The influence of chronic apical periodontitis on oral and general health.

In healthy condition, the periodontal space between the root surface and the alveolar bone is relatively poor in cells. In case of root canal infection however, large number of immune-inflammatory cells infiltrate the periapical region of the affected teeth. A major issue is if and to what extent microbial and host cells contribute to lesion formation and whether the local inflammation may impair general health. The question is important as it may fundamentally influence the therapeutic strategy in patients with apical periodontitis. The aim of this paper is to review the results of recent experimental and clinical observations that investigate the importance of cellular interactions in exerting protective and destructive effects in periapical inflammatory lesions. The majority of studies indicate that the lesion would not develop in the absence of permanent release of bacteria and their by-products from the infected root canal. On the other hand, the formation of the classical granulation tissue is dependent on the presence and proper function of host cells and regulatory molecules. The dynamic encounter of root canal microbiota and the local immune system prevents overwhelming bacterial infiltration of the periradicular space but it is also connected with degenerative changes, most importantly bone resorption, resulting ultimately in tooth loss. However, by the use of proper endodontic methods, the lesion can be successfully treated in the majority of cases. Remineralization of the lost hard tissue will occur or the lesion will transform into an inert periapical scar.