Norman:

Some responses to your post:

i have been sitting on some laser questions for a little while.  i am still trying to gather some working knowledge of hard tissue lasers.  but i am not sure i understand hydrokinetics…i believe only waterlase makes this claim…please let me know if other lasers also have this feature.

To my knowledge only Biolase mentions “Hydrokinetics”.

i have tried to read some of the postings with this research and that.  but can anybody help a brother out?  who can explain it to me in layman’s terms?  i don’t want to read scientific abstracts or paper.

The original theory explained to me years ago is that a water spray is shot in front of the erbium laser beam. The laser beam hits the water molecules and accelerates them toward the tooth so hard that water molecules actually chip away or cut dental structures.

in my understanding of physics, if you add energy to water, water will retain the energy and be converted to steam.  why would applying a laser cause the water to pick up photonic energy and act as a bullet against the target issue?  i could see that if the water was in like a pressure washer and runnng at so many psi, but the waterlase cannot be shooting the water out at that high psi, does it?  and are photons big enough or powerful enough to facilitate the moving or deflection of such a huge molecule such as water?

Personally I believe you are correct in your assessment here.

and does the waterlase cut hard tissue even if you switched the water off?  if it does cut without water, does that nullify or make the hydrokinetics a non-issue?  is the laser beam not the only ‘real’ source of any machine’s cutting power?

Yes, the Waterlase will cut hard dental structures such as enamel and dentin with the water cut off. It will however “char” the tooth. There is some evidence that adding a water film and spray to cool the site and wash away cut tooth products will increase the efficiency of cutting. In lab tests I’ve run, the Waterlase won’t cut gold crowns, porcelain on PFM crowns or very thin stainless steel matrix bands. To me this appears to discredit the “Hydrokinetic” theory. It is my personal opinion that yes the erbium laser beam is the only “real” source of cutting by reacting with water, hydroxyapatite or hydroxyl groups in dental or restorative materials.

if the laser beam is the only true cutting feature, then the most powerful beam will be the most efficient in cutting hard tissues?  the delight laser should cut better than the waterlase, shouldn’t it?

I’m not sure what you mean by “most powerful”. The peak power of both the Waterlase and DELight is roughly equal at about 6.0 Watts. The 2940 wavelength of the DELight Er:YAG is more efficiently absorbed by water. We have both the Waterlase and DELight in the office and do not see clinically significant differences in cutting efficiency.

please do not send me any ‘scientific american’ responses!  i am one of these guys that drives cars but really don’t care how they work…as long as the car works!

That’s fine and I really don’t understand how a lot of things work either. But based on my experience I think it’s really important to learn as much as possible about dental lasers prior to using them in the mouth on live patients. Personally if I had it to do over again I would get a Standard Proficiency certification from the Academy of Laser Dentistry prior to purchasing a dental laser. Now all of my initial laser patients are still alive and I’m joking as didn’t really have any problems but my initial training was very poor. With better training and an understanding of what I was doing things would have gone a lot smoother.

Al

Popping noise with lasers?

I saw the Waterlase in operation recently and there is a fairly significant popping noise when it is in use. Does the Delight laser also make the same level of noise?

For those who are Waterlase users, does this make patients nervous or do they just accept the popping noise?

Thanks!

The “popping” noise created by the erbium wavelength interacting with water molecules can be a factor when providing patient treatment. I have had a very small number of patients(< 5) complain about the noise, but that was probably during my initial learning phase.

I am somewhat hearing impaired but it does appear to me that the “popping” noise created by the DELight is less than that of the Waterlase. We have both units in the office. One factor to consider is that the Pulse Duration or “on time” of the erbium pulse on the Waterlase is approximately one-half that of the DELight. Therefore, at the same energy setting(milliJoules) it would appear to me that the Waterlase erbium beam would bang into water molecules harder than the DELight and perhaps create a louder “popping” noise. Another factor which may deserve consideration is that the Waterlase provides a diffuse water spray in front of the erbium beam whereas the DELight provides a more directed water coolant spray on the treatment site. Possibly there is a combination of these two factors or perhaps no relation at all – I have no background in physics or engineering. There is a definite, audible increase in the “popping” noise with both erbiums as energy settings are increased.

We adhere to the following protocol when using the erbium lasers:

1) My Laser Safety Officer Maria sets up the erbium, test fires and then places the erbium in STANDBY mode
2) Maria explains to the patient that we will be using a laser today to clean out the cavity and that most of the time the procedure can be performed without “numbing”
3) She goes on to explain the “popping” noise and uses the “popcorn popping” analogy. The patient is advised that they will feel something – that there will be a lot of water and they will feel the cooling effect of the water spray.
4) Patient is told that if the procedure becomes uncomfortable that they should raise their left hand
5) I test fire the erbium near the patient’s head at a low energy setting so that patient becomes accustomed to the “popping” sound

Using this techique we have not had a patient complain about the “popping” noise created by the erbium lasers. Patients will definitely prefer the “popping” noise over the high pitched whine of a high speed handpiece. I utilize electric handpieces and many times the patient’s greatest complaint regarding noise is when I adjust the composite restoration.

Al

Michael:

The Waterlase pulse frequency is set at 20 laser firings per second(20 Hz) with a Pulse Duration of about 140 microseconds.  The pulse frequency on the DELight may be varied from 3 to 30 firings per second(3 to 30 Hz) and Pulse Duration is roughly 250-300 microseconds.

Some users report a higher “no anesthesia” rate using the 2780 nm wavelength emitted by the Waterlase Er, Cr: YSGG.  Other users propose a greater “no anesthesia” rate utilizing the 2940 nm wavelength emitted by the DELight and some other 2940 nm erbiums.

We personally do not find any clinically relevant differences when comparing “no anesthesia” rates with the Waterlase and DELight.

Al