Young Bui
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WAS TAUGHT in school that a necrotic tooth with periapical lesions should
be cleaned out and medicated with Ca(OH)2 for at least a week before filling
it. Some still believe in that teaching while others believe in the
one-visit root canal treatment. The reason for the teaching of a
two-visit treatment is because the technology back then was not as advanced
as today. Most of the root canals in the study done by Bender and
Seltzer were performed using a .02 taper file to do the cleaning.
This method does not allow proper cleaning of the canal’s wall. Today,
canals are cleaned out using greater tapered files, thus allowing the removal
of more infected dentinal wall of the root canal system. I do most
of my cases in one visit using the SafeSiders® technique. This
technique allows you to clean and shape the canals to a .06 or .08 taper
as in any rotary NiTi system. The canals are constantly flooded with
NaOCl during the instrumentation process. Once the canals have been
cleaned and shaped, rinse them thoroughly with liquid EDTA to remove the
smear layer. Next soak the canals with a 2 percent chlorhexidine
solution and let it sit for about two minutes. By shaping the wall
to a .06 or .08 taper and then using the EDTA and 2 percent chlorhexidine,
you eliminate bacteria that are embedded in the dentinal wall. This will
ensure a clean canal and eliminate the use of Ca(OH)2 between visits.
By the way, Ca(OH)2 does not kill enterococci such as E. feacalis; 2 percent
chlorhexidine does. The molar in Figures 1 and 2 was done in one
visit. As you can see in the six-month recall, the root canal was
a success.
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| FIGURE 1: Molar x-ray showing
finished root canal and periapical area at the apices. |
FIGURE 2: The same tooth
as in Figure 1, six months later, with the apices healed. |
I’m sure everyone reading our newsletter has
read about the SafeSiders reamers. The reason for the flat side on
these instruments is threefold. First, the flat side reduces the
amount of binding along the length of the canal. This allows the
SafeSiders reamer to negotiate even tight and curved canals with ease.
Second, due to the flat side, the reamer is more flexible than regular
reamers thus preventing distortion in sharply curved canals. Lastly,
the flat side acts as a failsafe system. If you happen to separate
a SafeSiders reamer, you can bypass the reamer along the flat side because
it is not binding to the canal’s wall. I used rotary NiTi in my early
years, and I was constantly worried about separating the file. Rotary
NiTi can shape straight canals easily, but when it comes to curved ones,
that is where the stomach wrenching begins. I find the SafeSiders
technique to be better due to the fact that I’m not worried at all when
it comes to negotiating tight and curved canals as seen in Figures 3 and
4. The mesial and distal roots in this molar have sharp curves that
end up touching each other. I call this the “kiss of death.”
I had to use the SafeSiders reamers with the reciprocating handpiece to
instrument these canals. The #2 Peeso widens the upper portion of
the canal to reduce the amount of stress on the reamer at the curve.
The reciprocating motion also aids in the instrumentation with no distortion
at the curve. I was able to instrument to a 30/.02 stainless steel
SafeSiders reamer and end with a 30/.04 SafeSiders NiTi file. The
canals were filled using a single cone with EZ-Fill® cement.
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| FIGURE 3: Molar with curved
roots. |
FIGURE 4: Finished root
canal on the molar in Figure 3. |
When we perform root canal treatment on lower
premolars, we assume that the tooth has only one canal unless we see that
there are two roots on the x-ray. Sometimes, there is an extra canal
midway down the main canal. I’m never satisfied with the cleaning
of a lower bicuspid with one canal unless I have run up and down the length
of the wall with a bent #10 reamer. The reamer will get a catch along
the wall if there is another canal present. Figure 5 shows the pre-op
x-ray of a lower bicuspid with two roots. The case was referred to
me after the general dentist had a difficult time filling the canal.
After I cleaned and irrigated the two canals, I ran a #10 reamer up and
down the canal and found another canal along the wall. The other
two canals are straightforward, but in the case of the third, the instrument
must be pre-bent in order to engage the canal. I cleaned and shaped
it using the SafeSiders technique and filled it using a single cone with
EZ-Fill cement (Figure 6).
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| FIGURE 5: Pre-op x-ray of
a lower bicuspid with, apparently, two roots. |
FIGURE 6: The bicuspid from
Figure 5 with three roots filled. |
November-December 2005
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Today,
canals are cleaned out using greater tapered files, thus allowing the removal
of more infected dentinal wall of the root canal system.
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