Jacques, welcome to the boards!
Have you had the same sensitivity problems with the nontapered tips?

My experience has been similar to DoueckDental:

On the first day with the laser trainer standing over my shoulder, we hurt patients. Over the next few weeks we continued to hurt patients using company recommended settings and tips. I kept a log, and over the course of several months my need for anesthesia was 50%.

Use of the laser without anesthetic was so unpredictable that we now routinely anesthetize patients for cavity preps. We no longer market or present the laser as free from anesthetic.

Al

Guys, this is what I’ve been doing- understand I’ve just been at this about 2 months now.

Class III – .50 18/18 20 sec
               .75 18/18 20 sec
               1.0  25/25 20 sec
                1.5 30/30 20 sec
                1.75 40/40 prep enamel to outline extent of decay. Once enamel removed cut back to .75 18/18 to remove dentin or decay. If lots of decay then use round burr to remove decay and finish up going over prep 1 more time with laser ,then restore.
Class IV and Class V are similar. I’m still experimenting with air water settings but if I ever go above 2 W then I definitely have water and air at least 40/40
I have had more sensitivity with class 1’s but I think I need to raise the water air levels more.
Had to numb 2 class 1’s so far (both just about into pulp) others pt’s have rated sensitivity 3 or 4 out of 10. Always make sure to tell them ahead of time that it may feel cold and if so raise their hand so I can adjust the settings-if they raise their hand I cut back W and increase air /water. Haven’t numbed any pedo yet. Just wanted to add that these settings are with nontapered tips. I find with the tapered , even if I cut W in half I get alot more sensitivity. I’m guessing this has to do with the power density ( am I catching on Bob?)
Hope that helps and if others have better techinique they will share.

Ron,

Yes, you are catching on! The tapered tip increase the energy density (power relates to time, energy to intensity). So, of course the greater the energy dentisty, the greater the power density over the treatment time as well.

Let’s go though a few things. One parameter that I haven’t seen discussed is the Pulse Duration of your devices. Now, while you cannot select a different PD in your devices, it helps to know what it is and to keep that in mind as you consider which teeth may need anesthetic.

The WaterLase has a PD of 125 microseconds, if I’m not mistaken, whereas the Con Bio DELight has a PD of 250 usec, I think. Now, that might not seem like a lot of difference–and I have argued with many a laser engineer over this, but clinically it is HUGE. This means the intensity of each pulse hitting the tooth with the WaterLase is TWICE that of the Con Bio at identical settings! Wow!!

Another parameter not often thought about or considered clinically is the Repetition Rate or Pulses Per Second (PPS) or Hertz (Hz)–and is relationship to the Peak Power per Pulse you are delivering to tissue.

Let’s look at the following equation:

Average Power (W) divided by Rep Rate (Hz) divided by Pulse Duration (microseconds) = Peak Power/Pulse (W).

So let’s look at two Pulse Durations and two Rep Rates on the effect on Peak Power per Pulse to hard tisue as examples:

125 usec Pulse Duration at 10 Hz and 20 Hz and 1.0 watts Ave. Power
250 usec Pulse Duration at 10 Hz and 20 Hz and 1.0 watts Ave. Power

Average Power (1.00 W) divided by
Repitition Rate ( 10 Hz) divided by
Pulse Duration (.000125) {10-6 sec} =
Peak Power/Pulse (800 W/pulse)

Average Power (1.00 W) divided by
Repitition Rate ( 20 Hz) divided by
Pulse Duration (.000125) {10-6 sec} =
Peak Power/Pulse (400 W/pulse)

Average Power (1.00 W) divided by
Repitition Rate ( 10 Hz) divided by
Pulse Duration (.000250) {10-6 sec} =
Peak Power/Pulse (400 W/pulse)

Average Power (1.00 W) divided by
Repitition Rate ( 20 Hz) divided by
Pulse Duration (.000250) {10-6 sec} =
Peak Power/Pulse (200 W/pulse)

That’s quite a bit of difference in laser intensity delivered to tissue between devices with different parameters, AT THE SAME WATTS AND PPS SETTINGS.

Now this does not answer all the questions related to pain and sensitivity. But I hope this helps better explain that laser tissue interactions are more complex than manufacturers tend to represent and why some proficient users are more adebt , without fully understanding the physics behind their success.

I’ll post another tip later that should help, too.

Bob

I charged off in the beginning trying to drive the laser as fast as the drill. I had some similar problems and got lost in the woods as to what to do. I suggest you take a course from Dr. Chen or someone who can do pain free dentistry.

I now rarely have problems except with a few skiddish patients. I inject them. When I begin slowly as taught I find on the second tooth and beyond I can speed up with little awareness on the part of the patient. I use high magnification and enjoy watching the preparation develop. I drill all the time when I find the laser to be inefficient for a certain aspect. I use the 1/4 round bur for something almost every prep because I like to and it speeds up things. Afterwords I ask the patient how things went and they do not even know they have been drilled upon. I do use the electric drill which gives a different unfamiliar feel to the patient. This along with a touch of people skill learned the hard way seems to do it.

If you are like I was you bought a piece of equipment but have not sufficiently changed your former approach, concepts, goals and philosophy to comform to micro dentistry. Walk with a master somewhere for a day or two. It worked for me.

Pat Kelly