Apical periodontitis is a biofilm-mediated infection. The biofilm protects bacteria from host defenses and increase their resistance to intracanal disinfecting protocols. Understanding the virulence of these endodontic microbiota within biofilm is essential for the development of novel therapeutic procedures for intracanal disinfection. Both the disruption of biofilms and the killing of their bacteria are necessary to effectively treat apical periodontitis. Accordingly, a review of endodontic biofilm types, antimicrobial resistance mechanisms, and current and future therapeutic procedures for endodontic biofilm is provided.

The purposes of this study were firstly to investigate the any formation of precipitate after interaction between ALX and NaOCL and secondarily to analyze the PCA formation by using time of flight secondary ion mass (TOF-SIM) spectrometry. Mass spectrometry analysis was performed for the mixture of 0.5% ALX and 5.25% NaOCl. As controls, 2.5% CHX with 5.25% NaOCl and 1% PCA solutions were used. Any formation of precipitates in 10 tested solutions was evaluated by naked eye. Results of mass spectrum showed that the typical peak of PCA was not detected in mixed solution of ALX and NaOCl, whereas CHX/NaOCl mixture showed the same peak that found in the PCA spectrum. Precipitate formation was only observed in CHX/NaOCL mixture. The present TOF-SIM spectrometry results indicated that ALX can be a useful root canal irrigant combined with NaOCl during canal instrumentation. Further study is necessary to confirm the antimicrobial effect of ALX against endodontic pathogen before its clinical application as an endodontic irrigant.