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.