JPS6352897B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dental parallelizer, and in particular, to a dental parallelizer, which is configured to issue an alarm when the axis of the grinder and the axis of the abutment tooth deviate from parallelism by more than a certain angle. The present invention relates to a dental parallelizer.

[Conventional technology]

Abutment tooth preparation is an important fundamental technique in manufacturing a crown prosthesis, and involves providing an appropriate taper to the side wall of the abutment tooth. Generally, the taper that should be given to the side wall of the abutment tooth is approximately 5 to 10 degrees with respect to the axis of the abutment tooth.
The conical grinder used for abutment tooth preparation usually has a taper of 5 to 10 degrees with respect to its axis, and the handpiece to which the grinder is attached is simply moved parallel to the abutment tooth. can be cut as described above.

An example of a conventional dental parallelizer of this type will be explained with reference to FIG. In the conventional example shown in Figure 4,
The inclinometer 5 is attached by the clip 3 to the arm or handpiece 1A of the cutter 1 for the abutment tooth.
This inclinometer 5 can be freely tilted with respect to the handpiece 1A by means of a joint portion 4. At the time of starting cutting of the abutment tooth ST,
After making the axis of the conical grinder 2 attached to the tip of the handpiece 1A parallel to the axis Z--Z of the abutment tooth ST, the inclinometer 5 is made accurately horizontal. Inclinometer 5
is a type that, when tilted at a certain angle or more with respect to a horizontal plane, the internal conductive liquid comes into contact with the electrode and becomes conductive. Therefore, by connecting an alarm circuit externally, the shaft of the grinder 2 and the abutment tooth can be
An alarm is issued when the declination angle with the ST axis Z-Z exceeds a certain angle.

[Problem that the invention seeks to solve]

However, in such a conventional dental parallelizer, an alarm is output when the inclinometer 5 is tilted at a certain angle or more with respect to the horizontal plane, so if the abutment tooth ST side moves, the grinder Therefore, it becomes impossible to obtain a correct warning regarding the declination angle between the axes of ST and the abutment tooth ST. Therefore, the inclinometer 5
After aligning the and abutment tooth ST again as described above,
It is necessary to set the inclinometer 5 horizontally again, which has the disadvantage of poor operability.

In addition, the inclinometer 5 at the start of cutting the abutment tooth ST
The work of leveling the ground directly affects the accuracy of the alarm, so it must be done as precisely as possible. However, the work of leveling the inclinometer 5 requires the use of the grinder 2 and the abutment tooth.
Since it is necessary to maintain both axes of ST and the ST parallel to each other while looking at a spirit level attached to the inclinometer 5, the operation is extremely difficult and the horizontal accuracy is not very good.

Furthermore, since the alarm level is determined mechanically depending on the relationship between the electrodes in the inclinometer 5 and the conductive liquid, there is also the drawback that the alarm level cannot be set to match the working situation.

[Means for solving problems]

In the present invention, posture detectors 51 and 52 are attached to both the hand piece 1A having the grinder 2 and the abutment tooth side PA of the abutment tooth cutter 1, respectively, and which output signals proportional to their inclination angles. Attitude detector 5
By taking the difference between the outputs of 1 and 52, the relative inclination angle between the handpiece and the abutment tooth side is calculated, and a corresponding signal is output.A reset switch 6 is provided, and when this reset switch is activated, By memorizing the relative inclination angle between the handpiece and the abutment tooth side at the time, and calculating the difference between the relative inclination angle between the handpiece and the abutment tooth side and the memorized relative inclination angle, the reset switch can be activated. A dental parallel device that outputs a declination signal of the relative inclination angle between the handpiece and the abutment tooth side from the time when the handpiece is activated, and detects whether or not this declination signal exceeds a predetermined level. Provide a former.

[Effect]

The dental parallel formation of the present invention is performed using a hand piece 1A.
A posture detector, such as a two-axis inclinometer, which outputs a signal proportional to the inclination angle thereof is attached to both the handpiece 1A and the abutment tooth side PA, and the relative angle between the handpiece 1A and the abutment tooth side PA is determined. Calculate and further memorize the relative angle between the two at the time of starting cutting of the abutment tooth ST, and then detect whether the deviation angle between the two has exceeded a certain angle. The above problem is solved by issuing an alarm or stopping the drive source of the grinder 2.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention. First, its configuration will be explained. Reference numeral 1 indicates a cutting tool for the abutment tooth as a whole, 1A is its arm or handpiece, and 2 is a conical grinder attached to the tip of the handpiece 1A. Reference numeral 51 denotes a posture detector attached to the handpiece 1A, such as a two-axis inclinometer, which is detachable and can be freely tilted with respect to the handpiece 1A.

52 is a posture detector such as a two-axis inclinometer, which is attached to, for example, a patient having an abutment tooth ST (hereinafter referred to as abutment tooth side PA) via an attachment such as glasses SP; It is designed to be detachable from the pedestal side PA and can be tilted freely. The outputs of the inclinometers 51 and 52 are sent to the control circuit 7.

6 is a reset switch provided on the handpiece 1A, and when this reset switch 6 is activated,
A reset signal is sent to the control circuit 7. Note that the reset switch 6 may be provided in the control circuit 7.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be explained. First, the inclinometer 51 attached to the abutment tooth side PA is made approximately horizontal in advance. next,
When the axis of the grinder 2 is made approximately parallel to the axis Z--Z of the abutment tooth ST, the inclinometer 52 is attached to the handpiece 1A and adjusted so that it is approximately horizontal.
The inclinometers 51 and 52 are both biaxial inclinometers, for example, as described above, and output signals proportional to the inclination angles in the X direction and the Y direction, which are orthogonal to each other.

In the control circuit 7, the signals sent from the inclinometers 51 and 52 are used to control the handpiece 1A and the abutment tooth side.
Calculate the relative slope angle with PA.

At the time of starting cutting of the abutment tooth ST, after the axis of the grinder 2 and the axis Z-Z of the abutment tooth ST are made parallel, when the reset switch 6 is activated, a reset signal is sent to the control circuit 7. , the control circuit 7 stores the relative inclination angle between the hand piece 1A and the abutment tooth side PA at that time. During the subsequent cutting operation of the abutment tooth ST, the control circuit 7 determines whether the relative inclination angle between the hand piece 1A and the abutment tooth side PA is the relative inclination angle between the hand piece 1A and the abutment tooth side PA that was stored at the time of reset. By calculating how much the inclination angle has changed, the axis of grinder 2 and the abutment tooth can be equivalently determined.
Calculate the declination angle with the axis Z-Z of ST. Furthermore, the control circuit 7 controls the calculated shaft and abutment teeth of the grinder 2.
The declination angle from the ST axis Z-Z is at a predetermined level (angle)
If the limit is exceeded, a warning will be issued. Incidentally, at the same time as issuing this alarm, or instead of issuing the alarm, the drive source of the grinder 2 of the cutting tool 1 may be stopped.

Next, an example of the control circuit 7 of the present invention will be explained with reference to FIG.

First, its configuration will be explained. The adder circuit 71X in the control circuit 7, which is indicated by a dashed line block, is connected to the inclinometer 51 attached to the handpiece 1A.
The direction inclination signal 51X and the X direction inclination signal 52X from the inclinometer 52 attached to the abutment tooth side PA are received, the difference between the two is taken, and the relative relationship between the hand piece 1A and the abutment tooth side PA in the X direction is calculated. Outputs tilt angle signal.
The adding circuit 71Y receives a Y-direction tilt signal 51Y from the inclinometer 51 attached to the handpiece 1A and a Y-direction tilt signal 52Y from the inclinometer 52 attached to the abutment tooth side PA, and calculates the difference between the two. and outputs a relative inclination angle signal in the Y direction between the hand piece 1A and the abutment tooth side PA.

72X and 72Y are hold circuits, respectively, which receive the reset signal 61 from the reset switch 6.
is input, the adder circuits 71X and 7 at that time
Store the output of 1Y and output it. 73X and 73Y are adder circuits, respectively, which receive the output signals of the hold circuits 72X and 72Y and the output signals of the adder circuits 71X and 71Y, and output the difference between them. 74X and 74Y are filter circuits, respectively, and filter the outputs of the adder circuits 73X and 73Y. 75 is a filter circuit 74X and 74Y
This is a time constant setting circuit that sets the time constant of each filter. 76 is an alarm circuit, and filter circuit 7
It receives the outputs of 4X and 74Y, and outputs an alarm when at least one of them exceeds the level set by the alarm level setting circuit 77. Further, the drive source of the grinder 2 of the cutting tool 1 may be stopped at the same time as the alarm is output, or instead of outputting the alarm.
78X and 78Y are indicators, respectively, and these indicate the relative inclination angles in the X and Y directions at the time when the reset switch 6 of the handpiece 1A and the abutment tooth side PA, which is the output of the filter circuits 74X and 74Y, is activated. and X during cutting work after that point.
and the relative tilt angle in the Y direction.

Next, the operation of the control circuit 7 will be explained.

First, as described above, the inclinometer 51 attached to the handpiece 1A and the inclinometer 52 attached to the abutment tooth side PA are made approximately horizontal. At the time of starting cutting of the abutment tooth ST, the shaft of the grinder 2 attached to the handpiece 1A and the abutment tooth
After making the ST axis parallel to Z-Z, operate the reset switch 6. At this time, the reset switch 6 sends the reset signal 61 to both hold circuits 72X.
and 72Y, and store the outputs of the adder circuits 71X and 71Y at that time.

On the other hand, the adder circuit 71X receives the inclination signal 5 in the X direction from the inclinometer 51 attached to the handpiece 1A.
1X and inclinometer 5 attached to the abutment tooth side PA
2, the relative inclination angle in the X direction between the hand piece 1A and the abutment tooth side PA is constantly calculated, and a corresponding signal is output. Similarly, the addition circuit 71Y constantly calculates the relative inclination angle in the Y direction between the handpiece 1A and the abutment tooth side PA,
A compatible signal is being output. Therefore, the hold circuits 72X and 72Y control the handpiece 1A and the abutment at the time when the reset switch 6 is activated (i.e., when the axis of the grinder 2 and the axis Z-Z of the abutment tooth ST become parallel). This means that the relative inclination angle signals in the X and Y directions with respect to the tooth side PA are stored.

Next, the adder circuits 73X and 73Y calculate the difference between the outputs of the above-mentioned hold circuits 72X and 72Y and the outputs of the adder circuits 71X and 71Y, respectively, to calculate the difference between the handpiece 1A from the time when the reset switch 6 is activated. Change in the relative angle between PA and the abutment tooth side, that is, the axis of the grinder 2 and the abutment tooth
Outputs signal components in the X and Y directions of the declination angle with respect to the ST axis Z-Z.

Therefore, at the time of starting cutting of the abutment tooth ST,
By simply operating the reset switch 6, the declination angle between the axis of the grinder 2 and the axis Z--Z of the abutment tooth ST can be constantly obtained with high precision.

The filter circuits 74X and 74Y are each
The outputs of the adder circuits 73X and 73Y, the declination signals in the X and Y directions between the axis of the grinder 2 and the axis Z-Z of the abutment tooth ST, are filtered to remove high frequency components caused by external vibrations, etc. In addition to obtaining a declination signal, an appropriate delay time is provided for alarm detection by the alarm circuit 76. Both filter circuits 74X,
The time constant setting circuit 75 of 74Y is the filter circuit 7
This circuit sets the filter time constants of 4X and 74Y to desired values, and is used to select an appropriate alarm detection response time according to the work situation.

The alarm circuit 76 connects the shaft and abutment teeth of the grinder 2.
An alarm is output when the declination angle between ST and axis Z-Z exceeds a predetermined alarm level, and either filter circuit 74X or 74Y exceeds the level set by alarm level setting circuit 77. Outputs a warning if By allowing the alarm level setting circuit 77 to freely set the alarm level, for example, during training for abutment tooth formation, the alarm level can be selected according to the skill of each trainee, and the training effect can be improved. can be increased.

The alarm circuit 76 combines the outputs of the filter circuits 74X and 74Y, and issues an alarm when the magnitude of the declination between the axis of the grinder 2 and the axis Z-Z of the abutment tooth ST exceeds an alarm level. It may also be possible to output .

The indicators 78X and 78Y are for displaying the outputs of the filter circuits 74X and 74Y, respectively, that is, the X-direction component and the Y-direction component of the declination angle between the axis of the grinder 2 and the axis Z--Z of the abutment tooth ST. . The display method is not particularly limited, but for example, numerical values,
Display with LED, bar graph, meter, etc. By using this indicator, for example, the deviation angle between the axis of the grinder 2 and the axis of the abutment tooth ST during training can be determined.
The instructor can constantly monitor the system, increasing the effectiveness of teaching.

Note that the display circuits 78X and 78Y display the declination angle between the axis of the grinder 2 and the axis of the abutment tooth ST.
The outputs of the respective adder circuits 73X and 73Y may be used directly for display without using the filter circuits 74X and 74Y. The outputs of the adder circuits 73X and 73Y may be displayed via a filter circuit other than the filter circuits 74X and 74Y.

FIG. 3 shows another embodiment of the control circuit 7 of the invention.

In the example of FIG. 3, adder circuits 71X and 71
Inclinometer 5 with Y attached to handpiece 1A
1 and the output of the inclinometer 52 attached to the abutment tooth side PA, and calculate the difference between that output and the hold circuits 72X, 72Y and the adder circuits 73X, 73Y.
using the axis Z of the grinder 2 and the abutment tooth ST
- The process up to obtaining the declination angle with respect to Z is exactly the same as the embodiment shown in FIG.

Now, in the example of FIG. 3, the display circuits 78X and 7
8Y indicates the outputs of the adder circuits 73X and 73Y, that is, the X-direction and Y-direction components of the argument between the axis of the grinder 2 and the axis Z--Z of the abutment tooth ST, respectively; This embodiment is exactly the same as the embodiment shown in the figure, except that it does not include a filter circuit.

In FIG. 3, 79 is an angle synthesis circuit which calculates the absolute value of the argument between the axis of the grinder 2 and the axis Z-Z of the abutment tooth ST using the outputs of the adder circuits 73X and 73Y as input. and output it.
In addition, in the example shown in FIG. 3, one filter circuit 7
4 is used to filter the output of the angle synthesis circuit 79 to remove high frequency components due to disturbance vibration and to provide an appropriate delay time for alarm detection.
Further, 75 is a time constant setting circuit for setting the filter time constant of the filter circuit 74. An alarm circuit 76 receives the output of the filter circuit 74 and outputs an alarm when the output exceeds the level set by the alarm level setting circuit 77.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects can be obtained.

(1) By attaching an inclinometer to the abutment tooth side, even if the abutment tooth side moves, the true declination angle between the axis of the grinder and the axis of the abutment tooth can be obtained.

(2) Just by operating the reset switch at the start of cutting the abutment tooth, the accurate declination angle between the axis of the grinder and the axis of the abutment tooth can be obtained, making it possible to accurately level a conventional inclinometer. This eliminates the need for additional operations, greatly improving operability.

(3) By passing the declination signal between the axis of the grinder and the axis of the abutment tooth through a filter circuit whose time constant can be set arbitrarily, high frequency components caused by external vibrations are removed and a correct declination signal is obtained. , the response time for alarm detection can be selected according to the work situation.

(4) By making it possible to freely set the alarm level, for example, when training for abutment tooth preparation, the alarm level can be set according to the skill of each trainee, and the effectiveness of the training can be improved. can be increased.

(5) By providing a display that displays the declination angle between the axis of the grinder and the axis of the abutment tooth, the instructor can constantly monitor the work status of the trainee during training for abutment tooth formation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an example of a dental parallelizer according to the present invention, FIG. 2 is a block diagram of an example of its control circuit, and FIG. 3 is a block diagram of another example of the control circuit.
FIG. 4 is a schematic diagram of an example of a conventional dental parallelizer. In the figure, 1 is a cutter, 1A is a handpiece, 2 is a grinder, 6 is a reset switch, and 7
is a control circuit, 51 and 52 are attitude detectors, 71X,
71Y, 73X, 73Y are adder circuits, 72X, 7
2Y is a hold circuit, 74, 74X, 74Y are filter circuits, 75 is a time constant setting circuit, 76 is an alarm circuit, 77 is an alarm level setting circuit, 78X, 78
Y is the display, 79 is the angle synthesis circuit, ST is the abutment tooth,
PA indicates the abutment tooth side, and SP indicates the glasses.

Claims (1)

[Scope of Claims] 1. In a tooth parallelizer which is equipped with a posture detector that outputs a signal proportional to the inclination angle of a handpiece having a grinder of an abutment tooth cutter, the abutment tooth side A posture detector that outputs a signal proportional to the inclination angle is attached to the handpiece, and the first adding circuit of the control circuit calculates the difference between the outputs of the two posture detectors, thereby determining the relative position of the handpiece and the abutment tooth side. In addition to calculating the inclination angle and outputting a corresponding signal, a reset switch is provided, and the corresponding inclination angle between the handpiece and the abutment tooth side at the time the reset switch is activated is sent to the hold circuit of the control circuit. By memorizing the difference between the relative inclination angle between the hand piece and the abutment tooth side and the memorized relative inclination angle in the second addition circuit of the control circuit, from the time when the reset switch is activated, A declination signal of the relative inclination angle between the hand piece and the abutment tooth side is outputted, and the alarm circuit of the control circuit detects whether or not the declination signal exceeds a predetermined level, and the declination signal is detected by the alarm circuit of the control circuit. A dental parallelizer characterized in that an alarm is issued when a signal exceeds a predetermined level. 2. The dental parallelizer according to claim 1, wherein the drive source for the grinder is stopped when the deviation angle signal exceeds a predetermined level. 3 The declination signal from the time when the reset switch for the relative inclination angle between the handpiece and the abutment tooth side is activated is passed through a filter circuit to provide an appropriate delay time for alarm detection. The dental parallelizer according to claim 1, wherein the constant can be arbitrarily set so that the response time for alarm detection can be freely selected. 4. The dental parallelizer according to claim 1, wherein the alarm generation level can be set arbitrarily. 5. Claim 1, characterized in that a display device displays a declination signal from the time when a reset switch for the relative inclination angle between the handpiece and the abutment tooth side is activated. Dental parallelizer as described.