Three radiopacities on three panoramic films

Correct answer: B. Compound odontoma

• A. A cementoblastoma is a radiopaque mass FUSED to the root of a vital tooth, classically a mandibular first molar, surrounded by a radiolucent rim and frequently painful. It is attached to a root, not overlying an unerupted crown.
• B. CORRECT. A COMPOUND ODONTOMA is composed of multiple small, discrete TOOTH-LIKE structures (denticles), each containing enamel, dentin, cementum and pulp arranged in their normal relationship to one another, surrounded by a narrow radiolucent rim. It favours the ANTERIOR MAXILLA and is the more frequent of the two variants. Both odontomas are hamartomas rather than true neoplasms, both are treated by conservative surgical enucleation, and neither recurs. The commonest reason either is discovered is exactly this — investigation of a permanent tooth that has failed to erupt.
• C. Ameloblastic fibro-odontoma is a mixed lesion of young patients combining odontoma-like calcifications with ameloblastic fibroma soft tissue. It is expansile, considerably rarer, and does not present as discrete denticles.
• D. A COMPLEX ODONTOMA is an amorphous CONGLOMERATE mass of the same four dental tissues with NO resemblance to a tooth — a disorganised arrangement of tubular dentin, enamel and thin layers of cementum. It favours the POSTERIOR MANDIBLE. Location and internal architecture are the two discriminators, and this lesion fails both.

Note: The point the recall emphasises: BOTH variants contain all the dental tissues INCLUDING CEMENTUM. The exam discriminator is simply whether the lesion looks like teeth (compound, anterior maxilla) or like a shapeless mass (complex, posterior mandible). Compound is a lesion of childhood and adolescence; complex peaks in the second decade.

Correct answer: B. Pulp vitality testing

• A. CBCT will define the extent of the radiopacity and its relationship to the root, but no imaging modality can tell you whether the pulp is alive — which is the whole question.
• B. CORRECT. This is the entire distinction. CONDENSING OSTEITIS is a sclerotic bone REACTION to low-grade, long-standing pulpal inflammation, so the associated tooth is NON-VITAL or has an irreversibly inflamed pulp — and there is always a cause visible, such as the deep caries described here. IDIOPATHIC OSTEOSCLEROSIS (dense bone island, enostosis) has no inflammatory cause at all: the tooth is VITAL, the periodontal ligament space is regular and the lamina dura intact. Pulp testing separates them and also decides management — condensing osteitis is treated by root canal therapy or extraction, after which the radiopacity may persist as a residual ‘bone scar’, whereas osteosclerosis requires nothing whatsoever.
• C. Percussion is unreliable here. A chronically inflamed or necrotic pulp is frequently asymptomatic and non-tender, which is exactly why condensing osteitis is so often an incidental finding.
• D. Aspiration is a technique for cystic or vascular lesions. A solid sclerotic mass yields nothing and the procedure adds no information.

Note: Keep the full differential of a periapical radiopacity: condensing osteitis (non-vital), idiopathic osteosclerosis (vital), cemento-osseous dysplasia (mixed with a lucent rim, vital), hypercementosis (PDL space follows the enlarged root outline), cementoblastoma (fused to the root, painful) and complex odontoma.

Correct answer: A. Gardner syndrome

• A. CORRECT. GARDNER SYNDROME is a variant of familial adenomatous polyposis, autosomal dominant, caused by mutation of the APC gene. Its oral and skeletal triad is multiple OSTEOMAS of the jaws and skull, supernumerary and impacted teeth, and ODONTOMAS; extra-orally there are epidermoid cysts and desmoid tumours. It matters more than any of the alternatives for one reason: the colorectal adenomatous polyps undergo malignant transformation in essentially 100% of untreated cases, so recognising the jaw findings and referring for colonoscopy is potentially life-saving.
• B. Cleidocranial dysplasia shares a great deal of the dental picture — retained primary teeth, multiple unerupted permanents and numerous supernumeraries, in fact MORE supernumeraries than Gardner syndrome typically produces. But it is defined by hypoplastic or absent CLAVICLES and delayed closure of the fontanelles, and it produces neither osteomas nor intestinal polyps.
• C. Gorlin-Goltz syndrome produces multiple ODONTOGENIC KERATOCYSTS and basal cell carcinomas, not osteomas and odontomas. The lesions are radiolucent, not radiopaque.
• D. Hypohidrotic ectodermal dysplasia gives hypodontia or anodontia with conical teeth, reduced sweating with heat intolerance, sparse hair and dry skin. Its teeth are MISSING rather than supernumerary — the opposite dental finding.

Note: The pairing to carry into the exam, exactly as the recall frames it: ODONTOMA and OSTEOMA → Gardner. Multiple OKCs → Gorlin. Multiple unerupted teeth with absent clavicles → cleidocranial dysplasia. Dentigerous cysts around unerupted teeth are also a feature of cleidocranial dysplasia. Both Gardner and cleidocranial dysplasia can present with hypodontia or oligodontia alongside supernumeraries, which is what makes them so easy to confuse.