The present invention relates to a new generation of operating systems for a dental practice.

Computerized control of the operation of dental instruments in a dental unit as well as the perform- ance of various auxiliary functions not related to the instrument operation as such is well known in the art. A typical example in the prior art is disclosed in applicant's European patent EP-B-0 391 967, which discloses a dental unit including a microprocessor for supervision and control of instrument operation as well as a range of auxiliary functions, whereby instruments and auxiliary functions can be selected by means of a display with associated selection means.

A further example of computerized operation of a dental working environment including a dental unit with dental instrument and a patient's chair had been disclosed in Us-A-5,300, 926, in which a single actua- tion device in the form of a foot switch, that can be brought from an initial position into working posi- tions, is used for selection and control of a variety of functions, the user being guided by display of function display elements with symbol identifiers and optical signals on a display on a front side of the dental unit.

On the background of such prior art systems it is an overall object of the invention to provide an automated dental practice operating system to select, control and monitor all functions needed during a dental treatment with significantly increased effi- ciency for the dentist or the dental team, with in- creased integration of the control of dental instru-

ments, auxiliary functions and operation of facili- ties available from source external with respect to the dental work place and with high flexibility in terms of user individual configuration of a variety of elements of the system.

To achieve this and other objects as will become clear from the following description the invention relates more specifically to a dental practice oper- ating system comprising a dental unit including an instrument holder for a number of dental instrument, which are individually selectable by removal from the holder, and means for control and execution of a plurality of functions re- lated to a dental treatment including operational functions for said dental instruments and a first group of auxiliary functions, an adjustable patient's rest comprising means for control and execution of adjustment functions thereof, at least one activation device incorporating at least one operating member providing a plurality of distinct functionalities for activation and control signals for said dental unit and said patient's rest for the control and execution of said plurality of functions as well as said adjustment functions, and computer means interposed between said at least one activation device and said dental unit and pa- tient's rest for controlling each of said plurality of distinct functionalities, said computer means in- cluding interactive display means for display of con- figurations of functions included in said plurality of functions and said adjustment functions for any distinct functionality of the activation device.

According to the invention, the dental prac- tice operating system thus defined is characterized in that said computer means includes a user interface for simultaneous display on said display means of a first configuration of symbols representing a number of said plurality of distinct functionalities and a second configuration of symbols including, for each distinct functionality represented by a symbol in said first configuration, symbols representing a group of said plurality of functions and/or said ad- justment functions executable by activation and com- mand signals included in said distinct functionality and at least one symbol for changing the functional- ity of the activation devices, the symbol of said second configuration being individually selectable by one of said activation or control signals of said distinct functionality of the activation device.

As a result of the distinct display of the first and second symbol configurations, typically in dif- ferent sections of a conventional PC display screen, any functionality offered by the activation device for providing a set of activation or control signals for the execution of individual functions of a group of functions may be displayed during the dental treatment in the first configuration of symbols, whereas each actual function, that can be executed by an activation and control signal belonging to a dis- tinct functionality represented by a symbol in the first configuration, will be represented by a symbol in the second configuration to be selectable for ac- tuation by the corresponding activation or control signal from the activation device.

Thereby, an easily understandable guidance for the

execution of functions such as instrument operation and adjustment, adjustment of the patient's rest and a variety of auxiliary function is made available to the dentist at any time during a dental treatment.

The activation device of the operating system may comprise a single activation device or a combination of activation devices. A single activation device may comprise a single operating member operable to pro- vide a number of activation or control signals for individual functions, or it may comprise several op- erating members to increase the number of executable functions. More than one activation device, each in- cluding one or more operating members may also be used. Typical activation devices may include a foot switch, a mouse, a joystick, a keyboard, an interac- tive touch screen, a speech command device or any other conventional form of computer input device.

In a presently preferred embodiment the activation device comprises a foot-operated multi-function de- vice incorporating a first operating member and a second operating member, said activation and control signals being provided by individual distinct opera- tion of said operating members. By execution of all functions needed during a dental treatment by means of a single foot operated device the use of manually operated activation device and the risk of cross- contamination during a dental treatment resulting therefrom is avoided.

In an actually preferred embodiment the symbols of the first configuration are displayed by said display means as individual cells of a single linear bar of cells to facilitate individual selection and activa- tion of the symbols by operation procedures well

known to any user familiar with conventional PC op- eration.

The symbols of the second configuration may in a similar way be displayed in a pictorial representa- tion indicating each distinct operation of each oper- ating member of the activation device. In a preferred embodiment including a foot-operated multi-function activation device the symbols of said second configu- ration may advantageously be displayed as individual cells overlying a pictorial representation of the multi-function activation device including each oper- ating member thereof with each cell positioned in an unambiguous relationship to the distinct operation of the specific operating member associated with the distinct function represented by the symbol of the cell.

For easy selection and activation of a desired functionality of the activation device or devices each symbol of said first configuration may advanta- geously be switchable between a non-selected state, a selected stated and an activated state by a distinct activation signal from the activation device, said non-selected, selected an activated states being dis- played with distinct visual characteristics by the display means.

In a preferred embodiment using a foot-operated multi-function activation device as mentioned above, in which the first operating member comprises a foot- operated instrument operation member for operation of a selected dental instrument by movement in one and the other of two linearly aligned, but opposite di- rections and affording a further distinct operation by movement in a direction orthogonal with respect to

said linearly aligned directions, a simple and rela- tively straight procedure for any user familiar with conventional PC operation switching between activa- tion and deactivation of a selected symbol may be executed by said further distinct operation of said foot-operated instrument operation member, whereas selection of a new symbol within the first configura- tion in the deactivated state only of all symbols therein may be executed by operation of said foot- operated instrument operation member in any of said two linearly aligned directions.

As known per se from convention PC operation the selection of one or more cells in the first configu- ration may alternatively, in the deactivated state of all cells therein, by made by a distinct short-cut operation that may preferably comprise not more than two distinct operations.

As a further advantageous alternative option to the standard and the conventional short-cut opera- tions direct meta action selection of a desired func- tionality may be used by including in the first con- figuration of symbols at least one symbol represent- ing a group of functions divided in at least two sub- groups of functions executable by distinct function- alities of the activation device, distinct symbols representing said sub-groups being included in the second configuration of symbols for switching between said distinct functionalities by direct selection of any of said distinct symbols.

For the operation of functions conventionally used during a dental treatment such as instrument and chair functions and auxiliary functions operable via the dental unit the first configuration of symbols

may preferably, by selection of a dental instrument by removal from the instrument holder, be switched to include symbols representing operational functions and/or parameters of the selected instrument, whereas with all instrument resting in the instrument holder the first configuration of symbols will be in a de- fault mode including symbols representing distinct functionalities of said activation device other than instrument operation.

In addition to operation of these functions con- ventionally used during a dental treatment the inven- tion offers as a significant advantage, however, the possibility of controlling a second group of auxil- iary functions provided by an external facility by including in said default mode of the first configu- ration of symbols at least one symbol representing an additional functionality of the activation devices for controlling such a second group of auxiliary functions related to the dental treatment, but pro- vided by an external utility with respect to said dental unit and patient's rest. Typical auxiliary functions, for which this option add further utility to the operating system may include image processing and digital display of X-ray images and video camera inspection during a dental treatment.

The new generation operation system afforded by the invention may be shared by a number of dentists and for this object at least one distinct functional- ity of the activation devices may be user- configurable, the first configuration of symbols in- cluding in the default mode a symbol for selection of a registered user.

In the following the invention will be explained

in more detail by way of a non-limiting embodiment and with reference to the accompanying schematical drawings, in which Figure 1 is a block-schematic diagram showing es- sential hardware components of a dental practise for use in the operation system of the invention; Figure 2 shows an example of a general arrangement of a dental working environment as viewed from above; Figure 3 is a schematical representation of an em- bodiment of a foot operated multi-function activation device for use in the operating system; Figure 4 is a graphic representation of an example of a general layout of the visual display of symbols representing functionalities of an activation device as shown in figure 3 and distinct activation and con- trol actions to be executed by such a functionality, respectively; and Figures 5 to 9 show non-exhaustive examples of the application of the general layout shown in figure 4 for activation and control of a variety of functions related to a dental treatment.

The hardware components of a dental practise as illustrated in figure 1 comprise a dental unit 1 with an instrument holder 2 providing receptacles for a number of dental instruments 3 that may typically in- clude different types of motor or air-turbine oper- ated instruments. The dental unit 1 is positioned at one side of a patient's rest 4, and the instrument holder 2 is carried by a pivotal or otherwise movable table-like support 5 such that, during a dental treatment the table-like support 5 with the instru- ment holder 2 may be brought to an operative position overlying the patient's rest 4. For computer con-

trolled operation and parameter control and adjust- ment of an instrument 3 selected by removal from its receptacle in the instrument holder 2 a foot-operated activation device 6 is provided, which may serve also for the practise operation system according to the invention, the dental unit 1 and the activation de- vice 6 communicate with computer means 7 including a microprocessor and user interface. For visual presen- tation of the actual state of the dental unit 1 and dental instruments 3 and guidance of the dentist dur- ing a dental treatment a display 8 such as a conven- tional PC screen is connected with the computer means 7.

As illustrated in dashed lines one or more addi- tional activation devices 9 and an external facility 10 for additional auxiliary functions may be con- nected with the computer means 7 as well.

As shown in figure 2 the overall arrangement of the dental working environment include working posi- tions 11 and 12 for the dentist and a dental nurse, respectively, disposed at either side of the patient 13 resting on the patient's rest 4 to provide easy access for the dentist and the nurse to the dental instruments 3.

In the illustrated arrangement the activation de- vice 6 is a multi-function foot-switch shown in more detail in fig. 3 and being disposed on the floor to be easy operable by the dentist, in the illustrated arrangement by us of his left foot.

The display 8 in the form of a conventional PC screen may be disposed of the top and carried by the dental unit 1 to be easily visible from the working position 11 of the dentist.

The actual arrangement illustrated in fig. 2, which in its general form bas been disclosed in ap- plicant's co-pending international patent application PCT/DK/00164, filed 2003, the disclosure of which is incorporated herein by reference, is only a single example of the possible disposition of a dental work- ing environment, however. Thus, the individual hard- ware components may be positioned otherwise than il- lustrated and during certain forms of dental treat- ment the dentist in the position 11 may work without the assistance of the nurse.

Whereas the foot-operated activation device may in a preferred embodiment be used as s single activation device for the practise operation system of the in- vention other possible forms of activation devices may be used as well and, in particular, the use of additional activation devices such as an activation device for operation by the dental nurse for certain auxiliary functions may be foreseen, as will appear from the following.

As shown in more detail in fig. 3 the multi- function foot-operated action device 6 comprises sev- eral operating members.

A first operating member comprises a short arm 14 projecting from a generally elliptical housing for use in the normal instrument operation as customary in the art. The operating arm 14 is movable sidewise from a neutral position in opposite directions as il- lustrated by arrows L and R designating movement to the left and right, respectively. A third direction of movement for the arm 14 may be a downward movement from the neutral position as illustrated by the arrow D.

A second operating member comprises a joystick- like member 15, which like conventional joysticks is moveable in four different orthogonal with respect to each other as illustrated by the arrows designated N, E, S and W.

In the illustrated embodiment the activation de- vice 6 is provided with two additional operating mem- bers in the form of relatively simple press-down but- tons 16 and 17.

All operating members 14 to 17 of the activation device 6 are spring-controlled in the sense that for any movement the respective operating member will re- turn to its neutral non-operative position, when the action by the dentist's foot is released.

As will appear the multi-function activation de- vice 6 will thus provide the functionality of provid-- ing activation and/or control signals for nine dif- ferent functions by operation of the operating mem- bers 14-17 in the directions described.

The structural design described above for the multi-function activation device 6 bas been disclosed in applicant's above-mentioned co-pending interna- tional patent application PCT/DK/00164, the disclo- sure of which is incorporated herein by reference.

In the illustrated and actually preferred embodi- ment of the practise operation system according to the invention the multi-function foot-operated acti- vation device 6 is used to control not only the op- eration of any dental instrument 3, that has been se- lected for use by removal from its respective recep- tacle in the instrument holder, but also to provide activation or control signals for any other function needed to be performed or executed during a dental

treatment. This has the advantage that all functions are controlled by a single foot-operated activation device, there by avoiding any need for finger- operated devices like a keyboard, a mouse or a touch screen and significantly reducing the risk of cross contamination during a dental treatment.

With the development towards an increasing number of auxiliary functions involved in dental treatment procedures, as will become apparent from the follow- ing, the execution and control of all such functions by a single multi-function activation device will have as an evitable consequence that it must be pos- sible to switch the activation device between a cor- responding number of functionalities, each comprising a number of distinct functions of functions within the overall number of operations made available by operation of the operating member or members of the activation device.

Typical examples of auxiliary functions, which may have to be activated during a dental treatment in ad- dition to the operation of selected dental instru- ments, would comprise adjustment of the patient's rest between its operative lying position during the treatment and a sitting position needed by the pa- tient to enter or leave the rest or occasionally have access flushing water, adjustment of parameters for a selected dental instrument such as the maximum speed of a drilling instrument, starting a stop watch to monitor the duration of treatment procedure requiring a certain amount of time for completion, observation of an X-ray image relating to the actual treatment video camera inspection of the dental region under treatment etc.

This increasing number of auxiliary functions strengthens the need for the dentist to be kept ade- quately and precisely informed about the exact status of the hardware components and the actual functional- ity of the activation device at any point of time during a dental treatment in order to enable any needed action to be performed in time and avoid unin- tentional activation of other functions, which are undesirable or might harmfully interfere with the ac- tual stage of the treatment.

By the practise operation system of the invention an advanced solution is provided to these problems as will be apparent from following description of one preferred layout of some of the images as shown in figs. 4 to 9, which may be displayed to the dentist on the screen 8 during a dental treatment.

In fig. 4 the general image layout controlled by the user interface of the computer 7 comprises in ac- cordance with the invention the simultaneous display of a first configuration 18 of symbols, which each represent one distinct functionality of the activa- tion device or devices, in the illustrated example the multi-function foot-operator 6 shown in figs 1 to 3, and a second configuration 19 of symbols including symbols representing individual distinct functions belonging to a single distinct functionality of the activation device as represented by one of the sym- bols in the first configuration 18 together with at least one symbol for selection of a symbol within the first configuration 18 to change the activation to another distinct functionality comprising a new set or group of functions.

As shown in fig. 4 the symbols of the first con-

figuration 18 may advantageously be displayed in the form of individual cells 20 disposed along a single linear bar 21, which may as shown extend in the hori- zontal direction close to the bottom of the screen, but could obviously also have a vertical orientation and be shifted to a position close to the top of the screen.

To provide clear and unambiguous information about the functions that can be activated or controlled by any distinct functionality of the activation device the symbols of the second configuration 19 is advan- tageously displayed in a pictorial representation in- dicating each distinct operation of each operating member of the activation device or devices belonging to the same distinct functionality thereof. For the illustrated preferred embodiment including the multi- function foot-operator 6 this is preferably accom- plished by displaying the symbols of the second con- figuration 19 as individual cells 22 overlying a pic- torial representation 23 of the multi-function foot- operator 6 with its operating members 14 to 17, each of the cells 22 being positioned in an unambiguous relationship to the corresponding distinct operation of the specific operation member. This allocation of the cells 22 to the distinct operation of the operat- ing members 14 to 17 is illustrated in fig. 4 by ref- erences corresponding to each specific direction of the movement of the first and second operating mem- bers 14 and 15, i. e. L, R, D, N, E, S and W and the reference numerals 16 and 17 for the two press-but- tons.

In fig. 5 an example is shown of a default menu shown on the display 8 of a multi-user operation sys-

tem for use by any of a number of users registered in the computer 7, i. e. the menu displayed when turning on the operation system.

The first symbol configuration 18 comprises five symbols in cells labelled 20 a, b, c, d, and e each representing an individual distinct functionality.

The functions, which can be activated or controlled in this mode, will typically be auxiliary functions relating to adjustment of the patient's rest 4 and to functions, that although not related to operation of the dental instruments 3 are activated via the dental unit 1. The five functionalities represented by cells 20 a-e are displayed by graphic symbols as follows: 20a: User identification allowing the actual registered user to enter his name and thereby activate his individual configura- tion of certain user configurable func- tionalities of the system; 20b: Activation and control of auxiliary func- tions relating to adjustment of the pa- tient's rest 4 and auxiliary functions op- erated via the dental unit 1, e. g. filling the patient's water cup or calling the dental nurse; 20c: Activation of a stop watch and timer pro- gram allowing start and stop of a stop watch and a number of different timer con- trolled sound alarm functions; 20d: Activation and control of an external in- traoral video camera; 20e: User control of an external digital image processing programme such as the image processing software"Digora"@ available

from the Finnish company Soredex for ma- nipulation and display of a digital X-ray image on the screen 8; As a preferred feature of the invention each of the cells 20 a-e of in the horizontal bar 21 repre- senting the first symbol configuration 18 may switchable between a non-selected state, a selected state for preparing the cell for activation and an activated state. In the illustrated example the cell 20b representing the functionality of the foot- operator 6 for activation and control of auxiliary functions for the patient's rest and the dental unit.

Accordingly, of the nine different functions il- lustrated by graphic symbols in the cells 22 of the second configuration 19 the two functions activated by operation of the press-down buttons 16 and 17 are the auxiliary functions operated via the dental unit as exemplified above, whereas as the four functions activated by operation of the second operating member 15 in the directions N, E, S and W comprises raising and lowering of the patients rest adjustment of the back rest thereof. By operation of the first operat- ing member 14 in the direction L inflation of an air cushion in the patient's rest may be activated.

As an important feature, one of the symbols of the second configuration 19, in the illustrated example operation of the first operating member 14 in the downward direction D, is used for switching a se- lected cell in the first configuration between a se- lected, but deactivated state and an activated state as shown for the cell 20b. In a manner known in the art the display of cells 20 in the first configura-

tion is controlled to provide a clear visual distinc- tion between the non-selected, selected and activated states, for the activated state e. g. by changing the background colour of the cell.

Selection of a new cell 20 in the first configura- tion 18 may be made only by deactivation of the pre- viously activated cell. The deactivation caused by operation of the operating member 14 in direction D changes the content of the cells in the second con- figuration 19 e. g. by reserving two cells, e. g. those representing movement of the operating member 14 in the L and R directions for cycling through all the cells of the first configuration by shifting the cell selection to the left or right, respectively, to be described in the following with reference to the ex- ample shown in fig. 6.

The display illustrated in fig. 5 shows a further advantageous feature by addition of a third configu- ration 24 of symbols for functions, in this example for adjustment of the patient's rest, which can be activated or controlled by an additional activation device 9 as shown in fig. 1. The additional activa- tion device may typically be a further foot-operated joystick, e. g. for operation by the dental nurse, af- fording activation of four functions by operation in the N, E, S and W directions, respectively as for the operating member 15 of the multi-function foot- controller 6.

The screen picture examples shown in figs. 6 and 7 relate to the operation of a dental instrument, which in the actual presentation is an electric motor driven instrument. By removal of the instrument 3 from its receptacle in the instrument holder 2 the

picture shown in figure 7 is displayed, in which the first symbol configuration 18 in the illustrated ex- ample includes eight symbols indicated abbreviated text denotations such as GEN, MIN, MED, MAX, PRP MIN, PRP MAX, PROFY AND, ENDO contained in cells 20 f-m, respectively in the linear horizontal bar 21. The functionalities of the multi-function activation de- vice selectable from the first symbol configuration may for this example briefly be described as follows: GEN: a general motor program covering the entire speed range, e. g. from 50 to 40,000 rpm, of the selected instru- ment, with exponential speed control; MIN: Operation at low speed, e. g. 50 to 1,000 rpm, with linear control; MED: Medium-speed operation, e. g. from 1,000 to 20,000 rpm, with linear con- trol; MAX: High-speed operation, e. g. from 20,000 to 40,000 rpm, with two step control; PRP MIN: Slow-speed operation for preparation of a tooth; PRP MAX: High-speed operation in connection with preparation ; PROPHY: Low-speed operation without coolant for polishing of tooth coatings; ENDO: Low-speed operation without coolant for endodontic treatment: In the display illustrated in fig. 6 none of the cells 20 f-m in the bar 21 has yet been activated, but the cell 20 k for the functionality denoted PRP MIN has been selected for activation. In this mode

the symbols in cells D, L and R included in the sec- ond configuration 19 is used for activation of a se- lected cell such as the cell 20k and for selection of a new cell by stepping through the cells from the previously selected cell in the left or right direc- tion, respectively, by operation of the first operat- ing member 14 of the multi-function foot-operator 6 in the respective direction, as described in the foregoing.

In the display example in fig. 6 also the addi- tional feature of selection of a number of the func- tionalities represented by symbols in the first con- figuration 18 by a short-cut action is illustrated.

By way of example such a short-cut action may be im- plemented by using the remaining six symbols in the cells 22 of the second configuration 19 for direct selection of any of a corresponding number of the symbols of the first configuration 18 by operation of the joystick-like operating member 15 or the two press-down buttons 16 and 17, i. e. without any need for stepping through the first configuration 18.

Further illustrated in fig. 6 is an inactive instrument program window 25, generated by the selec- tion of the cell 20k.

In the display illustrated in fig. 7 the selected cell 20k denoted PRP MIN has been activated by opera- tion of the first operating member 14 in direction D with the result that the content of symbols in the second configuration is changed to indicate the func- tionality of the foot-operator 6 now made available for operation. In the illustrated example activation of the symbols representing operation of the first operating member 14 in the L and R directions will

cause operation of the selected instrument in either of the two possible directions of rotation, clockwise and counter-clockwise, respectively. The symbols rep- resenting operation of the second operation member 15 in the N and S directions may be activated for upward or downward adjustment, respectively, of the maximum speed of the instrument, a graphic illustration of which is presented in the upper section of the instrument program window 25. The symbols of the sec- ond configuration 19 representing operation of the second operation member 15 in the E and W directions may be correspondingly be activated for upward or downward adjustment, respectively, of the water con- tent in the coolant spray employed by use of the se- lected electric motor driven instrument, an indica- tion of this option is provided in the lower section of the instrument program window 25. The symbols of the second configuration 19 representing operation of the press-down buttons 16 and 17 of the foot-operator 6 may be used for changing the combination of water and air cooling to a drilling instrument and en- able/disable automatic chip blow, respectively.

In the illustrated example in fig. 7 a middle sec- tion of the instrument program window 25 is used for visual presentation of a specific contra angle for the selected drilling instrument recommended for the speed adjustment displayed in the upper section of the window.

A further advantageous application of the operat- ing system for monitoring and controlling software provided by an external utility is shown in fig. 8 illustrating as an example activation and control of an image processing program such as the programme

"Digura" mentioned in the foregoing. This func- tionality of the activation device or devices such as the foot-operator 6 may be selected in the default mode, in which the first symbol configuration 18 will be the same as shown in fig. 5. By selection of the cell 20e of the first configuration 18 and operation of the first operating member 14 in the direction D the image processing programme will become active and a second group of auxiliary function represented by symbols of the second configuration 19 will comprise a number of image processing manipulations that can be activated by operation of the operating members 14 to 17 of the foot-operator 6 for activation of any the cells 22 other than the cell used for activation and deactivation of a selected cell in the first sym- bol configuration 18.

By activation of the image processing facility a main menu thereof will be displayed in a relative large window 26 and make it possible to retrieve any of a number of digital X-ray images stored by the im- age processing facility or in the computer 7.

As will appear from fig. 8 the options made avail- able for activation by a symbol included in the sec- ond configuration 19 may include typical image proc- essing procedures like up/down adjustment of bright- ness and contrast, zoom-in and zoom-out, image re- trieval and filtering a retrieved X-ray image in the window 26. By way of the latter option the window 26 displaying the selected image will remain on the com- puter screen 8, if the functionality represented by the symbols of the first configuration is changed, e. g. by selection of a dental instrument for perform- ing a dental procedure on the tooth shown in the se-

lected image.

When an external facility such as the illustrated image-processing programme provides for individual user configuration of functions included in the sec- ond of auxiliary functions the configuration pre- ferred by a registered user is stored by the computer 7 and made available for the user when activating the external facility.

For a group of functions comprising a number of distinct functions exceeding the maximum number of symbols made available for activation by the second symbol configuration 19 a further advantageous short- cut operation possibility is illustrated in fig. 9.

The group of functions, exemplified by adjustment functions for the patient's rest 4 and auxiliary functions activated via the dental unit 1, may be di- vided into two or more groups, e. g. e. g. as illus- trated two groups for the patient's rest 4 and the dental unit 1, respectively and the second symbol configuration 19, which would otherwise be as illus- trated in fig. 5, may be split into two or more indi- vidually selectable sub-configurations, in the illus- trated example two sub-groups 27 and 28 containing symbols for the patient's rest adjustment and for ac- tivation of auxiliary functions respectively, each of these sub-configurations including symbols for acti- vation of either of the sub-configurations.

By activation of the symbol for the patient's rest/dental unit functions shown in cell 20b of the default mode display in fig. 5 only on of the two sub-configurations 27 and 28 of the illustrated exam- ple will be displayed instead of the single second symbol configuration 19 shown in fig. 5 to allow ac-

tivation of any of the functions included in the cor- responding sub-group. In addition to the symbols rep- resenting these functions each of the sub- configurations in the illustrated example 27 and 28 includes two symbols allowing direct Meta action switching between the two sub-configurations 27 and 28 by operation of the first operating member 14 in the L and R directions, in addition to the symbol for activation/deactivation of the selected symbol in cell 20b of the first configuration 18 by operation of the operating member 14 in the D direction as in- dicated by 29 and 30, respectively.

Whereas the dental practise operation system ac- cording to the invention has been described in the foregoing by way of a number of illustrative examples of groups of distinct that may be included in spe- cific distinct functionalities of the activation de- vice or devices other functions needed or desirable in the operation of a dental practice may be foreseen for integration with the practise operation system without departing from the scope of the invention.

Such functions could include for example operation of treatments protocols as disclosed as disclosed in the applicants above-mentioned co-pending international patent application PCT/DK03/00164 as well as control of external dental patient information and/or patient entertainment programs.