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Aim To compare the penetration resistance ( PR) of six thermoplastic gutta-percha ( GP) materials against needle penetration at different temperatures. Methodology The PR of the following materials based on warm gutta-percha techniques, Beefill GP Cartridge (Beefill), GP Obturator-Hard/Medium/Soft (Dia-H, Dia-M, Dia-S), Obtura (Obtura) and Tactendo Gutta (Tactendo), was measured as a function of temperature change (from 30 °C to 200 °C). The PR was measured using a force gauge, mounted on a motor-driven micrometre stage, which pushed the penetration needle against GP in a glass cylinder at the designated temperatures. Data were analysed using Kruskal-Wallis anova and Duncan's multiple range tests at 5% significance. Results The mean PR values for all assessed materials ranged from 15.55 MPa to 26.02 MPa at 30 °C, decreased to 0.18-1.61 MPa at 60 °C, and finally reached 0.02-0.12 MPa at 200 °C. The Obtura had the highest PR values at most of the measured temperatures. At 40-60 °C, Obtura had the highest PR value ( P < 0.05), and Tactendo had the lowest amongst the tested materials. At 70-200 °C, both the mean PR values and melt flow temperature ( MFR) of Obtura, Dia-H and Dia-M were significantly higher than those of other materials ( P < 0.05). Conclusions The PR values were changed by both the heating temperature and the brand or type of GP materials tested. Each material was associated with drastic decreases before reaching 60 °C in different degrees, and Obtura had the highest PR at most of the measured temperatures. [ABSTRACT FROM AUTHOR]

Aim To assess the antibacterial efficacy of a human β-defensin-3 ( HBD3) peptide against Enterococcus faecalis biofilms. Methodology Standardized human dentine blocks were infected with E. faecalis ATCC 29212 for 3 weeks. 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 1 week of medication, the dentinal samples at the depth of 200 and 400 μm were collected from medicated canal lumens. Bacterial growth was assessed by spectrophotometric analysis of optical density ( OD) after 72 h 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 ( P > 0.05). There was no significant difference ( P > 0.05) in the OD values of the inner (200 μm) and outer (400 μm) dentinal samples for any group. Conclusions The HBD3 peptide inhibited the growth of E. faecalis biofilms in infected dentine blocks. [ABSTRACT FROM AUTHOR]