrates a perspective view of a milling device for manufacturing a dental workpiece, according to an embodiment. FIG. 2 illustrates a cross-sectional view of a carrier plate where a model body and a blank of a copy milling device for manufacturing a dental workpiece are installed, according to an embodiment.

[35] FIGS. 3 and 4 illustrate a perspective view and a side view of a guide tool of a bur unit for manufacturing a dental workpiece, according to an embodiment. FIGS. 5 and 6 illustrate a perspective view and a side view of a milling tool of a bur unit for manufacturing a dental workpiece, according to an embodiment.

[36] A bur unit of a copy milling device for manufacturing a dental workpiece is provided according to an embodiment. Burs for manufacturing a workpiece are respectively disposed at a vertical upper side corresponding to a guide part and a milling part that is disposed at a carrier plate accommodating a model body and a blank material. The burs have sizes corresponding to a standardized inner surface (abutment coupling surface) of a blank material to process the inner surface.

[37] That is, since the inner surface of a blank material has a standardized shape to be coupled to an abutment, it is unnecessary to process the inner surface of the blank material using a bur for processing an outer surface, thus reducing process time.

[38] Referring to FIGS. 1 and 2, a model body 500 and a blank 510 to be cut for copying the model body 500 are fixed to an upper surface of a carrier plate 100.

[39] That is, the model body 500 and the blank 510 are respectively and firmly adhered to rotation plates 130 fixed to the insides of a ring-shaped guide part 110 and a ring- shaped milling part 120.

[40] The carrier plate 100 is rotatably supported by a base plate 300 through supporters

200 on both sides of the carrier plate 100. An angle adjustment lever 210, for adjusting a rotation angle, is disposed at one of the supporters 200 to fix the model body 500 and the blank 510 at desired positions.

[41] The copy milling device configured as described above accurately tracks the profile of the model body 500 through a tracking device 410 disposed on the vertical upper side of the model body 500, simultaneously with cutting the blank 510 at various angles through a machining tool 400 linked with the tracking device 410.

[42] In this case, various burs classified by size are not required to process the inner and outer surfaces of a blank material, and the discrete and dedicated bur for cutting the inner surface of a blank is provided to facilitate the processing of the inner surface of a blank material.

[43] That is, the discrete and dedicated bur group is installed on the tracking device 410 and the machining tool 400 to easily track the inner surface of a model body and mill the inner surface of a blank material.

[44] Since the burs of the bur unit are respectively fixed to the tracking device 410 and the machining tool 400 to correspond to the model body 500 and the blank 510 to be machined for copying the model body 500, the bur unit includes a guide tool 10 that is installed on the tracking device 410 and that has a diameter corresponding to an abutment coupled to the inner surface of the model body 500.

[45] The bur unit includes a milling tool 20 that is installed on the machining tool 400 to cut the inner surface of the blank 510 expanded through a primary sintering process, and that has a greater diameter than that of the guide tool 10 by a shrinkage rate of the blank 510 after a secondary sintering process.

[46] The milling tool 20 simply and quickly processes the inner surface (abutment coupling surface) of the blank 510 through a single cutting process.

[47] Referring to FIGS. 3 and 4, the guide tool 10 of the bur unit fixed to the tracking device 410 includes a cylinder part 11 having a cylindrical outer surface that is not processed to track the inner surface of the model body 500.

[48] Referring to FIGS. 5 and 6, the milling tool 20 fixed to the machining tool 400 includes a blade part 21 on an outer surface thereof. The blade part 21 rotates to cut the inner surface of the forming blank 510.

[49] The guide tool 10 has the same size as the inner surface of the model body 500, and the milling tool 20 has a greater diameter (about 20% to 30% greater) than that of the guide tool 10 by a shrinkage rate of the blank 510 after the secondary sintering process.

[50] That is, after a blank material having an about 20% to 30% greater diameter in a primary sintering process is copy-milled, the inner surface of the blank material is restored to its own size through a secondary sintering process. Thus, the inner surface of the blank material should be processed through an initial milling process to have an about 20% to 30% greater size than its original size.

[51] Exemplary embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.