Here is the paper from Keller et al. i noticed before. Ken was so kind to email it to me.

http://www.elexxion.com/images/Comparison.pdf

One thing is very important: The comparison was done at one fixed setting for both lasers (300 mJ/400 µs/4Hz). With other settings it might be completly different.

Olaf

Ron, I think a great deal of the success or failure is due to the patients anticipation and perception.  The success rate definitely can definitely be driven higher when the patient is preconditioned with the words -‘ we can always give you a shot, if we need to’ or ‘this is going to feel cold like eating ice cream’. I cringe when I hear the ‘shot’ technique being used, who wants a shot?
Now that being said, I do think that a patient often feels a difference in the procedure, especiallly when moving from a high energy analgesia technique to a prepping energy that is much lower. Again, this may be a way of preconditioning a patient by having them experience a certain level of percussion and energy, followed by a lesser level of percussion and energy, which in comparrison to the high levels, doesn’t seem too bad. Can’t say I ever had any success using the low energy/ slow analgesia technique.

I also agree with your statement about visualization. Since the scope I have pretty much abandoned either the high energy or the slow analgesia techniques and see no difference in my success rate. If you can visualize where the tissue and energy interact, you can control the amount of thermal change and keep many people comfortable during the procedure.    

As far as why some people react differently than others I wonder if the NTI guys aren’t on to something regarding the clenchers/ change of local pH ideas. Maybe the same thing is happening with the areas that respond somewhat hyperactively to the laser. Change in local pH affecting the speed of chemical Rx in the pain response.

Just my totally subjective , unscientific, anecdotal, two cents 😉

p.s. Bruce, if we’re going to standardize patients I’ve got a list of other attributes we should have them work on

I can’t explain “why” it works when it does…but I do know that more than half the time it does work. I also know that just because it fails on one tooth…it does not mean it won’t work on a different tooth in the same mouth. I’ve seen it happen many times. Why would it work with #19, but fail on #20? They’re side by side. A LOT of it has to do with how we remove the amalgams. The pulpal floor is the most sensitive…so I leave it till the very end. I especially want to remove all the amalgam around the edges early on. After I’ve got nothing but a VERY thin layer of amalgam left across the pulpal floor I’ll penetrate it (barely) to gauge their response. If they don’t flinch I’ll continue on. If they do flinch…I’ll try to flake it out with an explorer. You’d be surprised how many cases you thought were gonna fail that you can succeed with by doing this. You can usually flake out very thin amalgam with not much trouble.

All in all I’d say we get it done in a fairly comfortable fashion 75% of the time.

Dan