Glenn,
Thanks for the input. I have been using the technique Dr. Chen suggested and staying 2-3 mm from the apex, but sometimes I get some sensitivity. Guess I’ll go back to the old files, seems to have worked just fine for the last 25 years, and sterilize with the Nd:yag. Appreciate the info on the opening of the apex with the Er. That is why I have always finished the apex with a file.

Glenn,

Nice side-by-side demo.  Great pictures!!

Questions for you as far as hemostasis and laser wavelength and device configuration:

Looks like you are:

1.  using Argon Green 515nm?  Or are you using blue/green 488/515nm?

2.  using a 300 micron fiber, unconditioned?  That is, no “hot glass” effect?

OK, then based on that assumption:

I think we can agree we are dealing with a vascular area in these pictures?

I think we can also agree that these are realtively healthy gums and tissues and therefore the capillary size are to be expected to be in the range of 100-200 microns in diameter?

Glenn, on this one, I must beg to differ on your comparisons between Argon and Fr Nd:YAG for hemostasis.  

The real comment and comparison here is how bad a coagulator erbium is in a relatively minor vascular area.

I have an HGM surgical Blue/Green argon (since 1991), and it does a nice job in the small vascular areas and small capillaries that you are showing here. whereas the erbiums will have no hemostasis ability in a vascular area much at all.

Green argon (515 nm) is highly absorbed in oxygenated hemoglobin, whereas the pulsed Nd:YAG is highly absorbed in either oxygenated (very bright red) or dark, de-oxygenated (anoxic) blood just as well–in fact, if it is darker the better.

That and the ability to vary the pulse durations (in the PerioLase) to allow for depth of coagulation/hemostasis (say for larger capillaries like 300-600 microns) means the pulsed Nd:YAG gets my vote for the best coagulator over the Green argon for hemostasis.

Oh, and there is simply no comparison with the 980 or 810 diodes, which are continuous wave “CW” in their temporal emission modes “TEM” with 10’s of watts versus a free-running pulsed Nd:YAG with a TEM in the 1000’s of watts per pulse that can vary the repetition rate 10-100Hz and that can vary the pulse durations over many 100’s of microseconds.

I’m plugging in the HGM Argon (220 volts)!  Setting the camera up!  And comparing Argon to pulsed Nd:YAG ASAP!

Bob

Andrew:

Was nice to meet you in Anaheim.

I believe the reliability of the trunk fiber and mirrored handpiece delivery system on the Waterlase could be improved. Just too many reports of failure if you read the forums and talk to other dentists.

I did not look at other Erbiums.

Keep me posted on your experience with your new purchase.

Al

Hi Bruce,

Well this is the great thing about this forum, and having such a great guy like Glenn posting his outstanding photos–we all can read and make comment about “laser stuff” and learn an incredible amount from each other.

Thanks Glenn–I understood your comparison point between erbium versus dedicated soft tissue lasers–after I posted!  I was reacting to putting the Fr Nd:YAG in the same category as CW diodes especially.

Argon, from my experience, is a surface coagulator in oxy hemoglobin.  It does tend to char up in the blood when using green un-initiated, but not so much in contact with the activated/initiated fiber.

What the Fr Nd:YAG has is intensity at a depth of penetration through tissue that is defined by the pulse duration.  

For example:

100 usec PD ~/= 100 microns depth of penetration
150 usec PD ~/= 150 microns depth of penetration
350 usec PD ~/= 350 microns depth of penetration
650 usec PD ~/= 650 microns depth of penetration

This allows hemostasis at a controlled depth w/o charring.  It also takes place at relatively “cooler” temperatures say around 60 degrees Centigrade.

This phenomenon is also what allows a “soft clot” to form in the perio pocket to “close” the wound.

Argon and diodes stop bleeding by predominately a surface effect that tends to be more shallow, dry and “tense”, and easier to disrupt/dislodge and get breakthrough bleeding.

I’m trying to find the key to the Spectrum, but I don’t know where we put it.  Then I have to go find the fibers I think I put in storage……..aaaaarrrrrrrgggggg!

Camera is white balanced now.  We’ll see…..

Bob

Yeah Ray,

I though about that as I was hitting the “submit” button.

You don’t miss much!

As I re-read it, I should have said, “Depth of absorption”, or even “depth of coagulation” or even “foward zone of coagulation”.

And yes, it is based on experiments that we have conducted in artificial tissues, extracted teeth, and also performed by Joel White some years ago.  It is not exactly a linear relationship (hence the approximation symbol ~), but it is a good general and conceptual rule of thumb for understanding how pulse duration effects ablation rates (removal of tissue–both hard and soft) and hemostasis rates/depths (coagulation of tissue) in soft tissues.

You are also right about this as well (Geez, I love this guy and his questions! )–however–maximum absorption is dictated by the intensity of the beam’s forward penetration in causing a biologic effect before the beam becomes “extinguished” as it passes (transmits and scatters) through tissues for 30 K (although I think its more like 40 cm in human tissue).

Keep checking on me, Ray!

Bob