An automatic tooth cutting device based on ultrafast laser cutting

Abstract

The application discloses an automatic tooth cutting device based on ultrafast laser cutting, which comprises a laser system, a cooling system, a cutting arm, a control system and an imaging system; the laser system comprises a 1-micron ultrafast laser for generating 1-micron ultrafast laser and a 9.3-micron mid-infrared laser for generating 9.3-micron ultrafast laser; the cooling system is used for cooling during tooth cutting; the cutting arm is used for outputting laser to realize tooth cutting; the control system is used for controlling laser output, water flow speed in the cooling system and cutting of the cutting arm; the imaging system is used for real-time imaging of point positions in the oral cavity and feedback to the control system; the application adopts ultrafast laser as a tooth cutting tool, replaces a traditional cutting tool, has high tooth cutting precision and can accurately cut according to a pre-set shape.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tooth cutting device, and particularly relates to an automatic tooth cutting device based on ultrafast laser cutting. BACKGROUND

[0002] In dental treatment, sometimes the semi-hard layer such as dentin formed on the tooth surface and in the root canal needs to be cut. In order to cut such layer, a rotary driven cutting instrument is used.

[0003] The existing cutting instrument mostly comprises a handle part, a connector at one end of the handle part and a tool carrying driving head at the other end. The connector provides connection with various air, water, light and electricity supply pipelines, which are usually combined in a control cable. The driving head contains a tool rotating part, which is usually composed of a tool base or chuck and a motor or turbine rotatably installed in the head for driving the chuck. The cutting precision of such structure is seriously dependent on the clinical experience and technical level of the doctor. SUMMARY

[0004] The present application provides an automatic tooth cutting device based on ultrafast laser cutting to solve the problems in the prior art, comprising a laser system, a cooling system, a cutting arm, a control system and an imaging system;

[0005] The laser system comprises a 1 mu m ultrafast laser for generating 1 mu m ultrafast laser and a 9.3 mu m mid-infrared laser for generating 9.3 mu m ultrafast laser;

[0006] The cooling system is used for cooling during tooth cutting;

[0007] The cutting arm is used for outputting laser to realize tooth cutting;

[0008] The control system is used for controlling laser output, water flow speed in the cooling system and cutting of the cutting arm;

[0009] The imaging system is used for real-time imaging of the point position in the oral cavity and feeding back to the control system.

[0010] Further, the 1 mu m ultrafast laser comprises a ytterbium-doped fiber laser, a pulse time domain stretcher, a spectrum shaping module, a power amplifier module and a pulse compressor connected in sequence;

[0011] The ytterbium-doped fiber laser is used for generating seed laser pulses;

[0012] The pulse time domain stretcher is used for time domain stretching of the seed laser pulses;

[0013] The spectrum shaping module is used for spectrum shaping of the seed laser pulses after time domain stretching;

[0014] The power amplifier module is used for amplifying the seed laser pulse after spectrum shaping.

[0015] The pulse compressor is used for compressing the amplified seed laser pulse.

[0016] Further, the 9.3 μm mid-infrared laser includes a pump laser, a signal pulse generation module, a near-infrared optical parametric amplification module and a mid-infrared optical parametric amplification module.

[0017] The pump laser is used for outputting pump pulse light.

[0018] The signal pulse generation module is used for spectrum broadening the pump pulse light to obtain signal pulse light.

[0019] The near-infrared optical parametric amplification module is used for beam combining the signal pulse light and the pump pulse light, amplifying the signal pulse light, and separating the pump pulse light to obtain near-infrared pulse light.

[0020] The mid-infrared optical parametric amplification module is used for converting the pump pulse light into flat-top pulse light, beam combining the near-infrared pulse light and the flat-top pulse light, amplifying the near-infrared pulse light, and separating the flat-top pulse light to obtain 9.3 μm ultrafast laser.

[0021] Further, the power amplifier module adopts Yb:CALGO crystal as a gain medium.

[0022] Further, the signal pulse generation module adopts YAG crystal, the near-infrared optical parametric amplification module adopts LGS crystal, and the mid-infrared optical parametric amplification module adopts LGS crystal.

[0023] Further, the cutting arm includes a mechanical arm composed of a plurality of movably connected sleeves, and a silver film mirror for reflecting laser light is arranged at the sleeve connection position; the ultrafast laser generated by the laser system is emitted from one end of the mechanical arm and output from the laser output module arranged at the other end; a lens is arranged near the laser output end in the mechanical arm; a telescope system is further arranged in the mechanical arm for laser shaping; and the laser output by the laser output module is used for cutting teeth.

[0024] Further, the cooling system includes a pressure spray head arranged at a position corresponding to the tooth, and the pressure spray head is connected to a water inlet through a water inlet pipe.

[0025] Further, the laser output module includes, in sequence along the laser transmission direction, a third silver film mirror, a collimating lens, a high-speed scanning galvanometer, and an F-theta lens; further includes a micro motor for driving the F-theta lens to move along the height direction; and the micro motor and the high-speed scanning galvanometer are both connected to a control system.

[0026] Further, the imaging system comprises a plurality of miniature optical cameras arranged at the laser emission end of the laser output module; the miniature optical cameras are connected to the control system through a WIFI module.

[0027] Further, the control system is used for constructing a tooth spatial position model; the control system adjusts parameters of the high-speed scanning galvanometer and the miniature motor according to data information collected by the miniature optical cameras; the control system is internally provided with a neural network, which is used for learning cutting data.

[0028] The present application has the following advantages:

[0029] (1) The present application adopts a ytterbium-doped crystal to generate 1 mu m ultrafast laser, which has high energy, high peak power and high frequency adjustability, and meets different requirements such as depth during tooth cutting;

[0030] (2) The present application generates 9.3 mu m ultrafast laser of several watts, and realizes high-speed ablation of tooth tissue (hydroxyapatite);

[0031] (3) The present application can select 1 mu m ultrafast laser or 9.3 mu m ultrafast laser for cutting according to actual conditions;

[0032] (4) The present application adopts laser cutting, which can accurately control the shape and structure of the cutting surface according to the set parameters, and is beneficial to the subsequent filling after tooth filling;

[0033] (5) The present application can construct a cutting scheme by inputting the expected cutting effect parameters of the user, and adjust the parameters of each module, so as to realize automatic tooth cutting. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a system framework diagram of the device of the present application.

[0035] Figure 2 It is a cutting arm structure schematic diagram of the device of the present application.

[0036] Figure 3 It is a laser output module structure schematic diagram of the device of the present application.

[0037] Figure 4 It is a software flowchart for controlling cutting in the control system of the present application.

[0038] Figure 5 It is a scanning electron microscope schematic diagram after cutting by using the device of the present application in the embodiment.

[0039] In the figure: 1-sleeve, 2-telescope system, 3-first silver film mirror, 4-second silver film mirror, 5-control system, 6-water inlet pipe, 7-lens, 8-laser output module, 801-third silver film mirror, 802-collimating lens, 803-high-speed scanning galvanometer, 804-F-theta lens, 805-micro motor, 806-WIFI module, 807-micro optical camera, 9-teeth, 10-pressure spray head. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with the drawings and specific embodiments.

[0041] As shown in the figure, an automatic tooth cutting device based on ultrafast laser cutting includes a laser system, a cooling system, a cutting arm, a control system and an imaging system. Figure 1

[0042] The laser system includes a 1μm ultrafast laser for generating 1μm ultrafast laser and a 9.3μm mid-infrared laser for generating 9.3μm ultrafast laser.

[0043] The 1μm ultrafast laser includes a ytterbium-doped fiber laser, a pulse time-domain stretcher, a spectral shaping module, a power amplifier module and a pulse compressor connected in sequence.

[0044] The ytterbium-doped fiber laser is used to generate seed laser pulses; it provides seed laser pulses with a central wavelength of 1020-1040nm.

[0045] The pulse time-domain stretcher is used to time-domain stretch the seed laser pulses; specifically, a Martinez stretcher is used to stretch the seed laser pulses to 200ps.

[0046] The spectral shaping module is used to perform spectral shaping on the seed laser pulses after time-domain stretching; it adjusts the frequency components of the seed spectrum and suppresses the gain narrowing phenomenon.

[0047] The power amplifier module is used to amplify the seed laser pulses after spectral shaping; it uses a Yb:CALGO crystal as the gain medium and can amplify the seed laser pulses to 50W.

[0048] The pulse compressor is used to compress the amplified seed laser pulses; it uses a Tracy compressor to compress the amplified seed laser pulses from 200ps to 150fs.

[0049] Finally, the 1μm ultrafast laser obtains 1μm ultrafast laser with a central wavelength of 1030nm, a repeatable frequency of 3kHz-180kHz, a pulse width of 150fs and an average power of up to 40W.

[0050] ​9.3 mu m mid-infrared laser, comprising a pump laser, a signal pulse generation module, a near-infrared optical parametric amplification module and a mid-infrared optical parametric amplification module;

[0051] The pump laser is used for outputting pump pulse light, providing pump pulse light with an average power of 100 W, a pulse width of 200 fs and a repetition frequency of 500 kHz.

[0052] The signal pulse generation module is used for spectrum broadening the pump pulse light to obtain signal pulse light; the YAG crystal is adopted in the application to focus the pump pulse into the YAG crystal for frequency domain broadening.

[0053] The near-infrared optical parametric amplification module is used for beam combining the signal pulse light and the pump pulse light in the LGS crystal, amplifying the signal pulse light and separating the pump pulse light to obtain near-infrared pulse light;

[0054] The mid-infrared optical parametric amplification module converts the pump pulse light into flat-top pulse light by using a phase plate, then beam combines the near-infrared pulse light and the flat-top pulse light in the LGS crystal, amplifies the near-infrared pulse light and separates the flat-top pulse light to obtain flat-top 9.3 mu m mid-infrared laser with a center wavelength of 9.3 mu m, a repetition frequency of 500 kHz, a pulse width of 200 fs and an average power of several watts. When used, the user can select a 1 mu m laser with higher peak power or a 9.3 mu m laser with a resonance peak for hydroxyapatite (the main component of teeth).

[0055] The cooling system is used for cooling during tooth cutting; comprising a pressure spray head 10 arranged at the corresponding position of the tooth 9, the pressure spray head 10 being connected to the water inlet through the water inlet pipe 6. The pressure spray head 10 is fixed to the tip portion of the laser output module 8, so that the sprayed water flow is coaxial with the output laser, realizing accurate cooling and cleaning of the cutting point.

[0056] The cutting arm is used for outputting laser to realize tooth cutting; comprising a mechanical arm composed of a plurality of movably connected sleeves 1, the connecting portion of the sleeve 1 being provided with a silver film mirror for reflecting laser; three sleeves 1 are arranged in the application, and the connecting portions between the sleeves 1 are respectively provided with a first silver film mirror 3 and a second silver film mirror 4.

[0057] The ultrafast laser generated by the laser system is emitted from one end of the mechanical arm and output from the laser output module 8 arranged at the other end; the lens 7 is arranged near the laser output end in the mechanical arm; the telescope system 2 is further arranged in the mechanical arm and used for laser shaping; the laser output from the laser output module 8 is used for cutting the tooth 9. The water inlet pipe 6 is arranged in the sleeve 1, and the bottom of the sleeve 1 can be provided with a water pipe passage for facilitating opening and replacement of the water pipe. The ultrafast laser is input into the sleeve 1, reflected to the telescope system 2 for shaping by the first silver film mirror 3, output to the second silver film mirror 4 after shaping, reflected to the lens 7, and output to focus on the laser output module 8.

[0058] The laser output module 8 includes, in sequence along the laser transmission direction, a third silver film mirror 801, a collimating lens 802, a high-speed scanning galvanometer 803, an F-theta lens 804; further includes a micro motor 805 for driving the F-theta lens 804 to move along the height direction; the micro motor 805 and the high-speed scanning galvanometer 803 are both connected to the control system, and can also be connected to the control system through the WIFI module 806.

[0059] The laser output from the mechanical arm is output to the third silver film mirror 801, and the reflected output light enters the collimating lens 802, so that the divergent light reflected by the third silver film mirror 801 becomes collimated light. The collimated light is reflected to the F-theta lens 804 through the high-speed scanning galvanometer (Galvo mirror) 803, and the F-theta lens 804 focuses the collimated light on the tooth.

[0060] The imaging system is used for real-time imaging of the point position in the oral cavity and feeding back to the control system; includes a plurality of micro optical cameras 807 arranged at the laser emission end of the laser output module 8; the micro optical camera 807 is connected to the control system through the WIFI module 806 and transmits the collected image information to the control system. In the present application, four micro optical cameras 807 are arranged, and are arranged at four vertices around the tip of the laser output module 8 at equal distances. The WIFI module is arranged in the laser output module 8.

[0061] The control system is used for controlling the laser output, the flow rate of the cooling system and the cutting arm for cutting; the control system is used for constructing a tooth spatial position model; the control system adjusts the parameters of the high-speed scanning galvanometer 803 and the micro motor 805 according to the data information collected by the micro optical camera 807; the control system is built-in with a neural network for learning the cutting data, and the neural network can be realized by using an existing network structure, such as a CNN network, an LSTM network, etc.

[0062] The control system sends data to the high-speed scanning galvanometer 803 and the micro motor 805 through the WIFI module 806. The high-speed scanning galvanometer 803 adjusts the x-axis and y-axis angles according to the parameters, and changes the x-axis and y-axis parameters of the output light. The micro motor 805 is connected to the F-theta lens, adjusts the z-axis height according to the parameters, and changes the z-axis parameter of the output light to realize laser cutting.

[0063] Figure 4 The left side is the main program flowchart. After the system is initialized, the user inputs the intraoral standard film of the patient. The program constructs the spatial position model 0 of the teeth according to the intraoral standard film, which is used for reference by the user. Then the user inputs the cutting scheme according to the spatial position model. The program calls the database to obtain the x-axis parameter x0, the y-axis parameter y0, the z-axis parameter z0, and the laser parameters (power and repetition frequency) according to the cutting scheme. The laser is adjusted according to the laser parameters, and the user waits for the start of cutting. After the cutting is started, x0, y0, and z0 are assigned to x1, y1, and z1, respectively, to ensure that the x-axis, y-axis, and z-axis parameters are not wrong after the interruption occurs. Then the position of the f-theta lens is adjusted according to the z-axis parameter. After the adjustment, the Galvo parameters are adjusted according to the x-axis and y-axis parameters to start scanning. Then the laser is turned on, and the cutting starts. During the cutting process, the signals transmitted back by the WIFI module are received. If the feedback signal is 0, it is determined that the cutting is completed, the cutting parameters are saved to the database, and the program is ended.

[0064] Figure 4 The right side is the feedback receiving interruption subprogram flowchart. As shown in the figure, after the feedback interruption occurs, the CPU receives the data transmitted by the WIFI module. The group of data is received, and it is determined whether the current interruption statement of the main program is changing the parameters. If yes, the interruption flag bit is cleared to 0, and the exit is avoided to avoid assigning only part of the parameters at a time. If not, the spatial position model 0 is corrected according to the group of data. It is determined whether the correction amount is too large. If it is too large, the laser is immediately turned off to avoid unnecessary harm, an error is reported, and the program is terminated. If the correction amount is normal, the x-axis parameter x0, the y-axis parameter y0, and the z-axis parameter z0 are adjusted. Finally, the interruption flag bit is cleared to 0, and the next interruption is waited for.

[0065] After the interruption occurs, the spatial position model, the x-axis, the y-axis, and the z-axis parameters will change. The main program adjusts the Galvo galvanometer and the micro motor platform according to the new parameters to realize the effect of automatic cutting according to the feedback results.

[0066] Figure 5For cutting tooth section electron microscope graph using the device of the application, the left side graph is the cutting scheme on x axis and y axis; the right side graph is the cutting effect comparison graph using 1 mu m ultrafast pulse laser as cutting tool and using traditional tool, it can be seen that the section using traditional tool is relatively flat and smooth, which is not conducive to the retention of filling material after filling in tooth repair, and the section after cutting using the application depends on the cutting scheme, for example, in the graph, the step cutting on x axis and y axis can realize the zigzag and uneven of the cutting section, increase the friction coefficient of the cutting section, which is conducive to the retention of filling material after filling in tooth repair.

[0067] The application replaces the traditional cutting tool by using ultrafast laser as cutting tooth tool, the output light propagates in the sleeve transmission device through the mirror, lens and telescope system, and the light is output to the laser output module installed at the end of the sleeve connecting device. The Galvo mirror and the F-theta lens connected with the micro motor platform are adjusted by the control system, and the cutting point is precisely cooled and washed by using the high-pressure spray head, so that the three-dimensional movement of the cutting light is realized to achieve the cutting effect. In addition, the imaging and feedback camera group is used to transmit the spatial position data of the tooth back to the control module in real time, and the control module adjusts the Galvo mirror and the F-theta lens connected with the micro motor platform according to the new parameters, so that the feedback closed loop is realized, and the basic function of automatic cutting tooth is achieved. At the same time, the application can also achieve different section effects according to different data input by the user to meet the user's demand. These functions have great significance for automatic control, combination of medicine and engineering, and reduction of dentist cost.

Claims

1. An automatic tooth cutting device based on ultrafast laser cutting, characterized by, The application relates to a laser tooth cutting system, which comprises a laser system, a cooling system, a cutting arm, a control system and an imaging system; the laser system comprises a 1-mu m ultrafast laser for generating 1-mu m ultrafast laser and a 9.3-mu m mid-infrared laser for generating 9.3-mu m ultrafast laser; the cooling system is used for cooling during tooth cutting; the cutting arm is used for outputting laser to realize tooth cutting; the cutting arm comprises a mechanical arm formed by a plurality of movable sleeves (1); silver film mirrors are arranged at the connecting positions of the sleeves (1) and used for reflecting laser; the ultrafast laser generated by the laser system is emitted from one end of the mechanical arm and outputted from a laser output module (8) arranged at the other end; a lens (7) is arranged at the end of the mechanical arm close to the laser output; a telescope system (2) is further arranged in the mechanical arm and used for laser shaping; the laser outputted from the laser output module (8) is used for cutting teeth (9); the control system is used for controlling laser output, water flow speed in the cooling system and cutting of the cutting arm; the control system is used for constructing a tooth spatial position model; the control system adjusts parameters of a high-speed scanning galvanometer (803) and a micro motor (805) according to data information collected by a micro optical camera (807); a neural network is built in the control system and used for learning cutting data; the imaging system is used for real-time imaging of point positions in the oral cavity and feeding back to the control system; the imaging system comprises a plurality of micro optical cameras (807) arranged at the laser emitting end of the laser output module (8); the micro optical cameras (807) are connected with the control system through a WIFI module (806); the laser output module (8) comprises a third silver film mirror (801), a collimating lens (802), the high-speed scanning galvanometer (803), an F-theta lens (804) in sequence along the laser transmission direction; the laser output module (8) further comprises the micro motor (805) used for driving the F-theta lens (804) to move along the height direction; the micro motor (805) and the high-speed scanning galvanometer (803) are connected with the control system. The control system sends data to the high-speed scanning galvanometer (803) and the micro motor (805) through the WIFI module (806); the high-speed scanning galvanometer (803) adjusts the x-axis and y-axis angles according to parameters, changes the x-axis and y-axis parameters of the output light; the micro motor (805) is connected with the F-theta lens, adjusts the z-axis height according to parameters, and changes the z-axis parameters of the output light.

2. The automatic tooth cutting device based on ultrafast laser cutting according to claim 1, characterized in that, The 1-mu m ultrafast laser comprises a ytterbium-doped fiber laser, a pulse time domain stretcher, a spectrum shaping module, a power amplifier module and a pulse compressor which are connected in sequence; The ytterbium-doped fiber laser is used for generating seed laser pulses; the pulse time domain stretcher is used for time domain stretching of the seed laser pulses; the spectrum shaping module is used for spectrum shaping of the seed laser pulses after time domain stretching; the power amplifier module is used for amplifying the seed laser pulses after spectrum shaping; The pulse compressor is used for compressing the amplified seed laser pulses.

3. The automatic tooth cutting device based on ultrafast laser cutting according to claim 1, characterized in that, The 9.3-micron mid-infrared laser comprises a pump laser, a signal pulse generation module, a near-infrared optical parametric amplification module and a mid-infrared optical parametric amplification module connected in sequence; the pump laser is used for outputting pump pulse light; the signal pulse generation module is used for spectrum broadening of the pump pulse light to obtain signal pulse light; the near-infrared optical parametric amplification module is used for beam combination of the signal pulse light and the pump pulse light, amplification of the signal pulse light, and separation of the pump pulse light to obtain near-infrared pulse light; the mid-infrared optical parametric amplification module is used for conversion of the pump pulse light into flat-top pulse light, beam combination of the near-infrared pulse light and the flat-top pulse light, amplification of the near-infrared pulse light, and separation of the flat-top pulse light to obtain 9.3-micron ultrafast laser.

4. The automatic tooth cutting device based on ultrafast laser cutting according to claim 2, characterized in that, The power amplification module adopts Yb:CALGO crystal as a gain medium.

5. The automatic tooth cutting device based on ultrafast laser cutting according to claim 3, characterized in that, The signal pulse generation module adopts YAG crystal, the near-infrared optical parametric amplification module adopts LGS crystal, and the mid-infrared optical parametric amplification module adopts LGS crystal.

6. The automatic tooth cutting device based on ultrafast laser cutting according to claim 1, characterized in that, The cooling system comprises pressure nozzles (10) arranged at positions corresponding to the teeth (9), and the pressure nozzles (10) are connected to a water inlet through water inlet pipes (6).

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