Forums › Erbium Lasers › General Erbium Discussion › Laser tips and Alloy
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dkimmelSpectatorWhy is it that you can use an ER laser near a metal matrix and nothing happens? However, if you come anywhere close to an alloy ( always happens with a new tip) you get that spark and a factured tip!!!!
Is this spark a so called plasma spark? Then we have a shock wave generation which causes a splintering of the tip?
Why with an Alloy and not other metal like the matrix?
What is different about the interaction of the light with the alloy vs the matrix? Does the release of free Hg have a role in this rxn?Anyone have any ideas??
Glenn van AsSpectatorWhat laser fractures the tip…….not the Delight.
I thnk that the difference is the other materials in the alloy besides the metal component but I bet Graeme Milicich would have an answer.
Glenn
dkimmelSpectatorThe Delight tip just get a small chip. With the waterlase it can be a full chunk. Picture time I guess. I’ll run down to the office just for you Glenn and take some pictures. Susan will be a bit upset as she has some yard work for me to do today. Dentistry comes first!
dkimmelSpectatorEr tip vs alloy: Alloy wins!!
Just as a heads up I never try to have contact with a alloy. Plays heck on the tips, trunk fiber and Hg vapor is not a great idea.
There is also a difference in material the tips are made of the Biolase tips are Shapphire and the Delight tip shown is Quartz. The broken Biolase tip goes in a box and the Delight tip gets polished and reused.
AnonymousGuestDavid, a forward from a friend-
In Laser-Tissue Interactions: Fundamentals and Applications by Dr. Markolf Niemz Ph.D, he states on page 198, ”For the removal of metallic fillings, infrared lasers cannot be used, since the reflectivity of these materials is too high in that spectral range.” Niemz continues, “Amalgam should never be ablated with lasers at all …..as during irradiation, the amalgam melts and a significant amount of mercury is released that is extremely toxic for both patient and dentist.” Niemz then presents a photomicrograph of a melted amalgam crater, in an alloy irradiated with an Er:YAG laser at a 90 micosecond pulse duration of 100 millijules of energy.
The “sparking” effect that is seen, is most definately plasma sparking, (remember, we are using infrared energy and cannot see the beam, so it is not “reflected” laser energy) as the laser induced free mercury vapor from the melted amalgam absorbs more erbium photons in the next series of laser pulses. This immediate interaction rapidly ionizes the free mercury, producing an intense electric field seen as a spark.
As to why the tip fractures, let’s do a thought experiment:
If we are lasing a dark (non polished or corroded) amalgam, and hence ionizing free mercury, because the amalgam restoration is partially absorbing the energy instead of reflecting it (like is seen with a highly polished matrix band) this vaporized mercury is a very fast moving “plume” that then paints the distal end of the sapphire delivering the Erbium laser energy with a thin coat of mercury. As the laser fires again, the energy is now absorbed (remember the very high Watts/pulse with these FRP lasers we are dealing with) by the black “pigment or chromophore” now coated on the end of the sapphire tip. This intense instantaneous absorption then causes the tip to “blow out” as the laser pulse is “absorbed” by the tip, and not “transmitted” by it.
Why some tips blow out, and others do not, has to do with the “shape” and “hardness” of the synthetic sapphires, along with the amout of energy the laser is producing at a given moment in time. It has nothing to do with “recoil shock”
dkimmelSpectatorRon,
Thanks. That makes perfect sense. I kept looking at the splinering on the glass that Niemz shows when he talks about shock wave generation and I wondered if this was what I was seeing with the tips. Your friends thoughts make more sense.
Just as a reminder to anyone else reading this thread, You don’t want to ablate alloy with a laser. Sometimes I will find a little chunk of alloy in an undercut that I don’t see “bam” there goes the tip. It always seems to be a new tip for some reason.!!!!!!!!!Thank your friend for me and let him know it will be great to have him posting.
David
slobob49SpectatorDr. Kimmel,
The Biolase tip in your photograph is a tip that would be prime for refurbishment. If you don’t want to use refurbished tips yourself, I will be willing to purchase any used, sapphire, Biolase tips that you may have been saving. We have many Drs. using refurbished tips and we are always looking for used tips in the condition of the one in your photo. If you are keeping them, I would be happy to purchase them from you. I will pay you บ.00 each for tips in this condition.
If you are interested, feel free to contact me.
Bob Sloan
Precision Tips
800-675-1099
bs@dentallasertips.com -
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