JPH02140157A - dental bur - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dental bur used for grinding teeth, crowns, etc.

[Prior Art] In general, a conventional dental bur has the following features as shown in FIG.
A metal layer is formed on the surface of the base metal a by plating method,
By holding the abrasive grains C by this metal layer, the abrasive grains C are fixed to the base metal a.

[Problems to be Solved by the Invention] None of the conventional dental burs described above satisfies both lifespan and grinding performance at the same time, and when one is improved, the other becomes worse.

That is, from the viewpoint of service life, it is desirable to make the density of the abrasive grains C high. However, when the density of the abrasive grains C is increased, the distance between two adjacent abrasive grains c and c becomes narrower.
There is a problem that chips may get stuck between the abrasive grains c and c, and as a result, the grinding performance deteriorates. On the other hand, if the density of the abrasive grains C is made coarser, the grinding performance will improve, but since the amount of grinding per abrasive grain will increase, the abrasive grains will wear out early and the life of the tooth bar will be shortened. . In particular, unlike grinding wheels for machining, dental burs have a very small diameter, usually less than 1 mm. becomes extremely small. For this reason, the amount of grinding of each abrasive grain C increased excessively, and early wear of the abrasive grain C was more remarkable than in a grindstone for machining.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a dental bur that can improve both life span and grinding performance at the same time.

[Means for Solving the Problems J] In order to solve the above problems, the present invention forms a metal layer on the surface of the base metal and holds the abrasive grains by this metal layer, thereby transferring the abrasive grains to the base metal. In the dental bur that is fixed to the first held by both layers of the secondary metal layer
There are a method-rolled grain and a second method-rolled grain which is held by a second metal layer so as to be located between the first method-rolled grain, and the first method-rolled grain and the second method-rolled grain. have almost the same diameter, and the first
It is characterized in that the diameter is set larger than the total thickness of the secondary metal layer and the secondary metal layer.

1 Effect] Since the diameters of the first rolled grain and the second rolled grain are larger than the total thickness of the first metal layer and the second metal layer,
Both the rolled grains and the second rolled grains protrude outward from the second metal layer and are simultaneously subjected to grinding. However, since the diameters of the first rolled grain and the second rolled grain are the same,
The protrusion height of the second rolled grains relative to the second metal layer is higher than the protrusion height of the first rolled grains by the amount of the first metal layer.

Therefore, the amount of grinding of the second method grain is greater than the amount of grinding of the first method grain. In other words, the second process grain performs the main grinding,
The first process grain will perform sub-grinding.

In addition, since the protrusion height of the second method rolled grain is higher than that of the first method rolled grain, in other words, the protrusion height of the first method rolled grain is higher than the projection height of the second method rolled grain. Therefore, a void surrounded by the first method grain and the second method grain adjacent thereto is formed above the first method grain. This void becomes a chip pocket for chips ground by the second grain rolling process.

In this way, since both the first and second abrasive grains can be used for grinding, the life of the toothed bar can be improved by increasing the total density of both abrasive grains. can. Further, since chip pockets are formed around the second process grains that are subjected to main grinding, clogging with chips caused by the second process grains can be prevented, and grinding performance is also improved.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 2 shows a dental bur A according to the present invention, and reference numeral 1 indicates a rod-shaped base metal. A cylindrical shank portion 1a is formed at one end of this base metal, and a tapered portion 1b is formed at the other end. A metal layer is formed on this tapered portion lb by a plating method, and abrasive grains are fixed by this metal layer, thereby forming a grindstone portion 2.

FIG. 1 is an enlarged cross-sectional view of a part of the grinding wheel section 2.
A first metal layer 3 and a second metal layer 4 made of nickel or the like are sequentially formed on the surface of the tapered portion 1b by a plating method. A large number of first rough grains 5 are held and fixed by the first metal layer 3 and the second metal layer 4, and a large number of second rough grains 6 are held and fixed by the second metal layer 4.

In this case, the first method grains 5 and the second method grains 6 are dispersed almost uniformly and in a mixed state. Therefore, most of the first rolled grains 5 and the second rolled grains 6 are arranged adjacent to the other grain.

All of the abrasive grains 5 and 6 are made of diamond, cubic boron nitride, etc., and although they have different shapes, they have approximately the same diameter (same mesh).

Moreover, the diameter is larger than the total thickness of the first metal layer 3 and the second metal layer 4. Therefore, both abrasive grains 5 and 6 protrude from the second metal layer 4 to the outside. Further, since the abrasive grains 5 and 6 have substantially the same diameter, the second grain 6 protrudes more than the first grain 5 by the thickness of the first metal layer 3. In other words, the amount of protrusion of the first rolled grains 5 is smaller than the amount of projection of the second rolled grains 6, and as a result, on top of the blown abrasive grains 5 of the box 1, the first rolled grains 5 and A void surrounded by the adjacent second rolled grains 6 is formed. This space serves as a chip pocket 7 for storing chips generated by the second process grain 6.

When teeth or the like are ground by the dental bur A having the above configuration, the abrasive grains 5 and 6 grind simultaneously. However, since the second method rolled grains 6 protrude more than the first method rolled grains 5, the amount of grinding thereof increases, and main grinding is performed. On the contrary, the amount of grinding of the first method elongated grains 5 is small, and sub-grinding is performed. In this case, regarding the second method grains 6 that perform main grinding, since the first method grains 5 are located between the second method grains 6, the abrasive grain density is coarse. Therefore, its grinding performance is improved. Moreover, the chip pocket 7 is provided in the second method rolled grain 6.
Since this is provided, there is no risk of chips clogging, and this can further improve the grinding performance. Further, the grinding is not performed only by the second method grain 6, but also by the first method grain 5. Therefore, compared to the case where only the second method grains 6 are used, the abrasive grain density becomes denser by the amount of the first method grains 5, and the grinding load on the second method grains 6 is reduced.

Therefore, the life of the dental bur A can be improved.

Note that FIG. 3 is a cross-sectional view showing the blade portion 2 after the second processed grain 6 has fallen off, and grinding is possible even in this state. Therefore, also from this point of view, the life of this dental bur A is improved. Note that a recess 8 is formed in the second metal layer 4 at a portion where the second rolled grain 6 has fallen off. This concave portion 8 becomes a chip pocket of the first method rolled grain 5. Therefore, the grinding performance is good. However, in this state, the service life is reduced by the coarser abrasive grain density.

Next, a method for manufacturing the dental bur A will be described.

FIG. 9 shows an apparatus for manufacturing the dental bur A, and reference numeral 11 in the figure is a plating tank. This plating tank 11 contains an electrolytic solution 12 in which a metal such as nickel is dissolved. electrolytic? An ion-permeable ceramic container 13 and an electrode plate 14 are immersed in the ffl 12 .

To manufacture the dental bur A using the above-mentioned apparatus, first, a large number of abrasive grains 15 made of diamond or the like are placed in a container 13, and then this container 13 is immersed in the electrolytic solution 12. Next, the base metal 1 is inserted into the abrasive grains 15. At this time, base metal 1
The shank portion 1a is masked to prevent a metal layer from being deposited.

In the inserted state, as shown in FIG. 4, among the large number of abrasive grains 15, the density of the abrasive grains 15 that are in contact with the surface of the tapered portion 1b of the base metal 1 or very close to this surface is low.

In this state, by passing a current between the base metal 1 and the electrode plate 14, the primary metal layer 3 is deposited on the surface of the tapered portion 1b of the base metal 1. This primary metal layer 3 fixes the abrasive grains 15 near the surface of the tapered portion 1b to the base metal 1. Note that the thickness of the first metal layer 3 is 5 to 5 times the diameter of the first rolled grains 5.
It is desirable to set it to 30%, especially about 20%.

Next, the base metal 1 is removed from the container 13 and rubbed with a brush, or the base metal 1 is inserted into the abrasive grains 15 and ultrasonic vibrations are applied to the base metal 1 or the electrolyte 12. Brush off excess abrasive grains 15 from gold 1. At this time, as shown in FIG.
Items that are buried or where only the sharp parts are buried have weak holding power by the primary metal layer 3, so they are removed from the primary metal layer 3 by the above-mentioned scraping operation (8th figure). Therefore, as shown in FIG.
Only the abrasive grains 15 that are in contact with the primary metal layer 3 in a stable posture, are deeply buried in the primary metal layer 3, and are firmly fixed remain. This is the first rolled grain 5.

Next, when the base metal 1 is pulled out from the container 3, the tapered portion 1b of the base metal 1 is again buried in the abrasive grains 15 in the container 3. Further, when the base metal 1 is subjected to ultrasonic vibration while being buried in the abrasive grains 15, the buried state is maintained. Base metal 1
The arrangement state of the abrasive grains 15 relative to the base metal 1 changes by re-inserting the base metal 1 or by ultrasonic vibration. As a result, new abrasive grains 15 are placed between the first rolled grains 5, as shown in FIG.

After this, a new metal layer, ie the second metal layer 4, is deposited in the same manner as above. This secondary metal layer 4 allows the abrasive grains 15 that are in contact with or in the vicinity of the first metal layer 3 to
to fix. The abrasive grains 15 fixed at this time are the second method elongated grains 6.

Note that the total thickness of the first metal layer 3 and the second metal layer 4 is preferably 45 to 70% of the diameter of the abrasive grains 5 (6). In particular, the thickness of the primary metal layer 3 is set to 20% of the diameter of the abrasive grains 5.
%, the thickness of the secondary metal layer 4 is preferably about 40% of the diameter of the abrasive grains 5, and the total thickness is preferably about 60%.

Next, pull out the base metal 11 from the container 3 and remove the excess abrasive grains 15.
By brushing off the tooth bar A is obtained.

[Effects of the Invention] As explained above, according to the dental bur of the present invention,
The first and second rolled grains are separated by the first and second metal layers.
The second rolled grains are held and fixed by the second metal layer, and the first rolled grains and the second rolled grains have the same diameter and are different from each other. Since the bur is larger than the total thickness, it is possible to simultaneously improve the life of the dental bur and the grinding performance.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention. Figure 1 is an enlarged sectional view of the main part, Figure 2 is an overall view, and Figure 3 is where the second method grain has fallen off. 1 and 4 to 9 are diagrams for explaining the method of manufacturing a dental bur of the present invention, and FIG. 4 shows a base metal in abrasive grains. Figure 5 is a cross-sectional view showing the state after the first metal layer has been formed and removed, and Figure 6 is a cross-sectional view showing the state after the first metal layer has been formed and removed. A cross-sectional view showing the state in which the abrasive grains are inserted into the abrasive grains to form a second metal layer, FIG. 7 is a cross-sectional view showing the state in which the abrasive grains are held by the first metal layer, and FIG. FIG. 9 is a sectional view similar to FIG. 7, FIG. 9 is a sectional view showing an example of a manufacturing apparatus used in carrying out the manufacturing method, and FIG. 10 is a sectional view similar to FIG. 1 showing a conventional toothed bar. be. ■... Base metal, 3... First metal layer, 4... Second metal layer, 5... First rolled grain, 6... Second rolled grain.

Claims (1)

[Claims] In a dental bar in which a metal layer is formed on the surface of the base metal and the abrasive grains are held by this metal layer, the abrasive grains are fixed to the base metal. There is a secondary metal layer formed on the outside of the abrasive grains, and the abrasive grains include the primary abrasive grains held by both the primary metal layer and the secondary metal layer, and the There are secondary abrasive grains held by a secondary metal layer so as to be located between the abrasive grains, and the primary abrasive grains and the secondary abrasive grains have approximately the same diameter, and A dental bur characterized by having a diameter larger than the total thickness of a secondary metal layer and a secondary metal layer.