Young Bui
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TECHNOLOGY in dentistry advances, we approach our treatment techniques
in different manners. We continue to strive for perfection while
speeding up chair-time and reducing overhead costs. This methodology
applies to all specialties in dentistry including endodontics. The
fundamentals of endodontics remain the same. The only difference
is the process by which we attain our goals. With the many different
hand files and mechanical systems in the market today, we can reduce the
number of visits for our patients and still maintain a high rate of success.
Root-canal treatment usually required more than one visit in the past because
of the difficulty in cleaning and shaping curved and calcified canals and
the low success rate of non-vital or necrotic cases.
Most root canal systems are straight and patent
enough for a size 15 file to fit down to the apex with ease. However,
there are cases where the root is severely curved or dilacerated, and some
canals are tight due to calcification. To engage into such canals,
we need a file that has great tensile strength to resist deformation, flexibility
to negotiate the curves, and is thin enough to fit into such tight space.
Upon finding a tight canal, we automatically pull out the size 8 or 10
files either in Hedstrom, K-type, or reamers. The problem with these
files is that they have weak tensile strength. They tend to bend
or buckle at the tip when a little pressure is applied. They do not
have the strength to withstand the force exerted upon them as you try to
push them down the tight canal. I love to use Hedstrom files, but
what I found to be a great file for a tight or partially calcified canal
is the EZ-Fill® SafeSider™ size 10 file. This file can negotiate
a tight canal with ease and has the tensile strength to withstand deformation.
If you have not tried this type of file in a situation like this, I would
recommend it highly. I used to be a strong proponent of Hedstrom
files until I tried out the SafeSider files.
The success or outcome of a root-canal treatment
depends on the ability to remove all infected pulp tissues and then seal
the canal completely with gutta-percha and sealers. In order to have
a tight, dense fill we must first clean and shape the canals to fit the
gutta-percha point. Most of the landmark studies use a .02 tapered
file to clean and shape the canals. With a .02 file, you are not
able to clean out the infected wall of a necrotic canal successfully.
Studies show that the cleaning and shaping procedures do not remove all
the bacteria from necrotic root canals. Removing all the bacteria
requires the use of Ca(OH)2 in the canal as an inter-visit medicament to
aid in sterilizing the canal system; thus, the patient is required to make
a second visit.
However, there is another way. By using the
new nickel-titanium greater-tapered files of .06 to .08, you can remove
more infected dentinal wall of the root canal system and create a nice
tapered canal wall to fit the greater tapered gutta-percha cone.
Another instrument you can use is the #2 Peeso reamer. It can reduce
your cleaning and shaping time significantly. Once you have cleaned
and shaped the canal to a .06 or .08 tapered, use EDTA to remove the smeared
layer against the wall. Then irrigate the canal with full strength
NaOCl and clean the wall with an ultrasonic tip. The vibration will
allow you to kill the bacteria embedded .5 mm into the dentinal tubules.
By shaping the wall to a .06 or .08 tapered and then using the ultrasonic
tip, you eliminate bacteria that are embedded at least 1 mm into the dentinal
wall. This will ensure a clean canal and eliminate the use of Ca(OH)2
in between visits. By the way, Ca(OH)2 does not kill enterococci
such as E. feacalis. Potassium-iodine can kill all bacteria in the
canal in seconds. That is one alternative irrigating solution you
can use. Just be careful not to get it on the patient’s clothing.
September-October 2001
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can reduce the number of visits and still maintain a high rate of success.
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