S-6 - Biopsy Result of Surgeries

Histological examination of the periradicular pathologic soft tissues excised during apical surgery intervention is usually recommended, especially in those circumstances in which a neoplastic condition is suspected. Microscopic examinations of the root tip and the surrounding soft tissue have also been used in an attempt to evaluate the causes of root canal treatment failure. However, the studies conducted up to the ‘90s were plagued by methodological limitations, such as use of unsuitable specimens, random sections instead of serial sections, lack of bacterial staining, and insufficient criteria of analysis. Consequently, the role of residual infection in causing treatment failure was grossly underestimated. In this presentation, the procedures for obtaining suitable biopsies, adequate laboratory processing and tissue sections are illustrated. It is demonstrated how the most common cause of root canal treatment failure is the presence of bacterial biofilms in the apical canal, in the intricacies of the root canal system, or in the extraradicular compartment.