Which condition may present as a radiopaque lesion associated with the root of a non-vital tooth?

The correct condition that presents as a radiopaque lesion associated with the root of a non-vital tooth is focal sclerosing osteomyelitis. This condition is characterized by a localized area of increased radiopacity near the apex of a tooth, often as a response to chronic inflammation or infection associated with pulp necrosis or periapical pathology. In cases where the tooth is non-vital, the inflammation can lead to a reactive change in the surrounding bone, resulting in this radiopacity.

Focal sclerosing osteomyelitis usually occurs in younger individuals and is commonly found in the mandible. It is important to recognize this condition as it can mimic other lesions that might be seen on radiographs, but its association with a non-vital tooth root makes it particularly noteworthy.

In contrast, other conditions mentioned may present differently or are not specifically associated with a non-vital tooth. For instance, cementoblastoma typically presents as a radiopaque mass associated with the roots of vital teeth rather than non-vital. Periapical cemento-osseous dysplasia often presents with mixed radiolucent-radiopaque lesions around the roots of vital teeth. Idiopathic osteosclerosis appears as isolated radiopaque areas in the mandible but isn't