If a GP is found in a sinus tract but does not extend to the apex, what is the likely diagnosis?

In the scenario presented, the presence of a sinus tract that does not extend to the apex indicates that the issue is more related to the periodontal tissues rather than the pulp or apex of the tooth. This is characteristic of a periodontal abscess, which typically occurs due to the infection of the periodontal tissues leading to localized collections of pus.

A periodontal abscess is often associated with periodontal disease and reflects an infection in the supporting structures of the teeth, which might manifest as localized swelling and can drain through the sinus tract. The key point here is that the sinus tract's relation to the apex serves to differentiate it from other pathologies like a periapical abscess or periapical granuloma, which would typically extend to or originate from the apex of the tooth.

Therefore, the indication of a sinus tract not reaching the apex directly correlates with the diagnosis of a periodontal abscess, reinforcing its classification as a condition arising from periodontal issues rather than from endodontic (root or pulp) complications.