Radiology · patient case question
What does this radiolucent space represent?
Patient case: Radiographic follicular space around an unerupted second molar
Patient: Male, 12 years old
Chief Complaint: Routine recall. No symptoms.
Background: Healthy, no medications. Normal growth and development.
Vital Signs: BP 104/66 mmHg · HR 80 bpm
Findings: Panoramic radiograph shows late mixed dentition. The maxillary RIGHT second molar has erupted; the LEFT has not. Around the crown of the unerupted left second molar there is a well-defined, uniformly corticated RADIOLUCENT space measuring approximately 2 mm at its widest, attaching at the cementoenamel junction. The tooth is in a normal position with no displacement, and root formation is appropriate for age.
Show answer and explanation
Correct answer: D. A normal dental follicle
- A. An ameloblastic fibroma is a mixed odontogenic tumour of children and adolescents, typically a larger, well-defined uni- or multilocular lesion of the posterior mandible often associated with an unerupted tooth — but expansile, not a symmetric thin band.
- B. An odontogenic keratocyst grows antero-posteriorly along the marrow space, is usually larger, and does not present as a uniform 2 mm band conforming to a crown.
- C. A DENTIGEROUS CYST is diagnosed when the pericoronal space EXCEEDS roughly 4 to 5 mm, or when it is asymmetric, or when the tooth is DISPLACED, or when the adjacent roots resorb. None of those applies here, and calling a normal follicle a cyst leads to unnecessary surgery in a child.
- D. CORRECT. A NORMAL DENTAL FOLLICLE is the connective tissue sac surrounding the crown of a developing tooth. Radiographically it is a uniform, thin, corticated radiolucent band around the crown, and a width of up to about 3 MM is within normal limits. Asymmetric eruption between the right and left sides at this age is also entirely normal — up to six months of difference is common and requires nothing more than review.
Note: Two numbers decide most pericoronal calls: a follicular space up to 3 mm is normal; beyond 4–5 mm, treat it as pathological and investigate. Compare with the CONTRALATERAL side on the same film, which is the free control the panoramic gives you. When in doubt in a child, review radiographically in six months rather than operate.