Young Bui
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 OW
MANY TIMES have you crowned a root canal tooth with a history of a vertical
fracture and had the patient return within a few months or a year complaining
of pain when chewing? The patient becomes upset because he or she
wasn’t informed of the fracture and because the crown and root canal were
costly investments. I have encountered many cases in which root canal
therapy was needed due to vertical fractures. The prognosis for a
vertically fractured tooth ranges from good to poor depending on the extent
of the fracture. The prognosis also depends on the symptoms that
a patient is experiencing when he or she presents to the office for treatment.
If the fracture is down one wall but does
not enter the canal, the prognosis is good. This is just a coronal
fracture that will hold up well with a PFM crown. If the fracture
extends down the canal, then the prognosis is guarded to poor, depending
on other factors.
A thick, dark fracture line indicates that the fracture
has been there for a long time. The pulp in these canals tends to
be necrotic, and the patient has no pain when chewing. The only reason
such patients need root canal therapy is either a radiographic finding
like PAR from the infected pulp or swelling from the infection. This
type of fracture has a guarded prognosis as long as the root canal therapy
was done well and the tooth was restored right after with a PFM crown.
The tooth may hold up for as little as six months or longer than five years.
A tooth with a lighter fracture line indicates a
recent fracture. The pulp will still be vital, and the patient tends
to have pain when chewing. This type of fracture would have a poor
prognosis because the pressure from mastication is spreading the fractured
parts, causing the pain.
Another type of fracture with a poor prognosis is
a vertical fracture that goes down the canal, crosses the floor of the
tooth, and extends down the other canal. This through and through
fracture is always a failure.
With any type of fracture, patients should
be informed of the situation so that they can participate knowledgeably
in the decision making. Let the patient know the prognosis and see
what he or she would like to do. Some patients are willing to try
to save the tooth even if it is for one extra year. Some prefer an
extraction and an implant. If the patient wants to try to save the
tooth, then the tooth should be crowned as soon as possible after the root
canal therapy to help hold the tooth together.
Sometimes even when the crown is placed the
tooth can still fail if there is leakage through the fracture. In
a case like that, MTA would be needed to seal the fractured root.
The reason for the success of MTA is not really known. I know that
MTA provides a great seal in apicoectomy and also allows for periodontal
ligament (PDL) to grow on it. This would allow for complete sealing
of the fractured root and allow new PDL to grow along the fracture line.
You are probably asking why I don’t just seal the canal with MTA to begin
with and avoid having to go back in there a second time. Well, there
is no study out there that shows the success of MTA in sealing a fractured
root. Gutta percha and EZ-Fill cement have been successful so far
for me in many cases. There is also the potential of legal exposure
resulting from the fact that it is nearly impossible to go back and retreat
a canal filled with MTA. If this case fails, the patient would ask
why you didn’t use gutta percha and cement first.
The following case illustrates a failure of conventional root canal
therapy and a successful use of MTA to seal a vertical fracture in the
distal root of tooth #30. The patient presented to the office complaining
of pain in the presence of heat and cold. The tooth was tender to
percussion. She had no pain when chewing. The x-ray showed
thickened PDL at the apexes. The tooth was a virgin tooth with a
fracture line in the distal margin of the crown. In Figure 1 you can see
thickened PDL at the apices of #30. The patient was informed of the
fracture, and she wanted to try to save the tooth. Root canal therapy
was done in one visit.
After instrumentation, the canals were filled with
gutta percha and EZ-Fill cement. (See Figure 2.) She went back
to her dentist soon after and had the tooth crowned with a PFM crown.
She came back a year and eight months later with symptoms on #30.
The x-ray (Figure 3) showed periodontal breakdown along the distal root
on the furcation side. Apparently there was a vertical fracture along
the furcation wall that I had not noticed during the first visit.
I told the patient of the problem and informed her that the prognosis for
the tooth was poor. I gave her a choice of either having the tooth
extracted or letting me try an experimental procedure on it using a new
material. The distal canals were cleaned completely of old gutta
percha and the canals were dried with paper points. I mixed the MTA
with lidocaine into a putty consistency and then packed it down the two
canals with gutta percha points and x-coarse paper points. A seven-month
follow-up x-ray (Figure 4) shows complete healing of the periodontal defect
along the distal root. If this case holds up well at one-year and
two-year follow-ups, I think we will have found a new way to save vertically
fractured roots.
Summer 2004
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FIGURE 1: Showing thickened
PDL at the apexes of tooth #30.
FIGURE 2: Showing root canal
therapy completed and no perio destruction along the root.
FIGURE 3: Showing periodontal
breakdown along the distal root.
FIGURE 4: Healing of tooth
#30 with MTA in the distal root.
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