Figure 1: Occlusal view
Tips for economical, safe,
and efficient endodontics
Allan S. Deutsch, DMD, FACD
AS AN ENDODONTIST with more than 40 years of clinical experience, instructor at
our Hands-On Dental Education Center, international lecturer, and author, I enjoy
sharing my knowledge with general dentists. It has been stated that root canals
performed by general practitioners have an 80% success rate.
1 Throughout years of
teaching, I have found specific factors that many dentists overlook. The elements
listed below are likely to increase the rate of success for your root canal procedures.
When performing endodontic access, magnification and
illumination are the key. I recommend using a microscope,
such as the Evolution Zoom (Seiler Instrument Inc.), if
available. If not, 2.5x to 4.5x loupes are a bare necessity.
The roof of the pulp chamber can be removed by using a
round bur. After gaining initial access to the pulp chamber,
rotate the bur and withdraw in an occlusal direction to remove
the pulp chamber ceiling. Then use a non-end-cutting dia-
mond bur to push back the axial walls from the pulp chamber.
Using the color of dentin on the floor of the pulp chamber is
your best guide to finding the orifices to the canals. Do not
remove dentin where the floor is already white. Seek those
areas on the dentinal floor where the dentin is darkest. Pay
special attention to where the lighter color dentin of the axial
walls meets the darker color of dentin on the floor.
The darker portion of dentin on the floor will often have
the configuration of a square, triangle, rhomboid, or diamond.
The most likely location of the canal orifice will be at the
apices of these shapes. If highly calcified, relieving coronal
dentin from these sites will increase your chances of finding
the canals. A sharp explorer is mandatory here. Finding the
canal will produce a definite catch on the explorer when it
finds the entrance into a canal.
Not finding, and subsequently not instrumenting, the
MB2 canal is a very large source of many endodontic failures.
As previously noted, by following the darker portion of
dentin, if present, this canal is most likely located in the A,
B, or C position of a molar ( figure 1).
PROPER IRRIGATION OF CANALS
Unfortunately, endodontic instrumentation alone does not
remove 100% of bacteria and debris from the canal. Many
studies have shown the limited ability of instrumentation
alone to debride and clean the canal.
2-6 Wu et al. reported
uninstrumented areas in 65% of instrumented oval canals.
The most frequently used irrigant is sodium hypochlorite
(NaOCl). This irrigant has a great advantage in that it dissolves necrotic tissue and kills bacteria quite effectively.
However, it may not always kill Enterococcus faecalis. These
bacteria can often be found in biofilm in the canal and tubules. They are persistent and often resistant to calcium
hydroxide as well as NaOCl. E. faecalis seems to be especially
prominent in endodontic cases that have had root canal
treatment and are failing.
8 The prevalence of E. faecalis in
those infections ranges from 24% to 77%.
My endodontic protocol in the past was not only to use
NaOCl, but to add 2% chlorhexidine to combat E. faecalis and
also use EDTA to open the dentin tubules and remove the
smear layer. Just over a year ago, I switched to a new irrigation
product, Irritrol (Essential Dental Systems/EDS). This product
combines EDTA and chlorhexidine (CHX), thereby shortening
my procedural time. More importantly, Irritrol has a 99.99%
disinfection rate compared to CHX at 20%. For additional
activation of this two-in-one endodontic solution, I use a
passive ultrasonic irrigation (PUI) piezo tip (#6 EDS). PUI tips
are designed to activate irrigants ultrasonically, making them
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