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dfriedSpectatorI agree that pigmented caries preferentially absorb light at 1064-nm, see Harris et al. Selective Ablation of Surface Enamel Caries with a Pulsed Nd:YAG Laser, Lasers in Surg. Med. 30(5) 342-350(2001) and our acoustic measurements confirmed that. However, that does not mean it is safe or very useful. Simulations show that Nd:YAG laser energy goes right through the enamel and is scattered/absorbed near the Dentin-enamel junction (DEJ) see Seka et al.. Light deposition and thermal response in dental hard tissue. J Dent Res, 74, 1086-1092 (1995). So one might possibly have the same awful effect we observed with the Ho:YAG . The reason we don’t readily see the sub-enamel charring that we observed with the Ho:YAG with the Nd:YAG, is that the water absorption is so low that the energy is deposited over a much larger area beneath the DEJ.
Another problem is that we have no idea what is absorbing the light at 1064-nm. I can see how you can use a low energy setting on your Nd:YAG and just remove the pigmented tissue, i.e. you hear a pop when there is absorption and after the pigmentation is gone, there is no audible pop. I guess that if the energy setting is low enough so that the total energy required is low, the heat accumulation may be at a safe level. However, it is not clear what you are removing, i.e., whether or not you are removing a superficial stain or actual decay. I think you are better off using an Er:YAG or an Er:YSGG where the absorber is well established and the absorption is very strong.
If I was a dentist, I wouldn’t use an Nd:YAG on hard tissue. However, I am very curious about the actual source of pigmentation, i.e., whether it is tanin stains or necrosed bacteria or some other source.
Robert GreggParticipantHi Ray,
Am I Dr. Fried or Bob?? Or are you really me??:confused::biggrin:
Good questions.
One answer to the question about pulsed Nd:YAGs and caries and dentin removal is the pulse duration needs to be short (e.g 100 usec) to minimize lateral thermal burn. (Didn’t I show you 7 different pulse duration on an extracted root when you were here?)
The Lares laser has a pulse duration of 150 usec at the shortest–which is OK for caries removal, just not as good as 100 usec–less lateral thermal damage.
The Fr, Nd:YAG will NOT removal HEALTHY enamel. But it will remove diseased enamel, decalcified enamel and healthy dentin. Which is actually a neat thing when you think about it as a clincian. We can undermine the enamel that’s healthy, and not damage it, we can prep VERY thin area of DEJ (like incisals of lower anteriors), while removing decayed or even healthy dentin. Not many tools in my dental tool box can do that as selectively as a pulse 60 microns deep at a time!!
We NEVER use Fr, Nd:YAGs to prep under water. We use water only after the prep is completed to remove any discoloration from the plasma deposits on the tooth surface (carbon). Don’t see any problems in regards to fracturing or crazing with the FR Nd:YAG on vital tooth structure. The pulse preps are very clean.
Since I have a 2.1 micron Fr, Ho:YAG, (150 usec, 5-10 Hz, up to 500 mj/pulse) I can tell you I have been disappointed with its hard tissue capabilities. It just doesn’t absorb on dentin or pigmented caries much at all. But man does it heat up the vital tooth. Patients do NOT like it even when theya re numb!!
QUOTEAt higher incident fluence, thermal stresses generated at the DEJ produced large fractures transverse to the path of laser irradiation resulting in the destruction of the bovine enamel block. This result exemplifies the danger of irradiating teeth with free-running Nd:YAG and Ho:YAG laser pulses — even with entensive water spray.I question his conclusions. But I would need to know what his parameters of operation.
We typically use 2.5 Watts 10 Hz 250 mj/pulse at 100 usec, no H2O. What were Fried’s parameters?
Bob
dkimmelSpectatorPeriodontal tx before the laser was pretty sight forward in my office. Depending on the type tx ranged from simple OHI and prophys to RPCs , irragations and use of different subgingival antimicrobals. Often we refered for sx and just as often a patient declines and we watch and rescale as needed.
For example. Type 3 perio patient. Would get 4 appts of RPC with OHI( Arestin in pockets >4mm). Then a Fine scale with OHI and followed at 2 mo with post op probing and a 3 mo recall.
Now that I have the Waterlase and the Smilelaser now what?
Is everyone routinely doing a decontamination on all prophy patients?
Decontamination on all active perio sites?
Degranulation after RPC?
Any Degranulation with out RPC?
What frequencies do you use. Only once ? Every week for 4 weeks?
So far I have only seen hints of how treat is done and nothing specific!
Being a newbie I can tell you it feel sa lot like Voodoo Magic moving that tip around in a pocket!!
DAvid
Robert GreggParticipantHello Dr. Fried,
Welcome to the forum.
I enjoyed your presentation on P-OCT in Florida.
My Fr, Nd:YAG colleagues and I have been using them for caries removal, dentin prepping, dentin etching, etc for over 12 years without any adverse effects.
Our personal observations are we obtain better bonds to dentin when we etch with Fr, Nd:YAGs.
Fr, Ho;YAGs aren’t good on hard tissue even at 500 mj/pulse.
The reason many of us like the Fr, Nd:YAGs over Erbium in certain cases for hard tissue, is its ability to selectively remove only the organic plug, stain, caries, or dentin. Many times this means we do not have to prep the enamel, thereby conserving maximum tooth structure.
Erbiums are great for enamel preparations, and do so quickly without any thermal injury or fracturing to surrounding tooth, to be sure. It’s just I don’t always want to remove or etch or prep enamel, especially if I only want to determine if the decay remains in enamel.
Or maybe I just want to remove smoker’s stain or calculus from the pits and fissures. Easy to do with Fr, Nd:YAG.
Very useful diagnostic aid until Lantis makes P-OCT available.
Bob
Robert GreggParticipantWonderful! Welcome.
Bob
Robert GreggParticipantGlenn,
Nice case! CLAP, CLAP, CLAP!
Can’t tell if the 1st molar needs endo, or is just hitting hard?
Bob
Robert GreggParticipantGreg,
Ron is 100% correct.
QUOTEAs far as age or sun spots I think you’d want to use a laser that targets pigment rather than h20.Pulsed Nd:YAG’s take those off nicely,and w/o hurtin’. Right Rick?!
Bob
Robert GreggParticipantHey Todd,
Welcome to Ron’s forum!!
Thanks for the very kind words.
It was great to hang with you in Florida. Glad you made the decision to go forward with your PerioLase purchase. But I think you will find just how unbelievably valuable the PerioLase for LPT will be, the training you will get, the support, as well as all the other 101 things a pulsed Nd:YAG can do, including hard tissue stuff.
Thanks again and see you soon.
Bob
Robert GreggParticipantHi David,
“Is everyone routinely doing a decontamination on all prophy patients?”
If you mean recall or perio maintenance patients, yes.
“Decontamination on all active perio sites?”
Absolutely!
“Degranulation after RPC?”
Well, what do you mean by degranulation?
“Any Degranulation with out RPC?”
Same question….
“What frequencies do you use. Only once ? Every week for 4 weeks?”
Current diode protocols are full mouth decontamination once a week depending on pocket depth. .4-.8 watts
“So far I have only seen hints of how treat is done and nothing specific!”
Probably should get some training from diode trainer like Bob Barr or Don Coluzzi.
QUOTEBeing a newbie I can tell you it feel sa lot like Voodoo Magic moving that tip around in a pocket!!Yes, I remember the feeling–or lack there of. But it is working therapeutically.
Bob
(Edited by Robert Gregg at 9:01 pm on Mar. 17, 2003)
AnonymousSpectatorHi David,
I would second the recommendation of getting some training from Bob Barr and Gloria, see http://www.rwebstudio.com/cgi-bin….topic=5
The simple version of Tx is
scale/rt plane then-
1. treat quadrant with deepest pocket 1st
2. activated tip used to deepithelialize 1mm short of pocket depth
3. decontaminate pocket ,placement of tetracycline
4. 1 week later- do #2 followed by #3 in new quadrant and return to 1st quadrant to decontaminate again 1mm shorter than previous tx.
Occlusal adjustment as necessary.
Rule of thumb is pocket depth minus 3=# of treatments
7mm pocket will be revisited 4 times.
The de-epi is done w/ activated tip continous w/ local
The decontam is done w/ nonactivated tip , pulsed /no local
We’ve got nice results 6mm and less. Often resolve to 2’s and 3’s. Not been doing it long enough for xray’s to check bone.That being said, from my investigation and time spent w/ Bob G., I think his Periolase MVP-7 offers a much better result, with less patient time and retreatment. I’ll probably be selling my diode when the MVP-7 arrives , so if you know anyone who’s interested ….?
Hope that helps,
SwpmnSpectatorFor EMLA Users:
If you have found EMLA(AstraZeneca) topical anesthetic to be a useful component of your Erbium laser toolbox, I have an idea which may help with the current supply situation.
Can’t take credit for this as I it got from DentalTown.com but you may be able to locate a pharmacy in your area which will custom compound the medication. Call around, pharmacists are aware of the problem and some are willing to help us with compounding.
Al
SwpmnSpectatorRon:
Ha ha ha!!!! I got a good chuckle out of the last paragraph in your post. Sounds a lot like some of the frustrations I post with my Erbium. Actually it’s not really funny but that’s why we are here – to learn from one another.
Keep us informed on your experiences with the Nd: YAG once it arrives.
Al
dkimmelSpectatorBob, Thanks for the reply. By degranualation I would be refering to curettage.
Do you have a link to Don Coluzzi ? Plan on seeing Bob sometime this year. Going to see Rosenberg next month and plan on seeing Mark in July!
Ron ,Thanks but I am confused about the MVP-7.
David
AnonymousSpectatorSorry David,
I was referring to the Periolase MVP-7 that Bob Gregg and Del have developed.
http://www.millenniumdental.com/main.html
Didn’t mean to be confusing,I was kind of poking fun at myself because, if this forum was here last July and if I had done better research and investigation before buying my Twilite, I’m sure I would only have a Waterlase and Periolase MVP-7 and no diode. Instead I’ll have all 3.
Sounds like you’re going to be learning some great things, from some great people.
Be sure to share with the rest of us later,
Glenn van AsSpectatorHi Allen: thanks for the kind words.
The chisel tip is parallel to the fiber (it comes straight out of the pen type delivery system). Parallel to the fiber is right.
The Er:Yag is faster than the Argon (much much faster) and the chisel tip is very very efficient. I am making a video of using it for the flap that I cut for an osseous on a tooth…….its on this site.
The bleeding of course is often more than the Argon but faster healing in my books and bloody quick.
I dont have anything here but I do have a pan at work.
Want me to take a photo of it tomorrow and I will post it.Glenn
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