Abstract
The very close interrelationship between the tissue of periodontium and dental pulp allows dissemination of bacterial infection. Bacterial infection is commonly considered as a causative factor of periodontal and pulpal disease.
Differentiation between the disease of periodontium and pulp and its correct diagnosis could be very difficult and the symptomatic tooth can have pain of periodontal and/or pulpal origin. This paper discusses the relationship between both tissues and their diseases, presents recommendation for its right diagnose and treatment according to the new classification, which is enriched with the iatrogenic lesions .