The topic “Periodontal aspects of Endodontics” refer to the relationship and interactions between the dental pulp, root canal system, and the surrounding periodontal tissues. The presence of anatomical and functional relationship between these two entities was demonstrated by numerous studies held on this topic. Pathogenic bacteria and other irritants may migrate from the pulp to the periodontium and vice versa through physiological communication pathways such as apical foramen, dentinal tubules and lateral canals. Such exchange of pathogens often contributes into the development of the endo-periodontal lesions. Despite the presence of direct routes permitting the transmission of bacteria, the effect of periodontal lesions on the development of pulpal diseases is still controversial for many clinicians.