Dr. Emry Karst Printer Friendly Version

Endodontic Breakthrough and No More Separated Files

There are at least three things that should interest and encourage a general dentist into doing more root canal fillings. The first is to reduce the time it takes by 50% or more, second is no more separated files, and the third is a successful outcome with no symptoms or perapical radiolucency over a 5-year period.

Reducing the time by as much as 50% or more is entirely possible, but one must understand how to use hand and rotary files efficiently and safely. Hand files are used to negotiate to the apex, then rotary files are used to do the rest of the reaming. Rotary files that are #25 .06 taper are used to do most of the reaming. Sybron Dental makes a Twisted File and it is the safest and most efficient file on the market. The apical 5mm is done with larger rotary .02 taper files. K-3 files are the most flexible and Sybron makes these too, as well as a cordless reversible endo hand-piece, which is essential to preclude file separation as it can be set at the correct RPM and set to provide only so much torque.

There are a number of prominent endodontic clinicians who have stated that the cleaning and sterilization of the apical third of the root canal is the most critical step for a successful endodontic outcome. Success depends on a number of factors. The first is the removal of all organic and other debris, all the way to the apex. The use of rotary files can accomplish this 100% of the time if done in the right fashion. The rotation draws everything away from the apex. Next, most canals are oval and making a completely round canal in the apical 5mm is imperative.  

To create a round canal, the canal needs to be filed at least to a #45 (.02 taper) or larger. There should be at least one file used that is larger than the one that engages the walls of the canal, at least 2.5mm from the apex. Secondly, since obturators all come in a round configuration, voids could occur if the canal is not round and if the sealer does not fill in the void.

Because there may be remnants of organic materials and bacteria left in the canal, sodium hypochlorite is necessary to dissolve these and to sterilize the canal. This takes no more than one minute and then a plastic broach is rotated to the apex to remove the dissolved organic tissue. EDTA is then used in a similar fashion to remove the smear layer. 

Finally, a successful root canal requires a complete root canal seal. A modified lateral condensation technique will provide this. Sealer is always used in this process. The apical 5mm of a cleaned and shaped canal will have an .02 taper. Discus Dental makes a 5mm long .02 taper gutta percha point that is attached to a removable metal shaft, and is called a “SimpiFil” plug. When this plug (a size larger than the last file used) is pushed to the apex, it produces lateral pressure and the best seal possible. This process entombs any possible bacteria that may be stuck in the dentinal tubules.

The success rate of this procedure is about 95% over a 5 year period. This means the tooth is asymptomatic and the radiograph shows no lesion at the apex. In a classic study of 55 single-rooted teeth done by Sjogren et al using a similar protocol, complete periapical healing occurred in 94% of cases that yielded a negative culture.

For complete information on this procedure and to obtain 3 hours of CE credit, visit www.EndodonticBreakthrough.com

Dr. Karst is a graduate of Loma Linda University's School of Dentistry and has practiced cosmetic dentistry for over 25 years. A pioneer in such cosmetic techniques as porcelain laminate veneers, he has been administering aesthetic dentistry to his patients since the early 1980's.

If you would like additional information, Dr. Karst can be reached at: ittakesanartist@gmail.com

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