Tuesday, April 28, 2009

Free Running Pulsed Laser

More laser physics.

The Periolase is a Free Running Pulsed Laser. What that means is that it is pulsed at microseconds.

A microsecond (abbreviated as μs) is one millionth of a second

The Perioslase pulses at 100 microseconds with a repetition rate (Hz) of 20.

When the laser is pulsing at 100us 20hz it stays off for 49,000+us, the equivalent of the pulse being on for 1 second and off for 8 minutes -- plenty of time for the tissues to cool and not cause collateral coagulation and necrosis. The flashlamp gives the ability to have a duty cycle of 0.2% (the time the laser is on, compared to the time it is off). Each pulse at 100ms and 20hz is around 2000 watts which kills any p. gingivalis (pigmented or not) and lots of other species. Most diodes have a functional duty cycle of about 25% due to the low wattage and don't kill the bacteria for the same reason.

This is why a pulsed laser is needed for soft tissue treatment of periodontal disease -- wattages need to be high, duty cycles need to be low.


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