Dental laser system and treatment method
An improved dental laser system has been developed to cut enamel quickly and precisely, without detrimental residual energy, to provide a replacement for conventional high speed rotary burrs and commercially available dental laser systems.
1. A method for treating hard dental tissue, the method comprising steps of:
generating a radio frequency (RF) excited laser beam with a CO 2 laser operating with a gas in a range of 260 Torr to 600 Torr, the laser beam having an energy profile, a wavelength in a range of 9 μm to 10 μm, a pulse length of at least 5 μsec, and a repetition rate greater than 0.5 kHz, wherein the laser beam is powered by (i) a direct current (DC) power supply comprising a continuous wave (CW) DC section and a pulsed DC section powering (ii) an RF power supply coupled in series downstream of the DC power supply;
directing the laser beam at an exposed surface of the hard dental tissue through an optical component, such that the laser beam has a focal region either above or below the exposed surface and, at the exposed surface, has a spot size diameter in a range of 300 μm to 2000 μm;
controlling at least one of the wavelength, a pulse length, and the repetition rate of the laser beam to produce a pulse energy in a range of 0.1 mJ to 30 mJ; and
removing by ablation at least a portion of the exposed surface of the hard dental tissue using the pulse energy in a portion either above or below the focal region.
2. The method of claim 1 , wherein the laser beam comprises a fluence in a range of up to 50 J/cm 2 .
3. The method of claim 1 , wherein the repetition rate comprises a range of up to 4 kHz.
4. The method of claim 1 , wherein the gas is selected from the group consisting of 12 C( 18 O) 2 gas and 12 C( 16 O) 2 gas.
5. The method of claim 1 , wherein the laser beam is directed at the exposed surface of the hard dental tissue utilizing a hollow waveguide.
6. The method of claim 5 , wherein positioning of the hollow waveguide relative to the exposed surface of the hard dental tissue is manually controlled.
7. The method of claim 5 , wherein positioning of the hollow waveguide relative to the exposed surface of the hard dental tissue is robotically controlled.
8. The method of claim 1 , wherein the laser beam is moved relative to the exposed surface of the hard dental tissue to remove incrementally the portion of the exposed surface of the hard dental tissue.
9. The method of claim 1 , wherein a remaining portion of the hard dental tissue does not exhibit charring.
10. The method of claim 1 , wherein the hard dental tissue is removed at a rate of up to 0.5 g/sec.
11. The method of claim 1 , wherein the hard dental tissue is removed at a volumetric rate of up to 0.17 cm 3 /sec.
12. The method of claim 1 , wherein the hard dental tissue ablation comprises explosive vaporization.
13. The method of claim 1 , further comprising the step of directing a fluidic flow at the exposed surface of the hard dental tissue.
14. The method of claim 13 , wherein the fluidic flow is selected from the group consisting of a liquid, a gas, and combinations thereof.
15. The method of claim 13 , wherein the fluidic flow is adapted to at least one of:
contribute to controlling temperature of the hard dental tissue; and
contribute to reducing redeposition of removed material onto the exposed surface of the hard dental tissue.
16. The method of claim 13 , wherein the fluidic flow is directed to the exposed surface of the hard dental tissue at an angle of incidence in a range from 65 degrees to 90 degrees.
17. The method of claim 1 , wherein the hard dental tissue is selected from the group consisting of dental enamel, dentin, and bone.
18. The method of claim 1 , wherein during a single pulse the laser beam is adapted to contact a cross-sectional area in a range of 0.07 mm 2 to 3.14 mm 2 of the exposed tissue.
19. The method of claim 1 , wherein the step of directing the laser beam comprises delivering sequences of pulses for up to three minutes.
20. The method of claim 1 , wherein the laser beam is directed to the exposed surface of the hard dental tissue at an angle of incidence up to 90 degrees.
21. The method of claim 1 , wherein the step of directing the laser beam comprises:
focusing the laser beam using a lens having a focal length different from a distance of the exposed surface of the hard dental tissue relative to the lens.
22. The method of claim 1 , wherein the step of directing the laser beam comprises modifying the laser beam using an optical system, such that an energy profile of the modified laser beam is non Gaussian.