The relationship of the pulp and the periodontium is dynamic. the periodontium and the pulp are closely related , they are embryonic, anatomic and functional interrelationship . in 1919, Turners and Drew first described the effect of periodontal disease on the pulp. the relationship between periodontal and pulpal diseases diseases was first described by Simring and Goldberg in 1964. The clinician should be aware that endodontic and periodontal lesions arise from inflammation or degeneration of both the tissues. the function of tooth depends on health and vitality of periodontium and not on the state of the pulp. thus, the tooth depends on the biological unit. Understanding the interrelationship between endodontic and periodontal diseases are crucial for correct diagnosis,prognosis and treatment decision making. Pulpal and periodontal problems are responsible for more than 50% of tooth mortality. diagnosis is often challenging because the diseases have been primarily studied as seperate entities and each other primary disease may mimic clinical charecteristic of other diseases .