Antimicrobial efficacy of a human -defensin-3 peptide using an Enterococcus faecalis dentine infection model

Lee J-K, Park Y-J, Kum K-Y, Han SH, Chang S-W, Kaufman B, Jiang J, Zhu Q, Safavi K, Spangberg L. Antimicrobial efficacy of a human beta-defensin-3 peptide using an Enterococcus faecalis dentine infection model. International Endodontic Journal, 46, 406-412, 2013. Aim To assess the antibacterial efficacy of a human -defensin-3 (HBD3) peptide against Enterococcus faecalis biofilms. Methodology Standardized human dentine blocks were infected with E.faecalis ATCC 29212 for 3weeks. Aqueous calcium hydroxide paste (n=12, CH), a 2% chlorhexidine gel (n=12, CHX), an HBD3 peptide gel (n=12) and saline (n=12) were tested as experimental groups. A mismatched peptide gel group (n=12, MP) and sterilized but noninoculated block group (n=12) were included as controls. After 1week of medication, the dentinal samples at the depth of 200 and 400m were collected from medicated canal lumens. Bacterial growth was assessed by spectrophotometric analysis of optical density (OD) after 72h of incubation. Statistical analysis was performed with repeated-measures anova and Tukey's post hoc test. Results The HBD3 group was associated with significantly lower OD values (P<0.05) than the CH or CHX groups at both depths. The CH group did not differ significantly from MP or Saline group at either depth (0.05). There was no significant difference (0.05) in the OD values of the inner (200m) and outer (400m) dentinal samples for any group. Conclusions The HBD3 peptide inhibited the growth of E.faecalis biofilms in infected dentine blocks.