Jay Vuong
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DENTIST WHO creates a perforation in the process of performing a root-canal
procedure may benefit from knowing the factors that influence success
and failure after a repair of the perforation.
Problems arising from perforations can ultimately
be seen as problems associated with loss of attachment and destruction
of bone in the area adjacent to the defect. Loss of structural support
as a result of large perforations should also be a consideration.
Coronal perforations in unattached tooth surfaces (that is, coronal to
the periodontal attachment) can be viewed as deep restorative areas, which,
once repaired, have the potential for sulcular irritation unlike deep restorative
margins. Considered in this light, perforations of this type can
be repaired with a suitable restoration material to support the remaining
tooth structure and to reduce irregular margins, paying close attention
to the strength of the material and its ease of manipulation.
The perforations that require endodontic attention
are the ones that occur in areas adjacent to existing periodontal attachment,
which often includes the PDL and its associated lamina dura. This
type of perforation, if located near the sulcus of the tooth, can be seen
as a periodontal threat. If the attachment in this area does not
repair and the loss migrates to join into the sulcular space, periodontal
pocketing can result. Problems that occur with this periodontal situation
then must be alleviated in a periodontal manner. If the perforation
occurs more deeply (for example, in strip perforation of a canal), the
attachment loss may create a chronic potential for inflammation or infection.
Not unlike granulomas at the bottom of chronically inflamed root apexes,
the granulation tissue that may form in areas adjacent to failed perforation
repairs has a potential to cause pressure discomfort and to progress to
abcessing. In this situation, the perforation initially lacks a communication
with the sulcus and may progress to eventually become a periodontal problem
if the inflammatory process establishes a communication.
In light of the above discussion, the aim of perforation
repair should focus on repair of the attachment apparatus using the appropriate
endodontic or periodontic measure or both. Eliminating (or reducing)
bacteria at the site of the perforation during the time of repair and in
the future should be a priority. In choosing a reparative material,
you should consider
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Biocompatibility: The chosen material should decrease chronic inflammatory
response, promote epithelial or fibrous attachment, or both.
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Stability: The material should be structurally stable over time.
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Strength: It should have sufficient tensile and compressive strength if
the perforation has substantially weakened tooth support.
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Sealing ability: It should seal well enough to decrease future bacterial
contamination.
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Handling characteristics: It should be easy to use.
Allowing for a learning curve, the techniques for use of most repair materials
can be mastered with practice and an attention to detail.
No matter who does a perforation repair (generalist
or specialist), success usually depends on timing, size, location, and
disinfection.
Timing involves repairing the perforation ASAP if
possible. Delayed repairs require more difficult disinfection.
A perforation that is larger or located near but beneath the cervical attachment
has a worse prognosis than a smaller perforation located apically in the
canal (away from the sulcus). The larger the area of attachment loss
and bony damage, the more difficult disinfecting, sealing, and regenerating
will be. Also, the closer the defect is to the sulcus, the less chance
there is for a successful repair due to the future ingress of bacteria
from the pocket space. A periodontal problem will result. Disinfection
of the perforation usually demands good isolation and the use of disinfectants
(such as NaOCl).
Ultimately, success depends on the amount of bacterial
contamination still present beneath the perforation repair and the potential
of the repair material to seal against future bacterial contamination.
Controlling those circumstances becomes more difficult as perforation size
increases. Location plays a role in that the sulcus provides an additional
source of bacterial ingression that impedes attachment formation.
February -March 2003
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Ultimately,
success depends on the amount of bacterial contamination still present
beneath the perforation repair and the potential of the repair material
to seal against future bacterial contamination.
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