Reversible pulpitis describes which of the following conditions?

Reversible pulpitis is defined as a condition characterized by mild inflammation of the pulp inner tissue of a tooth. This condition typically arises from stimuli that are not excessively damaging, such as thermal or chemical irritants. The key aspect of reversible pulpitis is that the pulp can heal and regain its normal function once the irritants are removed or if appropriate treatment is administered.

This contrasts significantly with other options. Severe infection of the dental pulp would indicate irreversible pulpitis, where the condition is more serious and the pulp is damage beyond healing. A fracture involving the pulp may compromise the pulp's health but does not specifically define the inflammation state described in reversible pulpitis. Loss of pulp vitality refers to the pulp tissue being necrosed or non-living, which again does not align with the concept of reversible pulpitis, where vitality is generally maintained and healing is possible. Thus, the definition involves a mild inflammatory response, making it clear that option A, which describes mild inflammation of the pulp, is indeed the accurate description of reversible pulpitis.