Vital Pulp Therapy and the possibility to maintain pulp vitality in teeth with deep caries Within this lecture the histological events occurring in the pulp tissue below medium-deep caries lesions will be illustrated. It will be observed that inflammatory cells accumulate in the area adjacent to the pulpal termination of dentinal tubules affected by the caries process, accompanied by the formation of a ‘less-tubular’ tertiary dentin, and changes in the odontoblast layer. This inflammatory process can remain reversible for a considerable time. Bacterial penetration into the pulp tissue and the establishment of a minor area of necrosis is the determinant for the transition from a reversible to an irreversible inflammatory state. The opportunity to clinically diagnose reversibility/irreversibility of pulp inflammation will be discussed on the basis of recent literature and histological data. When a carious pulp exposure occurs, as long as the diagnosis is reversible inflammation an attempt can be made to maintain pulp vitality through a direct pulp-capping procedure. The initial area of necrosis will expand in time, involving larger areas of the pulp chamber. When the diagnosis becomes irreversible pulpitis, selective surgical elimination of the necrotic/infected tissue may allow maintenance vitality of part of the pulp. For many years calcium hydroxide has been the material of choice to apply onto the pulp wound. Over the last 20 years MTA has gained popularity, with several clinical studies highlighting its advantages and improved outcome compared with calcium hydroxide. More recently a new generation of bioactive materials have been introduced. The pulp tissue response to all these materials is evaluated by clinical observation and histologic analysis performed in sound and carious teeth and in teeth subjected to pulp capping and pulpotomy.