JP4291897B2 - Method for producing dental prosthesis - Google Patents

Description

[0001]
[Industrial application fields]
  The present invention relates to an apparatus for performing automatic measurement by computer control and automatic processing based on this measurement information, and by using automatic measurement and automatic processing means represented by a CAD / CAM apparatus, a precise dental prosthesis, and the like.Same, similar or corresponding to dental materialThe present invention relates to a dental prosthesis manufacturing method and a dental prosthesis manufacturing apparatus for measuring and manufacturing a workpiece.
[0002]
[Prior art]
  When a lump is cut or ground with a CAD / CAM device or an NC machine tool, there are a roughing process and a finishing process. In the former, a lump of a certain size is roughly processed up to an approximation of a target shape. At that time, a thick cutting or grinding tool is used. In the latter case, the material after roughing is processed up to the target shape. The processing method in the case of performing the above process has been processed in the form of digging with a cutting or grinding tool downward from the upper surface of the lump in order. This method has intensively used only the tips of cutting or grinding tools such as end mills and diamond bars.
  In the case of a general NC machine tool or CAD / CAM device, the measurement object and the workpiece are separately installed, or the measurement device and the processing device are separated.
  When preparing a dental prosthesis, an abutment tooth is impressed and an abutment tooth plaster model is prepared. On top of that, the shape of the dental prosthesis was made with wax and replaced with metal by casting. During this time, manpower and man-hours were required, and the quality varied.
  The production of dental prostheses (especially crowns) with NC machine tools is being researched and developed for practical use. In the process of manufacturing the dental prosthesis, a dental prosthesis model is made of wax or resin, the shape is faithfully measured, and finished by cutting or grinding with an NC machine tool. In addition, although it was only in the inlay, the teeth with cavity formation were photographed with a camera and grayscale3There is a system for creating and cutting dimensional shape data.
[0003]
[Problems to be solved by the invention]
  In the conventional method, when cutting or grinding a square or cylindrical lump, the cutting or grinding tool is dug downward from the top of the lump in order, so that cutting such as an end mill or diamond bar is performed. Alternatively, only the tip of the grinding tool was used, and the tool was severely damaged. For this reason, the tool life is short. Furthermore, blades and diamond grindstones other than the tip were not used and were wasted.
  In addition, since the engraving amount is concentrated on one point of the tool, machining time is required.
  Since the workpiece and the workpiece are installed separately, there is a problem that the measured data is shifted from the workpiece unless the position of the workpiece is accurately reproduced. In particular3When reproducing a three-dimensional shape, the workpiece and the workpiece may be rotated, which adds to the problem of alignment due to the rotation, and is further complicated. In order to eliminate this, it was necessary to accurately measure the position of the object to be measured and install the object to be processed, and time and labor were consumed. In addition, when measurement and machining are performed in the same work area, dirt due to machining may affect the measurement.
  In the field of dentistry, the production of dental prostheses was almost manual, and mechanization was delayed. In recent years, dental CAD / CAM devices have finally begun to be developed. However, there is a problem that time and running cost are very high because machining is applied to the above method. Also,3Dimensional shape measurement models must be made with high precision using wax or resin. That means3If the dimensional shape measurement model is bad, it becomes a bad dental prosthesis. In particular, manufacturing a dental prosthesis having a good margin line and a good fit requires advanced technology, and requires labor and time for a dental CAD / CAM device and a casting method. Furthermore, stable quality supply was also an issue. In the case of gray scale, the accuracy and resolution of the camera are not sufficient to withstand the accuracy of the dental prosthesis. As a result, the spread of mechanization in the dental field has also become a factor.
[0004]
[Means for Solving the Problems]
  The present invention makes it possible to effectively use a blade of a cylindrical portion (side surface portion), a diamond grindstone, or the like in addition to the end of a cutting or grinding tool such as an end mill or a diamond bar.
[0005]
  As a method,
  First, on the XY plane, a cutting or grinding tool is approached from the outside of the lump, and rough machining is performed up to the contour at the cylindrical portion of the tool (side surface portion of the tool).
    Next, the lump is rotated by 90 ° on the X axis, and the rough contour is similarly processed on the XZ plane.
  The finishing process is the same.
  However, depending on the target shape, there is a case where the finishing process is performed on the XY plane, and the finishing process is performed in the same manner by reversing 180 degrees on the X axis.
[0006]
  In this method, the outer shape obtained by projecting the processing shape on the XY plane can be processed by the cylindrical portion of the cutting or grinding tool. Further, if it can be rotated 90 ° around the X axis and can be made on the XZ plane in the same way, depending on the shape, the desired product can be obtained only by that process. In addition, if the lump that has been roughed by this method is finished according to the final target shape, the tool tip will be used mainly at the finishing stage. Processing can be performed continuously without changing tools. By dividing the work area for measurement and machining, measurement can be performed in a clean area. In addition, the positioning of the workpiece and the workpiece can be solved by installing them on the same axis. The same can be said for the rotational axis accuracy, which is particularly a problem, because they exist on the same axis.
[0007]
  Such as cutting and grinding3Dimensional shape data is created using an abutment tooth plaster model produced from a dental impression.
  As required by current dental technicians, the necessary part of the abutment gypsum model is extracted, and the gingival side below that line is easy to see the margin line of the abutment gypsum model in the Z-axis direction. Trimming to overhang on top.
  Trimmed abutment tooth plaster model from the largest ridge to the occlusal surface with wax or instant polymerized resin according to the size and shape of the adjacent teeth and counter teeth3Create a dimensional shape measurement model.
[0008]
  From the largest ridge to the margin line, it is appropriately produced or not produced so as to overhang at the ridge. Thereafter, the abutment tooth plaster model and the measurement model with the abutment tooth plaster model are measured with a three-dimensional shape measuring instrument.
  The overhang part of the data obtained by measurement is deleted in the data. The data can be deleted by either processing the data of the two-dimensional contour in the Z-axis direction for the margin line or the maximum rich part line and deleting the data below those lines, or Z without movement in the X-axis and Y-axis directions. There is a method to delete only the data moved in the axial direction. The data obtained by measuring the abutment tooth plaster model and processing the margin line data was converted into male and female and mirrored to obtain the inner surface shape data of a dental prosthesis such as a crown.
  At that time, the inner surface shape data may be offset in the normal direction in consideration of the cement portion.
  Prepare the processed data of the data and the maximum hoyutaka line, face the area of the largest hoyutaka from the margin line, and make one dental prosthesis3Dimensional shape data.
  In the oral cavity using instant polymerized resin3In the same way as above, we created a 3D shape measurement model.3Dimensional shape data can be acquired and processed, and a dental prosthesis can be produced using the inner surface shape data.3It is a dimensional shape measurement model. In this case, produced in the oral cavity3An ideal occlusal surface shape is obtained by allowing the patient to bite the dimensional shape measurement model to some extent. Therefore, it is possible to provide a dental prosthesis that does not cause a patient's discomfort.
[0009]
  Also,3A method that eliminates the production of a three-dimensional shape measurement model is also possible. General in advance3Prepare a database of three-dimensional shape models, perform processing on the computer, and use the inner surface shape data obtained by the above method to make one dental prosthesis3This is a method that is performed using dimensional shape data.
  Furthermore, in the field or on the model, we produced and measured a lump of wax or resin that contained the minimum necessary information such as contact points, movement paths, and hoyutaka, and measured a prepared tooth profile database.3A method to process and insert a deformed shape so as to fit the dimensional data is also presented.
  In the case of coping of a dental prosthesis, only the trimmed abutment plaster model is used. Trimmed abutment tooth plaster model3Measure with a dimensional shape measuring instrument and process the overhang part below the margin line. The data is used as inner surface shape data as described above. Also, the data is extracted from the margin line at a certain height and offset by a certain amount in the normal direction. The data and the margin line are flattened and used as the external shape data. These inner and outer surface shape data become coping shape data. In addition, machining data can be created for a denture base as well as this coping.
[0010]
  The material of the lump is ceramics, metal, synthetic resin, wood and others3With a dimension machine tool3It is made of a material that can be dimensionally processed and is not particularly limited as long as it can be processed.
  A tool will not be specifically limited if an end mill, a diamond bar, a grindstone, and other lump, ie, a workpiece, can be processed. The same applies to the processing plane.
  Further, for example, “on the same axis” is not particularly limited as long as the coordinate axes are the same by an orthogonal coordinate axis, a cylindrical coordinate axis, a spherical coordinate axis, and a certain function expression. In addition, the abutment tooth model, the workpiece and the material of the workpiece, the method of producing the workpiece,3The dimension shape measurement or acquisition method, processing method, data offset method and amount, and overhang direction are not particularly limited.
[0011]
[Action]
  By using the cylindrical portion (side surface portion of the tool) of the tool (cutting or grinding tool) to process the lump, the area of the tool that corresponds to the lump increases. This shortens the machining time and extends the tool life. In addition, the roughing and finishing tools were used separately, but the tooling was exchanged between roughing and finishing by separating the roughing from the side of the tool and finishing from the tip of the tool. There is no processing.
  By dividing the measurement area and the machining area and placing the workpiece and the workpiece on the same axis, the influence of the measurement due to the dirt on the machining is eliminated, and the positioning becomes simple.
  A dental prosthesis having a good fit of the abutment tooth and matching margin lines can be easily and quickly manufactured without depending on human skill.
[0012]
[Example 1]
  An embodiment of the present invention will be described in detail with reference to FIG.
  The cutting apparatus used as the present invention is based on an NC machine tool used as a machine for processing a die or the like.Body 3 shown in FIG.Is3Dimensional shape measurement area 4 and3Divided into a dimensional machining area 5.3Dimensional shape measurement area 4 has a contact element 8 attached.3A three-dimensional shape measurement probe 6 is installed.3Dimensional shape measurement probe 6 is on the X, Y, Z axis table,3Dimensional movement is possible. An AC servo motor with an encoder was used for the power of each shaft.3In the dimensional machining area 5, the spindle motor 7And grinding tool connected to this motor19 is installed.3As with the dimensional shape measurement area 4, the spindle motor 7 is also3Dimensional movement is possible. As for control of operation, thisBody 3 includes CRT1We performed with PC 2 connected. Furthermore, a water injection nozzle 32 is provided for the purpose of cooling and removing the processing waste from the workpiece,3Dimensional machining area 5InWaterproofed.3Dimensional shape measurement area 4The object to be measuredMeasurement model 11Gripping and rotatingA jig 10 to be attached3The workpiece 15 in the dimensional machining area 5Gripping and rotatingThe jig 9 to be attached is connected inside, and the jigs 9 and 10 can be rotated by an AC servo motor with an encoder used for the power of each shaft. When the measured data is processed as it is, the measurement model 11 is processed into a mirror-inverted shape. Therefore, once measured dataBy combination of general-purpose personal computer 2 and CRT1 of general-purpose personal computerMirror inversion of X axis and Y axisProcess toThen, data is sent to the NC machine tool for processing.
  Reference numeral 13 denotes a cable for sending three-dimensional shape measurement data to a general-purpose personal computer. Reference numeral 14 denotes a cable for sending data to control a three-dimensional machining area having the same configuration as that of an NC machine tool.
[0013]
  A crown model 11 was produced from an immediately polymerized resin on a gypsum model used for dental treatment, and attached to a measurement model rib 12 which could be positioned by measurement with an adhesive, and installed in the above-described apparatus. ThatDental prosthesisCrown model 113The shape was measured with the three-dimensional shape measurement probe 6 and processed by the personal computer 2 as measurement data. Further, the measurement data was processed into grinding data by the personal computer 2. Grinding data includes two types of data: rough processing data for processing from a lump to an approximation of a target shape and finishing processing for processing from rough processing to a target shape. In order to grind the crown, porcelain actually used for dental prosthesis was formed into a prism block and prepared. The porcelain prism block 153It was installed in the apparatus in the same manner as the measurement model 11 of the dimension shape measurement. The grinding method is based on the grinding data prepared on PC 2.Body 3And then do it. The grinding process is divided into roughing and finishing. A diamond bar tool of φ2 mm is used as a roughing processing tool and φ1 mm is used for finishing processing.
[0014]
  Roughing is performed by the processing method of the present invention.
  2, 4, and 5 are views of the block to be cut as viewed from the top, and FIG. 3 is a view as viewed from the side. The numbers assigned to the blocks may be different but are the same.
  FIG. 2 shows an example of a rough surface of an XY plane (crown model), FIG. 4 shows an example of a rough surface of an XZ plane (crown model), and FIG. 5 shows an example of a rough surface of an abutment tooth surface (inner surface).

    In FIG. 2, a diamond having a diameter of 2 mm extends from the approximate shape of the crown model 11 onto the porcelain prism block 15 onto the XY plane shown in FIG. 1 up to the outer shape of the crown model 17 projected on the XY plane (indicated by a dotted line). Grinding was performed on the side surface of the grinding tool 19 indicated by the bar tool. Reference numeral 18 denotes a movement trajectory of the grinding tool in the contour processing on the crown model XY plane, and the cutting state is indicated by the contour on the line.Trajectory18 of 1TrajectoryShows a single cutting, and shows a state in which the cutting changes over time by a plurality of times of cutting from the outside to the inside.
  Trace interval and its traceThe number of times of cutting indicated by is determined by comparing the measurement data and the size of the cutting block in the previous stage of cutting,
  When a large amount of cutting is performed, the interval is widened, and a small portion is set so as to reduce the interval, and the cutting operation is performed in a reciprocating manner while making a round around the block.
  still,TrajectoryAs shown in the figure, an operation of making a round trip so as not to end in the middle is preferable. However, the present invention is not limited to this, and it may stop and return in the middle. This is suitable when there is a large difference in the value of each part in the comparison between the model and the block, and it is not necessary to make a round.
  TrajectoryWhenTrajectoryIn the meantime, a range of 0.01 mm to 2 mm is preferable by the above-described control, but is appropriately selected according to the state of the material, for example, the porosity, the shape, etc. in the case of a porous material.
  After that, the porcelain prism block side face 22 cut to the outer shape 17 shown in FIG. 1 was rotated 90 ° about the X axis as shown in FIG. The rotation amount is preferably rotated every 90 °, but is not limited as long as the contact property of the processing surface with the processing tool is good, and the rotation amount is appropriately adjusted.
  Up to the outer shape (indicated by a dotted line) obtained by projecting the approximate shape of the crown model 23 on the XZ plane was formed while performing a plurality of times of cutting as shown in FIG.Reference numeral 24 denotes a locus of a grinding tool in contour processing on the XZ plane.
  Like the one shown in Fig. 1, cut from outside to inside,TrajectoryThe distance between them is preferably 0.01 mm to 2 mm, but is appropriately selected as described above.
  After roughing the XZ plane by the above grinding, it was rotated 90 ° about the X axis.
  FIG. 5 shows the state after rotation. FIG. 5 shows the abutment tooth surface. Reference numeral 20 denotes a porcelain prism block after the crown model contour processing.
  The abutment tooth surface side (inner surface) of the crown model 11 was ground on the contour line 21 to complete the roughing.
  One contour line21However, the interval is preferably 0.01 mm to 2 mm, and the interval is not limited. If the material is a porous material, for example, the porosity, the shape, etc. It is selected accordingly.
  If the interval between the contour lines forming the contour is large, the surface becomes rough, and if it is small, the surface becomes rough, so the finer is preferable. An interval of about 1 mm is preferable.
  The φ2 mm diamond bar tool was replaced with a φ1 mm diamond bar, and the abutment tooth side (inner side) of the porcelain crown was finished by a general method. One layer from the approximate shape to the target shape was ground, and then the work piece (the porcelain prism block) was turned 180 ° around the X axis, and the occlusal surface of the crown was finish ground. The finished crown was removed from the device, the rib part was excised by human hand, and hand polishing was completed.
[0015]
  When the rough machining method in which the diamond bar tool is dropped from the normal upper surface to the lower surface in order, about 4 hours were spent. Moreover, only two or three roughing operations could be performed with one diamond bar tool. When the roughing method was used by effectively using the processing surface of the processing tool as in the present invention, the processing was completed in about one hour. Moreover, 4 to 5 grinding operations could be performed with one diamond bar tool.
  Conventionally, the work area has been cleaned cleanly for each measurement. However, as shown in FIG. 1, the measurement area 4 and the processing area 5 are separated, so that it is not necessary to clean each measurement. Also, place the workpiece and workpiece on the same axis and insert them into the jig.For jig insertionrib16For adjusting the amount ofFor jig insertionrib16With the positioning stopper 33, positioning could be performed reliably, and the three-dimensional shape of the crown model could be reproduced.
  To the target shapeContour locusAs long as it is performed on the side surface of the processing tool, it is not limited to the example.
[0016]
[Example 2]
  In the apparatus used in Example 1, the inlay of the dental prosthesis was ground from the porcelain prism block. This is shown in FIGS. 6, 7 and 8 (a) (b).
  Porcelain prism block 25For jig insertionWith rib 16For jig insertionThe positioning stopper 33 of the rib 16 is connected.
FIG. 6 shows an example of a state in which XY plane roughing (inlay model) is performed, and FIG. 7 is a view showing a state in which the side surface of the grinding tool 31 at the time of contour machining in FIG. FIG. 8A is a diagram of an XZ plane roughening (inlay model), and FIG. 8B is a diagram illustrating a state in which FIG. 8A is rotated 90 ° backward about the X axis.

  An inlay model was prepared with an immediate polymerization resin on a gypsum model used for dental treatment, and grinding data was prepared in the same manner as in Example 1.
  A grinding tool 31 for both roughing and finishing, which is a diamond bar tool with a diamond grindstone of φ3 mm and φ1 mm, which can be used for both roughing and finishing of the porcelain prism block 25 was installed. Contouring was performed up to the outer shape obtained by projecting the approximate shape of the inlay model 26 on the XY plane with a cylindrical portion (side surface portion) of a thick φ3 mm portion of the grinding tool 31 made of a diamond bar tool.
  Of the grinding tool 31 in the contour machining of this embodiment.TrajectoryThe inlay model XY grinding tool for contour processing on the XY planeTrack 27ofTrace intervalIs preferably from 0.01 mm to 3 mm, and is appropriately selected depending on the material, for example, the porosity, shape, etc., if it is a porous material.
  As shown in FIG. 8, the porcelain prism block 28 after the inlay model contour processing was rotated 90 ° about the X axis. Grinding was similarly performed up to the outer shape (indicated by a dotted line) obtained by projecting the approximate shape of the inlay model 29 onto the XZ plane of the prism block 28.
  Of FIG.30 isThis is a locus of a grinding tool for contour processing by further rotating the XZ plane with respect to the outer shape projected on the XZ plane.ConcernedTrajectoryThe interval of 30 is 0.01 mm to 3 mm, and a material, for example, a porosity, a shape, and the like are appropriately selected in the case of a porous material.
[0017]
  Next, before proceeding to the finishing process, the roughly processed porcelain prism block was reversely rotated by 90 ° about the X axis so as to be on the XY plane before the roughing process. This state is shown in FIG.
  Similar to general finishing, one layer from the approximate shape to the target shape was ground.
  Thereafter, the work piece (a porcelain prism block) was turned 180 ° about the X axis, and the back side of the inlay was finish ground. What was used for the finishing process at this time was a process using a thin portion of φ1 mm of the diamond bar tool 31. The finished inlay was removed from the device, the rib part was excised by human hands, and hand polishing was completed.
[0018]
  When processing this inlay, it can be processed in the same manner as described above using only a diamond bar tool of φ1 mm. However, if this diamond bar tool 31 having both φ3 mm for roughing and φ1 mm for finishing is used, a large amount of grinding can be performed at the time of roughing, so that grinding can be performed in about half the time. Moreover, if it carries out by the method of this invention, it can perform continuously from roughing to finishing.
  It should be noted that the target shape is not limited to the example as long as the shape is matched with the contour and is processed on the side surface of the processing tool and processed with one processing tool.
[0019]
[Example 3]
  Using the apparatus of Example 1, a dental prosthesis crown was produced from the shape of the abutment tooth plaster model and the shape of the incomplete occlusal surface wax model.

  Model formation

  An impression was taken from the patient's mouth, and an abutment tooth plaster model was created. As shown in FIG. 9, an abutment tooth plaster model 34 in which a gingival portion below the margin line 36 was trimmed 35 was prepared.
  FIG. 10 shows a trimmed abutment tooth gypsum model in which a wax model 37 is produced in accordance with adjacent teeth and counter teeth. At that time, in normal wax-up, the crown shape is produced by paying attention to the margin line, which is regarded as important, but in the case of the present invention, if the lower side of the maximum bump 38 is overhanging, It doesn't matter if you
[0020]

  Model surface measurement

  FIG. 11 shows the wax model 37.3Dimensional shape measurementIn the figure which shows the three-dimensional shape measurement of the occlusal surface side which waxed upis there.
  Put wax model 37Abutment tooth plaster model34 was installed on the fixed adapter 40, and the rib 41 of the fixed adapter 40 was fixed to the mounting jig 10 in the measurement area 4 of the apparatus of FIG.
  As shown in FIG.Contact element 8 on the surface of wax model 37Measured data39, and the X, Y and Z coordinate points of the surface 39 were obtained. Wax model 37's largest holy part(line)The shape below 38 is not acquired because it is an overhang, and the largest holy part(line)It is acquired as a shape with 38 contours extended downward. At that time, set the PC 2 so that the contact element 8 does not hit the fixed adapter 40.The Z-axis direction of the contact element 8When the contact element 8 comes down to the lower limit line 43, it escapes in the XY plane direction.

  Then remove the wax model 37 and the surface of the abutment tooth plaster model 34Measured dataThe shape of 42 was measured in the same way. This is shown in FIG.FIG. 12 is a diagram showing three-dimensional shape measurement of the trimmed abutment gypsum model.In this case, the lower side of the margin line 36 isTrimmed part35, an overhanging state, that is, a state in which the measurement probe 8 is not in contact with the trimming portion and data cannot be obtained due to the protrusion of the margin line.
  Therefore, the surface 42 shape data of the abutment tooth plaster model 34 is obtained in the same manner as the surface 39 of the wax model 37. The surface shape 42 data is shown in FIG.
  FIG. 13 shows a state in which the area below the margin line of the data obtained by measuring the three-dimensional shape in FIG. 12 is deleted.
[0021]

  Processing of measurement data

  From the data measured for each shape3Create dimensional shape data. Fig. 14 shows how to process the shape measurement data of the abutment tooth plaster model.FIG. 14 is a diagram in which the data shown in FIG. 13 is processed into inner surface processing data by performing offset and male-female conversion.The shape data in which the margin line 36 of the abutment tooth plaster model 34 is overhanged on the lower side is the data moved in the Z-axis direction without the movement amount in the X- and Y-axis directions.
  Then, there is no movement amount in the X, Y, and Z axis directions and the previous movement amount in the X and Y axis directions, and the boundary line of the data moved in the Z axis direction becomes a margin line 36, and the boundary line, that is, the margin Data below the Z axis from the line 36 is deleted. The remaining data becomes the abutment tooth shape data.
[0022]
  Thereafter, the upper data is offset by 50 μm in the normal direction from the portion of the line 46 having a height higher than the boundary line, that is, the margin line 36, and the offset amount is reduced as the lower data is shifted from the line 46 to the lines 46 to 36. The data 45 was prepared by connecting to the line 36.
[0023]
  At this time, the certain height is set to 1.0 mm from the margin line 36. Further, the offset surface tension data 45 was converted into male and female to obtain crown inner surface shape data. The offset purpose is to make the crown easy to set up smoothly and also because of the space in the cement layer where the crown is attached. In addition, the escape of the machining tool is taken into consideration. Further, the crown outer surface machining data processing is performed in the same manner as described above.
  This offset value is determined by the amount of adhesive, ease of setting, etc., preferably in the range of 20 μm to 100 μm, and the curve obtained based on the offset value and the margin line is a spline. It is preferable to be determined by a smooth curve such as a curve or a Bezier curve, but is not limited thereto.
  The surface shape data 39 of the wax model 37 is shown in FIG.. FIG. 15 shows a state in which the area below the maximum ridge portion of the data obtained by measuring the three-dimensional shape shown in FIG. 11 is deleted.
  The data below the Z axis from the largest holy part 38Unnecessary three-dimensional shape data 58 that is overhanged,Removed this. The method of deleting data is the same as described above.
  The remaining occlusal surface shape data 47 and inner surface shape data 49 were synthesized.The inner surface shape data 49 was formed by male and female conversion of the abutment tooth shape data.In the synthesis, the positioning of the occlusal surface shape data 47 and the inner surface shape data 49 was based on the installation position of the abutment tooth plaster model 34. After that, the surface is stretched based on the surface data from the largest ridge 38 to the margin line 36.Form data 48,One crown shape data 50 was obtained. Surface data was created by calculating control points during that time.
  There are methods using a Bezier curve, a spline curve, etc. as a method of generating a curved surface by using the margin line 36 and the maximum bumpy portion 38 as a boundary curve and using control points between them. Curved surface data was calculated.
  The rib shape data 51 for gripping the workpiece during grinding is synthesized with the crown shape data 50.
  This is shown in FIGS.
  FIG. 16 shows a state where the surface from the margin line to the maximum ridge portion line is stretched, and FIG. 17 shows a state where the processing rib data is combined with the crown shape data.

[0024]
  From the crown shape data 50, grinding was performed with a diamond bar tool from a porcelain prism block in the same manner as in Example 1 to produce a crown of a dental prosthesis. Conventionally, matching of the margin line and the inner surface which require high technology can be performed well. Moreover, even if the wax model is made rougher than before, the method is not related to the accuracy of the dental prosthesis.
[0025]
  In this example, a wax model was prepared from an abutment tooth plaster model. However, if there is an abutment tooth model, one crown shape data may be used based on model data produced in the patient's oral cavity or data obtained by transforming or converting existing occlusal surface data. Boundary lines such as margin lines and maximum ridges can also be extracted by measuring the contour of the maximum area on the XY plane in advance and checking it against the shape-measured data to remove the overhang part. . Although the crown of a dental prosthesis has been illustrated, a connecting crown can be similarly performed. In the case of a bridge, it is possible to deal with by preparing pontic (dummy) data and performing transformation or conversion. In addition, the material of the abutment tooth model, workpiece and workpiece,3The dimension shape measurement method, processing method, data offset method and amount, and overhang direction are not limited to the examples.
[0026]
[Example 4]
  Using the apparatus of Example 1, a coping (frame) was produced from an abutment tooth plaster model. An impression was taken from the patient's mouth, and an abutment tooth plaster model was created. As shown in FIG. 9, an abutment tooth plaster model 34 in which a gingival portion below the margin line 36 was trimmed 35 was prepared.
  The shape of the abutment gypsum model was measured as in Example 3 (FIG. 12). Thereafter, the data of the overhang portion was deleted, and the abutment tooth shape data 44 was obtained.
  Further, similarly, the lower data is deleted from the boundary 46, that is, the line 46 having a height of 1.0 mm from the margin line 36, and the data 45 offset by 50 μm in the normal direction and the data 45 extending to the margin line 36 are provided. Prepared. The offset surface tension data 45 was subjected to male / female and mirror conversion to obtain coping inner surface shape data 52. The outer surface shape data 53 of the coping is obtained by deleting the lower data from the portion of the line 0.6 mm higher than the margin line 36 of the abutment tooth shape data 44 and offset by 0.5 mm in the normal direction. It is data that puts up to.Coping inner / outer surface shape data createdIs shown in FIG. FIG. 19 is obtained by synthesizing coping inner surface shape data 52 and outer surface shape data 53 into one coping shape data 54 and adding processing rib data 55.
  Based on this data, normal titanium cutting was performed with the apparatus of Example 1. A state in which the rib portion is cut from the finished titanium coping 56This is shown in FIG.The titanium coping 56 was baked with a porcelain material 57 and completed.
[0027]
  Connection crowns, bridge frames, and denture bases can be performed in the same manner. Material of the abutment tooth model and workpiece,3The dimension shape measurement method, processing method, data offset method and amount, and overhang direction are not limited to the examples.
[0028]
【The invention's effect】
  In the present invention, when processing up to a certain target shape, the processing time can be shortened, the life of the processing tool can be extended, and the number of steps can be reduced. In addition, it has become possible to easily perform inner surface matching and margin line matching of dental prostheses that require accuracy in the dental field.
  This has led to a significant promotion of mechanization, especially in the dental field. This eliminates the need for dental technician skills, makes it possible to reduce the man-hours and manual labor involved in the production of dental prostheses, and lead to the supply of high-quality dental prostheses.
[Brief description of the drawings]
FIG. 1 of the present inventionExamples are shownFigure.
FIG. 2 shows another embodiment of the present invention.Examples are shownFigure.
[Fig. 3]The figure for demonstrating the Example of this invention.
[Fig. 4]The figure for demonstrating the Example of this invention.
[Figure 5]The figure for demonstrating the Example of this invention.
[Fig. 6]The figure for demonstrating the Example of this invention.
[Fig. 7]The figure for demonstrating the Example of this invention.
[Fig. 8]The figure for demonstrating the Example of this invention.
FIG. 9The figure for demonstrating the Example of this invention.
FIG. 10The figure for demonstrating the Example of this invention.
FIG. 11The figure for demonstrating the Example of this invention.
FIG.The figure for demonstrating the Example of this invention.
FIG. 13The figure for demonstrating the Example of this invention.
FIG. 14The figure for demonstrating the Example of this invention.
FIG. 15The figure for demonstrating the Example of this invention.
FIG. 16The figure which shows the other Example of this invention.
FIG. 17The figure for demonstrating the Example of this invention.
FIG. 18The figure for demonstrating the Example of this invention.
FIG. 19The figure for demonstrating the Example of this invention.
FIG. 20The figure for demonstrating the Example of this invention.
[Explanation of symbols]
1 CRT of general-purpose personal computer
2 General-purpose personal computer
3Body
43Dimensional shape measurement area
53Dimensional machining area
63Dimensional shape measurement probe
7 Spindle motor
8 Contact elements
9 Jig for gripping workpiece (rotatable)
10 Jig for gripping the object to be measured (rotatable)
11 Crown model of dental prosthesis
12 Measuring rib with positioning stopper
133Cable for sending dimensional shape measurement data to a general-purpose computer
14 Cable to send data to control NC machine tools
15 Porcelain prism block

Claims (3)

The surface shape of the dental prosthesis model ( 11) is measured in the three-dimensional measurement area ( 4) and converted into three-dimensional shape data. Based on the data, the processing block ( 15) is cylindrical in the three-dimensional processing area ( 5) . In a method for manufacturing a dental prosthesis, a dental prosthesis is manufactured by processing with a grinding tool (19) composed of a shaped end mill or a diamond bar .
A plurality of trajectories (19) in which the grinding tool (19) formed around the outer shape (17) moves while having a shape along the contour shape of the outer shape (17) obtained by projecting the three-dimensional shape data onto a plane. In accordance with the data indicating 18), the processing block (15) is ground on the side surface of the grinding tool (19) inward from the outer locus (18) to form a contour shape of the outer shape (17). A method for producing a dental prosthesis, comprising: a step of performing a finishing process using a tip portion of the grinding tool (19) after the roughing . The method for manufacturing a dental prosthesis according to claim 1, wherein the three-dimensional shape data includes surface shape data of the dental prosthesis model (11) and rib shape data . The dental prosthesis production according to claim 1, wherein an interval of the locus (18) when the grinding tool (9) is moved when grinding the processing block (15) is 0.01 mm to 2 mm. Method.

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