Doug Kase
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 ELLO
AGAIN, my loyal readers. As the chill of our bitter winter begins to
give way to warmer temperatures, longer daylight hours, and hopes for a
beautiful summer to come, I figured that I would get back to some
“basic stuff” about doing endodontics. Forget for a moment those
difficult cases with canals in bizarre places, and let’s talk about
down-to-earth tips that will help you with your everyday endodontic
problems. Now, of course, the easiest way to avoid any endodontic
complications is not to do any endodontics and refer the case to your
friendly neighborhood endodontist. But for those who do wish to dabble
I will try to start at the top and impart any helpful tips that I can.
Let’s start at the beginning: anesthesia. I
particularly like Septocaine for maxillary infiltrations. It seems to
be much more profound and longer-lasting then good old standard
Lidocaine 1:100,000 epinephrine. I have shied away from giving it as
mandibular anesthesia due to some prior literature relating it remotely
to some cases of subsequent parasthesia. Thus, for me, Marcaine is a
better alternative for long-lasting mandibular blocks, particularly
when a patient comes in with a “hot” tooth. For mandibular blocks, I
usually give an initial injection with a 30-gauge short needle of
Lidocaine to make way for a second injection with a 27-gauge long
needle. Patients tend not to feel the initial injection as much due to
the shallower penetration and smaller diameter of the 30-gauge needle.
If a periodontal ligament injection is needed, it should be delivered
under pressure and very slowly. This technique will minimize trauma to
the periodontal ligament and a possible necrosis of the crestal bone
due to severe vaso-constriction. A slower delivery also minimizes the
systemic reaction (rapid heart rate and associated symptoms) to the
epinephrine in the anesthetic. With standard injections, I also use a
vibrating device, the VibraJect, which snaps onto the syringe; this
device helps to minimize the discomfort associated with the injection.
Placement of the rubber dam can be traumatic for
both patient and dentist. Make sure that you explain to the patient
what you are doing and what the benefits of working with the rubber dam
are. Show the patient that it will not block breathing and explain that
for gaggers it will actually reduce the gag reflex because no debris
will drop to the back of the throat. You should use a clamp with wings
to place the rubber dam and clamp as one unit. By doing so, you can
avoid having to ligate the clamp before placing the rubber dam. My
favorite clamps are numbers 4, 14, 1, 6, and a 5 every once in a while.
For badly broken-down molars or molars that have a small
mesial-to-distal diameter, you should use a #1 (bicuspid) clamp to
engage existing tooth structure rather than a molar clamp (# 14, 4, or
5) which may traumatize tissue or slip off the tooth entirely. Another
tip applies to a tooth that has some existing tooth structure, but is
too angled or sloped to retain a clamp: you can cut a small groove with
an inverted cone or round bur to help provide a spot of retention for
the clamp. Use a butterfly (#6) on broken-down bicuspids, or you can
also rotate it 180 degrees so that the buccal aspect clamps the
existing lingual tooth structure for a better fit and retention.
Sometimes it is necessary to clamp the tooth behind and drag the dam
material one tooth forward when drilling access and hunting for
calcified canals. This way the clamp will not obscure the crown-root
anatomical relationship and your subsequent orientation during drilling.
Gaining access is next on the agenda. I use a number
4 round bur to gain my initial access. It allows me to “feel” the ball
drop into a pulp chamber. I then use a barrel diamond to straighten the
walls to give me straight-line access to the canal orifice and a #6
slow-speed round bur to remove pulpal tissue and large calcifications
on the pulpal floor. In the case of calcified chambers, the
Pulp-Out® Bur kit is the way to go. Its fixed depth gives you
confident access to the pulpal floor and canal openings without the
risk of perforation. For me, the ultrasonic hand piece with CPR 2 and 3
tips under magnification is a must for careful excavation to find a
calcified canal. Remember to use radiographic confirmation to assure
that you are excavating in the correct direction. A radio-opaque marker
as simple as an explorer placed into the point of excavation is a good
compass on your x-ray film to make sure that you are on target. Very
important: when hunting for a calcified canal, don’t be thrifty. Use a
new explorer, or two, to help locate the opening.
What can I say that you haven’t already heard or
read about SafeSiders® instrumentation and reciprocation? If you
haven’t tried them and loved them, believe me or Barry or Allan or Amy
or Young or Claudia: the system is phenomenal. So here is an insight or
two. On severely curved canals, instrumenting the apex to a #30 with a
backstep of 1 mm with #35 and #40 will allow you to easily move the
25/06 NiTi (pink) instrument to the apex with reciprocation. Then take
the 25/08 (brown) to within 1 or 2 mm of the apex and you can still fit
a medium gutta-percha point to the apex. Remember to use copious
amounts of irrigation (NaOCl) in a slow drop-by-drop flow to flood the
canal in combination with RC Prep. Use EDTA with the last two
instruments to remove the smear layer and open the dentinal tubules and
make sure that you wash it out with sterile saline or anesthetic before
using chlorhexidine for two minutes. This procedure will eliminate the
formation of a white sticky precipitate that may be more difficult to
wash out.
Obturate using the EZ-Fill® technique. If your
sealer becomes too viscous or thick, you can loosen the mix by heating
your spatula slightly and re-spatulating the cement. To prevent
separation of the apical end of your EZ-Fill cement spiral, remember
not to let the spiral negotiate a severe curve.
When you look at your final film—or at anybody’s
final film—remember that you are seeing only a mesial-distal
representation of what is instrumented and not a true indication of the
actual three-dimensional instrumentation that must be achieved during
our technique or any technique. It is important to realize that a canal
has a wider buccal-lingual diameter particularly in its coronal aspect
than it has in its mesial distal diameter. Thus using an instrument
such as a #2 Peeso or the new Pleezer® reamer rather than
self-centering rotary NiTi instruments to work the outer walls within
the anatomy of the canal is of paramount importance to achieving
complete debridement and shaping of such canals. Thus when looking at a
final radiograph, knowing the limitations of a particular system or
conversely the advantages of another will give you greater insight into
what you are actually judging. See you next issue.
April - June 2007
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Let’s talk about down-to-earth tips that will help you with your everyday endodontic problems.
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