49-YEAR-OLD female presented to our office with the chief complaint, “I
had a root canal done about six months ago, and the tooth still hurts.”
The patient had no significant medical history and no history of allergies
or immune deficiencies. Upon examination, the extra-oral and intra-oral
examination were within normal limits. Tooth #30 was percussion positive
and palpation positive. There was no response to thermal tests.
Upon radiographic exam, tooth #30 showed completed root canal treatment
that appeared adequate, although there was a separated instrument in the
mesial buccal canal (see Figure 1).
The patient had been informed previously of the
presence of the separated instrument. The treatment plan was discussed
with the patient, and she was presented with all possible options: retreatment,
apicoectomy, or extraction. The patient decided to try retreatment,
knowing that the prognosis was guarded. The patient was advised that
if the source of failure was indeed the instrument, I would try to bypass
the instrument and fill around the instrument.
The tooth was accessed under rubber dam isolation
and the gutta percha was removed. The instrument in the mesial buccal
canal was not retrievable. All canals were cleaned and shaped.
A second distal canal was located and cleaned and shaped. Calcium
hydroxide was placed in all four canals.
The patient was brought back for a second visit
seven days later, and she stated that the tooth felt much better and no
longer had any pain. At this time, #30 was re-cleaned and obturated
after rinsing with liquid EDTA and chlorohexidine (see Figure 2).
Failure due to separated instruments depends on
several factors, such as when the instrument was separated in instrumentation,
whether the canal was cleaned prior to separation, and whether the tooth
was vital or necrotic.
Upon initial presentation, it was assumed that the
cause of failure with regard to #30 was the separated instrument, a common
procedural error. The primary cause of periradicular pathosis is
bacterial infection in the root canal system. Procedural errors,
such as separated instruments, do not jeopardize the outcome of treatment
unless concomitant infection is present. It is apparent from this
case that all etiologies of failure must be evaluated before treating a
tooth, and the most obvious cause is not always the correct cause of failure.
FIGURE 1: The starting film.
FIGURE 2: The final radiograph.