[Study on the causes of post-endodontic failures: a descriptive analysis of 198 cases of reoperation].

In this article, a statistical analysis describes 198 cases of post-endodontic failures referred from private practitioners for surgical retreatments. Biopsies of these lesions showed that 68.18 per cent of them were identified as apical granulomas, 3.5 per cent as cysts, 16.16 per cent as epitheliated granulomas and 12.12 per cent as "other" cases. The two main groups of causes associated with these failures are: technical errors (55.05 per cent of the cases) and procedural mistakes (17.68 per cent).