“I need some teeth here”

Correct answer: B. Focal cemento-osseous dysplasia

• A. A residual cyst is entirely RADIOLUCENT with a corticated border, left behind after extraction of the causative tooth. It does not develop internal opacity, and the mixed pattern here excludes it.
• B. CORRECT. FOCAL CEMENTO-OSSEOUS DYSPLASIA is a single-site fibro-osseous lesion arising from the periodontal ligament, with a strong predilection for the POSTERIOR MANDIBLE of middle-aged women — and it is very often discovered in an EDENTULOUS site during pre-prosthetic radiography, which is exactly this scenario. It is asymptomatic, non-expansile, under 2 cm, and matures through predictable stages: an early lucent phase, then a mixed phase, then a dense radiopaque phase with a thin peripheral lucent rim. Her older film showing a lucency in the same place documents that maturation. It needs no treatment — only periodic observation.
• C. Ossifying fibroma is a true benign NEOPLASM. It is well-demarcated but characteristically EXPANSILE, displacing roots and cortical plates as it grows, and it requires enucleation. A stable, non-expansile, incidentally found lesion does not fit.
• D. Condensing osteitis is purely SCLEROTIC — uniformly radiopaque with no lucent rim — and it is a reaction to low-grade pulpal inflammation, so it sits at the apex of a tooth with deep caries or a large restoration. There is no such tooth here, and the lesion is mixed rather than solidly opaque.

Note: Keep the three variants of cemento-osseous dysplasia straight. PERIAPICAL: anterior mandible, multiple teeth, and critically the teeth remain VITAL — pulp test before anyone starts a root canal. FOCAL: a single lesion, usually posterior mandible, often in an edentulous site. FLORID: multiquadrant and often extensive, most common in middle-aged Black women. All three are managed the same way — leave them alone.

Correct answer: A. Osteomyelitis

• A. CORRECT. Dysplastic cemento-osseous tissue is HYPOVASCULAR and relatively acellular. Any surgical entry — an implant osteotomy, an extraction, even a biopsy — introduces bacteria into tissue that cannot mount a normal vascular and inflammatory response, so infection is poorly cleared. The recognised consequence is a chronic, painful OSTEOMYELITIS with sequestration and a non-healing defect. That same reasoning is why biopsy of a radiographically classic lesion is contraindicated, and why the diagnosis is made on imaging and clinical stability alone.
• B. Cemento-osseous dysplasia is a reactive, self-limiting condition. Malignant transformation is not part of its recognised behaviour.
• C. Osseointegration is precisely what an implant is designed to achieve, so ‘ankylosis’ is not a complication of implant placement. The term belongs to natural teeth fused to bone with a lost periodontal ligament.
• D. A dentigerous cyst forms around the crown of an UNERUPTED tooth. There is no unerupted tooth in this site.

Correct answer: C. A removable partial denture

• A. Grafting means a second surgical insult to the same compromised bone, compounding rather than avoiding the problem. It does not make dysplastic bone behave normally.
• B. A wider fixture increases the volume of dysplastic bone violated and the surface area exposed to contamination. Primary stability is not the limiting factor here — vascularity is.
• C. CORRECT. The lesion itself needs nothing but observation, and her complaint is missing teeth. A REMOVABLE PARTIAL DENTURE restores function without entering the dysplastic bone at all, which is the whole objective. A conventional fixed partial denture is a defensible alternative where the abutments are suitable, for the same reason — it avoids surgery in the affected site.
• D. Observation is correct for the LESION, but it does not answer the patient. She presented specifically to have the missing teeth replaced, and there is a way to do that safely.