Prognosis of initial endodontic therapy

‘Prognosis’ is the forecast of the course of a disease. In the context of apical periodontitis, therefore, this term applies to both the time course and chances of healing. Over the past 80 years, an extensive volume of studies has been amassed that focuses on the prognosis of apical periodontitis after endodontic therapy. Cumulatively, the authors of these studies have recorded, grouped, and analyzed data from thousands of treated cases. Two major reviews had summarized the state-of-the-art knowledge at different timesa Strindberg (1) reviewed studies reported in the first half of the 20th century, and Friedman (2) reviewed studies reported from 1956 up to 1997. From those comprehensive reviews it has become obvious that the data pertaining to the prognosis of apical periodontitis after endodontic therapy is inconsistent and largely variable (2). Apparently, the wealth of available information is somewhat confused by the lack of standardization among the studies, with respect to material composition, treatment procedures, and methodology (2). Furthermore, certain clinical procedures performed in specific studies may no longer be relevant to the current practice of endodontics. Clearly, therefore, undiscerning review of all the existing studies can be ineffective and even misleading. For a review to yield reliable and valid information, it must focus on studies selected according to well-defined criteria. The purpose of this article is to review and discuss selected articles on the prognosis of initial endodontic therapy of apical periodontitis.