Photoactivated disinfection (PAD) in endodontics: an in vitro microbiological evaluation

Purpose: The objective of the present study was the in vitro evaluation by MTT test of the antimicrobial effect of photoactivated disinfection (PAD) and, comparatively, of a conventional 5.25% NaOCl irrigating solution. Methods: Enterococcus faecalis, Streptococcus mutans and Streptococcus sanguis strains were selected for the test. Freshly extracted single-rooted human teeth were endodontically treated, inoculated with bacterial strains and then divided into different groups, each of them treated with PAD, with PAD plus 0.5% NaOCl solution, with TBO, with PAD for longer time and with 5% NaOCl solution (positive control). Results: The results were significantly different among the various groups, and for Enterococcus faecalis, Streptococcus mutans and Streptococcus sanguis. PAD applied for a longer time (in respect to manufacturer's instructions) or PAD associated to 5% NaOCl showed the significantly higher antibacterial effects.