Sensitivity to palpation and percussion includes -

Tenderness/sensitivity to percussion and palpation primarily indicates inflammation of the periodontal ligament and periradicular (periapical) tissues, rather than inflammation confined to the dental pulp.

Percussion produces slight movement of the tooth within its socket and stresses the periodontal ligament (PDL). When the
PDL/periapical tissues are inflamed, this produces pain. Palpation over the root apex assesses inflammation that has extended into the periradicular tissues and adjacent cortical structures.

This is classically seen in symptomatic apical periodontitis.