ALL DENTISTS KNOW, accurate diagnosis is crucial and can be challenging.
A 46-year-old African American female presented to me with the chief complaint,
“I went for my regular check-up, and my dentist told me I need a root canal.”
The patient had an unremarkable medical history, and she had seen her dentist
annually for the past 20 years.
Upon clinical presentation, no nodes, masses, or swelling were
apparent. The patient had good oral hygiene with a dental history of endodontics,
restorative, fixed, and extractions.
The patient was referred for evaluation of tooth #19. Radiographically,
#19 had a large 2 cm well-delineated periapical radiolucency at the apex
of the distal root. The tooth had been restored many years earlier with
a MOD amalgam. (See Figure 1.)
The clinical exam revealed an asymptomatic molar
that tested vital with a normal response to cold stimuli. Number 19 was
negative to percussion and palpation. There was a mild buccal expansion
at the apex of #19. The tooth exhibited no mobility and pockets less than
3 mm. The fact that the tooth tested vital was unusual, but there
was the possibility that only the distal root had been necrotic and that
the mesial roots may have remained vital.
The patient was referred to an oral and maxillofacial
surgeon for consultation regarding the lesion on #19. The oral surgeon
evaluated #19 and reported that the lesion of the distal root was likely
a granuloma with a small amount of buccal expansion with over-lying mucosa
intact. The oral surgeon recommended root canal therapy and re-evaluation
in three to six months; if the lesion increased or did not respond to treatment,
#19 would receive an incisional biopsy, exploration, or both.
The differential diagnosis for this radiolucent
lesion in the posterior mandible is:
Periapical granuloma: involves a nonvital tooth
Periapical cyst: nonvital tooth
Periapical cemento-osseous dysplasia (early stages): mostly in African
American females; usually apical to mandibular anteriors; teeth are vital
Odontogenic keratocyst: unilocular radiolucency
Ameloblastoma: especially in the posterior mandible; often associated with
an impacted tooth (multilocular radiolucency)
Traumatic bone cyst: mandibular lesion that scallops up between roots of
teeth; usually in younger patients
The root canal therapy was performed as indicated, and
upon access into the canals vital tissue was evident in the distal and
mesial canals. The tooth was completed, and the patient remained
asymptomatic. The patient was then referred back to the oral and
maxillofacial surgeon for re-evaluation, and the pre-operative treatment
was to biopsy the lesion and possibly to perform an apicoectomy on the
distal root. The results of the biopsy would determine future proceedings.
After the biopsy, the surgical report came back
showing a diagnosis of viable bone and connective tissue consistent with
a traumatic (simple) bone cyst in the area around #19. This is a
benign, empty, or fluid-containing cavity within bone devoid of an epithelial
lining, a pseudocyst. The lesion is more common than the literature
indicates, and the etiology is uncertain. The typical presentation
is a well-delineated radiolucent defect that can range from 1 to 10 cm,
with domelike projections that scallop upward between roots. The
treatment is surgical exploration and curettage, the prognosis is excellent,
and reoccurrence is rare. Figure 2 shows the tooth at the time of
the four-month recall, illustrating that the majority of the lesion has
FIGURE 1: Radiograph of #19,
showing a large well-delineated periapical radiolucency at the apex of
the distal root.
FIGURE 2: Showing the tooth
at the time of the four-month recall.