Dental drill

Abstract

Invention details;

Description

Dental Handpiece

[0001] The present invention relates to an air turbine dental handpiece.

[0002] In an air turbine dental handpiece, compressed air supplied from a compressor rotates an impeller installed inside the air turbine at high speed, and a cutting tool attached coaxially to the impeller cuts and / or removes caries. Generally, an air turbine dental handpiece includes a housing, an air turbine with a cutting tool installed inside the housing, and a handle-side housing attached to the housing that houses an air supply passage and an exhaust passage for the air turbine. The handle-side housing may further house a water supply passage and / or an atomizing air passage. In some cases, the water supply passage is configured to be connected to or merge with an exhaust passage.

[0003] Compressed air from the compressor is supplied to the air supply passage via an air supply circuit equipped with an air supply volume adjustment mechanism formed by the pedals of the chair unit, etc., and an air supply tube or air supply conduit connecting the air supply circuit to the air supply passage built into the handle side housing.

[0004] However, in a dental handpiece with this configuration, compressed air from the compressor rotates an impeller inside the air turbine at high speed, generating a high-pitched whine from the air turbine, which is often unpleasant to the ears of dentists and patients. Although it is desirable for patients to feel at ease during dental treatment, this can frighten the patient.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an air turbine type dental handpiece that can reduce the noise level.

[0006] The dental handpiece of the present invention comprises a housing, an air turbine built into the housing for rotating a tooth-cutting tool, and a handle-side housing attached to the housing and provided with an air supply passage and an air exhaust passage for the air turbine, and the blades of the air turbine are toroidal blades.

[0007] In this dental handpiece, the air turbine in the housing is rotated by compressed air supplied from a compressor by the practitioner, and a cutting tool attached coaxially to the shaft of the air turbine performs treatment such as cutting the patient's teeth. Because the blade is a toroidal blade (a blade with two blades connected at a bridge), the generation of large vortices around the air turbine is suppressed, thereby reducing noise. This suppresses the generation of so-called blade tip vortices, which are one of the causes of reduced rotational efficiency of the air turbine and, ultimately, the cutting tool.

[0008] In the dental handpiece having the above configuration, it is preferable that the blade is detachably attached to the shaft of the air turbine.

[0009] According to the dental handpiece having this configuration, it is possible to use a plurality of types of blades, thereby improving the convenience and ease of use of the dental handpiece.

[0010] In the dental handpiece having the above configuration, it is preferable that the cutting tool is detachably mounted coaxially on the shaft of the air turbine.

[0011] According to the dental handpiece having this configuration, it is possible to use a plurality of different cutting tools, thereby improving the convenience and ease of use of the dental handpiece.

[0012] In the dental handpiece having the above configuration, it is preferable that the turbine blade is made of at least one of an aluminum alloy, a ceramic, and a heavy metal.

[0013] The present invention relates to a dental handpiece, a toroidal blade, and a dental handpiece according to an embodiment of the present invention.

[0014] An air turbine dental handpiece 1 according to one embodiment of the present invention, shown in Fig. 1, includes a housing 11 having a substantially cylindrical internal space, an air turbine 2 housed in the housing 11 for rotating a tooth-cutting tool 4, and a handle-side housing 12 attached to the housing 11 and provided with an air supply passage 121 and an exhaust passage 122 for the air turbine 2. The handle-side housing 12 is designed to have an appropriate shape and size for easy gripping by a practitioner such as a dentist. As shown in Fig. 1, an air supply conduit 101 is connected to the air supply passage 121, and an exhaust conduit 102 is connected to the exhaust passage 122.

[0015] The upper part of the housing 11 may be formed by a cover member, and opening or removing the cover member may allow access to the interior space of the housing 11, allowing replacement of the air turbine 2 (or the shaft sheath 210 and the blades 22 formed integrally therewith).

[0016] 1 and 2 , the air turbine 2 includes a substantially cylindrical shaft 21 and N (e.g., N=4, but N may be 2, 3, 5, or more) blades 22 extending radially from the shaft 21. The N blades 22 are arranged to have N-fold rotational symmetry about the central axis of the shaft 21. The shaft 21 includes a shaft sheath 210 formed integrally with the N blades 22. The shaft sheath 210 is formed in a substantially cylindrical shape, and its inner circumferential surface is pressed against the outer circumferential surface of the shaft 21 over the entire circumference, so that it is fixed to the shaft 21. When the shaft 21 and the N blades 22 are molded integrally, or when the shaft 21 and the N blades 22 are fixed, the shaft sheath 210 may be omitted.

[0017] As shown in Fig. 1 , the shaft 21 is rotatably held relative to the housing 11 via upper ball bearings 111 and lower ball bearings 112 at the upper shaft portion 211 and the lower shaft portion 212, respectively. A cutting tool 4 is fixed to the lower shaft portion 212 coaxially with the shaft 21. The cutting tool 4 may be detachably attached to the lower shaft portion 212, for example, by fitting an upper portion of the cutting tool 4 into a hole at the bottom of the lower shaft portion 212. As shown in Fig. 1 , at least a portion of the cutting tool 4 including the file portion 40 protrudes downward from the housing 11 through a through-hole 114 provided in the bottom of the housing 11.

[0018] 2, the blade 22 is composed of a first blade portion 221, a second blade portion 222, and a bridge portion 224. The first blade portion 221 extends radially and obliquely downward from the shaft sheath 210, then bends clockwise when viewed from above, and extends in a generally L-shape. The second blade portion 222 extends radially and obliquely upward from the shaft 21, then bends counterclockwise when viewed from above, and extends in a generally L-shape. The bridge portion 224 is a portion where the distal portion of the first blade portion 221 (the portion bent clockwise) and the distal portion of the second blade portion 222 (the portion bent counterclockwise) are continuous.

[0019] The second blade portion 222 has a shape that includes the central axis of the shaft sheath 210 and is a vertically inverted mirror image of the first blade portion 221 with respect to a plane perpendicular to the direction in which the first blade portion 221 protrudes from the shaft sheath 210. The axial and circumferential relative positions (phase difference) and relative attitudes of the continuous portions or continuous regions of the first blade portion 221 and the second blade portion 222 relative to the shaft sheath 210 are adjusted so that the first blade portion 221 and the second blade portion 222 are connected by a bridge portion 224 at their distal portions. The blade 22 may be configured so that the first blade portion 221 and the second blade portion 222 are continuous such that a portion of the distal portion of the first blade portion 221 overlaps or is common to a portion of the distal portion of the second blade portion 222. In this case, the overlapping portion forms the bridge portion 224.

[0020] The blade 22 may be formed in a substantially semi-annular shape, with the twisted portion of a Möbius strip included in the middle portion. In this case, half of the substantially semi-annular portion (a substantially quarter-annular portion) constitutes the first blade portion 221 and the second blade portion 222, and the twisted portion constitutes the bridge portion 224.

[0021] The blade 22 may be made of a light metal such as aluminum (specific gravity 2.7) or various aluminum alloys (specific gravity 2.6 to 2.8), such as duralumin (specific gravity 2.8). The blade 22 may be made of ceramics such as forsterite (2MgO·SiO2) (specific gravity 3.0), silicon carbide (SiC) (specific gravity 3.16), silicon nitride (Si3N4) (specific gravity 3.3), aluminum nitride (AlN) (specific gravity 3.4), alumina (Al2O3) (specific gravity 3.8), yttria (YO3) (specific gravity 4.9), or zirconia (ZrO2) (specific gravity 6.0), or a metal composite material such as cermet (TiC·TiN) (specific gravity 6.0). The blade 22 may be made of a heavy metal such as iron (specific gravity 7.9), nickel (specific gravity 8.8), copper (specific gravity 8.9), or an alloy thereof. If the blade 22 is made of chromium or lead, it is preferable that the entire blade be plated with a non-toxic metal such as silver or nickel. Blades 22 having complex shapes can be fabricated using a three-dimensional printer and / or laser processing of raw material powder.

[0022] The blade 22 may be configured so that the specific gravities of the first blade portion 221, the second blade portion 222, and the bridge portion 224 are greater than the specific gravities of the shaft sheath 210. The blade 22 may be configured so that the specific gravities of the bridge portion 224 are greater than the specific gravities of the shaft sheath 210, the first blade portion 221, and the second blade portion 222. For example, the blade 22 may be configured from a base material such as a light metal or ceramic, and a thermally sprayed film of ceramic having a higher specific gravity than the base material is formed on a portion of the blade 22, thereby producing a blade 22 having different specific gravities in different portions. Furthermore, the blade 22 may be configured from a base material such as a heavy metal or ceramic, and a thermally sprayed film of ceramic having a lower specific gravity than the base material is formed on a portion of the blade 22, thereby producing a blade 22 having different specific gravities in different portions.

[0023] (Operation and Effect) With the dental handpiece 1 configured as described above, compressed air is supplied from the compressor to the interior space of the housing 11 through the air supply conduit 101 and the air supply passage 121 by operation by the practitioner. In the air supply circuit communicating with the compressor, the amount of compressed air supplied is adjusted by an air supply volume adjustment mechanism constituted by a pedal or the like of a chair unit. The air turbine 2 in the interior space of the housing 11 is rotationally driven by the compressed air, and treatment such as cutting of the patient's teeth is performed by the cutting tool 4 coaxially attached to the shaft 21 of the air turbine 2. The compressed air is exhausted from the interior space of the housing 11 to the outside of the dental handpiece 1 through the exhaust passage 122 and the exhaust conduit 102.

[0024] The blade 22 is a toroidal blade (a blade having a shape in which a first blade portion 221 and a second blade portion 222 are connected at a bridge portion 224 (see FIG. 2 )). This suppresses the generation of large vortexes around the air turbine 2, thereby reducing the volume of generated noise. The generation of so-called blade tip vortices, which is one of the causes of reduced rotational efficiency of the air turbine 2 and, ultimately, the cutting tool 4, can be suppressed.

[0025] (Another embodiment of the present invention) A dental handpiece 1 as another embodiment of the present invention shown in Figure 3 has the same configuration as the dental handpiece 1 of the above embodiment (see Figure 1) except for the configuration of the handle side housing 12, so the same reference numerals will be used for the similar configuration and descriptions will be omitted.

[0026] 3, the handle side housing 12 is provided with an air supply passage 121 and an exhaust passage 122 for the air turbine 2, as well as a water supply passage 124 that communicates with the external space of the handle side housing 12 and opens downwardly from the housing 11. As shown in FIG. 3, the water supply conduit 104 is connected to the water supply passage 124, and the exhaust passage 122 is arranged to merge with the water supply passage 124.

[0027] In the dental handpiece 1 having this configuration, compressed air is supplied from the compressor to the interior space of the housing 11 via the air supply conduit 101 and the air supply passage 121 by operation by the practitioner. In the air supply circuit connected to the compressor, the amount of compressed air supplied is adjusted by an air supply volume adjustment mechanism, such as a pedal on a chair unit. The compressed air rotates the air turbine 2 in the interior space, and treatment such as cutting the patient's teeth is performed using the cutting tool 4, which is coaxially attached to the shaft 21 of the air turbine 2. The compressed air is discharged from the interior space of the housing 11 to the outside of the dental handpiece 1 through the exhaust passage 122 and the exhaust conduit 102. Water is supplied from a water source to the water supply passage 124 via the water supply conduit 104. The water is atomized by the shear force of the compressed air flowing from the exhaust passage 122 to the water supply passage 124, and the atomized water is sprayed downward in the housing 11 to clean the affected area around the cutting tool 4.

[0028] Because the blades 22 are toroidal blades (blades in which the first blade portion 221 and the second blade portion 222 are connected at the bridge portion 224 (see FIG. 2 )), the generation of large vortices around the air turbine 2 is suppressed, thereby reducing the volume of noise generated. The generation of so-called blade tip vortices, which is one of the causes of reduced rotational efficiency of the air turbine 2 and, ultimately, the cutting tool 4, can be suppressed.

[0029] The dental handpiece of the present invention reduces the volume of sound generated by the high-speed rotation of the air turbine using compressed air, thereby alleviating anxiety felt by patients due to the generated sound and allowing dentists to have more technical and psychological freedom, thereby contributing to the development of the dental industry.

[0030] 1. Dental handpiece 101. Air intake conduit 102. Exhaust conduit 104. Water supply conduit 11. Housing 111. Upper ball bearing 112. Lower ball bearing 114. Through hole 12. Handle side housing 121. Air intake passage 122. Exhaust passage 124. Water supply passage 2. Air turbine 21. Shaft 210. Shaft sheath 211. Upper shaft 212. Lower shaft 22. Blade 221. First blade portion 222. Second blade portion 224. Bridge portion 4. Cutting tool 40. File portion.

Claims

DEPCT681. Dental drill incorporating: a pneumatic driven crown built into the crown and molded to rotate the cutting tool for tooth cutting; a handle end attached to the crown and provided with air delivery and exhaust passages for the pneumatic driven crown, in which the blades of the pneumatic driven crown are molded by toroidal blades; 2. Dental drill in accordance with claim 1, in which the blades are provided to be detachable from the shaft of the pneumatic driven crown; 3. Dental drill in accordance with claim 1, in which the cutting tool is provided coaxially to be detachable from the shaft of the pneumatic driven crown; 4. Dental drill in accordance with claim 1, in which the blades are made of at least one type of aluminum, ceramic and heavy metal alloy;

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