METHOD FOR POLYMERIZING DENTAL POLYMERIZATION COMPOSITE RESIN, AND LIGHT IRRADIATING DEVICE

Abstract

The invention relates to a method for polymerizing and curing a dental polymerization composite resin using a light irradiating device, said light irradiating device comprising at least one blue LED with an emission peak at a wavelength between 430 nm and 490 nm and at least one ultraviolet or near-UV LED with an emission peak between 350 nm and 420 nm, the at least one blue LED is first operated without the at least one ultraviolet or near-UV LED, and the at least one ultraviolet or near-UV LED is operated later, wherein the power of the at least one blue LED and the power of the at least one ultraviolet or near-UV LED are controlled in a programmed manner based on time, and the light irradiated from the at least one blue LED and the at least one ultraviolet or near-UV LED of the light irradiating device is irradiated onto the dental polymerization composite resin, wherein the dental polymerization composite resin is thereby polymerized and cured.

The invention also relates to a light irradiating device for polymerizing and curing a dental polymerization composite resin, said light irradiating device having at least one blue LED with an emission peak at a wavelength between 430 nm and 490 nm and at least one ultraviolet or near-UV LED (2) with an emission peak between 350 nm and 420 nm, and a controller for temporally controlling the power of the at least one blue LED and for temporally controlling the power of the at least one ultraviolet or near-UV LED independently of each other, wherein the controller is designed, in particular programmed, to carry out such a method.

Claims

1. A method for polymerizing and curing a dental polymerization composite resin using a light irradiating device, said light irradiating device comprising at least one blue LED with an emission peak at a wavelength between 430 nm and 490 nm and at least one ultraviolet or near-UV LED with an emission peak between 350 nm and 420 nm, the method comprising: first operating the at least one blue LED without the at least one ultraviolet or near-UV LED, and operating the at least one ultraviolet or near-UV LED later, wherein a power of the at least one blue LED and a power of the at least one ultraviolet or near-UV LED are controlled in a programmed manner based on time, and irradiating light irradiated from the at least one blue LED and the at least one ultraviolet or near-UV LED of the light irradiating device onto the dental polymerization composite resin, wherein the dental polymerization composite resin is thereby polymerized and cured.

2. The method according to claim 1, wherein the programmed controller produces a software-modulated and/or a hardware-modulated power control of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED.

3. The method according to claim 1, comprising operating the at least one blue LED and/or the at least one ultraviolet or near-UV LED periodically at least at times.

4. The method according to claim 1, comprising increasing and/or reducing the power of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED in a controlled manner based on time by at least one power ramp.

5. The method according to claim 1, comprising starting the program for temporally controlling the power of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED by operating an operating element of the light irradiating device or of an input device or of a computer which is connected to the light irradiating device or which is a part of the light irradiating device.

6. The method according to claim 1, comprising using a camphorquinone and a tertiary amine or an acylphosphine oxide or diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) or 1-phenylpropane-1,2-dione (PPD) as a photopolymerization catalyst of the dental polymerization composite resin to polymerize and cure the dental polymerization composite resin.

7. The method according to claim 1, comprising depositing or storing a plurality of different programs for temporally controlling the power of the at least one blue LED and of the at least one ultraviolet or near-UV LED in the light irradiating device, and selecting a program by an input, by operating an operating element, by scanning a code or a label, and/or by a measurement with at least one sensor.

8. The method according to claim 1, comprising controlling the power of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED with a programmed pulse width modulation.

9. The method according to claim 1, comprising controlling the power of the at least one blue LED and the power of the at least one ultraviolet or near-UV LED in a programmed manner based on time in such a manner that the operation of the at least one blue LED starts first and the operation of the at least one ultraviolet or near-UV LED starts thereafter and the operation of the at least one blue LED is ended prior to or at the same time as the operation of the at least one ultraviolet or near-UV LED.

10. The method according to claim 1, wherein the light irradiating device has at least one fan for air cooling the LED.

11. The method according to claim 1, wherein the light irradiating device has a motor for rotating a rotary plate, wherein the rotary plate is arranged in an irradiation region of the light irradiating device and the dental polymerization composite resin is arranged on the rotary plate to cure the dental polymerization composite resin.

12. The method according to claim 1, comprising adjusting at least two different nominal powers greater than 0 Watt during the programmed control of the power of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED.

13. The method according to claim 1, comprising irradiating at least a part of the light of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED which does not directly hit the dental polymerization composite resin with the aid of a reflector or with the aid of a plurality of reflectors onto the dental polymerization composite resin.

14. The method according to claim 1, wherein the light irradiating device has an irradiation opening for irradiating the light of the at least one blue LED and of the at least one ultraviolet or near-UV LED having an area of at least 10 cm.sup.2,

15. The method according to claim 1, wherein the dental polymerization composite resin is arranged on a carrier element, and the method comprises irradiating the dental polymerization composite resin located on the carrier element with the light irradiating device.

16. The method according to claim 1, comprising first operating the at least one blue LED without the at least one ultraviolet or near-UV LED and switching on the at least one ultraviolet or near-UV LED later, so that the at least one blue LED and the at least one ultraviolet or near-UV LED are operated at the same time at least at times as of a later point in time.

17. A light irradiating device for polymerizing and curing a dental polymerization composite resin, said light irradiating device having at least one blue LED with an emission peak at a wavelength between 430 nm and 490 nm and at least one ultraviolet or near-UV LED with an emission peak between 350 nm and 420 nm, and a controller for temporally controlling the power of the at least one blue LED and for temporally controlling the power of the at least one ultraviolet or near-UV LED independently of each other, wherein the controller is designed to carry out a method according to claim 1.

18. The light irradiating device according to claim 17, wherein the light irradiating device has at least two blue LEDs with an emission peak at a wavelength between 430 nm and 490 nm and the light irradiating device has at least twice as many of the at least two blue LEDs as the at least one ultraviolet or near-UV LED.

19. The light irradiating device according to claim 17, wherein the at least one blue LED is constructed as multiple groups of two to twenty series-connected blue LEDs and the at least one ultraviolet or near-UV LED is constructed as at least one group of two to twenty series-connected ultraviolet or near-UV LEDs.

20. The method according to claim 3, comprising controlling the frequency in a programmed manner.

21. The method according to claim 4, comprising increasing and/or reducing the power within a period of at least 1 second and a maximum of 300 seconds from a first power to a second power and/or the at least one power ramp is controlled with a linear, logarithmic, or exponential time-dependent course or with a passage of time which follows another mathematical function.

22. The method according to claim 5, comprising starting the program for temporally controlling the power of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED by operating a switch, a button, a rotary pulse generator, a keyboard, a voice control, a touchscreen, or a lever of the light irradiating device or of the computer.

23. The method according to claim 7, wherein the measurement is effected with at least one sensor by an analysis of the dental polymerization composite resin or of at least one of the components of the dental polymerization composite resin.

24. The method according to claim 10, wherein the light irradiating device has one fan for air cooling of the at least one blue LED, and has a fan for air cooling of the at least one ultraviolet or near-UV LED, wherein the at least one fan is driven by at least one motor which is controlled in a programmed manner similarly to the controller of the power of the at least one blue LED and/or of the at least one ultraviolet or near-UV LED.

25. The method according to claim 11, wherein the motor for rotating a rotary plate is preferably controlled in a programmed manner.

26. The method according to claim 14, wherein the light irradiating device has an irradiation opening for irradiating the light of the at least one blue LED and of the at least one ultraviolet or near-UV LED having an area of at least 100 cm.sup.2.

27. The method according to claim 15, wherein a dental model or a framework is used as the carrier model.

28. The light irradiating device according to claim 18, wherein the light irradiating device has at least four times as many of the at least one blue LED as the at least one ultraviolet or near-UV LED.

Description

[0055] Embodiment examples of the invention are explained below with reference to a schematically represented figure and a power-time diagram without, however, limiting the invention in the process. In this case, FIG. 1 shows a schematic representation of a light irradiating device according to the invention and the power-time diagram according to FIG. 2 shows an power control of the blue and ultraviolet or near-UV LEDs according to the invention in accordance with a method according to the invention.

[0056] The light irradiating device has five groups of five blue LEDs 1 each, the irradiation of which has an emission peak at a wavelength between 430 nm and 490 nm. The five groups of the blue LEDs 1 can preferably be switched on and off in groups, in order to adjust the power of the blue LEDs 1.

[0057] Two to five groups of two to five blue LEDs each or an individual group or only one individual blue LED can alternatively be used as well within the framework of the invention.

[0058] The light irradiating device has a group of five near-ultraviolet LEDs 2 as well, the irradiation of which has an emission peak between 350 nm and 420 nm. This is only one example and more or less near-ultraviolet or UV-LEDs can also be used. The near-ultraviolet LEDs 2 and the blue LEDs 1 can each be cooled with a separate fan 3, 4. The fans 3, 4 are driven with the aid of motors. It is also possible to cool all of the LEDs 1, 2 with just a single fan 3. The cooling is effected by an air flow which washes around the LEDs 1, 2. Alternatively, cooling with a liquid coolant and/or cooling with the aid of Peltier elements is also possible.

[0059] The LEDS 1, 2 and the fans 3, 4 or respectively the motors of the fans 3, 4 are separately actuatable by means of a microcontroller 6 such as, for example, a stored-program control (SPC). In a reflector pot 8, which contains a dental polymerization composite resin 11 to be cured, the dentures to be produced are cured with the aid of irradiation by the LEDs 1, 2. The reflector pot 8 is equipped with reflectors on the inner side, which reflectors reflect the light irradiated by the LEDs 1, 2 and thus irradiate on all sides onto the dentures or respectively the dental polymerization composite resin 11 to be produced. In order to further improve the uniformity, the reflector pot 8 is arranged on a rotary plate 14 which is driven by a motor 16. The motor 16 for rotating the rotary plate 14 is controlled by the microcontroller 6. The microcontroller 6 is able to actuate the LEDs 1, 2 and the fans 3, 4 as well as the motor 16 with e.g. a phase width modulation (PWM).

[0060] According to the invention, the light irradiating device is suitable for optimized polymerization and curing of different dental polymerization composite resins 11. To this end, multiple program sequences, by means of which the power of the blue LEDs 1 and the power of the near-ultraviolet LEDs 2 as well as the engine speed of the motors of the fans 3, 4 and the engine speed of the motor 16 for rotating the rotary plate 14 can be temporally controlled, are stored in the microcontroller 6. The program can be selected, for example, by means of a computer 12 or an input device 12. It is also possible that a bar code on a packaging of the dental polymerization composite resin 11 to be polymerized and to be cured is read in with the computer 12, and the computer 12 automatically selects the appropriate program for polymerizing and curing the dental polymerization composite resin 11 identified by the bar code on the same. It is also possible to establish the type of dental polymerization composite resin 11 with the aid of sensors which are connected to the computer 12 and to start the appropriate program in the microcontroller 6 depending on the evaluation. The computer 12 or respectively the input device 12 can be connected by means of a cable, network or a wireless connection such as, for example, ethernet, WLAN, Bluetooth, USB, to the microcontroller 6, so that the information for inputting or respectively for selecting the program is conducted to an input of the microcontroller 6, and the desired program for controlling the LEDs 1, 2 in the microcontroller 6 is selected. The microcontroller 6 then starts the selected program, wherein it is also possible to wait for a start command of the input device 12 or respectively of the computer 12 for this purpose.

[0061] However, the program can also additionally or alternatively be selected based on the strength or respectively the geometrical dimensions of the dental polymerization composite resin 11 to be polymerized and to be cured.

[0062] The programs which are stored in the microcontroller 6 for temporarily controlling the power of the LEDS 1, 2 differ in particular in that they control the power of the blue LEDs 1 and of the near-ultraviolet LEDs 2 based on time. The blue LEDs 1 and the near-ultraviolet LEDs 2 are thereby operated differently. In particular, ramps are deposited in the programs, with which ramps the power of the blue LEDs 1 and of the near-ultraviolet LEDs 2 are increased and/or reduced based on time.

[0063] According to the invention, the blue LEDs 1 are preferably operated first, in order to initially polymerize and harden the regions which are located deeper in the dental polymerization composite resin 11 with the aid of the blue light. The regions of the dental polymerization composite resin 11 located closer to the surface are subsequently irradiated with the aid of the near-ultraviolet LEDs 2 and, as a result, are polymerized and cured.

[0064] These programming possibilities make it possible to cure the dental polymerization composite resin 11 in the best possible way, based on the composition thereof and/or the geometrical dimensions thereof.

[0065] FIG. 2 represents one exemplary temporal course of the power of a group of blue LEDs 1 and a group of ultraviolet (UV) LEDs 2, which are operated in accordance with a method according to the invention, in the form of a power-time diagram. The power axes of the blue LEDs 1 and of the UV LEDs 2 are linear and run from 0% to 100% of the maximum power of the LEDs 1, 2. The power axis of the blue LEDs 1 and the course of the curve for the blue LEDs 1 are represented in FIG. 2 by continuous lines, whilst the dashed power axis and the dashed power curve refer to the UV LEDs 2, the dashed curve therefore represents the temporal course of the power of the UV LEDs 2.

[0066] The power of the blue LEDs 1 (represented in FIG. 2 as a continuous line) is initially brought with a ramp, which has three different linear increases in power, to a first power (nominal power) and is operated there with this first power for approximately 18 seconds. During this time, the blue light of the blue LEDs 1 can also penetrate the deep regions of the dental polymerization composite resin 11 and initiate the desired polymerization and curing of the dental polymerization composite resin 11 there. Subsequently, the power of the blue LEDs 1 is again increased with the aid of an inversely exponential ramp to a second power (nominal power) and is held there again for approximately 15 seconds. As a result of this second increase in power, the starting polymerization can be accelerated somewhat. During this, the power of the UV LEDs 2 is increased along a linear ramp. On achieving the first nominal power of the UV LEDs 2, the power of the blue LEDs 1 is reduced with a linear ramp to zero. This therefore results in a short temporal overlap, in which both the blue LEDs 1 and the UV LEDs 2 are operated at the same time. The blue LEDs 1 are preferably operated first according to the invention, because the UV light of the UV LEDs 2 disperses more strongly on the material surface of the dental polymerization composite resin 11 and, as a result, cures and polymerizes the latter. However, following the curing and polymerization of the dental polymerization composite resin 11, this is less transparent for the irradiation of the UV LEDs 2 and also of the blue LEDs 1, so that the irradiation can no longer penetrate as deeply into the dental polymerization composite resin 11. Since the blue light of the blue LEDs 1 has a larger penetration depth due to the lower dispersion, a quicker or respectively more extensive curing and polymerization, even at greater depths of the dental polymerization composite resin 11, can be achieved by the indicated sequence according to the invention. The regions at the surface can subsequently be quickly and efficiently cured with the aid of the UV LEDs 2.

[0067] The power of the UV LEDs 2 is held at the first nominal power for approximately 19 seconds and the UV LEDs 2 are subsequently operated for approximately 32 seconds with a pulse width modulation in which the power of the UV LEDs 2 is operated between the first nominal power and a lower second nominal power at uniform frequency.

[0068] A plurality of different programs for controlling the power over time are stored for the blue LEDs 1 and the UV LEDs 2 in the microcontroller 6. The programs can be selected or performed with the aid of the computer 12 or respectively the input device 12. The programs preferably differ due to the duration of the power stages, the frequency of the pulse width modulation, the gradient and the form of the ramps during increases in power and reductions in power as well as due to the power of the power stages and nominal powers of the blue LEDs 1 and the UV LEDs 2. The programs are thereby matched to the dental polymerization composite resin 11 to be polymerized and cured and can also depend on the geometrical form of the material to be cured.

[0069] The suitable courses of the program can be empirically determined in that the respective dental polymerization composite resin 11 is polymerized and cured with a particular test program and subsequently the hardness of the material and, in particular, also the curing depth are determined, that is to say the depth up to which the dental polymerization composite resin 11 is polymerized and cured up to a particular degree. By comparing these measuring results with respect to hardness and/or curing depth during different test programs, the best suited test program can be found for the respective dental polymerization composite resin 11 and can be deposited in the SPC 6. The program is then selectable, for example, by means of an obvious identifier via the computer 12 or respectively the input device 12.

[0070] A freely programmable microcontroller 6 can also be used, which makes it possible to define a separate program. To this end, program modules can be deposited in a memory in a modular manner, which can be selected and put together in order to create separate programs. Ramps, gradients, time steps, masking, flashing, post-curing or cooling, for example, are possible program modules.

[0071] In addition to a purely empirical procedure for determining suitable programs, specific adaptations can also be provided. Thus, thicker or respectively deeper geometrical structures require a larger proportion of blue of the irradiation, since the blue irradiation penetrates deeper into the material. If a dental polymerization composite resin 11 having a larger quantity or respectively a higher density of dispersing particles, which influence the aesthetic appearance of the dental polymerization composites resin 11, is used, the UV light can be irradiated as of a later point in time, in order to provide the blue light with an opportunity, ahead of this, of reaching the deeper regions of the dental polymerization composite resin 11 for a longer period of time. In addition, the power can then be reduced, in order to give the deeper regions more time for polymerizing and curing.

[0072] The features of the invention which are disclosed in the foregoing description as well as the claims, figures and embodiment examples can be essential, both individually and in any combination, for the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMERALS

[0073] 1 Blue LED

[0074] 2 Ultraviolet or near-UV LED

[0075] 3 Fan

[0076] 4 Fan

[0077] 6 Microcontroller

[0078] 8 Reflector pot with dental polymerization composite resin

[0079] 11 Dentures/dental polymerization composite resin

[0080] 12 Input device/Computer

[0081] 14 Rotary plate

[0082] 16 Motor