A radiolucent area surrounding the apex of a tooth root is most likely indicative of a periapical abscess or cyst.

- Radiolucency on a dental radiograph means that the area appears darker due to less dense tissue allowing more X-ray penetration.
- The apex of a tooth root is a common site for pathological processes related to the pulp and periapical tissues.
- A periapical abscess is an accumulation of pus caused by bacterial infection spreading from the necrotic pulp.
- Similarly, a periapical cyst (radicular cyst) results from chronic inflammation at the apex, leading to the formation of a cystic cavity.
- Both conditions create bone resorption around the apex, seen as a radiolucent (dark) area.
- In contrast, condensing osteitis and sclerosing osteomyelitis are characterized by a radiopaque (white or denser) area due to increased bone formation.
- Hypercementosis refers to excessive cementum formation along the root surface, which appears as a radiopaque enlargement rather than a radiolucent area.

Thus, the presence of a radiolucent area at the root apex strongly suggests periapical pathology involving infection and bone resorption, such as an abscess or cyst.

Reference: Orban's Oral Histology, 13th Edition, Chapter 6: Pulp and Periapical Diseases / Page 220