A recognition system is provided for tools, such as drill bits and milling bits, which are insertable into dental treatment instruments, each of the tools having an optimum speed at which the tool must be rotated for effective treatment. In the recognition system, each tool is provided with a code corresponding to the speed or speed graduation necessary to effectively use the tool. The system also includes a reader which reads the code on each tool, and generates identifying signals in accordance with the code, which are supplied to an evaluation logic. The logic converts the signal from the reader into control signals for the drive motor used to operate the tool, as well as indicator signals for visually displaying information relating to the tool currently in use.

A dental treatment apparatus comprising at least one dental treatment instrument, a control data store in which certain fixed control data values are stored and from which they can be called-up as and when necessary, and a display device. In order to permit modification of the control data emitted in each case from the control data store, without the need to refer to the display device, a control member is coupled with the control data store and converts the control data emitted in each case from the control data store into corresponding analog voltages, which can be modified by the emission of an analog voltage corresponding to a desired modification, and which act as operating signals for the instruments.

A dental apparatus is provided with a group of standard preparation instruments that are held in deposit devices having sensors allocated to each device to determine the configuration and deposit condition of the preparation instrument in the deposit device, the apparatus has a second group of non-preparation instruments which include image-acquiring instruments for diagnostic purposes. Both instrument groups or types share a personal computer with a keyboard and a monitor in common through one interface data where the instrument-related functions can be read in and read out so that the installed program of the personal computer is activated dependent on the particular instrument being used.

A switching arrangement for the control of setting or control elements which are associated with the treatment instruments of a dental treatment location, including a control data memory in which there are stored predetermined control data constants for the treatment instruments. The data is retrievable through a control component for the adjustment of the presently considered control element, and includes a first signal or voltage output arrangement which, through its supplied signals or voltages, facilitates changes in the control data which are conveyed to the control component from the control data memory. A second voltage output arrangement is connected with the control component which supplies a voltage variable from an initial or zero value, and wherein in the active switching thereof, there is prevented the receipt or delivery of signals from the control data memory and of signals or voltages from the first signal or voltage output arrangement through the control component. This renders possible the direct setting of the control elements which are associated with the dental treatment instruments from predetermined initial or zero positions, without necessitating that the signals or data, which have been currently retrieved from the control data memory, be varied in the control component.

A gage block case includes a plurality of gage blocks mounted within the case, each gage block having opposed gage surfaces with a nominal dimension therebetween and a known deviation from the nominal dimension. Sensors associated with each gage block sense the removal of each gage block from the case. A signal generator provides a distinct signal corresponding to which gage block is removed from the case. A memory stores the known deviation of each gage block within the case. A control unit responsive to the signal generator addresses and retrieves from the memory the known deviation for each gage block which is removed from the case, combines the known deviation with the deviations of previously removed gage blocks and outputs the total deviation to a display device. In a second embodiment, the control unit selects and indicates which gage blocks are to be removed from the case to form a specified stack height input to the control unit.