Calcification of the root canal (commonly referred to
as pulp canal obliteration, or PCO) is a common sequel
following luxation injuries to permanent teeth,
particularly teeth that have been injured before their
root formation has been completed.
Abbott and Yu have discussed the terminology regarding this condition
and they have recommended the use of the term
“calcification” (rather than “obliteration”) as it more
accurately describes what is happening, or what has
happened, within the root canal. Obliteration implies
complete blocking or elimination of the canal which is
unlikely, even in a tooth that radiographically appears
to have no root canal present.
Clinically, a yellowish discolouration of the crown
may be observed. Pulp canal calcification is also a
common occurrence in root-fractured teeth occurring
principally in the region of the fracture, and in the
apical fragment. It may also occur in teeth associated
with alveolar and jaw fractures.
In most traumatized teeth that have pulps under-going calcification,
the hard tissue is deposited
longitudinally along the dentinal walls of the pulp
canal, which gradually diminishes in size until it can
barely be observed radiographically. In view of the
manner of calcification, there is always a canal present
and endodontic management is usually able to be
performed, if it becomes necessary, by an experienced
clinician. On the other hand, however, pulp canal
calcification that occurs in traumatized, root-fractured,
open-apex teeth and in immature canine teeth that have
had prolonged orthodontic treatment is often irregular
and these teeth are difficult to manage endodontically if
such treatment becomes necessary.
Fortunately, only a small percentage of teeth with
pulp canal calcification develop pulp necrosis and
become infected.
Pulp necrosis and infection is more
likely to occur in teeth in which the pulp appears
almost totally calcified, in teeth with completed root
formation that have had severe periodontal injury at
the time of trauma, and in teeth that have shown
“rapid” calcification of the canal after injury. Pulp
necrosis and infection may occur up to 20 years
following injury. However, the pulps in most teeth with
pulp canal calcification remain healthy and do not
require endodontic treatment. Assessment of the status
of the pulp is difficult since these teeth do not usually
respond to thermal pulp sensibility testing. Most,
however, do respond to electrical stimulus, and
therefore electric pulp sensibility testing is the desirable
method for assessing the status of the pulp in calcified
teeth.