Bulbous root form on a recall radiograph

Correct answer: D. Hypercementosis

• A. Cementoblastoma is a single, well-circumscribed radiopaque mass fused to one root with a radiolucent rim, usually the mandibular first molar, and it is usually PAINFUL and expansile. This is generalised and asymptomatic.
• B. Ankylosis is fusion of root to bone, so the defining sign is the OPPOSITE: LOSS of the PDL space and lamina dura, with the root blending into the trabecular pattern. That the PDL is preserved here rules it out.
• C. Condensing osteitis is sclerosis of the BONE around the apex of a non-vital or chronically inflamed tooth. The root itself is normal in shape and the tooth is typically non-vital.
• D. CORRECT. Hypercementosis is excessive deposition of cementum producing a bulbous, club-shaped root. The decisive radiographic sign is that the PERIODONTAL LIGAMENT SPACE AND LAMINA DURA REMAIN INTACT and follow the enlarged contour — the thin radiolucent line around the swollen root tells you this is cementum belonging to the tooth, not bone fused to it.

Note: Causes worth knowing: Paget disease of bone, acromegaly, chronic low-grade periapical inflammation, occlusal trauma or hyperfunction, and supra-eruption of an unopposed tooth. It also occurs idiopathically with age.

Correct answer: A. Scaling and root planing

• A. CORRECT as the exception. Scaling and root planing works on the cervical and coronal root surface within the pocket. The bulbous cementum of hypercementosis is APICAL and mid-root, so it does not materially change instrumentation or debridement. It is the one listed procedure that proceeds essentially as normal.
• B. Root canal treatment is complicated because excess cementum obscures the true radiographic apex, making working-length determination unreliable, and apical constriction anatomy is distorted.
• C. Orthodontic movement is impaired because the increased root surface area and altered root form raise resistance to movement, and the risk of resorption and ankylosis is higher.
• D. Extraction is the classic complication. The bulbous apical mass is wider than the socket above it, so the tooth cannot be delivered along its long axis. Sectioning and surgical removal with bone removal are frequently required, and root fracture is common.

Correct answer: B. Paget disease of bone

• A. Osteopetrosis is a failure of osteoclastic resorption producing diffusely dense, brittle bone with obliterated marrow spaces, anaemia and a high risk of osteomyelitis after extraction.
• B. CORRECT. Paget disease is disordered, accelerated bone remodelling in patients over about 40. The classic triad in this vignette — increasing hat size from cranial enlargement, HEARING LOSS from narrowing of the internal acoustic meatus, and a COTTON-WOOL radiographic pattern with hypercementosis — is the exam presentation. SERUM ALKALINE PHOSPHATASE is markedly elevated while calcium and phosphate stay normal.
• C. Fibrous dysplasia presents in children and adolescents as a painless unilateral swelling with a GROUND-GLASS pattern that blends imperceptibly into normal bone. It stabilises after skeletal maturity and does not cause progressive skull enlargement in later life.
• D. Hyperparathyroidism gives generalised demineralisation with LOSS of the lamina dura, a ground-glass or granular trabecular pattern, and brown tumours — plus RAISED SERUM CALCIUM, which Paget disease does not produce.

Note: Dental relevance: enlarging jaws mean dentures stop fitting, extraction sockets heal poorly, and there is a small risk of osteosarcoma in affected bone. Patients are frequently on bisphosphonates, adding MRONJ risk.

Correct answer: A. A diet high in glucose

• A. CORRECT as the exception. Dietary sugar intake is a CARIES risk factor. It has no established role in the metabolic bone diseases — Paget disease, fibrous dysplasia, hyperparathyroidism, osteopetrosis — whose drivers are genetic, endocrine or idiopathic remodelling defects.
• B. A raised alkaline phosphatase reflects osteoblastic activity and is the standard biochemical marker of Paget disease. It is genuinely associated.
• C. Bilateral symmetric jaw enlargement is characteristic of several bone diseases, cherubism and Paget among them.
• D. Cranial nerve compression from bony overgrowth at skull-base foramina is a recognised feature of both Paget disease and osteopetrosis — hearing loss, visual loss and facial palsy.