Method for photo-curing polymerizable compositions with pulsed light
A method for curing polymerizable compositions by irradiating the compositions with a pulsed light that is emitted from an LED. The method of the present invention is especially suitable for curing dental compositions.
1. A method for curing polymerizable compositions with a pulsed beam of light said method comprising the step of:
irradiating the polymerizable composition with a beam of pulsed light emitted by at least one Light Emitting Diode (LED) wherein said pulsed light has a pulse duration of between about 0.05 to about 75 μs and a pulse repetition interval of about 0.25 to about 100 μs.
2. The method of claim 1 , wherein the cured composition has a higher hardness value than the same composition cured with a continuous wave light source with the same emission spectrum and for the same total exposure.
3. The method in claim 2 , wherein the cured composition has a characteristic hardness of about 40 or more on the Barber-Coleman Hardness scale when cured at a power level of 20 mW and a cure duration of 20 seconds.
4. The method in claim 2 , wherein the cured composition has a characteristic hardness of about 50 or more on the Barber-Coleman Hardness scale when cured at a power level of 20 mW and a cure duration of 20 seconds.
5. The method of claim 1 , wherein said LED irradiates less total exposure than is required for a continuous wave light source with the same emission spectrum to cure a like composition to the same depth of cure.
6. The method of claim 1 wherein said polymerizable composition is a photo-curable dental composition.
7. The method of claim 1 , wherein said polymerizable composition comprises liquid acrylic monomers.
8. The method of claim 1 , wherein said polymerizable composition comprises camphorquinone as a photoinitiator.
9. The method of claim 1 , wherein said polymerizable composition comprises a photoinitiator and wherein said LED emits light that has an excitation peak that falls within about 40 nm of the absorption peak of a said photoinitiator.
10. The method of claim 1 , wherein said LED emits blue light.
11. The method of claim 1 , wherein, said LED emits light with an excitation peak that falls within the range of 440 to 500 nm on the electromagnetic spectrum.
12. The method of claim 1 , wherein said pulse duration is from about 0.1 to about 10 μs.
13. The method of claim 1 , wherein said pulse duration is from about 2 to about 3 μs.
14. The method of claim 1 , wherein said pulse repetition interval is between about 1 to about 10 μs.
15. The method of claim 1 , wherein the pulse repetition interval is from about 2 to about 5 μs.
16. The method of claim 1 , wherein said pulse duration and said pulse repetition interval are selected such that the pulse operates with a duty cycle of from about 5 to about 50%.
17. The method according to claim 1 , wherein the cured composition has a cure depth of about 2.8 mm or more.
18. The method according to claim 1 , wherein the cured composition has a cure depth of about 3 mm or more.