TECHNICAL FIELD OF THE INVENTION

The present invention relates to a dental tool for use in a dental CNC milling/grinding machine for machining a dental restoration from a workpiece. The present invention also relates to a dental CNC milling/grinding machine for machining a dental restoration from a workpiece using one or more dental tools.

BACKGROUND ART OF THE INVENTION

In general, a dental CNC milling/grinding machine has a mounting unit for mounting at least one workpiece; and one or more carriage units each for driving at least one dental tool for machining a dental restoration from the workpiece. The shaft of the dental tool is mountable to a dental tool motor in the carriage unit. Usually a CAD/CAM software is used to construct the dental restoration and to provide the corresponding machining data to the dental CNC milling/grinding machine. The workpieces as well as the dental tools are consumables. The workpieces and the dental tools available on the market vary in size, shape, and material. Prior to the machining, the dental CNC milling/grinding machine must be equipped by a user with the desired workpiece and at least one adequate dental tool. If the dental tool does not specifically match the machining process, there is a risk that the dental restoration cannot be machined with the desired quality. In the worst case, the dental tool may be overrun its total service life or remaining service life if it has been used before in a preceding machining process. In such an event, the dental tool will break, and the dental restoration will receive damages. In less severe cases, the machining of the dental restoration is completed with an unacceptable low quality due to the use of the inadequate dental tool. In all these cases, the user satisfaction may decrease, and the users may complain about the quality.

DISCLOSURE OF THE INVENTION

An objective of the present invention is to overcome the above-mentioned problems of the prior art and to provide a dental tool for use with a dental CNC milling/grinding machine which can prevent or reduce the risk that the dental restorations produced are unusable or have an unacceptable, low quality. This objective is achieved through the dental tool as defined in claim 1, and the dental CNC milling/grinding machine as defined in claim 13. The other claims relate to further developments.

The present invention provides a dental tool for use in a dental CNC milling/grinding machine for machining a dental restoration from a workpiece. The dental tool has a shaft, and a miniaturized RFID tag which is arranged in front of the back end of the shaft.

The present invention also provides a dental CNC milling/grinding machine. The dental CNC milling/grinding machine comprises: at least one carriage unit adapted to exchangeably receive and drive one or more dental tools of the present invention; at least one transceiver unit adapted to read and/or write the miniaturized RFID tag of the dental tool; and a control unit adapted to control the transceiver units, and the carriage units based on the information read from the one or more miniaturized RFID tags.

A major advantageous effect of the present invention is that the miniaturized RFID tag can be used to store dental tool specific information which relates to the dental tool. Thereby, the dental tool specific information can be quickly and unambiguously acquired by means of the transceiver unit of the dental CNC milling/grinding machine. Accordingly, the dental CNC milling/grinding machine can be operated based on the dental tool specific information. Thereby, the risk of machining the dental restoration from the workpiece with an unacceptable, low quality can be prevented or reduced as much as possible. Thereby, also the risk of breakage of the dental tool and the resulting damages to dental restoration can be avoided or reduced as much as possible. Another major advantageous effect of the present invention is that the need that the user remembers or keeps a log of the dental tool specific information can be obviated, and the dental CNC milling/grinding machine can be operated safely and user-friendly. For instance, the user may safely re-use a dental tool when the dental CNC milling/grinding machine has determined that the dental tool has enough remaining service life for the machining process. For instance, the user can be prevented from using a dental tool in an undesignated dental tool motor on the carriage unit. Another major advantageous effect of the present invention is that the miniaturized RFID tag can be effectively read out by simple handling, namely by approaching the back end of the dental tool to the transceiver unit so that safe reading and/or writing can always take place in the range from direct contact up to a distance of a few millimeters. As the miniaturized RFID tag is arranged in the front of the back end of the shaft, a rotation- independent angular range with at least a hemispherical solid angle for communicating with the miniaturized RFID tag is guaranteed.

According to an embodiment of the present invention, the dental tool preferably has a robust protective housing that accommodates and seals the miniaturized RFID tag. The protective housing is preferably made from plastic material that encapsulates the miniaturized RFID tag. The front section of the protective housing is preferably mechanically connected to the back end of the shaft. Alternatively, an adhesive can be used for the connection. The miniaturized RFID tag is preferably embedded into the rear section of the protective housing, outside the shaft, for facilitating the RF communication with the transceiver unit of the dental CNC milling/grinding machine. The space between the miniaturized RFID tag and the protective housing is preferably filled with a sealing material. The protective housing and the miniaturized RFID tag preferably have a concentric, rotationally symmetric and balanced arrangement on the shaft of the dental tool. Thereby, the dental tool can be used in the dental tool motor of the carriage unit at relatively high rotational speeds, for instance, up to 60,000 revolutions per minute without any problems. The protective housing is optional. Thus, the miniaturized RFID tag can be directly arranged in front of the back end of the shaft and fixed in place through an adhesive seal or the like.

According to an embodiment of the present invention, the front section of the protective housing is preferably fitted into a bore that has been formed into the back end of the shaft of the dental tool. Thereby, the connection and the sealing can be further improved. In this embodiment, the rear section of the housing that accommodates the miniaturized RFID tag is arranged in front of the back end of the shaft, specifically outside the bore. Thereby, the transceiver unit can unimpededly communicate with the miniaturized RFID tag through the entire rearward direction and the entire radial direction.

According to an alternative embodiment of the present invention, the front section of the housing is preferably fitted onto a reduced diameter section that has been formed into the back end of the shaft of the dental tool. Thereby, the connection and the sealing can also be further improved. In this embodiment, the rear section of the housing that accommodates the miniaturized RFID tag is arranged in front of the reduced diameter section, specifically outside the shaft. Also, in this alternative embodiment, the transceiver unit can unimpededly communicate with the miniaturized RFID tag through the entire rearward direction and the entire radial direction. In addition, the reduced diameter section preferably has one or more circumferentially extending protrusions. And the front section of the housing is fitted onto the protrusions. Thereby, the connection and the sealing can be further improved. Alternatively, the reduced diameter section has one or more circumferentially extending grooves that respectively engage with matching claws formed on the front section of the housing. Thereby, the connection and the sealing can also be further improved.

According to an embodiment of the present invention, the miniaturized RFID tag is preferably a read-only type. The miniaturized RFID tag stores dental tool specific information which specifically relates to the dental tool. The dental tool specific information includes at least a unique ID, e.g., a universal unique identifier (UUTD) for unambiguously identifying the dental tool. The dental tool specific information preferably further includes information on at least one of the type, the manufacturer, the lot number, the length, and the concentricity of the dental tool. According to an alternative embodiment, the miniaturized RFID tag is preferably a read & write type. In this alternative embodiment, the dental tool specific information preferably further includes the remaining service life of the dental tool or alternatively the usage time of the dental tool which can be both determined through the dental CNC milling/grinding machine and written through the transceiver unit into the miniaturized RFID tag. The miniaturized RFID tag preferably has a miniaturized air core coil.

According to an embodiment of the present invention, the dental CNC milling/grinding machine is preferably provided with a communication unit for transmitting information to and/or receiving information from a data storage unit for at least storing the above- described dental tool specific information of one or more different dental tools. The data storage unit may be accessed for reading, writing, overwriting, updating the dental tool specific information via the unique ID. The data storage unit may be internal or external to the dental CNC milling/grinding machine. The data storage unit may be accessible via a network, internet or the like. The data storage unit stores at least a unique ID for identifying the dental tool, and dental tool specific information on at least one of the type, the manufacturer, the lot number, the length, and the concentricity, and the remaining service life of the dental tool. According to an embodiment of the present invention, the dental CNC milling/grinding machine preferably has a display for displaying information based on the dental tool specific information relating to the dental tool uniquely identified through the transceiver unit. The miniaturized RFID tag of the dental tool is read out by means of the transceiver unit. Thereafter, the dental tool specific information read from the miniaturized RFID tag and/or received from the data storage unit is displayed on the display. Thereby the user can gain detailed information on the identified dental tool and determine whether this dental tool is adequate for the forthcoming machining process. The display also preferably shows dental tool specific information about the dental tool or the dental tools that are needed for the forthcoming machining process and the associated positions on the carriage unit where the dental tools should be mounted by the user. Thus, the display serves for informing and also guiding the user for the forthcoming machining process in terms of the dental tools, the workpieces etc.

According to an embodiment of the present invention, the control unit inhibits drive of a carriage unit if it determines that the dental tool is worn or has an insufficient remaining service life based on the dental tool specific information or is mounted to an undesignated i.e., wrong, position in the carriage unit.

According to an embodiment of the present invention, the dental CNC milling/grinding machine has a panel that covers the transceiver unit. The panel is sufficiently thin and close to the transceiver unit so as to allow RF communication between a miniaturized RFID tag and the transceiver unit. The location of the transceiver unit is marked or easily recognizable on the panel such that the user can easily locate the dental tool near the transceiver unit. Thereby, the dental tool can be identified before mounting into any position on the carriage unit. Thereby the user can be guided, for instance, through the display before mounting the dental tool to the carriage unit. For instance, the user may be informed whether the dental tool is adequate for the forthcoming machining process and at which position it must be mounted on the carriage unit. Acoustic guiding may be alternatively used.

According to an alternative embodiment, one or more transceiver units are arranged close to the mounting positions of the dental tools in one or more carriage units. Thereby, a dental tool can be identified also after it has been mounted into a carriage unit. Thereby, the user can be informed whether an adequate dental tool has been mounted into the designated, correct position on the carriage unit. Similarly, the user can also be further guided through the display. The antenna of each transceiver unit is preferably configured by the associated stator of the dental tool motor in the carriage unit. Alternatively, one or more separate antennas may be arranged for each transceiver unit into the carriage units.

BRIEF DESCRIPTION OF THE DRAWINGS

In the subsequent description, further aspects and advantageous effects of the present invention will be described in more detail by using exemplary embodiments and by reference to the drawings, wherein

Fig. 1 - is a schematic cross-sectional enlarged partial view of the dental tool according to an embodiment of the present invention;

Fig. 2 - is a schematic cross-sectional enlarged partial view of the dental tool according to another embodiment of the present invention;

Fig. 3 - is a schematic cross-sectional enlarged partial view of the dental tool according to other embodiments of the present invention;

Fig. 4 - are schematic side views of various dental tools according to other embodiments of the present invention;

Fig. 5 - is a schematic enlarged side view of the protective housing for the miniaturized RFID tag of the dental tool according to an embodiment of the present invention;

Fig. 6 - is a schematic vertical sectional view of the protective housing of Fig. 5;

Fig. 7 - is a schematic perspective view of the protective housing of Fig. 5;

Fig. 8 - is a schematic front view of a dental CNC milling/grinding machine according to an embodiment of the present invention;

Fig. 9 - is a schematic perspective view of the dental CNC milling/grinding machine of Fig. 8, wherein the lid of the machine compartment has been opened;

Fig. 10 - is a schematic enlarged perspective view of the display of the dental CNC milling/grinding machine of Fig. 8, wherein the display shows the consumables.

The reference numbers shown in the drawings denote the elements as listed below and will be referred to in the subsequent description of the exemplary embodiments:

1. Dental tool

2. Shaft

2a. Back end

2b. Bore 2c. Reduced diameter section

2c- 1. Protrusion 2c-2. Groove

3. Miniatured RFID tag (with air core coil)

4. Housing

4a. Front section

4a- 1. Claw 4b. Rear section

5. Dental CNC milling/grinding machine

5a. Machine compartment

5b. Carriage unit

5c. Transceiver unit

5d. Camera

5e. Display

5f. Panel

5g. Lid

6. Workpiece

PI, P2 : Positions of dental tools (1) on the left carriage unit (5b).

PL, P2’: Positions of dental tools (1) on the right carriage unit (5b).

As shown in Fig. 9, the dental tool (1) of the present invention is suitable for use in a dental CNC (computer numeric controlled) milling/grinding machine (5) for machining a dental restoration from a workpiece (6). The dental tool (1) is suitable for milling/grinding the workpiece and preferably also for calibrating the dental CNC milling/grinding machine (5) through touching the workpiece (6). In Fig. 4, various dental tools (1) according to alternative embodiments of the present invention are illustrated. These dental tools (1) vary, for instance, in type, length, and concentricity. Their length typically ranges between 40 mm to 60 mm. As shown in Fig. 4, the dental tool (1) has a shaft (2) and a protective housing (4) which is connected to the back end (2a) of the shaft (2).

Fig. 1 shows the interior of the protective housing (4) of the dental tool (1) according to an embodiment of the present invention. As shown in Fig. 1, a miniaturized RFID tag (3) is arranged in front of the back end (2a) of the shaft (2). The miniaturized RFID tag (3) is preferably a read-only type. Alternatively, a read & write type may be used. The miniaturized RFID tag (3) may also be provided integrally with an air core coil. The miniaturized RFID tag (3) is covered by the protective housing (4). However, the protective housing (4) is optional. Alternatively, the miniaturized RFID tag (3) can be directly adhered to the front of the back end (2a) of the shaft (1) with some sealant adhesive. The front section (4a) of the protective housing (4) is connected to the back end (2a) of the shaft (2). The miniaturized RFID tag (3) is arranged outside the shaft (2) and in the rear section (4b) of the protective housing (4).

As shown in Fig. 1, the dental tool (1) has a reduced diameter section (2c) which has grooves (2c-2). The front section (4a) of the housing (4) has claws (4a- 1). The claws (4a- 1) are fitted into the grooves (2c-2).

Fig. 2 shows a dental tool (1) according to an alternative embodiment of the present invention. In this alternative embodiment, the reduced diameter section (2c) has protrusions (2c-l) instead of the grooves (2c-2). In this alternative embodiment, the front section (4a) of the protective housing (4) is provided without claws (4a-l) and is fitted onto the protrusions (2c-l). The dashed lines in Fig. 2 show the position where the miniaturized RFID tag (3) is located after the assembly.

Fig. 3 shows a dental tool (1) according to another alternative embodiment of the present invention. In this alternative embodiment, the back end (2a) of the shaft (2) has a bore (2b). And the front section (4a) of the protective housing (4) is fitted into the bore (2b).

Similarly, in Fig. 3 the dashed lines show the position where the miniaturized RFID tag (3) is located after the assembly.

In each of the embodiments as shown in Fig. 1 to Fig. 3, the miniaturized RFID tag (3) is arranged such that it is circumferentially and rearwardly unblocked by the shaft (2) for the RF communication. The protective housing (4) is permeable to radio frequencies. The housing (4) is preferably made from plastic material. The protective housing (4) is preferably cylindrical shaped with a generally u-shaped cross-section.

As shown in Fig 8, the present invention also provides a dental CNC milling/grinding machine (5). As shown in Fig. 9, the dental CNC milling/grinding machine (5) has a lid (5g) for opening/closing a machine compartment (5a) for accessing the consumables such as the workpiece (6) and the dental tools (1). The dental CNC milling/grinding machine (5) comprises: a mounting unit for mounting at least one workpiece (6); the machine compartment (5a) including two opposed carriage units (5b) for simultaneous machining, each adapted to exchangeably receive and drive one or more dental tools (1) according to the present invention; one or more transceiver units (5c) adapted to read the miniaturized RFID tag (3) of a dental tool (1); and a control unit adapted to individually control the transceiver units (5c) and the carriage units (5b) based on the information read from the miniaturized RFID tags (3). Each transceiver unit (5c) is adapted to only read a miniaturized RFID tag (3). Alternatively, the transceiver units (5c) may also be adapted to read & write a miniaturized RFID tag (3). The dental CNC milling/grinding machine (5) preferably has a communication unit for transmitting information to and/or receiving information from a data storage unit. This information may also relate to dental tool specific information. The data storage unit is preferably internal to the dental CNC milling/grinding machine. The data storage unit may also store dental tool specific information of the dental tool (1). Alternatively, the data storage unit may be external to the dental CNC milling/grinding machine (5), and accessible via a network, the internet or the like. The dental CNC milling/grinding machine (5) preferably has a display (5e), more preferably a touch-screen display (5e), for displaying information based on the dental tool specific information relating to the dental tool (1). The dental CNC milling/grinding machine (5) has a panel (5f) that entirely or partially covers one or more transceiver units (5c). The panel (5f) is sufficiently thin or has an aperture to allow RF communication between the miniaturized RFID tag (3) and the transceiver unit (5c). In addition, or alternatively, one or more transceiver units (5c) are arranged close to the mounting positions (R1,R2,RG,R2’) of the dental tools (1) in one or more carriage units (5b). The antennas of one or more transceiver units (5c) are preferably configured by the associated stators of the dental tool motors in one or more carriage units (5b). In addition, or alternatively, one or more separate antennas may be arranged for the transceiver units (5c) into the carriage units (5b).

The dental CNC milling/grinding machine (5) preferably also has camera (5d) for reading barcodes on the consumables such as the dental tool (1) or the workpiece (6) for recognizing them. The recognized consumables can be displayed using script and/or icons on the display (5e) with additional guidance information. The rear end of the shaft (2) preferably has a mounting thread (not shown) for mounting the same into the carriage unit (5b), namely into the spindle of the dental tool motor. The shaft (2) can be mounted by using a turning wrench that form-fittingly engages with the front end of the shaft (2) during the mounting process. Alternatively, instead of a mounting-thread other type of connections may be used.

The miniaturized RFID tag (3) of the dental tool (1) stores dental tool specific information which specifically relates to the dental tool (1). The dental tool specific information includes at least a unique ID for identifying the dental tool (1). The dental tool specific information preferably further includes information on at least one of the manufacturer, the lot number, the type, the length, and the concentricity of the dental tool (1). In case the miniaturized RFID tag (3) is a read & write type, then the dental CNC milling/grinding machine (5) also stores the remaining service life into the dental tool (1) via the transceiver unit (5c). Alternatively, or in addition, the data storage unit includes at least a unique ID for identifying the dental tool (1) and information on at least one of the manufacturer, the lot number, the type, the length, and the concentricity, and the remaining service life of the dental tool (1). The remaining service life of the dental tool (1) can be monitored by the dental CNC milling/grinding machine (5) on the display (5e)

The user can be guided, for instance, through a display (5e) of information relating to the workpiece (6) and the dental tools (1) that are planned for use in the next machining process set forth through the CAD/CAM software. For instance, the type of the workpiece (6), the type of the dental tools (1) to be used, the minimum necessary remaining service lives, their designated mounting positions (R1,R2,RG,R2’) on the carriage units (5b), or the like can be displayed on the display (5e) to the user as shown Fig. 10. The control unit can inhibit drive of a carriage unit (5b) when it has determined that the mounted workpiece (6) is wrong, or a mounted dental tool (1) is worn or has an insufficient remaining service life or is mounted to a wrong position in the carriage unit (5b).

The user can be informed, for instance, through the display (5e) of information relating to the dental tools (1) identified through the transceiver unit (5c) before mounting or after mounting to the carriage unit (5b). The dental tool specific information of the identified dental tool (1) such as the remaining service life, the type of the dental tool (1), the mounted position, and the like can be displayed to the user. The workpiece (6) can be provided with a barcode to be read through the camera (5d), and the relevant information can be displayed on the display (5e) as shown in Fig. 10.