Intracellular bacterial eradication using a novel peptide in vitro.

Aim: To determine the effect of a novel antimicrobial peptide (AMP; OP145) and cell-penetrating peptide (Octa-arginine/R8) conjugate on the killing of intracellular Enterococcus faecalis, compared to OP145 and an antibiotic combination recommended for regenerative endodontic procedures.

Methodology: The biocompatible concentrations of OP145 and OP145-R8 were determined by assessing their cytotoxicity against human macrophages and red blood cells. Spatiotemporal internalization of the peptides into macrophages was investigated qualitatively and quantitatively by confocal laser scanning microscopy and flow cytometry respectively.

Root canal debridement by negative pressure irrigation, ultrasonically activated irrigation and their combination.

Despite scientific evidence that root canal debridement is the cornerstone for successful treatment, the effectiveness of a combination of delivery and activation systems in cleaning root canals remains unknown. This study is the first to demonstrate the remaining pulp tissue in root canals after irrigation with various techniques such as positive pressure syringe-and-needle irrigation, ultrasonic activation, negative pressure irrigation and ultrasonic activation after negative pressure irrigation. The results showed that negative pressure irrigation alone and its combination with ultrasonic activation resulted in significantly superior effectiveness than positive pressure irrigation and ultrasonic activation alone in the apical-third of root canals.