Which of these is inflammation of dental pulp tissue?

Pulpitis is inflammation of dental pulp tissue. The pulp contains the blood vessels, the nerves, and connective tissue inside a tooth and provides the tooth’s blood and nutrients. Pulpitis is mainly caused by bacterial infection which itself is a secondary development of caries (tooth decay). It manifests itself in the form of a toothache.

Once the pulp has become inflamed, the tooth can be diagnostically divided into two categories: reversible pulpitis and irreversible pulpitis.

Reversible pulpitis is the condition where the pulp is inflamed and is actively responding to an irritant. This may include a carious lesion that has not reached the pulp. Symptoms include transient pain or sensitivity resulting from many stimuli, notably hot, cold, sweet, water and touch. The pulp is still considered to be vital. This means that once the irritant is eliminated, usually by removal of decay and the placement of a restoration, that the pulp will return to its normal, healthy state.

Irreversible pulpitis is the condition where the pulp is irreversibly damaged. The pulp cannot recover from the insult and damage. For example, decay that has reached the pulp of the tooth introduces bacteria into the pulp. The pulp is still alive, but the introduction of bacteria into the pulp will not allow the pulp to heal and it will ultimately result in necrosis, or death, of the pulp tissue.