J-shaped radiolucency

Correct answer: D. Vertical root fracture

• A. A periapical cyst produces a well-circumscribed radiolucency centred on the APEX; it does not extend up the lateral root surface as a continuous halo.
• B. A lateral periodontal cyst is a well-defined lucency BETWEEN the roots of vital teeth, most often in the mandibular canine/premolar region, and is unrelated to fracture.
• C. Condensing osteitis is a RADIOPACITY — a localised sclerotic bone reaction to low-grade pulpal inflammation, typically at a mandibular molar.
• D. Correct. A 'J-shaped' or 'halo' radiolucency that wraps from the apex up along the LATERAL surface of the root is the classic radiographic sign of a VERTICAL ROOT FRACTURE. It reflects bone loss along the entire length of the fracture line rather than a lesion confined to the apex.

Note: The clinical companion signs recorded elsewhere in this file: pain on biting plus a deep, NARROW, isolated probing defect (e.g. 9 mm on the distal only) — a solitary narrow pocket next to an otherwise healthy sulcus is a vertical root fracture until proven otherwise.

Correct answer: A. CBCT

• A. Correct. CBCT provides three-dimensional imaging free of superimposition and can demonstrate the fracture line and the associated bone loss pattern when conventional two-dimensional films cannot. A vertical root fracture is only visible on a periapical when the X-ray beam happens to pass directly along the plane of the fracture.
• B. A panoramic radiograph has low resolution and considerable superimposition — the least suitable choice for a fine fracture line.
• C. Bitewings image crowns and crestal bone only and do not display the root apex at all.
• D. Periapical radiographs are the usual first-line film and may show the J-shaped lucency, but they miss many fractures because of the beam-angle limitation. (This question specified that PA was not among the options.)

Note: Beware of beam-hardening and metallic artefacts from posts and restorations on CBCT — they degrade exactly the region you are trying to assess.

Correct answer: D. Extraction

• A. Retreatment does not repair a fracture; the bacterial pathway along the fracture line remains.
• B. Apicoectomy manages persistent APICAL pathology after failed endodontics; it does not address a fracture running the length of the root.
• C. Occlusal adjustment may reduce load but cannot resolve an existing complete fracture.
• D. Correct. A true vertical root fracture in a single-rooted tooth has a HOPELESS prognosis — the fracture communicates the canal with the periodontium and cannot be sealed. Extraction is the treatment. In a multi-rooted tooth, root amputation or hemisection of the fractured root is an alternative to extracting the entire tooth.