GB2371488A

GB2371488A - Dental handpiece

Info

Publication number: GB2371488A
Application number: GB0024611A
Authority: GB
Inventors: Jason Julian Greenwood
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-10-06
Filing date: 2000-10-06
Publication date: 2002-07-31
Also published as: GB0024611D0

Description

DENTAL HANDPIECE

The present invention relates to a method of manufacture of a dental handpiece and to a dental handpiece.

There are presently two types of dental handpiece: high speed and low speed. The present invention particularly addresses problems associated with manufacture of high speed handpieces, but is applicable to both types.

Conventional high speed handpieces comprise a head, housing a bearing cartridge for driving a dental bur, and an integrally formed handle. The bearing cartridge includes a compressed air driven turbine. In order to reduce the build up of heat when the bur is driven against a tooth an outlet is provided on the head through which water is sprayed towards the bur when in use. An outlet for air is also usually provided. The air helps to atomise the water and can be used on its own for drying or dusting an area being worked on. A problem can arise where a tooth or other object obscures the passage of water onto the bur. To reduce the likelihood of this it is known to provide two or three water outlets from which water is sprayed towards the bur from different directions.

To facilitate working in a patient's mouth the head of a conventional handpiece usually includes a light source, typically an optical fibre bundle.

A single light source can, however, lead to an undesirable shadow being cast by the bur, or a tooth, making working difficult. To overcome this it is known to provide more than one, or a diffuse, light source.

It will be appreciated, therefore, that the head of a dental handpiece must include conduits to conduct compressed air to and from the bearing cartridge, to drive the bur, and to conduct air, water and light to at least two outlets for each on the head of the handpiece. The head must also be sufficiently compact to use in the mouth of a patient, and be able to withstand repeated sterilisation in an autoclave. It is also usually desirable that the bearing cartridge can be removed for repair or replacement.

Some low speed handpieces include an electric motor and thus need to carry a supply of electric current.

Known types of high speed dental handpieces are cast or machined from metal. The head of the handpiece includes a machined recess for receiving and housing a bearing cartridge. A conduit along which compressed air is supplied to the bearing cartridge may be machined into the handpiece, but otherwise the handpiece is hollow and tubes for carrying air and water and optical fibres for carrying light must pass through the handpiece to suitable outlets in the head around the bearing cartridge, whilst allowing the bearing cartridge to be removed. Installing these tubes and fibres may necessitate machining of the handpiece, for instance to make an aperture for a tube to pass through, and generally makes manufacture of the handpiece time consuming and expensive.

Conventional manufacturing techniques also restrict the positioning of air, water and light outlets on the head of a handpiece.

It is known to form handpieces from plastics materials, but similar problems to those with metal handpieces are still encountered in installing and positioning the necessary tubes and fibres.

The present invention has been made in consideration of these problems.

According to the present invention there is provided a method of manufacture of at least the head of a dental handpiece comprising the steps of: providing a mould ; placing at least one conduit into a predetermined position in the mould ; and introducing material into the mould to form at least the head of a handpiece in which the conduit is incorporated.

According to another aspect of the present invention there is provided at least the head of a moulded dental handpiece, including at least one conduit encapsulated therein.

By conduit is to be understood a construction, for example a tube, optic fibre or electrical cable, which allows a fluid, light or electrical current to be conducted through the resulting handpiece.

The invention allows handpieces to be made with conduits in situ, overcoming the problems associated with conventional manufacturing techniques. The method allows conduits to be sited and, particularly, to be terminated at more convenient locations than before. The manufacturing technique is also more economic and convenient than some conventional techniques through avoidance of the need for machining of metal and for difficult installation of conduits in a handpiece subsequent to manufacture of the handpiece.

Preferably the at least one conduit is positioned so that it extends between two points on the surface of the handpiece or between a point on the surface of the handpiece and a bearing cartridge or electric motor. The handpiece preferably includes one or more of the following : a conduit for air for driving a bearing cartridge, a conduit for conducting exhaust air from a bearing cartridge, a conduit for conducting water to be directed onto a bur, a conduit for conducting air to be directed on to a bur, an optical fibre and an electrical cable.

A bearing cartridge may also be placed into the mould prior to introduction of the material. This may then become permanently encapsulated in the handpiece. The bearing cartridge is preferably connected to feed and return air conduits prior to introduction of the material into the mould. An electric motor connected to a suitable electric cable could be similarly introduced into the mould. The saving in cost resulting from the invention is such that it is sufficiently economic to replace a bearing cartridge or electric motor by replacing a complete handpiece.

Including a bearing cartridge or motor during moulding allows accurate positioning of the cartridge or motor, and likewise for conduits around the cartridge or motor. It is preferred that air, water and light sources are arranged generally evenly spaced around the cartridge in the head of the handpiece. More preferably two or three air, water and light sources are arranged around the head. In one embodiment a plurality of optic fibre ends form a ring around the cartridge.

There are various industry standard couplings for connecting dental handpieces to compressed air and the like supplies. A suitable coupling is preferably introduced into the mould and conduits connected thereto prior to the introduction of material into the mould.

The material is preferably a plastics material, more preferably a plastic-ceramic or metal powder reinforced plastic material. The material will preferably withstand repeated sterilisation in an autoclave.

The invention discussed above relates both to a complete handpiece and to just the head of a handpiece. This is because the present invention also provides a dental handpiece comprising releasably connectable handle and head portions. This allows a head manufactured in accordance with the invention to be mounted on a handle including a lamp for directing light along an optic fibre disposed in the head, but also has general application.

A single handle can be reused with many heads.

According to another aspect of the present invention therefore there is provided a dental hand piece comprising two releasably connectable portions.

In one embodiment one portion comprises a head and a handle defining a cavity for receiving a second portion. The second portion includes a light source and the first portion includes optic fibres arranged to conduct light from the second portion, when inserted into the cavity, to outlets on the head of the first portion.

In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example, with reference to the accompanying drawings of which: Figure 1 is a plan view of part of a mould ; Figure 2 is a view of the mould of figure 1 with various components introduced therein; Figure 3 is a view of a dental handpiece according to the invention; Figure 4 is a view of another dental handpiece according to the invention; Figure 5 is a view of a still further dental handpiece according to the invention; and Figure 6 is a view of an alternative embodiment of a head of a dental handpiece.

Referring to figures 1 to 3 a dental handpiece according to the invention is produced using a mould. One part of the mould 1 is shown in

figure 1. It includes a cavity 2 of suitable shape to form a dental handpiece. Another part (not shown) of the mould is placed against the illustrated part 1 to form a complete cavity into which molten material is then injected to form a handpiece. The two parts can then be separated to allow the moulded article to be removed.

Prior to closing the mould, however, a bearing cartridge 3, a connector 4 and various conduits 5 are positioned in the mould. The connector 4 will be used to connect the finished handpiece to appropriate air, water and light supplies. Each conduit 5 is connected to the connector 4. Two of the conduits are for conveying compressed air to and from the bearing cartridge 3 and are, accordingly, connected to the bearing cartridge 3. The remaining conduits are for conveying air, water and light to the head of the handpiece and are positioned in chosen positions in the mould. The conduits for conveying light comprise optical fibre bundles.

The mould may include means for positioning the conduits 5, bearing cartridge 3 and connector 4. In particular, the mould may include projections over which or apertures into which the free end of the air water and light conduits may be inserted to retain them in position during the injection of material into the mould.

Once the various components 3,4, 5 are in place the mould is closed and molten plastic ceramic material is injected into the mould cavity 2. The material is then allowed to solidify before the mould is opened to allow a handpiece 6 to be removed. The handpiece 6 comprises a handle portion 7 from which the connector 4 protrudes and a head portion 8 including an aperture 9 into which a dental bur may be inserted to engage it with the bearing cartridge 3. Surrounding the bearing cartridge 3 and spaced at approximately 120 degree intervals are the ends of three air 10, water 11 and light 12 conduits. Providing three spaced outlets for air, water and light reduces the incidence of shadowing of air, water or light during use of the handpiece.

The method according to the invention allows a dental handpiece to be formed in one operation, as well as permitting better positioning of water air and light outlets around the head.

Referring to figure 4 a handpiece may be made from two separate, releasably connectable portions: a handle portion 13 and a head portion 14.

The head portion 14 is manufactured in a similar manner to the handpiece shown in figure 3 and includes a connector 15 which enables it to be releasably connected to the handle portion 13. The handle portion 13 could be manufactured like the handpiece shown in figure 3 or using conventional techniques. The handle portion 13 could include a lamp.

Another embodiment of a handpiece comprising two separate releasably connectable components is shown in figure 5. Referring to figure 5 the handpiece comprises a first portion 16 including a head and handle, the handle defining a cavity 17 shown by dashed lines, and a second

portion 18. The first portion 17 includes optic fibres running between openings 19 in the head and cavity 17. The second portion 18 is configured to be inserted into the cavity 17 in the first portion 16 and includes a lamp which directs light through openings 20. The openings 20 are arranged so that when the second portion 18 is inserted into the cavity 17 in the first portion 16 light is picked up by the optic fibres terminating in the cavity 17 and transmitted to the head of the first portion 16. Having the second portion 18 largely contained in the first portion 16 when in use can allow improved hygiene over the arrangement illustrated in figure 4.

The first 16 and second 18 portions are arranged to be releasably engaged. The second portion 18 includes a coupling 21 to enable it to connect to a conventional air and water supply. Air and water may also be conducted between the second 18 and first 16 portions, to outlets on the head of the first portion 16.

Figure 6 shows the head of a dental handpiece with an alternative arrangement of air, water and light outlets. Referring to the figure the head includes a central drive 22 for receiving a bur, three circumferentially spaced air and water outlets 23 and a ring of optic fibre ends 24. The ring of fibre ends 24 is formed from a single strand or ribbon, comprising a plurality of fibres, in the body of the handpiece which splits into individual fibres in the head.

The above embodiments are described by way of example only, many variations are possible without departing from the invention.

Claims

CLAIMS 1. A method of manufacture of at least the head of a dental handpiece comprising the steps of: providing a mould ; placing at least one conduit into a predetermined position in the mould ; and introducing material into the mould to form at least the head of a handpiece in which the conduit is incorporated.
2. A method as claimed in claim 1, wherein a bearing cartridge is placed into the mould prior to introduction of the material.
3. A method as claimed in claim 2, wherein the bearing cartridge is connected to feed and return air conduits prior to introduction of the material into the mould.
4. A method as claimed in claim 1, wherein an electric motor is placed into the mould prior to introduction of the material.
5. A method as claimed in any preceding claim, wherein a coupling is introduced into the mould and conduits connected thereto prior to the introduction of the material into the mould.
6. A method as claimed in any preceding claim, wherein the material is a plastics material.
7. At least the head of a moulded dental handpiece, including at least one conduit encapsulated therein.
8. At least the head of a moulded dental handpiece manufactured by a method as claimed in any of claims 1 to 6.
9. Apparatus as claimed in either claim 7 or 8 including one or more of the following : a conduit for air for driving a bearing cartridge, a conduit for conducting exhaust air from a bearing cartridge, a conduit for conducting water to be directed on to a bur, a conduit for conducting air to be directed on to a bur, an optical fibre and an electrical cable.
10. Apparatus as claimed in any of claims 7 to 9, wherein the at least one conduit is positioned so that it extends between two points on the surface of the handpiece or between a point on the surface of the handpiece and a bearing cartridge or electric motor.
11. Apparatus as claimed in claim 10 when dependent on claim 9, wherein air, water and/or light sources are arranged generally evenly spaced around the cartridge or electric motor in the head of the handpiece.
12. Apparatus as claimed in claim 11, wherein at least two air, water or light sources are arranged around the head of the handpiece.
13. Apparatus as claimed in either claim 11 or 12, wherein a plurality of optic fibre ends are arranged in a ring around the cartridge or electric motor.
14. A dental handpiece as claimed in any of claims 7 to 13 comprising releasably connectable handle and head portions.
15. A dental handpiece as claimed in claim 14, wherein the handle

includes a lamp for directing light along an optic fibre disposed in the head.
16. A dental handpiece as claimed in any of claims 7 to 13 comprising a first portion comprising a head and a handle and defining a cavity for receiving a second portion.
17. A dental handpiece comprising two releasably connectable portions.
18. A dental handpiece as claimed in claim 17, wherein one portion comprises a head and a handle and defines a cavity for receiving a second portion.
19. A dental handpiece as claimed in claim 18, wherein the second portion includes a light source and the first portion includes optic fibres arranged to conduct light from the second portion, when inserted into the cavity, to outlets on the head of the first portion.
20. A method of manufacture of at least the head of a dental handpiece substantially as herein described with reference to Figures 1 to 3 of the accompanying drawings.
21. A dental handpiece substantially as herein described with reference to any of Figures 3,4, 5 or 6 of the accompanying drawings.