Apparatus and method for controlled fluid cooling during laser based dental treatments
A system for dental tissue treatment includes a system for directing a laser beam to an area of dental tissue to be treated, and a fluid-delivery system for directing and controlling a flow of a fluid. The fluid is directed to at least a portion of the area to be treated and the fluid flow is controlled to substantially prevent both a change in laser energy absorption by the dental tissue and attenuation of treatment efficiency due to fluid interference with the laser beam. The fluid present in at least a portion of the area to be treated may prevent or reduce the likelihood of melting of enamel in that area.
1. A method for dental tissue treatment, comprising:
generating a laser beam at a wavelength in a range from 5 μup to 15 μthat is absorbed by hydroxyapatite in dental tissue, using a laser source;
directing the laser beam to an area of dental tissue to be treated;
directing a flow of fluid in a direction toward the area to be treated and to form a coolant film on the area to be treated, while avoiding fluid interaction and intersection with the laser beam prior to impingement thereof on the dental tissue to be treated; and
using a controller to control the flow of the fluid to at least a portion of the area to be treated to prevent a change in laser energy absorption by the dental tissue resulting in a volumetric removal rate of less than fifteen percent of a peak removal rate, due to fluid interaction and interference with the laser beam.
2. The method of claim 1 , wherein the fluid comprises a liquid and a gas, and a proportion of a volume of the liquid with respect to a volume of the fluid is controlled.
3. The method of claim 2 , wherein the liquid comprises water.
4. The method of claim 3 , wherein the liquid further comprises a surfactant.
5. The method of claim 2 , wherein the gas comprises air.
6. The method of claim 2 , wherein:
a rate of flow of the liquid is adjusted.
7. The method of claim 6 , wherein a pressure of the liquid is adjusted such that the pressure is in the range from 0 psi up to 40 psi.
8. The method of claim 6 , wherein the flow of the liquid is switched on and off, so as to deliver a liquid burst.
9. The method of claim 8 , wherein a frequency of switching the flow of the liquid on and off is up to 10 Hz.
10. The method of claim 8 , wherein a duration of one liquid burst is up to 1000 milliseconds.
11. The method of claim 2 , wherein the flow of the gas is switched on and off, so as to deliver a gas burst.
12. The method of claim 11 , wherein a frequency of switching the flow of the gas on and off is up to 10 Hz.
13. The method of claim 11 , wherein a duration of one gas burst is up to 1000 milliseconds.
14. The method of claim 2 , wherein:
controlling the flow of the fluid is performed, at least in part, by a pressure relief regulator.
15. The method of claim 14 , wherein controlling the flow of the fluid comprises configuring the pressure relief regulator to adjust a pressure of the gas flow in a range from 0 psi up to 80 psi.
16. The method of claim 14 , wherein controlling the flow of the fluid comprises configuring the pressure relief regulator to adjust a pressure of the gas flow within at least one of:
a low pressure range, causing the fluid to form a droplet at delivery,
a medium pressure range, causing the fluid to form a column at delivery, and
a high pressure range, causing the fluid to form a mist at delivery.
17. The method of claim 2 , wherein:
the controlling the flow of the fluid comprises pumping the fluid using a positive displacement pump.
18. The method of claim 17 , wherein:
the positive displacement pump comprises a peristaltic pump;
the controlling the flow of the liquid comprises operating the pump at a frequency of up to 750 rpm; and
the frequency of the pump controls a rate of flow of the liquid.
19. The method of claim 17 , further comprising:
monitoring the flow of the liquid using a fluid flow switch; and
controlling the laser beam if at least one of a lack of fluid flow and a fluid flow comprising bubbles is detected during the monitoring.
20. The method of claim 1 , wherein the fluid is delivered using a nozzle forming at least one orifice.
21. The method of claim 20 , wherein:
the nozzle forms a plurality of orifices; and
each orifice of the plurality of orifices has a diameter in a range from 0.008 inches up to 0.15 inches.
22. The method of claim 21 , wherein the plurality of orifices is configured in a circular pattern.
23. The method of claim 20 , wherein an orientation of the nozzle with respect to an axis of the laser beam is adjustable.
24. The method of claim 23 , wherein the orientation of the nozzle is adjustable at an angle in a range from 0° up to 90° with respect to the laser beam.
25. The method of claim 23 , wherein the orientation of the nozzle is 77° with respect to the laser beam.
26. The method of claim 20 , wherein a distance between a tip of the nozzle and the area of the dental tissue to be treated is in the range from 2 millimeters up to 50 millimeters.
27. The method of claim 1 , wherein the fluid flow is adjusted to be one of a series of droplets, a series of columns, and a mist.
28. The method of claim 1 , wherein the area to be treated is in a range from 0.00005 square inches up to 0.055 square inches.
29. The method of claim 1 , wherein the flow of the fluid is controlled to provide a sufficient amount of fluid to prevent melting of the dental tissue.
30. The method of claim 1 , wherein the flow of the fluid is controlled to limit an amount of fluid to limit absorption of the laser beam in the fluid.