Microbial irritants

Microbial irritation of the pulp occurs usually with caries that extends to the dentine, and with leaking fillings. Pulp inflammation starts long before whole bacterial cells have reached the pulp. Bacterial antigens released from the microbial cell walls and from dead and dying bacteria diffuse through dentinal tubules to the pulp and stimulate the host defence systems.

Temporary irritation of limited magnitude leads to reversible pulpal inflammation which is usually, but not always, symptom-free. Prolonged or more intense irritation may lead to irreversible (permanent) damage of the pulp. Pulpitis may be symptom-free or symptomatic. Depending on the nature of the irritation and the pulp's ability to respond, a development from pulpitis into necrosis may take place rapidly within days or, more often, during several months or even years.