Molecular biology techniques hold the hope of making the knowledge of endodontic infectious processes still more accurate. Culture analysis of samples from root canals shows that the persisting microorganisms are mainly Gram positive and facultative such as Streptococci, Enterococci, Lactobacilli, Propionibacteria and Actinomyces. Undoubtedly, the well-directed use of molecular methods will provide additional valuable information regarding the identification and understanding of the causative factors of apical periodontitis. Additionally, molecular methods have the potential to make diagnosis...