METHOD FOR POLISHING ARTIFICIAL TOOTH AND DEVICE FOR POLISHING ARTIFICIAL TOOTH

Abstract

An artificial tooth 30 to be polished is fixed at a tooth neck 32 side and rotated about a tooth axis 33. Abrasives, preferably elastic abrasives formed by kneading abrasive grains into or supporting abrasive grains on an elastic material, are ejected together with a compressed gas at an ejection pressure of from 0.1 MPa to 0.5 MPa onto an occlusal portion 31 side of the artificial tooth 30 while the artificial tooth 30 is being rotated. The abrasives are ejected at an inclination angle with respect to the tooth axis 33 of the artificial tooth 30 of from 0 to 90, and preferably from 15 to 75. Portions on the occlusal portion 31 and side surfaces 38 of the artificial tooth 30 are thereby polished at the same time by the abrasive sliding over these portions.

Claims

1. A method for polishing artificial teeth comprising: fixing an artificial tooth to be polished at a tooth neck side of the artificial tooth, and rotating the artificial tooth about a tooth axis of the artificial tooth; and polishing an occlusal portion and a side surface of the artificial tooth by ejecting an abrasive together with compressed gas through a blast nozzle having a tip pointing toward the occlusal portion of the rotating artificial tooth, with the blast nozzle inclined so that an inclination angle of a central axis of the blast nozzle with respect to the tooth axis is from 0 to 90.

2. The method according to claim 1, wherein an elastic abrasive formed by dispersing abrasive grains within an elastic material, or an elastic abrasive formed by adhering abrasive grains to a surface of a core formed from an elastic material, is employed as the abrasive.

3. The method according to claim 1, wherein the abrasive is ejected in a state in which the central axis of the blast nozzle is inclined so that an inclination angle with respect to the tooth axis is from 15 to 75.

4. The method according to claim 1, wherein: a plurality of artificial teeth are moved along a common movement path; the tip of the blast nozzle which is common to the plurality of teeth is placed so as to point toward a treatment position at a predetermined position on the movement path, so that the tip of the blast nozzle points toward the occlusal portion of the artificial tooth present at the treatment position.

5. The method according to claim 1, further comprising a step for mounting a spindle acting as an axis of rotation at the tooth neck side of the artificial tooth coaxially with the tooth axis, and wherein: the artificial tooth is an artificial tooth including a hollow portion open on the tooth neck side of the artificial tooth; and the spindle is mounted to the artificial tooth by heating to soften a thermoplastic material that softens at a temperature at or below 100 C., filling the hollow portion of the artificial tooth to be polished with the thermoplastic material from the tooth neck side of the artificial tooth, and after inserting one end of the spindle into the softened thermoplastic material, cooling to harden the thermoplastic material.

6. The method according to claim 1, wherein the artificial tooth is an artificial tooth of a molar single crown manufactured from a resin containing an inorganic filler.

7. A device for polishing artificial teeth comprising: a support tool including a head for fixing an artificial tooth to a tooth neck side of the artificial tooth, the support tool rotating the artificial tooth fixed to the head about a tooth axis; and a blast nozzle that ejects an abrasive together with compressed gas, the blast nozzle including a tip pointing toward a position where an occlusal portion of the artificial tooth fixed to the head of the support tool is placed, and a central axis of the blast nozzle being inclined so that an inclination angle with respect to a rotation axis of the head is from 0 to 90.

8. The device according to claim 7, wherein the inclination angle of the central axis of the blast nozzle with respect to the rotation axis of the head is from 15 to 75.

9. The device according to claim 7, comprising: a plurality of the heads moving along a single same movement path; and the blast nozzle which is common to the plurality of heads, the blast nozzle being placed so that the tip points toward a treatment position at a predetermined position on the movement path of the heads.

10. The method according to claim 2, wherein: a plurality of artificial teeth are moved along a common movement path; the tip of the blast nozzle which is common to the plurality of teeth is placed so as to point toward a treatment position at a predetermined position on the movement path, so that the tip of the blast nozzle points toward the occlusal portion of the artificial tooth present at the treatment position.

11. The method according to claim 2, further comprising a step for mounting a spindle acting as an axis of rotation at the tooth neck side of the artificial tooth coaxially with the tooth axis, and wherein: the artificial tooth is an artificial tooth including a hollow portion open on the tooth neck side of the artificial tooth; and the spindle is mounted to the artificial tooth by heating to soften a thermoplastic material that softens at a temperature at or below 100 C., filling the hollow portion of the artificial tooth to be polished with the thermoplastic material from the tooth neck side of the artificial tooth, and after inserting one end of the spindle into the softened thermoplastic material, cooling to harden the thermoplastic material.

12. The method according to claim 4, further comprising a step for mounting a spindle acting as an axis of rotation at the tooth neck side of the artificial tooth coaxially with the tooth axis, and wherein: the artificial tooth is an artificial tooth including a hollow portion open on the tooth neck side of the artificial tooth; and the spindle is mounted to the artificial tooth by heating to soften a thermoplastic material that softens at a temperature at or below 100 C., filling the hollow portion of the artificial tooth to be polished with the thermoplastic material from the tooth neck side of the artificial tooth, and after inserting one end of the spindle into the softened thermoplastic material, cooling to harden the thermoplastic material.

13. The method according to claim 2, wherein the artificial tooth is an artificial tooth of a molar single crown manufactured from a resin containing an inorganic filler.

14. The method according to claim 4, wherein the artificial tooth is an artificial tooth of a molar single crown manufactured from a resin containing an inorganic filler.

15. The method according to claim 5, wherein the artificial tooth is an artificial tooth of a molar single crown manufactured from a resin containing an inorganic filler.

16. The device according to claim 8, comprising: a plurality of the heads moving along a single same movement path; and the blast nozzle which is common to the plurality of heads, the blast nozzle being placed so that the tip points toward a treatment position at a predetermined position on the movement path of the heads.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0052] The objects and advantages of the invention will become understood from the following detailed description of preferred embodiments thereof in connection with the accompanying drawings in which like numerals designate like elements, and in which:

[0053] FIG. 1 is a perspective view from the front of a polishing device of the present invention;

[0054] FIG. 2 is a perspective view from the side of a polishing device of the present invention;

[0055] FIG. 3 is an explanatory diagram of a polishing method of the present invention;

[0056] FIGS. 4A and 4B are explanatory diagrams of polishing a crown, FIG. 4A is when polished under conditions of the present invention, and FIG. 4B is when polished under conditions lying outside the scope of the present invention;

[0057] FIG. 5 is an explanatory diagram of a conventional polishing device (JP2015-223325A); and

[0058] FIGS. 6A and 6B are explanatory diagrams of an artificial tooth, FIG. 6A is a front view of a molar crown, and FIG. 6B is a cross-section of the molar crown.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] A description follows regarding embodiments of the present invention, with reference to the appended drawings.

[0060] Polishing Subject

[0061] The subject of polishing by the polishing method of the present invention is an artificial tooth used in dentistry. There are no limitations to the type of artificial tooth used in dentistry, and the polishing method is applicable to various types of artificial tooth.

[0062] Examples of such types of artificial tooth include artificial teeth to be fitted directly to anchor teeth such as crowns or bridges, as well as artificial teeth that are employed by embedding in a denture base such as artificial teeth used for false teeth (dentures), and artificial teeth that are fitted to a patient through a member other than an anchor tooth, such as artificial teeth used in implants, artificial teeth serving as upper structures mounted on artificial roots through abutments, and the like. Preferably application is made to an artificial tooth 30 that includes a hollow portion 36 open on a tooth neck 32 side thereof, such as a crown or bridge, or artificial teeth serving as the upper structure of implants.

[0063] Types of artificial teeth include replicas of incisors, canines, and molars corresponding to natural teeth types, and these may all be subjected to treatment by the polishing method of the present invention.

[0064] Moreover, materials for artificial teeth include various materials such as metals, ceramics, resins, and the like, and the polishing method of the present invention is applicable to artificial teeth manufactured from any of these materials, and is also applicable to artificial teeth of various other known materials for artificial teeth.

[0065] The durability of artificial teeth differs according to the material thereof. Artificial teeth manufactured from a resin are the most inferior in terms of durability compared to artificial teeth manufactured from a metal or a ceramic as mentioned above. This tendency is also similar for artificial teeth manufactured from a composite resin, called a hybrid resin or the like, in which resistance to wear is improved by blending in a filler made from synthetic silica, ceramic, or the like. The effects of lowered strength etc. due to wall thinning from over polishing is most significantly apparent in artificial teeth manufactured from a resin, including artificial teeth manufactured from a hybrid resin.

[0066] The reduction in strength due to wall thinning is generally a significant problem that occurs with crowns that include a hollow portion 36 for inserting an anchor tooth into and that have a hollow interior. Uneven polishing is liable to occur in artificial teeth replicating molars, where there are cusps 31a that are protrusions and fissures 31b that are indentations on an occlusal surface 31.

[0067] The polishing method of the present invention is able to uniformly polish without unevenness even artificial teeth that include indentations and protrusions such as artificial teeth for molars, is not liable to polish the inside of the hollow portions 36 as described later even when applied to crowns, and is able to prevent over polishing of margin portions 34 etc. as described later. Thus, although not limited thereto, the polishing method of the present invention is applicable to polishing molar crowns manufactured from a resin, and in particular CAD/CAM crowns manufactured from a hybrid resin, for which there is an increasing demand for high volume polishing with increasing demand resulting from transitioning from a leading edge treatment to a treatment covered by health insurance.

[0068] In the following description, unless stated otherwise, an example will be described of a case in which the polishing method of the present invention is applied to polishing CAD/CAM crowns (molars) manufactured from a hybrid resin.

[0069] Polishing Device

[0070] (1) Overall Configuration

[0071] An example of a configuration of a polishing device 1 used in the polishing method of the present invention is illustrated in FIG. 1 and FIG. 2.

[0072] The polishing device 1 illustrated in FIG. 1 and FIG. 2 is what is referred to as a blasting apparatus for treating workpieces by ejecting abrasives together with compressed gas (compressed air). The polishing device 1 includes a cabinet 10 that serves as an equipment housing and forms an interior space serving as a treatment chamber 11, and a blast nozzle 20. The blast nozzle 20 inside the treatment chamber 11 formed within the cabinet 10 ejects abrasives together with compressed gas onto artificial teeth 30 to be polished.

[0073] The treatment chamber 11 is formed with a hopper 12 having an inverted trapezoidal shaped lower section for catching the abrasives 60 ejected through the blast nozzle 20. The treatment chamber 11 is configured to recover, in the hopper 12, fallen abrasives 60 ejected into the treatment chamber 11. The recovered abrasives 60 can then be re-ejected through the blast nozzle 20 via an abrasive feed pipe 13.

[0074] In the illustrated embodiment, the blasting apparatus is configured with a suction type of blast nozzle 20, as illustrated in the enlarged cross-section in FIG. 2. In what is referred to as a suction type model, a negative pressure is generated in a mixing chamber 23 by compressed gas introduced through the rear end of the blast nozzle 20 being ejected toward a nozzle tip 22 by a jet 21. The abrasives 60 inside the hopper 12 are sucked by the negative pressure through the abrasive feed pipe 13. This configuration enables the sucked abrasives 60 to be mixed with the compressed gas in the mixing chamber 23 and ejected through the nozzle tip 22.

[0075] The illustrated embodiment is an example of the polishing device 1 of the present invention configured by a suction type blasting apparatus. However, a blasting apparatus to be employed in the polishing device of the present invention may employ various known configurations of blasting apparatus instead of the suction type illustrated.

[0076] Examples of such blasting apparatuses are commercially available and include a gravity type blasting apparatus that causes abrasives falling from a non-illustrated abrasive tank disposed in an upper section of the cabinet 10 to be carried and ejected by compressed gas, a direct pressure type blasting apparatus in which compressed gas is introduced into a tank filled with abrasives and the abrasives are ejected by merging the flow of abrasives from the abrasive tank with a compressed gas flow from a separately provided compressed gas supply source, and a blower type blasting apparatus that carries and ejects the compressed gas flow from a direct pressure type blasting apparatus with a gas flow generated by a blower unit. Any one of the above may be employed to configure an abrasive accelerator in the polishing device 1 of the present invention.

[0077] Note that the reference numeral 14 in FIG. 1 and FIG. 2 indicates a dust collector. The dust collector 14 is configured such that dust mixed with exhaust from air sucked out from inside the treatment chamber 11 through an exhaust pipe 15 is caught in a filter 14a provided inside the dust collector 14. Clean air from which the dust has been removed is then exhausted.

[0078] (2) Support Tool

[0079] In the polishing method of the present invention, as illustrated in FIG. 3, the artificial teeth 30 to be polished are fixed at the tooth neck 32 side thereof. The artificial teeth 30 are each rotated about a tooth axis 33, and abrasives are ejected together with compressed gas toward the occlusal portion 31 of each of the rotating artificial teeth 30.

[0080] In order to enable the abrasive to be ejected in such a state, the polishing device 1 employed in the polishing method of the present invention includes support tools 40 for supporting the artificial teeth 30 inside the treatment chamber 11, and for rotating each of the artificial teeth 30 about the tooth axis 33.

[0081] As illustrated in the enlarged illustration in FIG. 1, the support tools 40 each include a rotatable head 41 to mount the artificial tooth 30 to be polished on. The artificial tooth 30 to be polished is fixed in a predetermined position so as to be rotatable about the tooth axis 33, by mounting the artificial tooth 30 to the head 41 such that a rotation axis 42 of the head 41 and the tooth axis 33 of the artificial tooth 30 are disposed coaxially.

[0082] Mounting of the artificial tooth 30 to the head 41 may be achieved by any method that enables the fixed state of the artificial tooth 30 to be maintained even when the mixed flow of the compressed gas and the abrasives ejected from the blast nozzle 20 is being blown onto the artificial tooth 30. The illustrated embodiment is an example in which a tool 45 including a support base 45a and a spindle 45b is prepared. In this example, the artificial tooth 30 is fitted to the support base 45a of the tool 45 such that the tooth neck 32 side of the artificial tooth 30 is fixed to the tool 45. The tool 45 is mounted and fixed by a mechanical chuck 43 or a magnetic chuck (not illustrated in the drawings) provided to the head 41 of the support tool 40.

[0083] The tool 45 may be mounted to the artificial tooth 30 by, as described in the related art, fixing the artificial tooth to a tool provided with a plaster support base using an adhesive. However, when the artificial tooth 30 to be polished is an artificial tooth including a hollow portion 36 open on the tooth neck 32 side, such as a crown, the tool 45 equipped with the support base 45a and the spindle 45b as described above can be fixed to the artificial tooth 30 in the following manner. The hollow portion 36 is filled from the tooth neck 32 side with a thermoplastic material in a state softened by heating. Such a thermoplastic material is configured by a blend of a synthetic resin that softens at a temperature at or below 100 C., at about 60 C. for example, a natural resin, a wax, beeswax, or the like. After the spindle 45b has been inserted into the filled thermoplastic material, the support base 45a described above is formed by cooling to harden the thermoplastic material inside the hollow portion 36 by, for example, ejecting a coolant as a cold spray.

[0084] By forming the support base 45a using the thermoplastic material filled in the hollow portion 36 in the above manner, the artificial tooth 30 can be strongly fixed by hardening the thermoplastic material. Moreover, after polishing is finished, the tool 45 can be easily detached by softening or dissolving the thermoplastic material configuring the support base 45a by heating to a temperature at or below 100 C., for example, by cleaning with warm or hot water.

[0085] In the polishing device 1 of the present embodiment, each one of a plurality of the support tools 40 described above is further installed at regular intervals along the peripheral edge of a turntable 50, in a configuration in which the heads 41 of the support tools 40 can be moved along a single same movement path by rotating the turntable 50.

[0086] Mounting each of the artificial teeth 30 to the heads 41 of the respective support tools 40 in the configuration described above results in a configuration in which each of the artificial teeth 30 mounted to the heads 41 can be sequentially moved to a treatment position P provided at a predetermined position on the movement path as the turntable 50 is rotated.

[0087] Rotation of the turntable 50 may be achieved by a configuration in which the turntable 50 is intermittently rotated by an angle predetermined according to the number of the support tools 40 mounted, after the elapse of intervals of the time required to polish each of the artificial teeth, so as to sequentially polish each individual artificial tooth 30 that has been moved to the treatment position P. Alternatively, a configuration may be employed in which the turntable 50 is continuously rotated at a predetermined rotation speed, so as to treat plural of the artificial teeth 30 at the same time by blowing the abrasive sequentially onto the artificial teeth 30 as they pass the treatment position P.

[0088] For example, the present embodiment employs a configuration in which the heads 41, and hence the artificial teeth 30, are rotated at a rotation speed of from 4 to 100 min.sup.1 (rpm), and the turntable 50 is rotated by an angle of 72 each of a set treatment time for each artificial tooth elapses (every 2 minutes, for example), such that each of the artificial teeth 30 is disposed at the treatment position P and polished for 2 minutes. However, instead of such a configuration, a configuration may be adopted in which plural artificial teeth are polished by continuously rotating the turntable 50 at a predetermined rotation speed.

[0089] (3) Blast Nozzle Placement

[0090] As illustrated in FIG. 3, the blast nozzle 20 that ejects abrasives onto the artificial tooth 30 mounted to the head 41 of the support tool 40 is placed such that the tip 20a of the blast nozzle 20 points toward the occlusal portion (occlusal surface) 31 of the artificial tooth 30 mounted to the head 41 of the support tool 40, and such that an inclination angle of a central axis 24 of the blast nozzle 20 with respect to the rotation axis 42 of the head 41, and hence with respect to the tooth axis 33 of the artificial tooth 30, is from 0 to 90.

[0091] Namely, in the polishing device 1 of the present invention, the placement range of the blast nozzle 20 is a range indicated by the bold arrow in FIG. 3.

[0092] The inclination angle is more preferably set at from 15 to 75, such that the abrasives are incident at an angle to both the occlusal surface 31 and the side surfaces 38 of each of the artificial teeth 30.

[0093] In a configuration in which a single support tool 40 is installed inside the treatment chamber 11, as illustrated in FIG. 3, the blast nozzle 20 may be placed at the position and angles described above with respect to the single support tool 40. However, in a configuration of the polishing device 1 of the present embodiment in which the plural support tools 40 are installed at even separations around the peripheral edge of the turntable 50 as described above, the tip 20a of the blast nozzle 20 is disposed pointing toward the treatment position P provided at the predetermined position on the movement path of the heads 41. The tip 20a of the blast nozzle 20 is thereby pointed in the direction and angle described above toward the artificial tooth 30 that has been moved to the treatment position P, from out of the plural artificial teeth 30 mounted to the respective support tools 40.

[0094] (Polishing Conditions)

[0095] (1) Abrasives Employed

[0096] Various types of known abrasives may be employed as the abrasives employed in the polishing method for artificial teeth of the present invention performed with the polishing device 1 as described above. Various types of abrasive grain may be employed in the polishing method of the present invention, including metal-based, mineral-based, ceramic-based, resin-based, glass-based, and plant-based grains. The substance and the particle diameter of the abrasive may be suitably selected according to the material and the finishing state of the artificial teeth to be polished.

[0097] Preferably an elastic abrasive is employed as the abrasives employed in the polishing method of the present invention.

[0098] Elastic abrasives include structures in which abrasive grains are adhered to the surface of cores formed from an elastic material, and structures in which abrasive grains are kneaded into an elastic material. An elastic abrasive with either of these structures may be employed with the polishing method of the present invention.

[0099] Moreover, various materials are proposed as elastic materials for use in elastic abrasives, such as rubber and elastomers, as well as materials configured by gelatin, glucomannan, or the like. The polishing method of the present invention is obviously able to employ such materials, and may also employ various known elastic abrasives using other elastic materials.

[0100] Though the particle diameter of the elastic abrasive employed is not particularly limited when using an elastic abrasive, preferably an elastic material with an average particle diameter of from 200 m to 1000 m is employed. This enables polishing to be performed right to the bottom of indentations, even in cases in which the artificial teeth to be polished have indentations such as fissures present in the occlusal surfaces, as is the case with molars.

[0101] Moreover, the substance and particle diameter of the abrasive grains kneaded into the elastic material, or adhered to the surface of cores formed from the elastic material, may be suitably selected according to the material and finishing state of the artificial teeth to be polished. However, abrasive grains having an average particle diameter from several m to several tens of m are preferably employed in order to achieve a glossy finish or a mirror finish, and the elastic abrasive that have abrasive grains of smaller particle diameters kneaded therein, or adhered thereto, may employed in a stepwise manner according to the state of polishing.

[0102] (2) Ejection Conditions

[0103] The abrasives are ejected together with the compressed gas onto the artificial tooth 30 described above through the blast nozzle 20 that has been placed at the position and angles described above.

[0104] The compressed gas employed to eject the abrasives may be compressed air, and may also be a compressed gas of an inert gas such as argon or nitrogen. However, it is advantageous to use compressed air from the perspective of cost.

[0105] The ejection pressure of the compressed gas employed to eject the abrasive should be selected from a range of 0.1 MPa to 0.5 MPa based on the material and treatment time of the artificial teeth 30 to be polished (i.e., time for ejecting the abrasives to the artificial teeth 30 to be polished) as well as the particle diameters and the substance of the abrasive employed, and the like.

[0106] The treatment time needs to be suitably adjusted according to the material and shape of the artificial teeth to be polished, and the substance and particle diameter of the abrasive (abrasive grains) employed. However, the treatment time for each individual artificial tooth is from several tens of seconds to several minutes, approximately.

[0107] (Operation Etc.)

[0108] By pointing the tip 20a of the blast nozzle 20 toward the occlusal surface 31 of the artificial tooth 30, and by ejecting the abrasives together with the compressed gas in a range in which the inclination angle of the central axis 24 of the blast nozzle 20 with respect to the tooth axis 33 is from 0 to 90, as described above, the compressed gas ejected through the blast nozzle 20 impacts the artificial tooth 30, and then forms a flow along the surface of the artificial tooth 30.

[0109] As a result, the abrasives ejected together with the compressed gas move along with the flow of the compressed gas, and the surface of the artificial tooth 30 is polished by the abrasives sliding over the surface of the artificial tooth 30.

[0110] Due to ejecting the abrasives in the ejection direction described above, a flow of abrasives is generated at the side surfaces 38 of the artificial tooth 30, flowing from the occlusal surface 31 side of the artificial tooth 30 toward the tooth neck 32 side thereof as illustrated in FIG. 4A. An edge 35 portion of the margin portion 34 is accordingly polished by a natural transition from the margin portion 34 toward the support base, and wall thinning etc. due to over polishing of the margin portion 34 can be prevented.

[0111] Moreover, due to the flow of the abrasives being generated in this manner from the occlusal surface 31 side to the tooth neck 32 side, the entry of abrasive into the hollow portion 36 is not liable to occur even in cases in which polishing is performed in a state in which the hollow portion 36 has not been sealed off Falling out or loose fitting due to polishing an internal wall 37 of the hollow portion 36 can accordingly be prevented.

[0112] On the contrary thereto, when the abrasives are ejected toward the tooth neck 32 from a position in which the inclination angle exceeds 90, not only would the occlusal surface 31 not be polished, but a flow of the abrasives at the side surface 38 portion of the artificial tooth 30 would be generated from the tooth neck 32 side to the occlusal surface 31 side, as illustrated in FIG. 4B, thereby the margin portion 34 and the edge 35 of the margin portion 34 are ground by the abrasives. Accordingly, the strength would be decreased due to wall thinning of the margin portion 34, and a not-flat portion would appear between the anchor tooth and the edge 35 of the margin portion 34 after being fitted.

[0113] Moreover, when polishing is performed in a state in which the hollow portion 36 of the artificial tooth 30 is either unsealed, or insufficiently sealed, the abrasive would enter into the hollow portion 36 and the internal wall 37 would be polished. This would give rise to a concern regarding falling out or loose fitting after being fitted. However, the polishing method of the present invention is able to prevent such a decrease in strength, prevent a not-flat portion from appearing, and prevent loose fitting from occurring.

[0114] Moreover, in the polishing method of the present invention, polishing to a glossy finish or a mirror finish can be achieved due to abrasives entering even into fine indentations present on the surface of the artificial tooth 30, such as fissures 31b formed in the occlusal surface 31 of the artificial tooth 30. This enables all the portions of the artificial tooth 30 to be polished in a single polishing device, without separately performing polishing of the fissures 31b by manual operation, or the like.

EXAMPLES

[0115] Examples of polishing tests in which artificial teeth were polished by the polishing method of the present invention will now be illustrated by Examples.

[0116] (Test Method)

[0117] Polishing was performed by the polishing method of the present invention on artificial teeth manufactured from a resin (Example 1), on artificial teeth manufactured from a metal (Example 2), and on artificial teeth manufactured from a ceramic (Example 3). The materials of each of the artificial teeth and the polishing conditions are listed in Table 1.

[0118] Note that the artificial teeth that were treated were all crowns replicating molars.

TABLE-US-00001 TABLE 1 Materials of Artificial Teeth and Polishing Conditions Example 1 Example 2 Example 3 Material Hybrid resin Cobalt-chrome Zirconia (hardened resin in which silica powders having a major particle diameter of 10 m or less are contained) Abrasive Sirius Z, manufactured by Fuji Manufacturing Co., Employed Ltd. (an elastic abrasive in which abrasive grains kneaded into an elastomer). Average particle diameter: 800 m. Abrasive Grains: Diamond #10000 (D50: 0.6 m) Blasting Suction type (see FIG. 1 and FIG. 2) Apparatus Angle 30 30 30 between nozzle and tooth axis Ejection 0.2 MPa 0.3 MPa 0.3 MPa Pressure Ejection 20 mm 20 mm 20 mm Distance Rotation Speed 4 min.sup.1 30 min.sup.1 50 min.sup.1 of Artificial Teeth Treatment Time 2 min/tooth 3 min/tooth 3 min/tooth

Test Results

(1) Example 1

[0119] The surface roughness of artificial teeth as per Example 1 (polishing artificial teeth manufactured from hybrid resin) was measured before and after polishing using a contact needle type of surface roughness measuring instrument (manufactured by Tokyo Seimitsu Co., Ltd.). The results thereof are listed in Table 2 together with the results of observing the state of glossiness with the naked eye.

TABLE-US-00002 TABLE 2 Surface Roughness Before and After Polishing (Artificial Teeth Manufactured from Hybrid Resin) Ra (m) Before Polishing Ra (m) After Polishing Occlusal Surface 0.82 0.08 Side Surface 1.73 0.56 Glossiness None Good

[0120] It is apparent from the above results that the surface roughness can be greatly improved and polishing can also achieve a state of good glossiness by polishing artificial teeth manufactured from a hybrid resin using the polishing method of the present invention. The finishing polish of the artificial teeth can also be achieved in an extremely short duration of 2 minutes per tooth.

[0121] Moreover, there was absolutely no polishing reaching the hollow portion of the artificial teeth observed after polishing, and no wall thinning or deformation (such as retreating peripheral edge) observed at the margin portion after polishing. A polished state was achieved in which there were no concerns of cracks and breaks, wobbling, appearance of a not-flat portion against the anchor tooth, or the like after being fitted.

[0122] Note that a finish giving a feeling of excellent glossiness could similarly be obtained in the artificial teeth after polishing for Example 2 (polishing a crown manufactured from a metal) and for Example 3 (polishing a crown manufactured from ceramic). The polishing method of the present invention was confirmed to be suitably applicable to performing a finishing polish of artificial teeth, irrespective of the material of the artificial teeth.

[0123] Thus the broadest claims that follow are not directed to a machine that is configure in a specific way. Instead, said broadest claims are intended to protect the heart or essence of this breakthrough invention. This invention is clearly new and useful. Moreover, it was not obvious to those of ordinary skill in the art at the time it was made, in view of the prior art when considered as a whole.

[0124] Moreover, in view of the revolutionary nature of this invention, it is clearly a pioneering invention. As such, the claims that follow are entitled to very broad interpretation so as to protect the heart of this invention, as a matter of law.

[0125] It will thus be seen that the objects set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

[0126] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

[0127] Now that the invention has been described;

DESCRIPTIONS OF REFERENCE NUMERALS

[0128] 1 polishing device [0129] 10 cabinet [0130] 11 treatment chamber [0131] 12 hopper [0132] 13 abrasive feed pipe [0133] 14 dust collector [0134] 14a filter [0135] 15 exhaust pipe [0136] 20 blast nozzle 20 [0137] 20a tip (of blast nozzle) [0138] 21 jet [0139] 22 nozzle tip [0140] 23 mixing chamber [0141] 24 central axis [0142] 30 artificial tooth (crown) [0143] 31 occlusal portion (occlusal surface) [0144] 31a cusps [0145] 31b fissures [0146] 32 tooth neck [0147] 33 tooth axis [0148] 34 margin portion [0149] 35 edge [0150] 36 hollow portion [0151] 37 internal wall [0152] 38 side surface [0153] 40 support tool [0154] 41 head [0155] 42 rotation axis [0156] 43 chuck [0157] 45 tool [0158] 45a support base [0159] 45b spindle [0160] 50 turntable [0161] 60 abrasive [0162] 100 polishing device [0163] 101 first rotation shaft [0164] 102 second rotation shaft [0165] 103 holder [0166] 104 abrasive tank [0167] 130 artificial teeth (crown) [0168] 131 occlusal portion (occlusal surface) [0169] 131a cusp [0170] 131b fissure [0171] 133 tooth axis [0172] 134 margin portion [0173] 135 edge [0174] 136 hollow portion [0175] 137 inner wall [0176] 138 side surface [0177] 145 tool [0178] 145a plaster support base [0179] 145b spindle [0180] 160 abrasive [0181] 170 anchor tooth [0182] 171 shaft face [0183] P treatment position [0184] M motor [0185] inclination angle