There seems to be an inate belief that doing something the hard way makes it a better way. That is often just the opposite of the truth.

Sometimes the simplest way is the best way because it allows us to concentrate on what really matters.

In endo there are two overriding factors namely that the canal must be clean and then the space must be obliterated.

The first, cleaning is a simple mechanical activity. The objective is to get the debris out of the canal and off of the canal walls from the coronal opening to the apical terminus. We believe this can be better done with automated methods than by hand methods and have always advocated some mechanical debridment method, all of which have improved over the years.

Unfortunately some of the proposed methods actually take a step backwards. Rotary files is one of them.

Instead we use linear motion for two very good reasons. First rotating files get stuck and when they do, they break. It is as simple as that. Wire, from which files are made, is inherently weak when torsion is applied and conversely it is remarkably strong when linear stress is applied. We suspend bridges on wire all over the world.

Secondly, rotating files do a very poor job of removing debris and tooth structure except in one very narrow case and that is when the canal is perfectly round. To clean a canal that is NOT round requires moving the file around the circumference of the canal and applying lateral pressure. If a canal is enlarged to the point where an elliptical, crescent shaped or ovoid canal is touched by all the surfaces of a round instrument very often is much too large and weakens the tooth.

If that canal can be cleaned by removing only enough tooth structure to get it clean and the canal can be left out-of-round, the structural integrity of the tooth can be maintained...and incidentally a lot of work can be saved.

We instead use reciprocal linear motion, a filing action, and mechanize that by using a dental handpiece as a power source. The file moves in and out of the canal at up to 350 times per SECOND with each stroke slightly to the side of the previous thus covering all the circumference.

This has the added advantage of using fewer files because it matters very little what size the file is as long as it fits freely in the canal. And thus many canals can be done with one file instead of incrementally larger files as the canal gets larger.

We also have proven that when water is added to the canal while filing, water carries the debris away WHILE FILING as fast as it is generated, thus eliminating the need to stop and irrigate. Each out stroke creates a partial vacuum which aspirates water into the canal to the depth of the prep and each inward stroke displaces it coronally carrying the debris with it.

But all of this wonderful scenario would be useless if the preparation did not suit our obturation needs. Which is where the second major component of our method comes into play.

Our objective is to seal and fill a canal. We do this with a specially designed syringe that injects a putty-like cement into the canal from the apex upward to the crown.

We look upon gutta percha only as anothr method of introducing cement as everyone will readily admit that it is the cement that does the sealing, not the gutta percha.

Recent studies in the Journal of Endodontics indicate that not only may cement be as good as gutta percha plus cement, that it is actually better.

And when we have available to us a sealer that is certified by the ADA as a 'sealer and filler with or without solid core materials' we have the best of both worlds.

The last part of the puzzle is to have a syringe that will deliver, under control, that cement in a carefully controlled manner. We have that syringe. It is reliable and costs less than one anterior root canal.

So we have a preparation method that cleans without breakage, uses a minimum of files, a syringe that seals, a sealer that is non-toxic and holds up well in the canal, is radioopaque and a teaching faculty with 30 years experience, and over 16,000 users in the U.S.

It is not hard to understand why we are enthusiastic boosters of these methods.

Are you still doing mobile classes?

Unfortunately I am not travelling any more.

For those of you who are not familiar with 'the good old days' from 1976 thru about 1995, the "Automated Endo" course travelled all over the United States, starting in 1976 with a van and moving up thru two motor homes, two trailers and eventually two large buses.

The first bus was an old GMC in which I lived and travelled and eventualy (1992) in a NeoPlan bus converted into a mobile class room.

Many of you remember the "Magic Endo Bus" as it was frequently dubbed and attended seminars in it as it was parked outside many dental offices which acted as hosts for the course.

Now the only courses are monthly courses here in Kissimmee, FL and this CDROM course.

Recently we have added another type of seminar, distance learning via video conference. If you are properly equipped I can do the seminar directly from my office to yours via the internet. Since I don't have to travel and your study group doesn't have to travel, the costs in money and time are greatly reduced.

For instance, I can do one seminar in New York, NY on Monday morning and another in New Delhi, India in the afternoon and still another in New Zealand in the evening, all without packing a suitcase.

The secret weapon is a Macintosh computer with an iSight camera running OS 10.4 (known as "Tiger"). With this system I can talk directly to a group anywhere in the world.

Can I really do a root canal with a toothbrush?

Well not exactly. But close.

In June of 1994 I modified a Sonicaire toothbrush by removing the brush and replacing it with our Fine Cut Sonic Adapter.

The concept is this.

Circumferential filing can be broken down into two actions, that of the circumferential movement around the circumference of canal, and linear oscillation, that is moving the file in and out.

Click here to see an animated GIF of Circumferential filing

Since the average dentist can move up and down about 5 strokes per second and the toothbrush moves 250 up and down strokes per second, you can cut dentin at least fifty times faster than you can by hand...and that is exactly what you must do when you use any sonic or ultrasonic handpiece.

This is why the variability in the reported effectiveness of sonic systems.

If you expect it to do your work for you, you will be disappointed.

YOU have to do the cutting.

The only function of the vibration (which by the way waggles the file back and forth, not linearly), is to keep the file in motion and stir up the water.

That new system which we called the STS( Successor To Sonics ) does the up and down motion for you.

All you need to do is steer it around the periphery of the canal.

So, although it is technically no longer a toothbrush, you can do endo with it.

Those who use it report that it is nothing short of amazing.

It takes less than a minute in some cases to to the entire enlargement and cleansing of the canal, providing more comfort for both patient and dentist.

If you already own a Sonicaire toothbrush all you need is some Fine-Cut Files, and the modified brush head with the Fine Cut Sonic adapter.

The modification will cost about $230 and the files are about $5 each.

Both these products are available from Special Products. Their phone number is (800)538-6835.

(Note: That product came into being in 1998 and is called the Fine-Cut Endo Contra-Angle and is currently available at this writing(May 2004)). It attaches to any E-type motor such as MTI or some of the electric motors.

It is much smaller and eliminates most of the objections people have to using a toothbrush to do endo.

It is autoclavable, small, variable in speed( it depends on the speed of your handpiece ), can be operated with your existing foot control. It still used Fine-Cut files, the same ones we have used in the ultra-sonic, sonic, and toothbrush systems.

Note: It is currently available and enjoying good acceptance from those fortunate enough to have purchased it early.

If it's so fast, why don't you zip apices?

Zipping requires repetitive filing near the apex, around a curve with large files. The only files that go near the apex using our handpiece and filing system are #15.

Since these files cut only on the way out, they do not create ledges and this allows us a technique trick that is unavailable to others, namely to do the bulk of our filing, keeping the tip of the file a few millimeters from the apex, and then going back to finish the apex at our leizure.

This method is the epitome of "crown-down filing" because of the incapability of the system causing ledges i.e. the coronal portion of the prep can be done first, the middle next and the apex at the end.

Can I prep your way and still fill with gutta percha?

Absolutely. But the real advantage comes in using both techniques concurrently.

Our suggestion is that you do a crown down preparation, dress the apex to the size you want and then prepare a seat for the gp to 1mm from the apex using Fine Cut NiTi 02, 04 or 06 tapered system to size 35. The important factor is getting a canal that is at least 0.30mm 1mm from the apex.

A recent(April 2005) article shows something that I've known for years, namely that backfilling a canal with cement alone is 24 times as effective as backfilling with gutta percha AND cement. The actual data shows that the average amount of leakage with cement alone is 0.92% of the canal length and the average leakage with gutta percha alone or molten gutta percha with cement was 24% of the canal length.

Can I fill with your method and prepare by hand?

Preparing canals by hand today is like using chisels, hoes and diamond disks to do operative. It's possible, but why would anyone do that?

Having said that, one of the most valuable skills learned at the course is initial probing, and there are a lot of older patients who have canals that are impossible to do with ANY automated technique, including this one.

Interestingly, there is no other endo course (at least that I know of) that even teaches how to work the first file through the canal to the apex i.e. initial probing. In fact we have several techniques and instruments designed specifically FOR that.

Who teaches the course?

All courses are taught by Dr. Jack Jacklich himself...that's me :). Most old fashioned people who can't bring themselves to use first names call me Dr. Jack. Most dentists call me Jack.

By the way, "Jacklich" is pronounced with a long "A" as though it were spelled "Jake-lich."

When I started teaching, I lived in Joliet, Illinois. From 1977 until 2004 I lived in Santa Cruz, CA. Now Marian and I make our home in Kissimmee, FL. In case you are not familiar with Kissimmee it is in Osceola County about 10 miles east of Disney.

Since 1977 I have devoted my life to teaching, writing, doing research and inventing dental instruments and techniques.

My teaching methodology has been the subject of a PhD thesis and is unique in the dental field. Very few courses in dentistry are designed from the ground up with the behavioral model in mind.

I have been quoted as saying, "It is totally irrelevent whether I can do a root canal. (In fact I'm pretty good at it.)

The important thing is that after you leave my class that YOU can do a root canal.

I have always combined lecture, video demonstration and then hands-on drilling ( if you non-dentists out there in cyberspace will pardon the pun ) until the dentist feels that he can perform the same procedure sucessfully the next morning on his next patient. Recently I have prepared a slide presentation because we now have our own teaching facility here in Kissimmee.

This teaching technique has been carried into the "Automated Endo on CDROM". course being produced now. It is teaching by objectives where the educational objectives are clearly implemented in both didactic and laboratory exercises. The dentist has the further option of practicing these techniques on patients as soon as he/she feels competent to do so.

(The following is for historical perspective as the travelling course is no longer given)

One of the most unique facets of the course is WHERE the course is given. He uses a 40 foot long mobile classroom converted from a NEOPLAN bus ( you readers in Europe will recognize the name ). It is fully equipped with all the air turbine handpieces, air-water syringes, xray, computers, video that are needed for 16 dentists at a time to partipate.

In addition to teaching he drives and maintains the bus himself and has personally taught his course in 49 of the fifty states. ( All except Alaska )...No, he doesn't drive the bus to Hawaii!

He parks the bus in the host Dentist's parking lot and thus can bring the course near to almost any dentist in the US.

Of late the courses are only given on a twice-monthly basis in Kissimmee, Florida, usually on Thursday and Friday the first and third weeks of the month.

Who is Dr. Kit Weathers?

Those of us who are proud to be his friends know him as one of the brightest lights in dentistry. His clear writing and lucid explanations of endodontics has for years now enabled many dentists to overcome their fear and dislike of endo.

He is a true 'renaissance man'. He publishes 'Practical Endodontics', practices endo, has written two books on dental photography, video tapes, edits his own video and with Dr. Bill Strupp runs the Video Dental Study Club.

Although he and I differ on how to teach endo (he's a more talented showman than I) we both adhere to the same basic premises of endo, namely that the main goal is to clean and fill the canal in the most expeditious way.

Where are courses given?

Courses used to be given in all the lower 48 states in the U.S.A. and Hawaii.

Generally they were held at one of our attendees offices in a mobile endodontic laboratory teaching facility that one of our attendees once called 'The Magic Endo Bus'.

Fortunately now anyone, anywhere can learn the "Automated Endo" technique by signing up for the in-office participation course "Automated Endo on CDROM" or by arranging for a video conference course anywhere in the world.

You can also travel to Disney's back yard (Kissimmee, FL) and take one of our two day seminars.

And here's the latest( April 2005) news. By special arrangement you can connect your Macintosh to mine and have a course for free almost anywhere in the world. The new OS 10.4(Tiger) has a feature where groups from all over the world can video conference. An email will get the ball rolling toward such a conference for your office or study group.

E-mail your comments to

If it's so good, why don't the dental schools teach it?

We really don't know.

Traditions die pretty hard.

Many schools have long term purchasing agreements with the large dental corporations and we're pretty small as dental manufacturers go.

For several years I (Dr. Jack Jacklich) taught at Loyola Dental School and University of Illinois, in Chicago and pretty much wrote off the dental schools as hopelessly mired in the past when I left them in 1974. I'm more than happy to share my knowlege with anyone who asks. All the schools have to do is ask.

What is the Milton Syringe?

The Milton Syringe was essentially a miniature syringe. The critical factor in the accuracy of a syringe is the internal diameter. Each time you reduce the diameter by half, you increase the required plunger travel AND the accuracy by four.

Each millimeter of travel of the Milton Syringe produces 0.0009cc of cement. Since we have the capability of moving the plunger in tenth of millimeter increments, the accuracy is plus or minus 0.00009cc.

As you can imagine, it would take forever to fill a canal at this rate, so the Milton is used to seal the apex, under pressure and then back filling is done with either the Precision Endo Syringe, the Precision Multi_Mode Syringe or the newest Precision Endo Obturating Cartridge Syringe.

The "Milton Syringe" has now been relegated to research status. A new syringe incorporating an actual micrometer is now available that exceeds the capabilities of the "Milton" in that it is possible to move the plunger as little as 0.00025 inches and thus with the 0.119 inch diameter of the cement cartridge, deliver cement with such control that we can actually now predetermine the SIZE of the puff.

What do you mean by "Automated Endo"?

In 1976 when the Automated Endo Course was first taught, the standard method of doing endo was to prepare the canal with hand instruments (usually K-files) and fill it by packing it with gutta percha (usually laterally condensed).

Dr. Jacklich, at the time was doing endo for a group practice in Downers Grove, Illinois, USA and was getting overloaded with endo.

In an effort to keep up, he dug out his Giromatic that he had bought in 1963 ( and had never really learned how to use ) and found the old PCA Pressure Filling Syringe had buried in his dental antique closet (doesn't every dentist have one? ) and set about learning to do endo faster.

To make a long story short, he soon was preparing molars in less than half an hour and filling them in less than ten.

At the time he was also the Director of Continuing Education at Loyola Dental School in Chicago.

On July 12, 1976 he rounded up twelve dental engines, borrowed 12 giromatics and took his course on tour in Wisconsin.

Close enough to drive to but far enough away that if he flopped, no one he knew would know.

Well...he didn't flop.

The course was an instant success and in the last 26 years he has taught the technique and it's successor to over 22000 of his colleagues in the US.

Over the years the Giromatic gave way to sonics and sonics gave way to the STS system and the STS has now been replaced with the Fine-Cut Endo Contra-Angle.

The old PCA Syringe was followed in 1978 by the Precision Endodontic Syringe and then the new Multi_Mode Precision Endo Syringe which arrived on the scene in 1996.

The latest iteration of the original syringe idea is a syringe (the Precision Endo Obturating Cartridge Syringe) with throwaway cartridges instead of a barrel. It is also available with a micrometer attachment to move the plunger in increments of thousandths of inches.

The course is now presented on a regular basis in Kissimmee, FL(Disney World to you non-Floridians). It has been enhanced by a self-taught course in a box called "Automated Endo on CDROM". It is also available as a video conference but requires the use of a Macintosh running OS 10.4 and a digital video camera.

What's the Dual_Mode? How does it differ from the Precision Endo Syringe?

(this name was determined to be unsuitable after new "modes" were discovered and now it is referred to as the "Multi Mode Endo Syringe.") More recently with the introduction of the cartridge syringe this syringe is obsolete and no longer sold.

There are two basic kinds of syringes, micrometer screw and push plunger(like a hypodermic). It takes considerable pressure to get a very putty-like mix of cement through the bore of a 30gauge needle which has an I.D. of 0.15mm. One cannot just push a plunger an accomplish anything so it requires the mechanical advantage of a screw or ratchet to do that.

The Precision Endo Syringe has since 1978 set the standard for endodontic syringes. The inside diameter is 0.120" and it uses a 5-40 thread on the plunger to force the cement through the needle.

This is fine for most apical sealing but then large canals might take as much as two or three minutes to fill. The Multi_Mode Syringe allows you to use the ratchet-drive mechanism of the PDL intraligamentary syringe to back-fill much faster, once the tip of the canula is away from the apex.

In April 2005 we announced the introduction of a new device called a GPS( stands for General Purpose Syringe ) which can replace the screw mechanism of the endo syringes (either Multi-Mode or Cartridge ) and can be used in the ratchet mode for backfilling and in the micrometer mode for sealing the apex.

New Endo Contra-Angle Opens new Possibilities

Qualitative change

Since the advent of the the new Endo Contra-Angle for root canal preparation we have found that it is more than a quantitative change. It is qualitative as well. The best example I can give is the difference in dentistry before and after belt driven handpieces were replaced with air turbines.

After having opened the access and flushed the pulp chamber with water, we now use a size 25 or 30 Fine Cut File[First File] in the Fine-Cut Endo Contra-Angle and inserting just the tip, move in a circuferential manner. As we do so that the orifice opens up allowing the file to enter further. We proceed with this technique(called Spiraling Down) which combines orifice opening and crown down preparation and which is called, you guessed it "the Crown-Down-Orifice-Opening Technique". In many cases, the tip of the file ends up more than half way to the apex and in some cases within a few millimeters.

All this while using a constant supply of water. Water enters the canal by capillary action. There is no need to aim or direct the water. Simply flood the access cavity.

Each stroke of the file(1mm in and out) displaces the water from the tip of the file coronally and each up stroke capillaries more water to the end of the file. This creates a circulating pattern that completely flushes the canal every two seconds.

At a certain point, the file will get stuck. (Not to worry, this doesn't hurt anything.) This indicates one of two things. Either the canal is too small for the file or the canal is too curved for the file.

Then it is a simple matter to use a smaller file to do the rest of the canal or to pre-curve the file or both.

Getting a Fine-Cut SPeed file stuck is of no consequence since these files are the same design as the Fine-Cut Hand Files and have been designed to pull themselves free without danger of breakage. In fact they are used for probing calcified canals.

At this point probe and measure. Once you have probed to the apex to a size 15, the next step is to use a #20[Second File], inserting it close to the apex and as you move circumferentially, move the file out of the canal(spiraling out). Repeat this process six or seven times.

At this point you have a canal that is smooth, patent, clean and tapered.

What's left to do depends on how you intend to fill it. With the pressure filling technique with the new Multi-Mode or Cartridge Syringe you can fill it immediately. Simply blot dry and fill.

No need for post-preparation irrigation

There is no need for irrigation AFTER you prep because you have been doing irrigation all the while. After filing with the Fine-Cut system the canal is already as clean as you can get it by irrigating.

If you choose to irrigate with sodium hypochlorite solution, you can do that after the final stages of filing, following with a sterile water rinse. In other words, there is no need to use a syringe as irrigating while filing is much more effective. In fact if the canal is smaller than size 35, there are no needles small enough to get into that canal and if you were to push it in, there would be no back flow and the fluid would go out the apex.

If you still use the Passive Filling Technique I taught many of you in the last 25 years, there are a few more steps. Mainly preparing a seat for the needle(30 gauge is 0.29mm) using a size 35 hand file or a series of LightSpeed NiTi files(my favorite is a size 32.5) or a size 35 in the new Endo Contra-Angle to the 1mm point.

If you are still packing gutta percha, there are even more steps. Why anyone would want to spend the extra time and enlarge a canal beyond clean, smooth and patent is beyond me, when we have methods today that enable a fill with an ADA certified cement under very good control.

In the April issue of the Journal of Endodontics research has shown that indeed the BEST method of backfilling is to inject cement.

But that requires a more complete explanation that I have room for here.

If I get involved with your technique, can I get follow up support?

Our main mission is education. The supplies and products take a back seat to the education that we do.

Our telephones are open five days a week from 8am to 8 pm East Coast time. The number is (800)538-6835.

All of our staff members have actually taken the "Automated Endo" participation course and have prepared and filled canals using the methods we teach and many of the questions can be answered immediately. If it is beyond their capabilities or if you prefer to talk directly to Dr. Jacklich, he is available any days he is not teaching at (407)344-0550.

If you have email you can ask and get answers that way. OR you can catch me on AOL Internet Messenger or better yet, if you have a Macintosh use iChat AV and we can connect using video conferencing. My iChat(or AOL IM address) is drjackjacklich. My video camera is usually nearby and I can video conference with a few minutes preparation.

By reading our web page you can also pick up a lot of information that you may have missed earlier.

Almost the entire course is packaged and is available on the web as a link from our home page. You will probably want to bookmark this one because it takes an average of 4-10 hours to work your way through it.

Our FAQ file is under continual renovation and updating. Read it frequently for newest information.

And we have several sources where we can get the answers if we don't have them.

What do I have to buy and where can I buy it?

There is no requirement to purchase anything before the course. After the course you can use your tuition credit toward the purchase of any of the equipment.

Everything is available by calling Special Products at (800)538-6836 or you can order directly from the internet if you have already established an account.

Some of the items you will need are

  1. Precision Endo Obturating Cartridge Syringe
  2. PCA Root Canal Sealer Powder and Liquid
  3. 30 gauge endo cartridges
  4. The New Fine-Cut Endo Contra-Angle
  5. Fine Cut Hand Files sizes 15-40 in 25mm length
  6. Fine-Cut SPeed Files sizes 15-40 in 25mm length

Some optional items are:

  1. Digital Caliper
  2. Optical Comparator
  3. Microcopy Portable Darkroom
  4. Rubber Stop Kit

What does STS Stand For?

Back in 1992 I happened up the Sonicaire toothbrush while on vacation. When I returned I whittled off the plastic toothbrush, finding a metal rod beneath it. I then attached one of our Fine Cut Sonic Adapters to it. It was really amazing how fast it cut. For a couple years we marketed this modification for Sonicaire toothbrushes and many dentists used them very successfully.

It is no longer available commercially. It has been replaced by the FineCut Endo Contra Angle.

STS stands for "Successor To Sonics". It is a modification of a battery powered electric toothbrush that moves the file linearly in an out of the canal a precise half a millimeter about 250 times per second.

Anyone who has done circumferential filing will recognize that it does mechanically, consistently and accurately what you have been doing with great difficulty all these years.

It is safe, effective and FAST. It is common to enlarge a canal from size 15 to 50 in as little as two minutes using as few as two files.

As we have been telling people for years sonics do not cut. All they do is vibrate to make the cutting smoother by reducing the coefficient of friction so that you can cut by moving the file past the tooth structure.

Do you ever split roots with your methods?

One of the neatest things about a cement technique is the cement is injected with a syringe. Thus there is no "log-splitter" pluggers ever used and the cement is simply flowed in.

Furthermore, with the Multi_Mode version of the Precision Endo Syringe or more recently the Precision Endo Obturating Cartridge Syringe we can now control the flow to +- 0.00009 cc

Do you still have copies of the (IN)famous August and September, 1990 issues of 'Endo for GP's'?

A little background here for those of you who haven't heard the story.

In August of 1990, Dr. Kit Weathers did an interview with this writer and wrote a two part series for 'Endo for GP's'. At the time, Boston University was the accrediting agency for the publication. Dentists could get continuing education credit by reading and filling out the quiz. (For those readers outside the U.S. B.U. is the center of the gutta percha universe.)

The August issue contained the story of my course and how I had been one of the foremost teachers of mechanical canal debridment and enlargement for over 15 years.

The issue was already in the mail when the directors of the continuing education program found out. They didn't like it but there was little they could do about it.

When the September issue came out and the headline proclaimed 'GP Does Endo Without Gutta Percha' the 'defecation hit the ventilation' and the publishers were forced by 'you know who' to burn over 4000 copies and the September issue never happened. The October issue did go out and soon after that Kit was no longer the editor.

Fortunately, an arrangement had been made directly with the printer to ship me 100 copies for distribution every month to my course attendees as a promotional method.

They had already been shipped and I still have them. But no, I can't send you one. Sorry.

Is the sealer that you use ADA approved?

Yes. Since 1986 the ADA has Certified PCA Root Canal Sealer for use as a 'sealing and filling material with or without solid core filling materials'.

But, does that make other sealers bad. No. But only one other sealer has the certificate of approval of the ADA and that one is Ketac, which is not nearly syringeable and is VERY hard after setting and sets very quickly.

One unique thing about PCA is that the particle size is small enough to go through the bore of a 30 gauge needle (0.006" inside diameter). Other cements clog up any needle smaller than about 25 gauge.

Can I retake as often as I want?

We have had that policy since 1976 and is still in effect but with some modifications.

At our courses in Kissimmee we have a modification of the basic offer. We have always allowed free retakes but only on a space available basis. Since we hold reservations open until one week before the course, all free retakers are confirmed one week before the course.

Since many will be coming into Florida from other parts of the country and must make travel plans, there is a second option. You can reserve a regular place in class and pay full tuition like the newbies. This will guarantee you a place in class.

What probing technique do you use?

Probing and filing

The defining difference between probing and filing is that when filing the assumption is that the file is smaller than the canal. In probing, the file is larger than the canal.

Filing to me means circumferential filing, that is moving he file linearly while moving around the circumference of the canal. There are of course other ways of enlarging a canal, such as reaming, PQTP( Push-Quarter-Turn-Pull) filing, drilling etc.

Fine-Cut Files are unique in their design. To the untrained eye they look much like hedstrom files. They are not. The only resemblance is that both have a positive rake angle.

Fine-Cut Files differ in that the helical angle is consistantly low from shank to tip but the inter-flute distance varies. On a hedstrom file the inter-flute distance is the same and the helical angle varies. It gets greater as you approach the tip.

The result is that at the tip of a Hedstrom file, the weakest part of a file, the tortional stress is the greatest. This is why you must never get hedstrom files stuck in the canal. At the instant that the file breaks free, the torque created by the helical spiral gives the file a quick twist. Sometimes more than the metal of the file can take.

File-Cut Files are designed to get stuck and take it. In fact you can quite literally pound them into a tooth with a hammer and pull them out with a pair of pliers and they won't break. The reason is simple. Wire has tremendous tensile strength but poor torsional strength.

Furthermore, the included tip angle of a Fine-Cut File is a 60 degree cone.

When a pulp is irritated by caries, abrasion, restoration, occusal trauma etc. the pulp reacts by laying down reparative dentin and the inorganic part of the tooth grows inward like a plasterer laying down layer upon layer of plaster on walls until the room gets smaller.

The pulp eventually, totally obliterates itself coronal to apical. Therefore the oldest part of the reparative dentin and thus the most mineralized is farthest from the center. The most organic and the softest is nearest the center.

If there is a canal left, you can use a small file to work your way through. If there IS NO CANAL left, that presents a different problem.

Fine-Cut files can be pushed(literally forced) into the softer core of dentin and pulled out with each cycle of push-pull going deeper. The conical tip keeps the file centered and the fact that the files can get stuck and be pulled out allows us to progress down the canal.

Thus is is possible, even when there is literally no canal left, to work a file through the secondary dentin and follow the path left by the previous canal. Often this requires a slight modification of the technic whereby the file is screwed in slightly and then released and pulled out. Since the helical angle is lower, it translates what small amount of torque is applied into a lot of apical pressure. Much more than one could apply without buckling the file.

Push-Turn-Pull is really Push-Turn-Release-Pull. You turn until torsion is felt. Then let go of the file and release the torsion before you pull. You will be able to probe some pretty calcified canals this way.

This is an especially useful technique for the coronal portion, which is frequently difficult to probe.

What is Pressure Filling?

Pressure Filling

Most people do not distinguish between Pressure filling and passive filling much as non-football fans don't distinguish a line-man from a line-backer from a line-judge.

Pressure filling assumes one very important factor, namely that the needle is wedged in the canal. If the needle is wedged, there is only one place for the cement to go. In effect the canal beyond the needle is an extension of the lumen of the needle.

There are two critical factors in pressure filling.

First, you must have patency. That is, the air in the canal apical to the needle wedge point must exit before any cement can enter. If you do not have patency then you simply compress the air apical to the cement and as soon as you relieve the pressure, the air expands and pushes the cement back up the canal. By the way, this is also true of gutta percha techniques that fill from the crown down and do not provide a vent for the air.

Second, you must know how much cement to extrude. This has several implications.

If the pressure filling is a prelude to an apico, any extrusion can be removed during the surgery. In fact this was the first way injectable endo was done back in 1946.

Another way to control it is incremental filling. That is,

Until the cement is where you want it.

If you knew the volume of the canal beyond the wedge point you could then extude just the right amount.

This approach has two components, the calculation and the control of flow.

We have solved both problems...theoretically. The calculation is done by plugging numbers into a spread sheet to produce a table of all possible values for various needle sizes, apical sizes and canal lengths. The syringe is the new Cartridge Endo Syringe from Special Products(800)538-6835.

In fact the pressure filling part has been an important aspect of our passive filling concept for the last 40 years(Yep, I'm one of those old codgers that graduated in 1962). The needle is placed 1mm from the apex and a known, safe, amount of cement is injected usually about 1/16 to 1/8 turn, which moves the plunger 1/320 of an inch and extrudes about .007 cubic mm.

As the cement flows, the needle is withdrawn at a fixed rate to fill the apical 3mm. After that, the canal is large enough that even with zero tissue fluid pressure at the apex, the fluid friction of the cement apical to the needle tip, will prevent the cement from flowing apically. Once this point is reached the needle can be left in place while filling the portion of the canal coronal to the tip of the needle and the needle is withdrawn while backfilling.

This method is also a perfect adjunct to the use of an apical plug of gutta percha. After all even if you don't agree that you want to use cement in the apical portion of a canal, there is little reason not to use cement once the apex is closed. (See Journal of Endodontics April 2005) This concept enables one to use circumferential filing in the coronal aspect and rotary NiTi filing for only the apical 3-5mm...but that is an entirely different issue.

How do the PCA Pressure Syringe and the Precision Endo Syringe Differ?

The PCA Pressure Filling Syringe has a threaded plunger in a threaded cement chamber. It has several drawbacks. Cement leaks past the threads and you have to dissolve the cement out of the inside threads to clean it.

The Precision Endo Syringe and it's successors, the Multi_Mode Syringe and Fine-Cut Endo Cartridge Syringe has a smooth barrel, and uses a disposable nylon ball to push the cement out. This eliminates any blow-by of cement and when the syringe is empty it is already clean because the ball has wiped it clean.

What is Passive Filling?

Passive filling makes an important assumption. That the needle is not wedged in the canal and that the path of least resistance is coronal rather than apical.

This requires a consideration of canal size at the extrusion point and a consideration of the tissue fluid pressure beyond the apex.

There is one simple fact that we have relied on for years.

  1. That is that if the apex is reasonably small, i.e. under size 30.
  2. And that the canal is a size 50 or greater at the extrusion point.
  3. And that the needle is a 30 gauge.
  4. And that the extrusion point is more that three millimeters from the apex.
  5. The path of least resistance is coronal.

As you can see this takes several techniques.

  1. First, the canal at the apex must be small.
  2. Second, you must use a sealer that will flow through a 30 gauge needle. This eliminates most sargenti sealers, molten gutta percha and most others. This leaves basically PCA root canal sealer, one of two that are ADA certified for both sealing and filling. PCA is specially ground and sifted to assure that all the particles in it will fit through the bore of a thirty gauge needle.
  3. Third, the needle must fit loosely, i.e. in a size 50 canal.
  4. Fourth that the dentist be well trained.

The Automated Endo Seminar has trained over 20000 dentists over the last 20 years and we continue to do so. Unfortunately, those of you who live in other parts of the world may find it difficult to attend. But now the course is available in hypertext on the internet, that problem may yet be solved. Additionally, if you are properly equipped, you can arrange a video conference seminar using iChat AV on the Macintosh. (There are other ways too but they are more expensive and cumbersome.)

This method has some technical drawbacks in that it is difficult to get a tooth opened to size 50 if the root tip is small or curved. Again, training helps.

There is another point that must be made. That is that if we keep the apex small and we only get pressure relief in a large canal, we must have another way to fill the apex. In fact we have been using a form of pressure filling of the apex for years.

We insert the needle to one millimeter from the apex and extrude a quantity of cement that, "we could live with if it went through the apex." And then, passive filling the rest of the canal.

Thousands of dentists have used this technique successfully on hundreds of thousands of teeth over the last twenty years.

The question is, why change now. The answer is, that we have now seen the way clear to taking the technique and personal skill that takes years of practice and reducing that to hours. With the new Cartridge Endo Obturating Syringe and the control it gives us, it is now possible to calculate the volume of a root canal and deliver that quantity consistantly and accurately. (If you are really a stickler for accuracy you can add the Micrometer Extrusion Control Device.)

Do you ever give courses outside the U.S.?

Occasionally we venture into Canada, but only on invitation from study groups and dental societies.

Unfortunately we do not routinely advertise our courses in Canada.

With the advent of high speed internet connections and the Macintosh iChat AV system, you can have a course no matter where in the world you may be. Once we check out your connection, you assemble your group and at a pre-arranged time you attend a lecture and demonstration in your office. Contact me by e-mail or by iChat or AOL Internet Messaging to inquire as to the feasablility of this arrangement. Unfortunately, the only language I speak is English.

There are only three, PCA, Centrix and Ketac. Ketac is not syringeable and Centrix is no longer manufactured.

Why have I not heard of this before?

We have using direct mail to inform people about this and have currently about 130,000 dentists on our mailing list. If you have moved we may have lost you. If you don't read 'junk mail' you may have tossed our brochures. But now that you know about us, keep looking. We're here.

The mail will usually have 2540 Greenwood Drive, Kissimmee, FL as a return address.

If I am not a dentist where can I get questions answered?

Unfortunately we only have room for dentists. There is very little to interest dental assistants, hygienists and non-dentists. We get pretty technical for the layman anyway.

If I haven't done endo in years, can I learn it?

Endo is basically simple. You clean the canal. Then you obliterate the space. Some people try to make it very complex. Of course there are complex cases, but the basics are very simple.

Any dentist can re-learn how to do endo the way we teach it. But it does not end there. You can start simple. Refer the tough cases. Then gradually, as your confidence grows, tackle cases staying within your comfort level.

Do you use Nickel-Titanium Files?

It appears that a lot of people are fascinated with what the vehicle is made of and care very little whether it's a Porsche or a coaster wagon.

Nickel-Titanium alloy has some interesting properties. It is indeed very flexible. It is also soft.

To fully understand the NiTi you have to ask, what techniques is it good for and under what circumstances.

To do vertical condensation of warm gutta percha it is essential that you be able to get your pluggers close to the apex because heat only travels a short distance through gutta percha.

It is also essential that the canal be round. If the canal is ovoid and the plugger is round, pressure is dissipated laterally instead of longitudinally and if the diameter of the plugger is greater than the minor diameter of the canal, potential root splitting pressure is exerted on the walls of the canal.

Therefore if you are going to do warm gutta percha properly, you have to have a round canal near the apex even if that is around a curve.

To do this you must either carefully precurve files or use a very flexible instrument in a rotating handpiece.

My argument against NiTi rotating files goes like this:

If the handpiece rotates 300 rpm that is 5 rotations per second.

How many times can you rotate a NiTi file after it gets stuck before it twists off. Perhaps two. Maybe three. (Studies show 540 degrees)

That gives you 2/5ths to 3/5ths of a second to notice the sticking and stop the handpiece before it breaks the file.

In order to enlarge a canal by rotary reaming, which is what rotary files do, it is necessary for the entire surface of the file to be in contact with dentin. The more surface area in contact the more friction and thus the more torsion placed on the instrument.

To a great extent this can be mitigated by lubrication and more importantly by technique. Lubrication can only be applied until the surface of the file contacts the surface of dentin but as soon as cutting occurs, lubrication can no longer reach the interface.

That leaves us with technique. The idea behind the technique is that downward pressure increases friction and thus torque. The operator...that's you... have to learn not to apply enough pressure to create enough torque to break the file. How much that is is undefinable. You just have to develop the technique.

Circumferential filing eliminates both of these hazards. The lubrication and irrigation can reach the interface because the file is only in contact at one locus of points along the long axis. This also minimizes friction and not just incidentally, allows the debris to escape with the irrigation fluid.

It also means that the canal can be scrubbed clean without demanding that it be made round.

Properly done(and it is easy to do it properly) circumferential filing does not cause breakage since the file rarely or never gets bound.

Now you can learn this technique by taking the course in your own office via the video conferencing route. If you have a Macintosh computer, video conferencing is built in. All you need to add is an iSight camera which plugs into a USB port and uses iChat software, which is part of system 10. Simply arrange a time and gather your group in front of the computer. Groups of one or more can be accommodated.

What's this about a NEW Precision Endo Syringe?

Yes, and it is now available. In fact the Precision Endo Syringe(22.8K JPEG) is no longer being manufactured. The new one is better and only slightly more costly.

Twenty years of work with the original Precision Endo Syringe went into it's design.

Engineering drawing of New Multi_Mode Endo Syringe(0.9K GIF) Note: This has been superceded by the Precision Endo Obturating Cartridge Syringe.