Dr Bornstein:

(1) Newton’s 3rd law require a analysis over a well posed domain. The domain in this case is force-target at the instant that the force starts interacting with the target. The force in this case would be the detonated water (HK or pick your own catchy name).

(2) I don’t think anybody is debating that the speed of light is faster than other shocks. The issue to focus on (pun intended) is understanding how the light rays travels through through water of various geometric shapes, distribution and density and whether the photons become scattered or whether they magically refocus. Lets start with the simple case of 1 narrow beam and 1 transparent sphere that does not change shape with incident photons. Some photons will transmit through and hit the target where you aim the beam and a majority of photons are refracted and reflected. Now take the realistic case where the sphere is opague (high absorption) and where the shape changes soon after interaction with photons. That opague droplet will cast a shadow.

Eric,

Excellent explainations concerning the physics in simple terms for us to understand.

I think part of the question is why the company feels it is so important that energized-water be the mechanism that they defend it so strongly in the absence of credible science or logic–and now in the presence of credible research and references that disprove it???

Eric, you posted some of the unproven energized-water claims from the company website.  Here is a jpeg photo of an animation that the company had on their site at one time.  It portrays the concept that they are trying to get everyone to accept.  One wonders why it was removed when the website claims are the same.

What this animation shows is the water droplets (above and below) coming into the path of the Er, Cr: YSGG photons coming down the fiber.  The photons are completely absorbed into the water droplets and the droplets accelerated to the speed of light (apparently) towards the target tissue.

The company and their representatives are extremely defensive when these sorts of questions are raised.

Why?

I’m sure it’s because they are ultimately insecure about their claims and don’t want new prospects to hear a contradictory opinion. If it isn’t water doing the cutting, then it is photons. If it’s photons, then the prospects have other laser devices to take a look at. If it isn’t energized-water, then those new 1-800-DENTIST ads thye plan to run in California to the public (now on their website) aren’t accurate.

Bob

Dr Bornstein

looks like we are talking past each other again and I am sure we would both be taking remedial physics classes and go through Feyman notes if we had to take a test.  

(1)  Newton’s law only apply to bodies with mass.  It appears to me you are raising issues about water-laser interaction.  If you make the assumption that the water droplet explodes from the center of the mass (the droplet’s mass), then you would be right in questioning whether there will remain anything usable afterwards.  That’s a big assumption.  To answer that, you have to estimate how far the photons have to penetrate a water droplet before it explodes.  It would depend on droplet size or  if we are dealing with a film, film thickness.  If rapid water vaporization happens close to the surface of the droplet (given a big enough size), as I think it does, then there would be enough mass left over to form a high velocity shock.

(2)  I don’t believe anyone disputes that photons do get through the mist or films since the amount of water contained in the space in front of the laser has to be volumetrically small compared to air volume even at the highest water setting.  The question is whether those photons are useful for vaporization ablation, Fried’s latest results says not even close to the ablation you can get with interaction water film+laser (at settings close to actual clinical practice).

(3) Based upon postings in DT, you appear to discredit all studies published (refereed or not) when a Biolase researcher is involved or if a study supports Biolase clinical claims (Biolase supported or not) such as the two Japanese bovine bone experiments that Ron Schalter posted.  I am starting to go through some of those papers in their entirety.  Since the argument in favor of “ablation mechanism has to be enamel vaporization” and one of the effects has to be tooth heating (second law), then the following experimental study (under the auspices of Biolase)  has to be flawed.  Please read the article and educate us as to why in your view, it is flawed:

 http://www.etechadvisors.com/PDF/Pupal_temp_YSGG.PDF

username = dentaltown
password = member

(I am trying to limit access to people involved in the science discussion because of copyright)

(Edited by lagunabb at 8:36 am on Sep. 18, 2003)

Ray:

Let us take your points one at a time:

You posted:

(1) Newton’s law only apply to bodies with mass. It appears to me you are raising issues about water-laser interaction. If you make the assumption that the water droplet explodes from the center of the mass (the droplet’s mass), then you would be right in questioning whether there will remain anything usable afterwards. That’s a big assumption. To answer that, you have to estimate how far the photons have to penetrate a water droplet before it explodes. It would depend on droplet size or if we are dealing with a film, film thickness. If rapid water vaporization happens close to the surface of the droplet (given a big enough size), as I think it does, then there would be enough mass left over to form a high velocity shock.

Response:

If we use Hale and Querry’s water absorption coefficient data, and perform the simple calculation of (1/absorption coefficient) to get the absorption length, (1) this data reveals that the optical penetration depth in water of the Er,Cr:YSGG laser is about 2um. This optical penetration depth of 2um is a 40% increase over the optical penetration depth of the Er:YAG beam per pulse, which Niemz (2) calculated at .8um. This means, that with an Er,Cr:YSGG laser, you are much more likely to explode the water droplet FROM THE CENTER OF THE MASS instead of close to the surface “front surface” of the water droplet. If we are dealing with a 1 micron water film, then you are already into the dental enamel. ANY WAY YOU SPIN THIS, there are credible issues to be answered, not just my opinion.

1 Hale, G.M., Querry, M.R. (1973): Optical constants of water in the 200-nm to 200- um wavelength region. Appl. Opt. 12, 555-563

2.Niemz, M: Laser-Tissue Interactions. Fundamentals and Applications, Berlin, Springer, pp45-80, 2002

You posted:

(2) I don’t believe anyone disputes that photons do get through the mist or films since the amount of water contained in the space in front of the laser has to be volumetrically small compared to air volume even at the highest water setting. The question is whether those photons are useful for vaporization ablation, Fried’s latest results says not even close to the ablation you can get with interaction water film+laser (at settings close to actual clinical practice).

Response:

In Erbium laser ablation of hard dental tissue, the operator is constantly attempting to keep the Ablation Front of the laser tissue interaction ahead of the Thermal Front of the laser tissue interaction. An operator must always keep in mind that with 200-400 microsecond pulse widths (all conventional Erbium dental lasers), he/she is dealing with a thermally driven mechanical (vaporization) ablation effect. Not a true photoablation or “shock wave” reaction. The heat and thermodynamics of the reaction is the most important issue. With these pulse widths, the water acts as a heat sink to keep the ablation front ahed of the thermal front. I refer you again to previous logic on the DT board.

When the Erbium water interaction is explained on a molecular level, the obvious disparity in thermal clinical data between the different erbium wavelengths becomes clearer. In a study conducted by Shori et al, describing the Quantum Mechanics of the water molecule under Erbium laser irradiation, he recently confirmed the results of a group of previous water absorption studies with erbium lasers and reported the following:

1 As water absorbs more of the incident energy of an Er:YAG laser, and the temperature of the water increases, the length and strength of the OH bond
in the water molecule changes because of the large increase in kinetic energy.

2) While this important phenomenon occurs (the lengthening and weakening of the OH bonds), the absorption peak for the water molecule shifts to
wavelengths that are significantly shorter than 2.94um.

3) This negative shift in the absorption peak for water, greatly diminishes effectiveness of the beam to perform further controlled thermal mechanical ablation on tissues.

Shori et al, Quantification and Modeling of the Dynamic Changes in the Absorption Coefficient of Water at 2.94um. Journal on Selected Topics in Quantum Electronics, Vol 7, No 6, Nov/Dec 2001 pp959-970

Now, if all of the above is happening as a clinician is lasing hard tissue, and the heat is building up at the ablation event horizon, the kinetic energy of the water in the unablated tissue matrix is rising substantially, and hence is changing the vibrational modes of the water molecules making the absorption coefficient for the next series of erbium pulses go way down and become less efficient.

According to the Quantum Mechanic and Thermodynamic realities of the Erbium laser energies that we are dealing with; more energy means a hotter laser tissue interface, a hotter laser tissue interface creates a faster negative shift in the absorption coefficient for water, becausee the Er,Cr:YSGG absorption coefficient for water is almost 45% deficient to the Er:YAG to begin with, it will definitely produce greater heat.

AT THESE PULSE WIDTHS, THAT IS WHY WATER SPRAYED ON THE IRRADIATION SITE IS NECESSARY

Now, I will present another study to further back up this logic, and Shori’s findings:

Erbium laser ablation: The effect of dynamic optical properties Joseph P. Cummings and Joseph T. Walsh, Jr.

Applied Physics Letters Vol 62(16) pp. 1988-1990. April 19, 1993

In the conclusion, this Cummings and Walsh study states: “ A dynamic coefficient model for absorption has been developed based on the known change in the absorption coefficient of water as a function of absorbed energy. The model explains the shorter penetration depth during ablation, and the subsequent greater overheating at the 2.79um wavelength. The assumptions strictly hold only for Q-switched ablation where thermal diffusion is not significant. Thermal diffusion will slightly mitigate the observed effects during long pulse of erbium lasers.”

In other words, this study found that with Q-switched pulse widths (ie. In the nanosecond range) that are much closer to the “shock-wave” generation model that we previously discounted for these lasers, that the water coefficient absorption change during ablation is also greater with Er:YSGG wavelengths, and hence inhibits ablation. We are again using thermal-mechanical in 140-400 microsecond range or the “long-pulse” that the study discussed.

You Posted:

(3) Based upon postings in DT, you appear to discredit all studies published (refereed or not) when a Biolase researcher is involved or if a study supports Biolase clinical claims (Biolase supported or not) such as the two Japanese bovine bone experiments that Ron Schalter posted. I am starting to go through some of those papers in their entirety. Since the argument in favor of “ablation mechanism has to be enamel vaporization” and one of the effects has to be tooth heating (second law), then the following experimental study (under the auspices of Biolase) has to be flawed. Please read the article and educate us as to why in your view, it is flawed:

I am in NO WAY SHAPE OR FORM discrediting “ALL STUDIES” when a Biolase researcher is involved. Let’s review exactly what I wrote from the DT thread.

Now since the literature has established that the Hydrokinetic Er:YSGG produces heat like every other Erbium laser, let’s review a couple of more important studies, like these three from Eversole, Rizoiu, and Levy.

“It is already known that the infrared lasers are more likely to be associated with a thermal mechanism that causes vaporization of bone structure. The absorption of laser energy (which occurs when the tissue components absorb the laser wavelength), and conversion into thermal energy results in a local deposition of heat. The dissipation of thermal energy into the surrounding tissues is a process that continues to occur even after laser exposure. This process will enlarge the damage envelope when no limiting factors occur. Many studies suggest that cooling the ablation site will reduce the amount of heat that is transferred into the surrounding tissue.”

Rizoiu I, and Levy G., The Efficiency of Bone Ablation with an Nd:YAG Laser Beam Delivered with a Cooling Spray: An In Vitro Study, Compendium, VolXV ,pp106-111, 1994.

In the above study, Rizoiu at least recognizes that Infrared Lasers on bone produce and deposit heat, even though it is an Nd:YAG.

“Hard tissue ablation occurs in a nonthermal mode with an erbium laser used in conjunction with a water spray…….. Most importantly, the critical role that the water spray plays in allowing the process to occur in a mechanical matter needs to be better understood.”

Rizoiu I., and DeShazer L., New Laser – Matter Interaction Concept to enhance Hard issue Cutting Efficiency, Laser-Tissue Interaction V, SPIE Vol. 2134A, 1994.

In this study, Rizoiu explains her new concept as essentially the uncoupling of the THERMAL from the MECHANICAL in what is really an already well explained (at this time in 1994) Thermal-Mechanical ablation process with erbium lasers. NO WHERE IN THIS STUDY DOES IT MENTION AN AERATED WATER SPRAY IN FRONT OF THE BEAM. The study was done with a traditional water spray aimed at the irradiated tooth structure from a fixed point at 45 degrees.

From where does she get the New Concept?

Even with the plethora of work published before 1994 discussing the Thermal-Mechanical ablative effect of erbium lasers, Rizoiu only references two studies in this paper. One well known paper from 1964, and one paper from 1989 discussing laser applications of erbium YAG lasers in dentistry.

The following study however is the one that really stands out.

“The wound cavities were smooth, clean and straight. At 24 hours, the wound sites for both bur and Hydrokinetic System showed a clean cut margin with a thin zone of basophilia characteristic of a thermal coagulative effect.The zone measured 40-60 microns.”

Eversole L.R., Rizoiu I, Kimmel A., Osseous repair subsequent to surgery with an erbium hydrokinetic laser system, International Laser Congress, International Proceedings Division, Sept 25-28, Athens Greece 1996, pp 213-221.

This is the inventors OWN WORDS with his/her OWN SYSTEM giving results of a “Thermal Coagulative Effect” with the hydrokinetic system.

Here is problem: It is not safe to tell any dentist that does not understand the thermodynamics and physics of these systems (95% of them) that they are using a laser device to cut BONE that does not produce HEAT! The inventors said it themselves in their own article.

THAT IS WHAT I WROTE. Check the DT thread. I completely agree with the first and last studies from Eversole and Rizoiu. It is the second study that I disagree with.

Finally, with the Bovine studies that you mentioned, again, THIS IS WHAT I WROTE.

I have not read either study that you have posted, but would certainly like to before a full comment.

1) Could you e-mail them to me?

2) Were the sites lased with the Er,Cr:YSGG energy with water spray on the site of irradiation/ablation in the bone, or with a system that sprays water in front of the beam?

Without having read the studies, my assumptions would be these:

A) 1st assumption is that there was enough water on the site of irradiation/ablation (as delivered by any delivery system)to act as a viable heat sink to prevent thermal damage to the bone. Since these were done in Tokyo, (no questions about the science), just which laser and water delivery system was the Er,Cr:YSGG crystal in?

2) 2nd assumption is that with either laser (Er:YAG and/or Er,Cr:YSGG) -(did all of my your just an OpusDent pusher critics catch that) if there was enough water on the site of lasing, the results seem reasonable.

Again, my main issues are with the “no heat” logic and an “aerated water spray” in front of any erbium beam on dental or bony tissues, instead of on the irradiaton/ablation site.

Waiting impatiently to see the studies. Thanks.

Eric Bornstein DMD

Let me try to be clear on these points, from not only a physics point of view, but from a medical and histological point of view.

First, you posted:

I think your numbers are close enough for engineering purposes even not taking Shori’s et al findings into consideration. Now we have to throw in thermodynamics. The energy required to convert liquid water to supersaturated vapor is the enthalpy going from room temperature to 100 C plus the enthalpy of vaporization expressed in total enthalpy required per unit mass. Can you take a guess as to which part of the droplet (or water film) converts to vapor first? It is most definitely the outer shell whether you have a YAG or an YSGG.

Response:

Ray? We are dealing with infrared photons traveling at 300,000Km/sec! I do not think it means a dam thing what part of the droplet is igniting first, at this speed, from a force-counterforce perspective. When Newton’s third law is interpreted with propulsion in mind, the whole droplet is essentially igniting at the same time with a 2um absorption length in water at these speeds, unless the droplet is over 8um in size. Even then, (in my mind) there is no way “enamel cutting force” is or can be imparted on the tooth by the rest of the water droplet. I do not think simple enthalpy plays any significant part in arguments at relativistic speeds like this. Also, THE REST OF THE ERBIUM ENERGY IS STILL HITTING THE TOOTH FIRST. Bottom Line.

You posted:

(3) You still haven’t educated us to the flaws in this paper: (here in its entirety)

http://www.etechadvisors.com/PDF/Pupal_temp_YSGG.PDF

I have read the above paper many times, and here are my comments on its flaws:

First, and most important, the following were the only studies cited, when Rizoiu and Eversole discussed the “hydrokinetic system” being used in the paper.

1) Rizoiu I., and DeShazer L., New Laser – Matter Interaction Concept to enhance Hard
tissue Cutting Efficiency, Laser-Tissue Interaction V, SPIE Vol. 2134A, 1994.

In this study, Rizoiu states:

“Hard tissue ablation occurs in a nonthermal mode with an erbium laser used in conjunction with a water spray…….. Most importantly, the critical role that the water spray plays in allowing the process to occur in a mechanical matter needs to be better understood.”

In this study, Rizoiu explains her new concept as essentially the UNCOUPLING of the THERMAL from the MECHANICAL in what is really an already well explained (at this time in 1994) Thermal-Mechanical ablation process with erbium lasers. NO WHERE IN THIS STUDY DOES IT MENTION AN AERATED WATER SPRAY IN FRONT OF THE BEAM. The study was done with a traditional water spray aimed at the irradiated tooth structure from a fixed point at 45 degrees. From where does she get the New Concept?

Even with the plethora of work published before 1994 discussing the Thermal-Mechanical ablative effect of erbium lasers, Rizoiu only references two studies in this paper. One well known paper from 1964, and one paper from 1989 discussing laser applications of erbium YAG lasers in dentistry.

That study was the predicate seminal work to the next two studies cited in the paper we are discussing, “Pulpal thermal Responses to an erbium, chromium, YSGG Pulsed Laser Hydrokinetic system” by Rizoiu, Kimmel and Eversole, published in Oral Surgery, Oral Medicine and Oral Pathology in August of 1998.

2) Eversole LR, Rizoiu IM., Preliminary investigations on the utility of an erbium, chromium, YSGG laser. California Dental Association Journal 1995:23:41-47.

I have requested the paper from the CDA, and have not received it yet.

3) Kimmel AI, Rizoiu IM, Eversole LR, Phase doppler particle analysis of laser energized exploding water droplets. Abstracts of the International Laser Congress; Sept 1996; Athens, Greece, Abstract #67.

This (Abstract) study is long gone and hard to find. I have never been able to find it (in all of cyberspace), and never spoken to anyone that has ever seen it. You be the judge.

Now, this study (we are currently debating) again is: “Pulpal thermal Responses to an erbium, chromium, YSGG Pulsed Laser Hydrokinetic system” by Rizoiu, Kimmel and Eversole, that was published in Oral Surgery, Oral Medicine and Oral Pathology in August of 1998.

In the results section of this study, Rizoiu et al states, “ On the basis of Phase Doppler partical analysis, Kimmel et al (see above reference #3) have proposed that the laser-target tissue interaction is dependent on a hydrokinetic tissue-cutting effect. Hydrokinetic tissue- cutting refers to the process of removing biologic materials through the use of high speed controlled water droplets. Strong absorption of laser energy at 2.78um by fine water droplets results in a violent yet controlled microexpansion inducing strong mechanical forces on targeted tissue surfaces. Resulting hydrokinetic forces produce mechanical separation of the calcified tissue surface, yielding quick and clean tissue removal. Other factors at the tissue interface that involve water, mineralized tissue, and photon energy may also contribute to the cutting effect.”

Let us try to decipher this paragraph in sections:

Problem #1: “Strong absorption of laser energy at 2.78um by fine water droplets results in a violent yet controlled microexpansion inducing strong mechanical forces on targeted tissue surfaces.”

What the hell does that mean? It sounds like they are describing the forces imparted on enamel by water expansion IN the enamel (the correct thermal-mechanical mechanism).

Problem #2: “Resulting hydrokinetic forces produce mechanical separation of the calcified tissue surface, yielding quick and clean tissue removal”.

Hydrokinetic forces from what? They have still not mentioned in this paper anything other than “microexpansion” of the water. THERE IS NO MENTION OF THE WATER BEING PROPELLED AT THE TOOTH.

Problem #3: “ Other factors at the tissue interface that involve water, mineralized tissue, and photon energy may also contribute to the cutting effect.”

NO KIDDING! It is only the other forces (that we all know as thermal mechanical ablation) that are contributing to the cutting effect!

They are completely Double-Speaking around the ablation mechanism, completely confusing and uncoupling the THERMAL from MECHANICAL in an attempt to explain Hydrokinetics.

Please, someone else chime in here and tell me if I am full of Sh-t.

With questions like that about their results, how should I interpret the Data?

Now, on to your Bone question:

You Posted:

You cited the study below regarding bone cutting. I haven’t read the paper (please email if you have it).

First, I do not have it in a PDF file. However, this is directly from the results section:

“The wound cavities were smooth, clean and straight. At 24 hours, the wound sites for both bur and Hydrokinetic System showed a clean cut margin with a thin zone of basophilia characteristic of a thermal coagulative effect.The zone measured 40-60 microns.” The conclusion to this study was essentially that the heat, and thermal coagulative effect in the bone, was equivalent to that seen with a dental surgical bur on bone. This is from:

Eversole L.R., Rizoiu I, Kimmel A., Osseous repair subsequent to surgery with an erbium hydrokinetic laser system, International Laser Congress, International Proceedings Division, Sept 25-28, Athens Greece 1996, pp 213-221.

Now, let us compare and contrast this hydrokinetic bone study by the Hydrokinetic System Inventors, to these results with Er:YAG lasers and water sprayed ON the ablation site:

Er:YAG bony ablation has been successfully accomplished in a variety of clinical situations. In a review of the use of this laser for middle ear ablation procedures, Frenz et al (1) stated that otological surgeons have identified the advantages of this laser for osseous surgery. These are the water absorption characteristics of the wavelength, and the precise bone ablation with minimal residual thermal energy. The histological data for Er:YAG lasers, when used by otological surgeons to perforate stapes footplate (osseous ear tissue) in surgical procedures, demonstrates that the lateral thermal damage associated with the bony cut was restricted to only 5-10µm beyond the cuts.

When attempting to cut nasal bone with a laser, Truong et al (1) described two specific criteria that should be met before a laser wavelength is chosen. These are rapid tissue ablation and an absence of visible char in the ablation site. They concluded that an Er:YAG laser produced an excellent result, and further stated that the addition of a water spray on the area being irradiated during ablation resulted in the lowest level of char and presumably the lowest thermal damage to the tissue. It was also noted that as long as the surface of the ablated tissue remained moist with a water spray throughout the ablation process, and the laser was used at appropriate settings, char was not seen regardless of the size/volume of the treated tissue. (2)

These results agree with an earlier study by Romano et al (3) using Er:YAG lasers to cut cortical bone. These investigators observed a linear increase of ablation depth with the number of pulses. A greater number of pulses, translates into more ablative energy in the area being irradiated per unit time. It was found that as long as adequate water spray was provided to the area, more bone was ablated with additional pulses (per unit time) without the char formation that would normally be an expected consequence of extra heat from the added pulses. It was also calculated that repetition rates beyond 20Hz would not significantly increase the peripheral thermal damage to the bone. These studies are germane since all commercially available FDA approved Er:YAG dental lasers function from 7 to 30Hz with a continuous water spray option.

1) Frenz, M. et al, Laser Applications in Middle Ear Surgery: Advantages and Possible Side-Effects. Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems XII, SPIE Vol. 4609, 2002

2) Truong, M. et al, Erbium:YAG Laser Contouring of the Nasal Dorsum: A Preliminary Investigation. Lasers in Surgery: Advanced Characterization. Therapeutics, and Systems XI, SPIE Vol. 4244, 2001

3) Romano, V. et al, Bone Microsurgery with IR-Lasers: a comparative study of the thermal action at different wavelengths. SPIE Vol. 2077, 1994

Now, You further Posted:

It sounds as if Dr Eversol may have turned down the water spray to purposely achieve some coagulation or may be not. Also, since bone is much more porous than enamel, there is little advantage to having an external water film (or droplets). Just blast the water that’s already in situ by turning the water spray low and vaporize away. Again, I am guessing and would rather read the whole paper.

My Response based on the above literature findings:

First of all, PRIMARY FOCUS OF CUTTING BONE IS TO KEEP IT COOL. There is absolutely NO reason to want or desire coagulation in bone. Ultimately we want the bone to heal. This occurs with the pluripotent mesanchymal cells from the marrow spaces repopulating the area where the bone was ablated to form new bone tissue. Under no circumstances do we want to heat (to a point of coagulation) the haversian canal system in the bone that will act as a conduit to repopulate the bony ablation site with these bony osteogenic and morphogenic cells. ALL RELEVENT STUDIES DISCUSSING CUTTING OF BONE WITH LASERS THAT I HAVE EVER SEEN, AGREE WITH THAT LOGIC.

Even Rizoiu:

“It is already known that the infrared lasers are more likely to be associated with a thermal mechanism that causes vaporization of bone structure. The absorption of laser energy (which occurs when the tissue components absorb the laser wavelength), and conversion into thermal energy results in a local deposition of heat. The dissipation of thermal energy into the surrounding tissues is a process that continues to occur even after laser exposure. This process will enlarge the damage envelope when no limiting factors occur. Many studies suggest that cooling the ablation site will reduce the amount of heat that is transferred into the surrounding tissue.”

Rizoiu I, and Levy G., The Efficiency of Bone Ablation with an Nd:YAG Laser Beam Delivered with a Cooling Spray: An In Vitro Study, Compendium, VolXV ,pp106-111, 1994.

Ray, unfortunately it seems to take someone with significant background to take this argument apart and make sense of it. I have the significant background, and to me it makes perfect sense.

1)Er:YAG’s produce less heat.

2)Water spray on the irradiation site acts as a necessary heat sink.

3)Water (in any form) in front of the beam attenuates the ablation effect, and requires more energy output for the ablation.

4) Please do not try and bullsh-t me with an effect that has no real basis in fact (that I can see) and the the inventors (in your cited article) either cannot, or will not adequately explain.

5) ALL of these lasers are safe and effective if used properly. BUT THEY ARE SAFER IF DR’S ARE TOLD HOW THEY REALLY WORK, AND WHAT KIND OF HEAT THEY PRODUCE.

Eric Bornstein DMD

Eric,

I would love to chime in on your discussion with Ray, but your logic and science and facts are doing a terrific job.

Ray simply doesn’t want to accept that the company he has invested lots of money in, makes sales on a “New Theory” that is not supported in science, and is likely to be a discredited theory soon, as will be the company for promoting it.

I have watched Ray talk back and forth with you here and on DT, try to match your references, stretch the findings to suit his bias and interpretation, and he has failed completely to provide any credible evidence or science that HKS is in play. And when that hasn’t worked, he trys to talk over and around your well stated and supported points.

You are absolutely correct on the mechanisms in play for pulse durations in the 140 to 400 microseonds that are comercially available today for the dental marketplace.

In pulse durations of 1 microsecond or less, Ray may have a point. But that’s not what our erbiums used in dentistry deliver in pulse duration.

Bob

Dr Bornstein,

The posts are getting quite long so I would first like to discuss the Pupal Temperature Response experiments by Riziou et al.  My understanding of what you view as problems with the paper are the authors limited citations of prior work and their characterization of ablation mechanics (HK).  You did not address directly the meat of the article which is the pupal temperature response data on beagle dogs.  Do you see any problems with the way the measurements were done, the data, or the way temperature response was interpreted.  

Thanks.
 

(Edited by lagunabb at 7:47 pm on Sep. 18, 2003)