WO2008068380A9

WO2008068380A9 - Console for devices and dental care unit

Info

Publication number: WO2008068380A9
Application number: PCT/FI2007/050635
Authority: WO
Inventors: Arto Huotari; Jari Koponen; Mika Tarvainen; Lauri Nordlund; Godzinsky Christian De
Original assignee: Planmeca Oy; Arto Huotari; Jari Koponen; Mika Tarvainen; Lauri Nordlund; Godzinsky Christian De
Priority date: 2006-11-22
Filing date: 2007-11-22
Publication date: 2008-08-28
Also published as: ES2666943T3; EP2088983A1; EP2088983A4; DK2088983T3; JP5631002B2; EP2088983B1; WO2008068380A1; JP2010510014A

Abstract

The invention relates to a dental care unit and its device holder unit. In the device holder unit, there are device- places and the device-places are arranged such that the device holder unit can be fitted with different and/or different types of devices. Preferably, in a device hose, or in a device connected to a hose, there is a colour identifier, and the device-places of the device holder unit are provided with optical sensors capable of colour separation, which sensors are arranged to identify the colour identifier in question. The invention enables implementing the device order of the console such that places of the devices in the console are freely changeable.

Description

CONSOLE FOR DEVICES AND DENTAL CARE UNIT

The invention relates to dental care units. Especially, the invention relates to device holder units of dental care units, in which devices needed in dental care can be stored during treatment. Most particularly, the invention relates to a device holder unit in the use of a dental assistant, which unit typically comprises a so-called suction holder unit, but is also applicable to a device holder unit in the use of a dentist. The device holder units typically include arranged side by side several device-places, which comprise device holders.

Two basic types of devices are typically connected to dental care units: instruments (e.g. a micro motor/a turbine (a drill), a sealer, a curing unit, a syringe etc.) and, on the other hand, suction devices for removing saliva and byproducts of treatment from the mouth. The instruments and the suction devices are connected to the central unit of the dental care unit by hoses. The hoses of the suction devices are typically semi-rigid tubes, whereby they can be used for suction purpose by means of negative pressure created at the other end. The hoses of the instruments can include, according to the instrument type, inter alia, water connections, air connections and electric wires.

The device holder unit or console is typically a device in the use of either the dental assistant or the dentist, in which one may place devices and from which they are easily taken into use for operations. Most typically, the device holders are set side by side in the holder unit.

There are, again, two basic types of device holders: open and closed. An open holder refers to a holder from which the device as well as its hose can be freely removed. A closed holder refers to a holder from which the device can be removed so that its hose still passes trough the holder. Furthermore, the holders for instruments and suction devices have unique properties of their own, inter alia, with respect to the geometry of their holding zone and different hose thickness required by different device types.

In order for the dental care operation to be fluent, the dental care units commonly include such a functionality that, when the device is removed from its holder, the dental care unit identifies removal of the device and performs some preparatory actions, e.g. starts a suction pump located downstream of the suction hose. This function can be called activation. For enabling the function in question, the device console thus has to include detectors for detecting if the device lies in its holder or not. In this document, activating a device of a dental care unit refers to a measure in which the user takes one device from the console and the dental care unit identifies this as a choice of the device. Identifying is a necessary step in case there are more than one such a device to choose which are controlled by a single control or in case activation of the device relates to some automatically starting action.

The identification of activation can be implemented in many different ways. Most commonly used are the following identification techniques

mechanical identification (e.g. microswitch) , - mechanical-optical or optical (IR) switch (light port), inductive or capacitive identification.

Microswitch identification is based on a button, locating in the holder, which is pressed by an instrument or a suction head when being placed in the holder. The microswitch can only be utilised in open holders from which the hose is removed for the duration of use. In through-rolling holders, the hoses may cause faulty identifications when hitting the microswitch. The inductive/capacitive identification is based on recognising the electric properties of the device. It functions in open as well as closed holders but requires that the device to be identified and/or its hose is especially designed for this purpose because, e.g. electrically non- conductive material cannot be detected by this method (e.g. suction heads/sealer handpieces) .

Prior art optical methods can only be used in open holders, since when the hose of the device rolls through a closed holder, no such substantial change occurs in the surroundings of the holder which could be reliably detectable by a light port, for example.

According to the prior art, out of the above-mentioned identification techniques, the most suitable arrangement for each device and respective device holder is always chosen according to the properties of the device and the device holder, and also taking into consideration the cost effects of the arrangement. This, and the other functions and properties mentioned above related to the device holder and the devices, set limitations for the conceivable places for the devices in the console.

The object of the invention is to provide an improved device console for dental care units, especially for facilitating the work of dental care personnel and for enhancing the versatility of the console, and a dental care unit comprising an improved device console.

A device console (device holder unit) according to the invention comprises at least two device-places, which device- places are arranged such that at least two devices used in dental care, or two different device types, can be fitted in the device console. Each device-place further comprises a device holder for keeping the device in place in the device console. Furthermore, the order of the devices or device types in the device console is changeable and the device holder unit comprises means for identifying the device set in the device-place, or its type, when the device is set in the holder. The identification of the device/device type is performed especially by means of optical sensors capable of colour separation.

According to the invention, the device console comprises e.g. a housing and several device holders connected to the housing, whereby means for identifying devices and/or device types set in the device-places are located in the housing to observe the device-places. Thus, when changing places of the devices, said means can transmit a new device order of the console from the device console to the control of the dental care unit. Also, when a device is removed from its holder, said means can transmit an activation signal to the control.

A dental care unit according to the invention comprises at least one device console as well as a central unit in which device hoses for using devices needed in dental care, to be set in the device holders of the device console, are connected. Said device hoses and their respective device holders are typically designed for at least two different device types, such as suction devices and instruments, to be connected to the dental care unit. The device console comprises means for identifying the device, or its type, set in the device-place when the device is set in the holder.

Most preferably, identification of the device or its type is based on a specific colour identifier (or lack of a colour identifier) placed in the device or especially preferably in the device hose. In the system of two device types, there should thus be an identifier in the devices or hoses of the other device type at least. Preferably, the identifier is a colour code arranged to the end of the device hose close to the device, i.e. it is arranged to an area which remains inside or in proximity of the device holder when the device lies in its place. Correspondingly, a sensor capable of colour separation is used as identification means, such as a light source - detector configuration utilising two or several different wavelength ranges. The sensor is located in the device holder unit such that light emitted by the light source/sources is arranged to reflect or scatter from the device set in the device holder, or from its hose, to the detector.

In identification of the device type, if the colour identifier is e.g. on the suction hoses, there is no need to use a separate identifier in the instrument hoses. On the other hand, if there are several device types to be identified, they can have their own colour codes for which the identification means are sensitive. Further applied, the invention thus enables identification of not only the device type order but also the order of individual devices.

The identifier is most preferably local, whereby it is detected only when the device lies still in its holder. Contrary to e.g. a light port or a mechanical switch, such an identification arrangement is also applicable to be used in the case of closed device holders, because the change in activation mode is detected when the hose is being pulled out (the identifier exits from the vicinity of the sensor) .

According to one preferable embodiment, the device holders are detachable from the housing, whereby there are arranged in the housing means for receiving device holders re- detachably.

Considerable advantages are attained by means of the invention. Namely, identification of the order of setting of the individual devices or device types in the console allows for a quick reprogramming of the dental care unit any time the device order in the console is changed. Therefore, the handedness of the console, and further of the whole dental care unit, can easily be changed e.g. due to the routines or left/right handedness of the dentist or the dental assistant. Identifying the instrument type enables sending of a correct activation signal to the control unit of the device despite the changed device order in the console.

Earlier, for each device and especially for each device type, there has been in the device console a certain, defined place in which there is a unique activation identifier designed for that device. Thus, there has been no need to identify the device type. In the arrangement according to the invention, identification of the device type prevents changing of the device order in the console leading to an incorrect activation identification signal and thus to an incorrect activation of a device.

It should be noted that means according to the invention for identifying the type of a device set in the device holder is applicable for identifying at the same time if the device is in its place in the holder or removed from it. Therefore, no separate activation identifiers are needed.

The term 'device type' primarily refers to the division commonly used in dental care for separating suction devices and instruments. After reading a detailed description of the invention, those skilled in the art understand that the invention can be applied more extensively also in the case of other divisions of device types. Furthermore, the invention can also be used for identifying individual devices in the device console (e.g. for distinguishing two instruments of the same type, such as two turbines, from each other) .

In suction device consoles, suction devices are almost always set in closed device holders, because the quite rigid hoses of them may thus be kept under better control during treatment. Above-described deficiencies relating to identification technique have, nevertheless, limited changing the placing order of devices in the console. By means of different embodiments of the invention, especially this deficiency related to prior art can be eliminated. More generally, it also provides an advantage in instrument consoles which are used by the dentist. Thus, also typical instruments of the dentist, such as a drill, a syringe, a dental imaging camera, a UV curer or corresponding special instruments, can be handled totally as device types of their own.

An optical sensor capable of colour separation refers here primarily to a sensor which is capable of spectrally separating surfaces of different colours, i.e. at least two surfaces of different colours, from each other. Such a sensor thus utilises, in addition to the intensity of a reflected or scattered ray, also information on the spectral intensity- distribution of the ray.

Next, embodiments of the invention will be described in more detail with reference to the accompanying figures in which

Fig. 1 shows a perspective view of a device console provided with five device holders,

Fig. 2 shows, as an example, an exploded view of one device holder and a sensor arrangement related to that,

Figs. 3a-3f show perspective views in stages of the configuration of the sensor arrangement according to Fig. 2,

Fig. 4 shows, as an example, a side view of an optical beam pattern of the sensor arrangement,

Fig. 5 shows a lateral cross section of one possible sensor arrangement,

Fig. 6 demonstrates the problem lying in the background of the invention, and

Figs. 7a and 7b show perspective views of a configuration of a device console comprising adjacent device-places and sensor modules in connection with it. Fig. 1 shows one device console 10 to which, by means of an example, five device holders 12, 13, 14, 15 and 16 are connected. The holders 12 and 13 are typical open instrument holders and they are shown in the figure as turned at different angles. The holders 14 and 15 are typical open suction device holders, which are also shown in different positions. The holder 16 is a closed suction device holder, which differs from the open holders by that the hose passing through the holder does not come off the holder during use of the device but 'rolls' over a roller arranged in it.

Fig. 6 demonstrates, by means of an example, one possible console configuration with devices connected to it. The device holders are designated with letters A-E. The holders C and D are open, the others are closed. Suction devices (dark ones) are designated with letters I_n, whereas instruments with letters i_n. The arrow at the bottom of the figure depicts the possibility of changing the order of device holders.

The holder order configurable by the user necessitates that in each device-place there is an identification means which is capable of identifying suction hoses/suction devices and instrument hoses/instruments from each other. By simple optical or mechanical identification, i.e. by switches, by light ports or by solely measuring the intensity of reflection, one is not able to get the desired end result. Use of light ports and mechanical switches is ruled out by the fact that the geometry of the suction hoses/suction devices and the instrument hoses/instruments is quite similar. A reflection, on the other hand, does not separate the devices from each other as their level of gloss-level may vary quite freely. Especially by means of these techniques, the simultaneous identification of the device type and activation mode is not attained in closed holders: a reflection would occur regardless whether the hose as a whole lies in the holder or is pulled out. Below, one generic arrangement for he device type identification will be described in more detail, i.e. one taking into consideration all the degrees of freedom of the console arrangement at hand.

We have discovered that the use of colour identifiers and the identification capable of colour separation resolve both the problem of type and activation identification in a reliable and cost-effective manner. For example, if a ring connected to the suction hose is stained with a colour different from the rest of the hose, it is possible to identify from it if the suction hose is in its holder or pulled out. By means of the same identification means, it is possible to see if a device in an open holder is in the holder or removed from the holder. If one desires to provide an arrangement in which there are devices of both device-types in closed holders, their hoses can be coded different from each other (e.g. device type 1: grey hose, blue code; device type 2: red hose, grey (free) code). No change is required in the detector.

An applicable detector can be manufactured in many different ways. The basic principle is to send light towards the device or the hose of the device by a first element and to detect reflected light by a second element. The elements are mutually arranged such that appropriately different colour surfaces give a different response at the detector. The elements can be narrow or broadband or e.g. double channel (two sources with different bands) . From the signal of the detector, a certain wavelength or band or several wavelengths or bands is/are selected, out of which the colour of the reflective surface can be deduced. Most preferably, identification is done by comparing intensities of two wavelength bands with each other.

Referring now to Figs. 2 (and 3), one embodiment utilises two light sources 206, 208 (306, 308) of a different wavelength range, preferably LED lights, and a detector 210 (310) sensitive to these wavelength ranges, preferably a photodiode. The light sources 206, 208 (306, 308) and the detector 210 (310) are located such that light emitted by the light sources is arranged to reflect from the device set in the device holder 202 (302), or from its hose, to the detector. Light from the light sources can be directed in a desired direction by means of a prism 218 (318) or some other optical conductor. The prism may be, in a way shown by the figures, common for both light sources and double, whereby one accomplishes an extremely compact sensor structure. Components and other electronics that may be required can be placed on a circuit board 228 (328). The optics unit thus obtained is placed in a module 204, (304) to be arranged in the device console. In the module, there is an opening or openings 222 for light. The module may be placed in a support 224 (324) of the console. The device holder 202 (302) is placed into proximity of the module such that an optical connection with the device or hose placeable in the holder remains. The legs of the light sources 206, 208 (206, 308) are attached on the circuit board 208 (308) (not shown) . The implementation and assembly providing the desired effect may vary even considerably from the one shown in the figures.

The above-described embodiment has proven favourable and well suitable for colour separation in addition to which it enables manufacturing of a detector which is extremely narrow in lateral direction. The advantage of a multiple prism is that it properly scatters the light beams, whereby a more consistent light is provided on the target. Thus, the geometric tolerance of the placement of the colour identifier and the detector increases.

Correspondingly, it is possible to use light sources of different colours and a broadband detector, a broadband light source and a multi-band detector.

The embodiment shown in Fig. 5 comprises a transmitter 58 implemented with a white LED, whose signal is evaluated by means of two pairs of very close located photodiodes 59 and filtered for blue and red light. This technique has proven favourable and functioning.

Preferably, wavelength ranges clearly apart from each other are used, e.g. blue and red light, and correspondingly blue or red identifiers. Those skilled in the art understand that, by means of the technique described, it is also possible to implement a sensor applicable to reliably separate even more colours.

The colour identifiers are preferably plastic or metal sleeves or labels placed on the device-hose or connector or around them, whereby 360° identification is possible. The staining of the sleeves may be performed in a way known as such, e.g. by painting or anodising. For guaranteeing reliable operation of the identifiers, the specular reflection of their identifiable wavelength is preferably at least 1%, most preferably at least 10%. On the other hand, measuring can also be based on scattering of light from a surface or even on a secondary light i.e. fluorescence or phosphorescence .

In a preferable embodiment of the invention, the 'depth vision' of the optical sensoring is limited, preferably e.g. with an arrangement as shown in Figs. 4 and 5, in order for the sensors 40, 50 not to pick up error signals e.g. from the clothes of the care personnel, or the like, which fall in the vicinity of the holder. Preferably, the depth of vision of the optical sensor is limited to the area of a holder 42. Limiting the depth vision according to Figs. 4 and 5 is based on the angular position of the beams 44, 54 of the light sources and a beam 46, 56 seen by the detector with respect to each other. The angle is preferably 2-45°, typically 5- 25°. As the beams have a limited spread angle, their intersection area is limited. Therefore, the colour surface to be identified has to fall within this intersection area. The length D of the identification area can be e.g. 1-3 cm, i.e. of the same order of magnitude as the diameter of the hoses and the holder.

If the spread angles of the beams of the light sources or the detector are naturally large, such as is the case generally with semiconductors, the spread angle of the beams is limited preferably by means of a collimator or collimators set between the components and the target. The collimators are preferably located in the housing or connecting elements of the sensor, or in the shell of the console. In Fig. 5, the collimators are designated with reference numbers 51 and 52. In the middle of the beam, also the intensity is at its highest and undesired azimuthal reflections can be minimised.

The dental care unit can be arranged to automatically learn, or identification of the device types can be taught to it in a situation in which all suction and instrument hoses are in their places. When being taught, the dental care unit may identify targets strongly reflecting a certain colour, e.g. blue, as suction hoses and ones reflecting e.g. grey scales

(e.g. blue and red) as instruments. For teaching, the apparatus preferably comprises a button, during pressing of which the learning is performed. Alternatively, learning may take place e.g. in connection with starting the apparatus or in connection with some other specified operation (e.g. the change of the handedness of the device and/or the running of the dental chair to a treatment position) . If the mutual order of the devices of a certain device-type does not change (e.g. suction hoses mutually in the same order and instrument hoses mutually in the same order) , such a simple teaching based on colour sensors is totally adequate. When using one- colour identification, in the case of a totally freely configurable console (device hoses can cross) , further teaching via the user interface will still be required. This problem can naturally be solved by means of multi-colour sensoring. The operation of the identifiers may change if the target to be identified is in a position substantially deviated from vertical with respect to the sensor. If the device holder is turnable, the sensor may be arranged turnable along with that, e.g. such as shown in Figs. 2 and 3. Thus, the identification set may be assembled on individual cards which are mutually in a bus. The optical parts of the detector may be left under a cover or a lens, whereby the device will be easily cleanable.

Figs. 7a and 7b show, by way of examples, placing identification modules 73 in the device console. Each module is arranged as a unit rotating separately in the vertical direction such that the sensoring turns together with a device holder 71 connected to it. Reference number 75 designates a spring which is arranged to lock the connecting elements of the device holder 71 in the module 73.

Referring to especially the arrangements shown in Figs. 2 and 3 and respective ones, the electric control of the sensor is preferably performed such that it includes compensating ambient light (e.g. sun light and room lighting) in order to avoid error identifications. Sun light and light of the bulbs can be compensated by using short identification periods and by compensating the ¹DC light', i.e. the light component that stays substantially constant, from the detector signal. Fluorescent lamp light can, again, be eliminated from the result by taking two measurements by the detector in quick succession (considering the oscillation frequency of light, gen. 50/60 Hz), out of which one measurements produces a comparison result and the other one a measurement result. During measuring, a signal is transmitted by a desired light source. When these are deducted from each other, the residual is substantially the contribution of the light source. With the same principle, the measurement is repeated for all the wavelength bands used, preferably with a continuous cycle. If one wants that the light produced by the optical sensor is not perceivable by an eye or not disturbing at least, the pulses of the light sources can be kept very short or at least their flicker frequency be adjusted to be undetectable by the eye.

For increasing the dynamic range of the detector, the measuring electronics preferably comprises adjustable attenuation by means of which the measured voltage produced by light received by a photodiode or some other sensor element will reach the desired region before its analogue- digital conversion and further processing.

Preferably, the sensors are on a continuous identification mode or at least use a very quick periodical identification cycle, in order to identify activation of the device immediately after implementation (or return) and the desired control of the physical magnitudes related to the device

(usually pressure or electric control) can be started (or ended) .

The central unit preferably comprises a programmable unit in which information of the device type or the device related to each colour identifier may be programmed. The central unit is arranged to utilise this information especially when it detects removal (return) of a device from some device-place, whereby it can (de) activate physical magnitudes related to this device-place.

The console may include light indicators to show the mode of each holder (the device in place/out of place) .

The invention is especially suitable for device consoles and dental care units in which there are

at least two, typically 2-7 places for instruments/suction holders, a typical selection of odontological instruments, and/or at least one closed suction holder or a possibility to use such.

No prior art identification method would function in an apparatus fulfilling the above-mentioned criteria as such. The greatest obstacle is the closed form of a suction holder which is however essential with respect to the fluency of treatment (the suction device returns to the holder automatically) . Especially, by means of the invention, it is possible to realize a new suction device console in which there are at least one closed suction device holder for a suction device and at least one other holder for another device such that the order of the devices in the console is changeable.

A problem common for mechanical sensors is poor hygiene. An electric sensor, again, emits to its environment disturbances of radio-frequency (EMC) which makes it poorly suitable as such for new products. The electric sensor may also pick disturbing signals from the environment, whereby treatment is disturbed.

In the case of detachable instrument holders, also their type can be identified, if desired, by some arrangement.

The identification technique described can be used, in addition to the case of conventional suction devices or instruments, also in the case of special devices and still unknown odontological devices. One can mention as an example a suction device, which is provided with some dynamic device, such as a motor, a turbine, an intraoral camera, a light curer or a tartar removing sealer.

It should be noted that, related to dental care devices, some systems are known for identifying which device is connected to which device port of a dental care unit. EP publication 0736288 suggests using impedance measured through the cord of the device for identifying the device. A system for identifying a dental imaging camera is, again, described in FI publication 109521.

Claims

1. A device holder unit for a dental care unit, which comprises device-places in such a way that at least two devices used in dental care can be arranged to the device holder unit, and in which a device-place comprises a device holder for keeping a device set in a device-place in its place in the device holder unit, and in which - the mutual order of the devices in the device holder unit is arranged changeable,

characterised in that

- in the device holder unit, means is arranged for identifying a device or a device type set in a device- place when the device is set in the holder, which identification means comprises optical sensors capable of colour separation.

2. A device holder unit according to claim 1, characterised in that said optical sensors are arranged to emit light towards the device or a hose connected to the device by a first element and to detect reflected light by a second element, whereby the elements are mutually arranged such that reflective surfaces of different colours give a different response at the detector.

3. A device holder unit according to claim 2, characterised in that the sensor is set in the device holder unit such that the light emitted by the first element is arranged to reflect or scatter from the device set in the device holder, or its hose, to the detector.

4. A device holder unit according to any one of the preceding claims, characterised in that the sensors comprise at least two light sources, preferably LED lights, of different wavelength range, and a detector sensitive to these wavelength ranges.

5. A device holder unit according to any one of the preceding claims, characterised in that the sensors comprise a broadband light source and a detector capable of separating at least two wavelength ranges.

6. A device holder unit according to any one of the preceding claims, characterised in that the sensors comprise a light source the light sent by which is directed towards the device or its hose by means of a prism or prisms.

7. A device holder unit according to any one of the preceding claims, characterised in that the depth vision of said sensoring is limited such that the length of the identification area of colour separation is of the order of 1-3 cm.

8. A device holder unit according to any one of the preceding claims, characterised in that the sensoring is realized such that a sent and a detected beam are at an angle with respect to each other, which angle is 2-45°.

9. A device holder unit according to any one of the preceding claims, characterised in that the travel of light used by the optical sensors is limited by collimators for limiting the effective identification distance of the sensors.

10. A device holder unit according to any one of the preceding claims, characterised in that in each device- place, the means for identifying the type of a device set in the device holder are completely or substantially similar.

11. A device holder unit according to any one of the preceding claims, characterised in that the means for identifying the type of the device set in the device-place are also arranged for identifying if the device lies in its holder or not.

12. A device holder unit according to any one of the preceding claims, characterised in that

the device holders are detachable the device holder unit comprises means for receiving the device holders re-detachably such that their mutual order is changeable.

13. A device holder unit according to any one of the preceding claims, characterised in that there are at least two types of device holders and that the types of the holders are arranged to correspond said device types.

14. A device holder unit according to any one of the preceding claims, characterised in that at least one device holder is closed and at least one other device holder is open.

15. A device holder unit according to any one of the preceding claims, characterised in that at least one device holder is designed for a suction device and at least one device holder for an instrument.

16. A device holder unit according to any one of the preceding claims, characterised in that the sensors are arranged to spectrally separate from each other at least two, preferably at least three colour surfaces of different colours .

17. A device holder unit according to any one of the preceding claims, characterised in that it comprises device-places for at least two different device types, such as suction devices and instruments.

18. A suction device holder unit for a dental care unit, which comprises at least two device-places and in which the device-places are arranged such that at least one device of suction device type and at least one device of some other type may be fitted in the device holder unit, and in which the device-place comprises a device holder for keeping the device set in the holder in its place in the device holder unit, and in which at least one holder is a closed suction device holder, characterised in that

the placing order of the device types in the device holder unit is arranged changeable, and the device holder unit comprises means for identifying the type of the device set in each device-place when the device is set in the holder.

19. A suction device holder unit according to claim 18, characterised in that it is integrated as one device holder unit with a device holder unit according to any one of claims 1-17.

20. A dental care unit, which comprises

a device holder unit comprising at least two device- places, and a central unit, in which device hoses are connected which are designed for at least two odontological devices connectable to the central unit by means of device hoses and placeable in the device holder unit,

characterised in that

in at least one device hose or device connected to it there is a colour identifier, and - the device-places of the device holder unit are provided with optical sensors capable of colour separation, which sensors are arranged to identify a colour identifier arranged in a device hose or a device connected to the device hose, when the device is set in the device holder unit .

21. A dental care unit according to claim 20, characterised in that said device holder unit is a device holder unit according to any one of claims 1-17.

22. A dental care unit according to claim 20 or 21, characterised in that at least one of the device hoses is a suction hose for a suction device and at least one other is an instrument hose for an instrument, and that the dental care unit is arranged by means of said sensors to identify at least the types of the hoses in question, or the types of the devices connected to them, and/or also to specify the devices.

23. A dental care unit according to any one of the claims 20-

22, characterised in that it comprises several instrument hoses and/or several suction device hoses and that it is arranged by means of said sensors and the colour identifiers arranged in at least part of the hoses or the devices connected to them to identify the devices connected to- the hoses .

24. A dental care unit according to any one of the claims 20-

23, characterised in that the central unit comprises a programmable unit in which information on the device type or the device related to each colour identifier may be programmed.

25. A dental care unit according to any one of claims the 20-

24, characterised in that a device-place of the device holder unit comprises a device holder arranged particularly to a device to be connected to the device-place in question.

26. A dental care unit according to claims 20-25, characterised in that, in the device holder unit, there is a closed device holder for at least one hose or device connected to hose, typically for a suction hose or a suction device.

27. A dental care unit according to claims 20-26_r characterised in that the colour identifier is arranged to set in the area of the device holder of the device holder unit when the device is in its place in the device holder.

28. A dental care unit according to any one of claims 20-27, characterised in that it is arranged as a response to a command signal to identify the device or its type lying in each device-place at the time a command signal is given, and further to arrange control of the central unit such that, when picking a certain device or a device of a certain type from its device holder, the dental care unit activates ready to perform operations characteristic for this device or device type.

29. A dental care unit according to any one of claims 20-28, characterised in that the sensors are also arranged to identify if the device is in place in the device holder unit or not, and the central unit is further arranged to control at least one physical magnitude related to this device-place if a change is detected in this mode.

30. A dental care unit according to any one of claims 20-29, characterised in that it is arranged as a response to a command signal given by the user to identify the type of a device being in each device-place at the time the command signal is given and further to arrange control of the central unit such that, when picking a device of a certain type from its device holder, one may perform operations characteristic for this device type.

31. A dental care unit which comprises

at least one suction device holder unit comprising several device holders for at least one suction device and at least one other device type connected to the dental care unit, in which the device holders are designed for said device types and at least one suction device holder is closed, and - a central unit, in which several device hoses are connected or are connectable for use of devices needed in dental care to be places in the device holder of the device holder unit, whereby the device hoses are designed for said device types,

characterised in that

the order of the device types in the device holder unit that is feasible is arranged changeable and the device holder unit comprises means for identifying the type of the device set in the device holder when the device is set in the holder.

32. A dental care unit according to claim 31, characterised in that the device-places of the device holder unit are provided with optical sensors capable of colour separation, which sensors are arranged to identify a colour identifier arranged in at least one device hose or device connected to a device hose.

33. A dental care unit according to claim 31 or 32, characterised in that it is integrated as one dental care unit with a dental care unit in accordance with any of the claims 20-30.