A patient presents with an ACUTE apical abscess of 48 hours' duration. What would you expect to see on a periapical radiograph?

Correct answer: A. Little or no change — an acute lesion usually has no radiographic sign yet

• A. CORRECT. Radiographs are INSENSITIVE early. Roughly 30–50% of the mineral content of bone must be lost before a lesion becomes radiographically detectable, and cancellous bone changes may be invisible until the CORTICAL plate is involved. In a truly acute abscess the only findings may be a slightly widened periodontal ligament space or a subtle loss of lamina dura at the apex — often nothing at all. The diagnosis is therefore CLINICAL: severe spontaneous pain, exquisite tenderness to percussion, swelling, a non-responsive pulp and possibly systemic signs.
• B. A diffuse periapical radiopacity is CONDENSING OSTEITIS, the sclerotic bone reaction to a low-grade CHRONIC pulpal irritation — the opposite end of the intensity spectrum.
• C. External inflammatory root resorption is a slow process requiring sustained stimulation over weeks to months; it is not a feature of a 48-hour lesion.
• D. A well-defined, corticated radiolucency indicates a CHRONIC, slowly progressing lesion that has had months to develop — a granuloma or a radicular cyst, not an acute abscess.

Note: Board principle worth carrying: a normal radiograph NEVER excludes an acute apical abscess. Conversely, a large corticated radiolucency in an asymptomatic tooth points to chronic disease. Match the timescale of the finding to the timescale of the symptoms.