Australian Dental Council (ADC) Test 2025 – 400 Free Practice Questions to Pass the Exam

Diagnosing a periapical abscess primarily involves identifying the characteristic signs and symptoms associated with it. Pain on percussion is a classic symptom of a periapical abscess because it indicates inflammation at the root apex, which can be exacerbated by physical pressure on the affected tooth. This pain arises due to the presence of pus in the periapical tissues and the subsequent inflammatory response, which makes the area sensitive to touch.

In contrast, pain when eating hot or cold food typically relates to other dental conditions, such as pulpitis or dental caries, rather than indicating a periapical abscess. Such temperature sensitivity often results from the pulp's reaction to stimuli rather than the inflammation surrounding the apex of a tooth.

The thickness of the periodontal ligament on X-ray is also significant, as it can provide diagnostic clues about the health of the surrounding tissues. However, it is not as definitive for diagnosing a periapical abscess as the clinical symptom of pain on percussion, which directly relates to the inflammatory process that defines an abscess. Thus, the presence of pain on percussion serves as a strong clinical indicator of a periapical abscess.