The buccal bifurcation cyst (BBC) is an uncommon lesion associated with the permanent
mandibular first or second molar in children. Usually it is identified just prior to
eruption. Stoneman and Worth in 1983 were the first to describe the lesion and report its
radiographic and clinical features.1 They named the lesion mandibular infected
buccal cyst. Similar lesions have been described in the literature under a variety of
names. They include the circumferential dentigerous cyst,2 the inflammatory
paradental cyst,3 and the inflammatory collateral dental cyst.4 The World
Health Organization5 describes this lesion under the name "paradental
cyst." Neville, Damm and Allen et al. state that this latter name should be avoided
because it is non-specific.6 Pompura, Sàndor and Stoneman7 argue
for the term BBC, because the lesion is site- and age- specific. It has a constant
relationship to the mandibular first molar's buccal bifurcation (Table I).
Table II |
Radiographic Features of the Buccal Bifurcation
Cyst |
|
The histology of this lesion is non-specific and reveals non-keratinized
stratified squamous epithelium, areas of epithelial hyperplasia and an inflammatory
infiltrate in the connective tissue wall. Bacteriology reports have shown a mixed flora.7-9
The differential diagnosis of this lesion includes eosinophilic granuloma, lateral
periodontal cyst, traumatic bone cyst and periostitis ossificans. Usually, the clinical
and radiographic features distinguish the BBC from other conditions.8
Treatment of the BBC has evolved over time. The low incidence of this lesion makes
randomized controlled trials impractical. Stoneman and Worth report successful treatment
through tooth extraction and curettage of the lesion, as well as with endodontic treatment
of the tooth and curettage of the lesion.1 Enucleation and extraction are reported by
Trask, Sheller and Morton10 and more recently by Martinez-Conde, Aguirre and Pindborg.11
Stanback reports treatment via marsupialization.12 Enucleation alone is
reported by several authors.8,9,13,14 Pompura, Sàndor and Stoneman7 recently
report the successful treatment of 44 BBCs with enucleation alone (without tooth
extraction). The following cases illustrate an even more conservative approach to
treatment.
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Cases
Case 1
During an orthodontic consultation, an 8-year-old male was noted to have bilateral
cystic lesions of the mandible. He was asymptomatic, but on intraoral examination buccal
tilting of the associated teeth and deep buccal periodontal pockets were noted. Mild
bilateral swelling was noted extraorally. The lesions were pointed out to the patient and
his mother, who were advised to see an oral and maxillofacial surgeon for management.
The family moved away for a year and never sought treatment. At a follow-up visit 15
months later, the lesions showed definite signs of radiographic resolution. Six months
after this initial follow-up, there was no clinical or radiographic evidence of the cysts
at all (Figs. 2a-2f).
Case 2
A 9-year-old male had BBCs associated with teeth 3.6 and 4.6. These teeth were tilted
buccally and were associated with deep buccal periodontal pockets. No treatment was
rendered. During nine months of follow-up, the cyst adjacent to tooth 4.6 enlarged and
required surgical treatment, and the cyst adjacent to tooth 3.6 regressed without
treatment (Figs. 3a-3d).
Case 3
A 7-year-old male was treated by his physician with a course of amoxicillin for pain
and swelling of the mandible and was subsequently referred to his dentist. On examination,
the patient had swelling and tenderness in the region of the right angle of the mandible.
Intraorally, the soft tissues buccal to teeth 3.6 and 4.6 were inflamed and slightly
erythematous. Periodontal probing revealed depths of 11 mm to 12 mm bucally. Both crowns
were tilted buccally. The pockets were irrigated with saline and hydrogen peroxide and the
patient was instructed to irrigate these areas at home daily with saline rinses. The
patient was reassessed weekly. Over several months, the defects resolved with irrigation
and the periodontal status returned to normal. The probing depths were 2 mm to 3 mm
buccally, and the patient's pain, swelling and inflammation ceased (Figs.
4a-4d).
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Discussion
The etiology of the BBC remains uncertain. Different theories have been proposed.
During eruption, as the cusps penetrate the oral epithelium, a localized area of
inflammation may occur beneath the epithelial attachment. The fact that the mesiobuccal
cusp of the first molar is the first to break through the epithelium might explain the
development of the lesion on the buccal surface at about the time of eruption.1
The cystic epithelium may be derived from the cell rests of Serres, the cell rests of
Malassez, apical migration of cells of the dental lamina or reduced enamel epithelium.7 As
Camarda, Pham and Forest8 state, however, this explanation does not account for the reason
these lesions have not been seen with erupting incisors. Another hypothesis is simply that
this cyst is a variant of the lateral periodontal cyst.1 This lesion is also
site-specific, namely to the canine and premolar region, and rarely occurs in children.7
Enamel projections into the buccal bifurcation may also be a causative factor.
Pompura, Sàndor and Stoneman point out that these lesions are not seen in adults and
questioned whether they may be self-limiting.7 Evidence from these three
patients with five cysts indicates that some of these lesions are self-limiting. The
authors speculate that perhaps microtrauma and subsequent inflammation of the buccal
gingival tissues and the cyst lining may induce a small opening into the lesion. This
"automarsupialization" may allow the cyst to depressurize and heal
spontaneously. Periodontal probing may also result in "micromarsupialization."
Case 2 illustrates simultaneous regression of a lesion on one side and continued growth of
a BBC on the contralateral side. Factors that predict which lesions may be more
susceptible to spontaneous resolution are unknown. Although there are no guidelines on
which cysts need to be watched and which require surgical treatment, the authors emphasize
that at least some BBCs may not require surgery. Consideration should therefore be given
to managing BBC cases conservatively with an expectant "watchful inactivity."
Clinical and radiographic re-evaluation should occur at three- to six-month intervals.
Infected lesions or those increasing in size must be managed surgically.
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Acknowledgment: the authors thank Dr. M. Dagenais for her
radiographic contribution to this paper.
Dr. David is resident, Oral and Maxillofacial Surgery,
University of Toronto.
Dr. Sàndor is coordinator of Oral and Maxillofacial Surgery,
Hospital for Sick Children and Bloorview MacMillan Centre; director, graduate residency
program in Oral and Maxillofacial Surgery, The Toronto Hospital; and assistant professor,
University of Toronto.
Dr. Stoneman is professor emeritus, Department of Radiology,
Faculty of Dentistry, University of Toronto; and consultant oral radiologist, Hospital for
Sick Children and The Toronto Hospital.
Reprint requests to: Dr. G.K.B. Sàndor, Hospital for Sick
Children, 555 University Ave., Toronto, ON M5G 1X8.
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Fig. 1: Occlusal radiograph of a buccal
bifurcation cyst showing lingual displacement of the first molar roots and the resultant
increased prominence of the lingual cusps. Note also the thinning of the buccal cortex and
periosteal reaction.
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Fig. 2a: Large buccal bifurcation cyst around
tooth 4.6.
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Fig. 2b: Bone fill noted at 15 months without
treatment.
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Fig. 2c: Complete resolution of cyst with
uprighting of tooth 4.6 at 21 months.
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Fig. 2d: Lesion around tooth 3.6.
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Fig. 2e: Bone fill at 15 months without treatment.
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Fig. 2f: Complete resolution of cyst
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Fig. 3a: Lesion around tooth 4.6 with faint radiopaque
concave line at apices and prominent lingual cusps.
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Fig. 3b: Spontaneous enlargement of lesion 9 months
later.
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Fig. 3c: Lesion around tooth 3.6 with faint radiopaque
lines at apices and prominent lingual cusps.
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Fig. 3d: Spontaneous bone fill around apices and mesial
and distal of tooth 3.6 at 9 months without treatment.
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Fig. 4a: Faint radiopaque line at apices and distally
around tooth 3.6.
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Fig. 4b: Resolution of cyst at tooth 3.6.
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Fig. 4c:Smaller cyst at tooth 4.6; faint radiopaque
line at mid apices
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Fig. 4d: Spontaneous healing of cyst at tooth 4.6..
.