DE4036837A1 - METHOD AND DEVICE FOR PRODUCING DENTAL INSERTS - Google Patents

Abstract

In order to produce dental inlays made of dental ceramic or similar material, the invention calls for a moulded impression (1) to be made which serves as the original for the production of the inlay by grinding. For this purpose, the impression (1) and a blank (2) of the inlay are mounted on a common mouting (3). A copy-grinding machine scans the impression (1) with a probe (7) in a first setting and grinds part of the surface of the inlay on the blank (2). Subsequently, the impression (1) and the blank (2) are transferred to a second mounting (9), maintaining the same relative positions. The blank (2) is then finished by copy-grinding.

Description

The invention relates to a method for producing Tooth inserts made of dental ceramic or similar material by form grinding, and a device for Execution of the procedure.

The conventional manufacture of tooth inserts takes place in several stages, with at least two for the patient Sessions at the dentist are required. After Working out the tooth cavity is done in a first session made an impression. The tooth must be provisionally restored will. In the dental laboratory using this Imprint made a model according to which the tooth insert is poured. In addition to metals, the material is also ceramic materials in use after molding be burned. In a second session the Tooth insert inserted into the tooth cavity.

Due to the need for two sessions and the provisional care is the time and effort relatively high. That is why there was a procedure aimed at, in which the tooth insert in a single  Session in dental practice can, so the need for a provisional There is no supply.

In this context, under "Tooth insert" primarily inlays, but also onlays and Shell facings can be understood.

A method of the type mentioned at the beginning for Manufacture of dental inserts in a single session is known (Mörmann / Brandestini / Lutz, "The Cerec system: Computer-aided production of direct ceramic inlays in a meeting ", magazine" Quintessenz "3/87, presentation No. 6962, pp. 1-14). In this known method takes place an optical, computer-aided measurement of the Tooth cavity. In the monitor image generated from it with the means of computer graphics the shape of the tooth insert to be manufactured. From the Stored data becomes data for the control won a profile grinding machine with which from one Dental ceramic block a semi-finished dental insert will be produced. Using composite Fastening material is used in the tooth insert Tooth cavity used. Then the final contouring and elaboration of the fissures and Hump.

The need to change the shape of the tooth insert Constructing a screen requires that the dentist or his assistants in the area incorporated the computer graphics. The required Post-processing of the machine-made Tooth insert, especially the processing of the occlusal surface and the preparation of the occlusion by the dentist  associated with considerable workload and stands therefore a desired substantial reduction in Counteracting expenditure of time.

The object of the invention is therefore a method of train the type mentioned so that with easy process steps that can be learned a complete, all-round finishing of the tooth insert with very high accuracy is made possible, in particular a Finishing after machine production not applicable.

This object is achieved in that in the fully prepared tooth cavity to be filled Impression model made of a hardening material including contouring the exposed Surface is shaped that the impression model as Template is scanned using a copy button, and that according to the impression model in one Copy grinding process an all-round Tooth insert from an insert blank made of dental ceramic or similar material is manufactured.

Since the impression model already has all contours of the tooth insert to be produced, in particular including of the occlusal surface, and since these contours in Profile grinding process with high accuracy on the Workpiece is transferred in this way manufactured tooth insert not only completely edited, so that a complex post-processing omitted, but also agrees in all dimensions high accuracy with the impression model and thus also with the tooth cavity to be filled. With the The method according to the invention can therefore also be tooth inserts  be made, which consist of a material that an immediate without the use of composite material Establishes connection with the neighboring tooth material; The prerequisite for this is, however, that a very small one Gap width between the tooth insert and the neighboring tooth material is not exceeded. The very high manufacturing accuracy required for this Gear use with the inventive method reached.

In an advantageous embodiment of the inventive concept it is provided that the copy button and a Grinding tool arranged at a fixed distance from each other are and a common relative movement to that Imprint model and also at a fixed distance from it Execute the arranged insert blank. This will be in a lot easily achieved high copy accuracy.

A further development of the inventive concept is provided that in a first processing step part of the Surface in a first setup of the impression model and the insert blank is copied and that in one second processing step the remaining part of the Surface in a second setup of the impression model and the insert blank is copied, one defined position assignment in both clampings is observed. This is a simple Possibility created the surface of the tooth insert to be manufactured completely on all sides edit, observing the exact location assignment between the two setups ensures that any offset between those in the two setups machined surface areas is avoided.  

This is in a further embodiment of the Invention concept provided that the impression model and the Insert blank in the first setup on one common first carriers are included that after the first processing step the impression model and the partially processed insert blank together on one second carrier and that in the second Clamping on this second carrier Finishing of the insert blank for inserting teeth he follows. The inclusion of the Imprint model and the insert blank on the two Carriers by means of adhesive. Through the common Transfer of the impression model and the blank from the first carrier to the second carrier is in one particularly simple and reliable way ensured that the location mapping of these two parts to each other is maintained with high accuracy.

An advantageous device for performing the The process starts from that described at the beginning Form grinding machine in which a drivable Grinding tool is stored and a machine frame and a workpiece holder for the insert blank having. The device according to the invention is thereby characterized that a copy button and that Grinding tool arranged at a fixed distance from each other and that the impression model and the insert blank on a common jig and added Relative movements in three axes compared to the Copy button and the grinding tool are movable. The Device is of relatively simple construction and can be operated easily and without lengthy training. It enables the implementation of the inventive method. With the term  "Relative movement" means that the Clamping device and / or the copy button with the Grinding tool can be arranged movably.

The copy button and the grinding tool are preferred on a common, height-adjustable in the machine frame guided processing support arranged, and the Jig has one in two horizontal Movable axes with respect to the machine frame Clamping slide on.

Further advantageous embodiments of the invention Method and the device according to the invention Subject of further subclaims.

The following are exemplary embodiments of the invention explained in more detail, which are shown in the drawing. It shows:

Fig. 1 is a simplified spatial representation comprise a support for receiving a cast model and an insert blank,

FIG. 2a) -g) consecutive in a simplified representation steps in the manufacture of a dental insert,

Fig. 3 in a representation corresponding to FIG. 1, a modified embodiment of a carrier for receiving the cast model, and of the insert blank,

FIG. 4a) and b) is a simplified view of a modified processing step corresponding to that in Fig. 2af) and g) shown processing step,

Fig. 5 is a front view and partially in section a copy grinding machine for performing the method described,

Fig. 6 is a plan view in the direction of arrow VI in Fig. 5 on the jig and

Fig. 7 is a vertical section through a modified version of the clamping device.

In the method for producing tooth inserts, for example an inlay, explained with reference to FIGS . 1 and 2, an impression model 1 is produced from a hardening material in the fully prepared tooth cavity to be filled, with the contouring of the exposed surface, in particular the occlusal surface, already taking place , is formed. A tablet-shaped insert blank 2 made of dental ceramic or similar material is provided.

On a plate-shaped carrier 3 two plastic discs 4 , 5 are attached at a distance from each other, for example glued on. The top of both plastic discs 4 , 5 ( FIG. 1) is provided with an initially liquid adhesive wax 6 ( FIG. 2a), onto which the impression model 1 is applied to the plastic disc 4 and the insert blank 2 to the plastic disc 5 . After the adhesive wax 6 has hardened, the carrier 3 is inserted into a copy grinding machine which will be described in more detail later ( FIG. 2b, c).

A copy button 7 essentially scans the top, for example the occlusal surface of the impression model 1 , in the first setting shown in FIG. 2b and controls a grinding tool 8 , for example a diamond-coated grinding tool, which is mounted at a fixed or fixed distance from the copy button 7 .

As indicated in FIG. 2 by arrows, the copy button 7 and the grinding tool 8 perform relative movements in three axes with respect to the carrier 3 . The movement in the vertical axis is carried out by adjusting the height of the copy button 7 together with the grinding tool 8 , while the movements in the two horizontal axes are carried out by the carrier 3 accommodated in a clamping device.

After completion of the occlusal surface, the carrier 3 is removed from the clamping device of the grinding machine and turned, as shown in Fig. 2d.

In the meantime, a second carrier 9 has been provided, which is similar to the first carrier 3 and also carries two plastic discs 10 and 11 . These plastic disks 10 and 11 are each provided with an adhesive wax 12 which, like the adhesive wax 6, serves as an adhesive for receiving the impression model 1 and the insert blank 2 . However, the softening temperature of the adhesive wax 6 used in the first setting is lower than the softening temperature of the adhesive wax 12 used in the second setting.

Two centering pins 13 , which are inserted in centering bores 14 of the second carrier 9 and engage in centering bores 15 of the first carrier 3 , form a centering device with which the first carrier 3 is centered relative to the second carrier 9 . The first carrier 3 is pressed against the second carrier 9 , the impression model 1 and the partially machined insert blank 2 each pressing into the adhesive wax 12 and being fixed there.

After the adhesive wax 12 has hardened, the impression model 1 and the insert blank 2 are detached from the first carrier 3 by means of a heated blade, which can then be removed from the second carrier 9 together with the centering pins 13 . The remnants of the adhesive wax 6 are removed from the impression model 1 and from the insert blank 2 using a probe or a sharp blade.

The carrier 9 is received in the clamping device of the grinding machine for the second processing step (FIGS . 2f, g). The carrier 9 is moved in the two horizontal axes in such a way that the copy button 7 completely scans the peripheral surface and the upper surface of the impression model 1 , the grinding tool 8 processing the remaining surface of the insert blank 2 in the manner already described ( FIG. 2f , g).

The carrier 9 is then removed from the clamping device of the grinding machine. The impression model 1 and the tooth insert made from the insert blank 2 , which is finished on all sides, are detached with a heated blade and freed from the remains of the adhesive wax 12 . The tooth insert thus produced can be inserted into the tooth cavity; The impression model 1 used for production in the copy grinding process is disposed of.

The use of the plastic disks 4 , 5 and 10 , 11 is expedient so that damage to the carrier 3 or 9 is avoided during the vertical relative movement when the outer contour of the insert blank 2 is ground. The plastic discs 4 , 5 , 10 and 11 can be replaced after repeated use.

Fig. 3 shows a modified embodiment of the support 3 or 9. Here, the impression model 1 and the insert blank 2 are not clamped by adhesive wax, but by means of mechanical clamping devices 16 . This mechanical mount can be used in the first setup ( Fig. 2a) and / or in the second setup ( 2 f). Preferably, however, the described embedding in the adhesive wax 12 takes place in the second clamping.

A modification of the copy grinding method is explained with reference to FIG. 4. If the circumferential contour of the tooth insert to be produced deviates only relatively little from a round shape and in particular has no steep rises in the circumferential direction, after the first machining step, as shown in FIG. 2b, the second machining step can take place in such a way that both the impression model 1 and the insert blank 2 are each attached to a turntable 17 or 18 by means of the adhesive wax 12 . The turntables 17 , 18 are driven synchronously and in the same direction; the copy button 7 and the grinding tool 8 can be moved together in the horizontal direction and the vertical direction. The copy button 7 is pressed resiliently against the circumference of the impression model 1 . While the impression model 1 and the insert blank 2 rotate in the same direction and synchronously, the grinding tool 8 processes the circumference of the insert blank 2 .

Fig. 5 shows in a front view and partly in section, a copy grinding machine, on which the processing steps described are executed. A machine frame 19 has two vertical guide columns 20 , on which a cross slide 21 is guided so that it can move vertically. The cross slide 21 carries horizontal guide columns 22 , on which a machining support 23 is guided. The cross slide 21 and the machining support 23 can execute vertical infeed movements by means of a vertical spindle 24 . Instead, it can also be provided that the machining support 23 is resiliently received in the vertical direction, so that the copy button 7 can follow the contour of the upper side of the impression model 1 .

The copy button 7 is clamped in a holder 25 on the front of the machining support 23 . In addition, a drive unit 26 is clamped in the holder 25 , the rotationally driven spindle 27 receiving the grinding tool 8 .

A jig 28 used in the form of grinding machine has a base plate 29 on which a clamping slide 30 is guided movably on a cross slide 31 in two horizontal axes relative to the machine frame 19th This horizontal movement of the clamping slide 30 is carried out by hand by means of two handles 32 attached on both sides. The carrier 3 is exchangeably fastened on the clamping table 30 by means of a screw 33 . In the same way, the second support 9 can be screwed on. A coolant line 34 enables the supply of coolant to the grinding tool 8 .

In the exemplary embodiment shown, the copy button 7 is a copy pen which mechanically touches the impression model 1 and which has a spherical head which is preferably of the same diameter as the spherical grinding head of the grinding tool 8 . This results in a complete match between the scanned impression model 1 and the shaped inlay. If dimensional deviations are desired, the spherical head of the copy button 7 can be selected larger or smaller than the grinding tool 8 by the respectively desired dimension.

As can be seen from FIG. 5, all movement guides on the guide columns 20 and 22 and in the region of the cross slide 31 are equipped with ball guide bushes, so that the movements can be carried out with the lowest possible forces.

To carry out the processing step shown schematically in FIG. 4, the receiving device 28 can be exchanged for the receiving device 35 shown in FIG. 7. The two turntables 17 and 18 , which are used to hold the impression model 1 and the insert blank 2 , are each connected via a vertical shaft 36 and 37 to a toothed belt pulley 38 and 39 , which are in drive connection with one another by a toothed belt 40 . The shaft 37 is rotated by means of a hand crank 41 via a worm drive 42 . The toothed belt 40 drives the shaft 36 synchronously and in the same direction.

The horizontal movement of the machining support 23 required when the clamping device 35 is used takes place along the horizontal guide columns 22 . A tension spring 43 ( FIG. 5) pulls the machining support 23 to the right and presses the copy button 7 against the impression model 1 .

Also for use in the machining step shown in FIG. 4, it is provided that the copy button 7 is horizontally adjustable relative to the grinding tool 8 . For this purpose, the copy button 7 is clamped in a button carrier 44 which can be moved horizontally along the holder 25 and can be tightened by means of a screw 45 ( FIG. 5). An adjusting screw 46 is used for the horizontal adjustment of the button holder 44 . A dial gauge 47 is clamped on the holder 25 and rests with its probe on the upper end of the copy button 7 , so that the degree of horizontal adjustment on the dial gauge 47 can be read or set.

By adjusting the horizontal distance between the copy button 7 and the grinding tool 8 it is achieved that the diameter of the grinding tool 8 can be selected independently of the diameter of the copy button 7 . Different diameters of the grinding tools 8 used or the copy button 7 are compensated for by this horizontal adjustment. This horizontal adjustment also makes it possible to achieve predetermined dimensional deviations between the impression model 1 and the machined insert blank 2 . For example, the insert blank 2 can be pre-machined with a predetermined oversize in a first workflow. The final machining can then take place in a second machining operation, with only this excess being removed. This second machining process can thus be carried out with even greater accuracy than if the finished machining were to be carried out from the full material.

To mechanize or automate the To allow editing process may differ from the illustrated embodiment can be provided that all or individual movements are motor-driven and controlled. For example, a Program control can be provided.

In a departure from the exemplary embodiment shown, it can also be provided that the copy button 7 is a deflectable touch sensor which supplies copy control signals via a control device to feed drives which carry out the relative movements in the three axes.

Claims (16)

1. A method for producing dental inserts from dental ceramics or similar material by shaping, characterized in that an impression model ( 1 ) is formed from a hardening material including the contouring of the exposed surface in the fully prepared tooth cavity to be filled, that the impression model ( 1 ) is scanned as a copy template by means of a copy button ( 7 ), and that, according to the impression model ( 1 ), a tooth insert machined on all sides is made from an insert blank ( 2 ) made of dental ceramic or similar material in a copy grinding process. 2. The method according to claim 1, characterized in that the tracer point (7) and a grinding tool (8) at a fixed distance are arranged to each other and a common movement relative to the scanning model (1) and likewise arranged in a fixed distance to insert blank (2) To run. 3. The method according to claim 1, characterized in that in a first processing step, part of the surface is copied in a first clamping of the impression model ( 1 ) and the insert blank ( 2 ) and that in a second processing step, the remaining part of the surface in a second Clamping of the impression model ( 1 ) and the insert blank ( 2 ) is copied, whereby a defined position assignment is maintained in both clampings. 4. The method according to claim 3, characterized in that the impression model ( 1 ) and the insert blank ( 2 ) in the first clamping on a common first carrier ( 3 ) are received, that after the first processing step, the impression model ( 1 ) and partially machined blank insert (2) are transferred together to a second carrier (9), and that takes place in the second clamping on said second support (9), the finishing of the insert blank (2) for dental use. 5. The method according to claim 4, characterized in that the impression model ( 1 ) and the insert blank ( 2 ) are taken up on the two carriers ( 3 , 9 ) by means of adhesive ( 6 , 12 ). 6. The method according to claim 5, characterized in that an adhesive wax ( 6 , 12 ) is used as adhesive and that the softening temperature of the adhesive wax used in the first clamping ( 6 ) is lower than the softening temperature of the adhesive wax used in the second clamping ( 12 ). 7. The method according to claim 4, characterized in that the recording of the impression model ( 1 ) and the insert blank ( 2 ) in the first clamping and / or in the second clamping by means of mechanical clamping devices ( 16 ). 8. Device for carrying out the method according to any one of claims 1-7, with a form grinding machine in which a drivable grinding tool is mounted, with a machine frame and a workpiece holder for the insert blank, characterized in that a copy button ( 7 ) and the grinding tool ( 8 ) are arranged at a fixed distance from one another and that the impression model ( 1 ) and the insert blank ( 2 ) are received on a common clamping device ( 28 or 35 ) and for relative movements in three axes with respect to the copy button ( 17 ) and the grinding tool ( 8 ) are movable. 9. The device according to claim 8, characterized in that the copy button ( 7 ) and the grinding tool ( 8 ) on a common, vertically movable in the machine frame ( 19 ) guided processing support ( 23 ) are arranged and that the clamping device ( 28 ) one in two horizontal Axis movable clamping carriage ( 30 ) with respect to the machine frame ( 19 ). 10. The device according to claim 9, characterized in that the height adjustment of the machining support ( 23 ) is controlled in predetermined steps and that the clamping slide ( 30 ) is movable by hand in both horizontal axes. 11. The device according to claim 8, characterized in that the copy button ( 7 ) and the grinding tool ( 8 ) on a common, vertically movable in the machine frame ( 19 ) guided machining support ( 23 ) are arranged so that the machining support ( 23 ) can be moved in the horizontal direction and that the clamping device ( 35 ) has two turntables ( 17 , 18 ) which can accommodate the impression model ( 1 ) or the insert blank ( 2 ) and can be driven synchronously and in the same direction. 12. The apparatus according to claim 4, characterized in that a the impression model ( 1 ) and the insert blank ( 2 ) in the first clamping receiving first carrier ( 3 ) by means of a centering device ( 13 , 14 , 15 ) against which the impression model ( 1 ) and the insert blank ( 2 ) can be centered in the second support ( 9 ) receiving the second clamping. 13. The apparatus according to claim 12, characterized in that the two carriers ( 3 , 9 ) can be centered against each other by means of at least two parallel centering pins ( 13 ) which engage in centering bores ( 14 and 15 ) of the two carriers ( 9 and 3 ) . 14. The apparatus according to claim 8, characterized in that the copy button ( 7 ) is a copying pen mechanically touching the impression model ( 1 ). 15. The apparatus according to claim 14, characterized in that the copy button ( 7 ) has a spherical head and that the grinding tool ( 8 ) has a spherical grinding head with the same diameter. 16. The apparatus according to claim 8, characterized in that the copy button is a deflectable probe, the Copy control signals to feed drives that delivers Carry out relative movements in the three axes.