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Michael C. Goldman, DDS

Laser Root Canal Treatment

What is it? Is it any good?

Of the e-mailed questions   I get  - and I get a lot -  probably 75% or 80% of them are about Root Canals.  Lately several of you have asked about laser root canal treatment.

 

Lasers have been coming on  strong in the dental field and I believe they hold great promise  as equipment and applications evolve.  Lately, some dentists have been using lasers to help  in root canal treatment (RCT).

Here's a drawing I made to illustrate the  important  parts of a  tooth root regarding RCT.

rct tubule drawing 2.jpg (149382 bytes)      I would like you to notice that the  bulk of the  root is made up of Dentin.   Through the center is a hollow space called the Main Nerve Canal.  That's where the   nerve and blood vessels normally are

The outer covering of the  root is Cementum.

The  Dentin is made of a  crystalline structure   with MILLIONS and millions of tiny "holes" or "tubes" throughout  it, from the  nerve canal space all the way to the cementum.   These "tubes" are called Dentinal Tubules. They are known to be big enough  for  bacteria to get inside and "hide".

In addition to the main nerve canal, there are typically   smaller branches of  nerve called accessory nerves.  There could be many of these in any tooth root.

When root canal treatment is done, the contents of the Main Nerve Canal  is cleaned out and filled up with  some inert material (usually gutta percha).

 

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If you haven't done so, you really should read the other  two articles on RCT  in this website to get a fuller understanding of many of the  details and controversies and then come back to this one  and it will make more sense.

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There are many ways to clean out the nerve canal.  The problem is that if it is not completely cleaned out and sterilized.... and bacteria are left in the root...... then the bacteria may be able to mutate, multiply and  become a source of chronic toxicity long after  treatment is over.

We know that bacteria can go from the main nerve canal  out into the dentin  through the millions of tiny tubules.   We also know that  at best we can only clean out the main nerve canal and perhaps a large  accessory canal here and there if we are lucky enough to find it.   Most of the time we don't even know how many  accessory   canals there are  or where they are.  These accessory canals contain nerve and blood vessel tissue, too, and this tissue is food for bacteria.

For a long time now I have proposed that all  RCT be done using calcium hydroxide for a month to  not only   kill bacterial both in the main canal but throughout the  root  with all the  tubules, but also  because  it will dissolve remaining  tissue that the dentist was not able to  mechanically remove. 

Generally  the "alternative" dental community has  not favored doing  RCT  and   mostly recommended extraction. I have dealt more  with these issues in the other RCT articles in this  website. Recently, lasers have been adapted  to RCT use and are   being  promoted  by some in the "alternative" community. 

Lasers may be the greatest thing since  sliced bread, .... or ... they may not...we really don't know very much yet.  But just because they are "hi-tech" and very expensive, that does NOT mean they are   good!!!!  They are simply another tool to use.

Keep in mind that the inside of a   tooth root system is branched, much like anything in nature.  Like the branches on a  tree or the branching of arteries and veins in the body...that's the way nature makes things.  Things in nature are also not flat or straight.   They are generally curved in  a sort of  harmony of chaos.  Imagine looking down at a  river and its large and small  offshoots from an airplane.   That's nature.

Lasers shoot out a beam of light in a straight line.  Not like a light bulb,  where the light goes out all around.  What makes a laser a laser is that the light is different.  It is in phase with itself and   all the waves are parallel with each other.  The light is a  parallel beam of  intense light.  It goes straight out the tip of the  laser instrument in one  direction only.  You've probably seen or used laser "pointers" that  shoot a small straight beam of red light .  Often   lecturers use them to point to areas of a projected  slide on a  wall or screen from a computer projector or slide projector.

The  bulk of the tissue   in the main nerve canal  can be  pretty easily removed  with many   time-tested techniques.  There is no doubt in my mind that  a laser can also do a good job of removing that tissue.  That's not the problem.  It's the little offshoots and hidden places inside the  tubules.  The laser can't penetrate them as far as I know.  Or not very far beyond the main nerve canal inner surface.  The bulk of the dentinal tubules and accessory canals would still be potentially contaminated.  Claims are being made that this is not so, but independent research needs to  be done and published to convince me.  I am not just   being a stubborn disbeliever.  There are reasons I  feel this way.

First is the  idea that   as I said the  laser light goes in a straight  direction that would not easily follow the  tortuous  curves and bends of the  nerve canal.   Second, the  laser probe is too large to get into the  smaller accessory canals even if  we knew where they were (and we don't).

Third, the laser can melt and fuse much of the  inner surface of the  nerve canal which  means to me that medications placed in the canal are blocked from getting  out into the tubules to   kill "hiding" bacteria and to dissolve remaining  tissue (which there is  certain to be).  The bacteria  which are the major   concern, are effectively  trapped out in the tubules.   Their toxins, if the bacteria survive, can still potentially  travel out the tubules to the  cementum and out  the tooth (into  your body).

(Comment: Jan.2004)    Additionally, the heat from the laser can do damage to the  root, or to the surrounding ligament and bone if it is not very carefully controlled.  As   just one example,  IF the laser is used to clean and sterilize the very tip of the root (arguably the MOST IMPORTANT place) the laser  can  potentially   shoot out through the opening in the root end and the laser  then can damage   bone ... or worse, if the tip of the  root is next to a sinus or  major nerve (both of which are  common), the laser can potentially damage these structures!! 

I am not  just "making this up" ... Hebrew University  recently invented a special laser tip (about December 2004) that is designed to prevent the laser from shooting out the end of the root and also to shoot the light  sideways for  better cleaning effect.   I doubt that many of the dentists using lasers for root canals are using one of these special tips.  So obviously I am not the only one concerned about these issues.

 

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An email I recently  received   from England suggested the following VERY interesting and significant...and scary ideas:

  • Teeth that once  had   mercury fillings  probably have absorbed mercury  within them. Heating them with lasers  would likely vaporize that mercury  directly exposing the patient and dentist to the  most deadly toxic vapor (the  most toxic form of mercury is the heated  vaporized form - it is quite literally DEADLY ...)

  • Testing for sterility   of the  [main]  root canal space after laser use may be  false  because  if the tubules are sealed off from the main canal by the laser effect of  melting and fusing  the dentin, then the bacteria in the tubules may be sealed in the part of the tubule  now sealed off from the main canal.  But the bacteria  could still be alive and well and   producing toxins which can  continually come out  through the outside surface of the  tooth root.  But testing for  bacteria in the main canal space  might  still show NO BACTERIA.

Those are  the kind of   questions that  still need to be  answered by OBJECTIVE RESEARCH   DONE BY  researchers NOT CONNECTED WITH PROMOTING the SALE and use of a particular laser product  !!!!

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UPDATE July 2008:

One laser manufacturer - probably the most popular laser in  dental use -  Biolase, recently advertised that their root canal laser, the Endolase RFT  laser with  their new proprietary root canal tip [ sounds similar to the one designed at Hebrew University around 2004 - see a few paragraphs back ]   will penetrate  dentin and sterilize it up to "4 times the depth of sodium hypochlorite [Clorox bleach]".  My friend and excellent  root canal specialist, Dr. Julian Moiseiwitsch [Chevy Chase, Maryland] tells me sodium hypochlorite penetrates about 100 microns [0.1mm], so the laser must penetrate at best 400 microns [0.4mm].  Since that's the manufacturer's own ad and not peer-reviewed research data, we have to assume that's the  best spin/interpretation possible on  the research they have done.

By contrast, there are many studies of Calcium hydroxide used in the root canal treatment where the outside surface of the root is checked for changes in pH and it has often been shown that the outside surface becomes very alkaline [pH about 10 to 11].  That indicates that the Calcium hydroxide penetrated all the way to the outside surface  from the root canal space.  Calcium hydroxide kills bacteria and dissolves the bacteria's cell membrane which can still be a source of toxicity even  when the bacteria are DEAD!

Since the thickness of the dentin from the root canal space to the outside of the root is often well over 1mm, we can safely conclude that laser sterilization will only go perhaps half way  through to the surface....  That leaves about half or more of the dentinal tubules untreated.  That's my interpretation as I see it for now, but It's a fascinating area and I'll be watching for any new breakthroughs!

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UPDATE March  2012:

Laser root canals continues to be a hot topic and the subject of many emails I get.  Today I attended a continuing education  seminar given by the head of the Department of Endodontics at U. of Maryland Dental School, Dr. A Fouad.   He has written many research articles and is well respected as a researcher in endodontic microbiology.     I asked him about laser use for root canals and he said that the only way a laser currently can sterilize a root canal is to keep it in the  canal long enough that it would heat up the ligament that holds the root to the bone to the point of  causing damage to the  bone.  Short, quick use of the laser doesn't do the job.  I also asked about ozone use and he said that the research  has not supported its use in  root canal treatment at this time.

 

I looked up  laser root canal treatment on the internet and found  that the root canal specialists have already written an early  position statement on  it:

 

American Association of Endodontists - Lasers In Dentistry
Search POSITION STATEMENT ON THE USE OF LASERS IN DENTISTRY Laser use in dentistry was suggested approximately 35 years ago as a means of using energy generated by light to remove or modify soft and hard tissues in the oral cavity.
http://www.aae.org/lasers.html

On that website, the American Association of Endodontists say:

Laser energy, when added to root canal procedures, presents advantages and disadvantages. Currently, root canal procedures clean the canal space. Studies using extracted teeth inoculated with bacteria have shown that lasers can reduce the quantity of microorganisms. The walls of the prepared canal space contain tubular openings that harbor organisms, and the preparation itself causes formation of a layer of debris (smear layer) composed of organisms and tooth substances. Laser energy can remove the smear layer as well as dentin from the canal wall and will melt and re-solidify the dentin to close the tubular openings.

The advantages of using the laser, however, are balanced by several disadvantages. Root canal spaces are rarely straight and more often are curved in at least two dimensions. Root canal instruments used to clean the space throughout its length can be curved to follow the curvatures in a tooth root. Laser probes can clean an area in a root canal space that is straight as long as the probe is in contact with the dentinal wall. The probes are made of glass and cannot be curved to follow the natural curvatures of the tooth root. When in contact with the dentinal wall, laser probes are capable of cleaning an area in the root canal space that is straight.

Further, the interactions involved between laser energy and the tissue cause rises in temperature. These increased temperatures can char the canal space, damaging it to the point that the tooth may be lost. The increased temperatures also may extend to the outer surfaces of the tooth, damaging the soft tissue that connects the tooth to the surrounding bone. If the temperature is high enough, the bone surrounding the tooth may also be damaged, adversely affecting the entire area, which can result in ankylosis.

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In summary,  laser RCT may be the wave of the future...or it may be insignificant.  The equipment and the techniques have only now  started to be developed...and tested.  There are sound reasons to be hopeful for the  future and also sound reasons to be skeptical  in the  present. 

One final thought:  Root canal specialists  (endodontists) do root canals and only root canals...all day long, and mostly  by referral from general dentists.  There is a lot of money  to be made in doing all these root canals and so the  specialists are very competitive  with each other.  This is not to  disparage these fine men and women, it is only to make the point   that  if using laser equipment  would  give them  better, or quicker, or easier, or more patient-satisfying results, they  would be the   FIRST to jump  at this new technology.  Laser use in root canals is NO SECRET !

This laser  technology is widely known about and advertised.  The cost for the equipment, while high, is insignificant   if it  would  result in  being  more productive  on a daily basis and if  the  results were more satisfying to both the patients and to the  referring general dentists !  To my knowledge the endodontists are not   yet embracing this new technology.  I am very sure that they are, however,   watching it VERY carefully and closely...and will want to be the first on their block to have it  if and when it looks like the way to go !!!!

I, too, do lots of  root canal treatment, and I, too, will be watching closely.  When I learn more, you can look here to find out what I think.  Have a good one!

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I wrote the various parts of the above article for this website at different times over the past few years prior to 2006.  In May 2006, I found a brief abstract in The Compendium, a respected  dental journal, summarizing current research conclusions to date.  In spite of some advances in lasers and adaptations specifically to root canal treatment, it completely agrees with the ideas I have stated above:

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UPDATE November  2012:

This has been a busy year for lasers and root canals!  I read an interesting article in Dentistry Today Vol. 31 No. II, November 2012, pp124-127,  about a new way of using laser that may be promising in root canal treatment.  In the past and presently, lasers are used to heat up and vaporize tissue in the canals.  It's the heat that can cause unwanted side effects in the way lasers have been used up to this time.

In this article the authors  discuss the use of  a different kind of laser that does not  work by HEAT but instead causes a kind of sonic  explosive vapor bubbling within water or bleach or other liquid solutions placed inside the canal.  To me it seems like a sort of microscopic "powerwashing".  If you've ever done, or had done, a powerwashing of your car, deck or driveway, you are familiar with the dramatic cleaning power of just plain water when it's activated sufficiently!  So to me it sounds promising - just keep in mind this is not the kind of laser that is in use today  except in very limited situations.  If it  turns out to be as good as the authors  say, and research supports its use, it may become  a more common treatment modality.  You can see videos of it in action at : http://pipsdocs.com/vault.php

Dr.G's note:  In the abstract immediately above this last one [the one from Compendium 2006] it talks about "A new  laser system agitates water irrigant with an erbium...laser..." [ Highlighted in yellow ]  This is not the same thing as this last abstract - it's totally different even though it sounds similar.  It all gets very confusing! .....Sorry!

 

'Hope this was  helpful !

 

This pamphlet was written in the hope that it will increase understanding about a topic that seems important from time to time. Obviously it is only a part of the whole story, so if you have questions after reading this please do not hesitate to ask or call. Also, if there is a topic that you think would be helpful, please suggest it.

Michael C. Goldman, DDS

General and Cosmetic Dentistry
3815 East-West Highway
Chevy Chase, Maryland 20815
Phone (301) 656-6171

 

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More info about the following is available  if you select  "topics".

Holism in dentistry is an approach to dental treatment, primarily  caring for  patients' health and safety from both a conventional as well as  "alternative healthcare" point of view.   It is sometimes called "biological" dentistry or "biocompatible" dentistry.  In it's fullest sense, I believe it   acknowledges and deals with  the mind, body and spirit of the patient, not just his or her "teeth".  See Topics / Info.....

Cosmetic dentistry is about doing   quality , esthetic dentistry in a way that looks natural to begin with, and furthermore,   can even  improve  one's  attractiveness through techniques such as bonding, bleaching, veneers, caps, implants and more.  It can   be like "instant orthodontics" in correcting  crooked, twisted or misplaced teeth in many instances.  Dark or misshapen teeth can be restored.   Smiles that lack youthful vigor or beauty can be revitalized! See Topics / Info..

Bleaching, veneers, bonding, caps, bridges, and implants  are cosmetic dentistry treatments that are also  discussed in  Cosmetic Dentistry, and more...

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