What diagnosis should be considered if a patient experiences pain on biting after post and core placement?

When a patient experiences pain on biting following the placement of a post and core, a vertical fracture should be a primary consideration. This type of fracture often occurs due to the stress placed on the tooth, particularly when it has undergone significant dental work such as post and core placement.

In cases of vertical fractures, the tooth may present with sudden onset pain, especially during biting, as the forces applied can exacerbate the fracture. The pain is typically localized and can be sharp or intense, depending on the extent and location of the fracture.

Other conditions like pulpitis or internal resorption may also lead to discomfort, but the acute nature of the pain associated with biting, often increasing with pressure, points more towards a structural issue like a vertical fracture. A periodontal abscess, while causing pain, generally presents with other signs such as swelling and drainage, making it less likely to be the cause of isolated biting pain after such dental work. Therefore, considering the common presentations and associated symptoms, a vertical fracture is the most fitting diagnosis in this scenario.