Buccal Bifurcation Cyst (Mandibular Infected Buccal Cyst)
The round bumps in the cheek tissue over an erupting permanent molar in a child's lower jaw are most likely buccal bifurcation cysts (also called mandibular infected buccal cysts), which should be diagnosed with panoramic radiography and treated with simple enucleation while preserving the associated tooth.
Clinical Presentation
This lesion presents as a firm, round buccal swelling adjacent to a permanent mandibular first or second molar in children aged 6-10 years, typically occurring just prior to or during tooth eruption 1, 2, 3. The swelling is located in the buccal gingiva (cheek tissue), not on the gums themselves, and may cause pain on chewing 1.
Diagnostic Approach
Initial Imaging
Orthopantomography (panoramic radiograph) is the first-line diagnostic examination after age 6 for suspected dental anomalies 4. This will show:
- Well-defined radiolucent (dark) area at the buccal aspect of the molar
- Involvement of the tooth roots and possibly part of the crown
- Displacement of roots toward the lingual (tongue) side 3
Advanced Imaging When Needed
Occlusal projections provide the best presurgical diagnostic information, demonstrating the radiolucent lesion with periosteal bone reaction buccal to the involved tooth 3.
CBCT may be used for treatment planning when 2D imaging is insufficient to clarify anatomical relationships 5. A 2019 study demonstrated the value of three-dimensional reconstruction for visualizing the cyst's relationship to the molar and dental nerve 1.
Treatment
Simple enucleation without extracting the associated tooth is the definitive treatment 2, 3, 6. This approach:
- Successfully removes the cyst
- Preserves the permanent tooth
- Allows normal tooth eruption
- Results in no recurrences with proper follow-up 2
The involved tooth typically remains vital and erupts normally after cyst removal 2, 3.
Key Clinical Pearls
Do not confuse this with periapical pathology: The tooth is vital, and the lesion is inflammatory but not related to pulp necrosis. The histopathologic findings are non-specific, making clinical and radiographic features paramount for diagnosis 3.
Bilateral presentation is rare but possible: One case report documented bilateral buccal bifurcation cysts affecting both mandibular second molars 1, though unilateral presentation is typical.
Age and location are diagnostic: This specific entity occurs in children under 10 years old, associated with erupting permanent mandibular first or second molars on the buccal surface 1, 2, 6.