The presence of smear layer affects the antimicrobial action of root canal sealers.

AIM: To assess the chemical and microstructural characteristics of dentine after the use of two irrigation protocols and correlate this with the antimicrobial properties of hydraulic calcium silicate cement (HCSC) sealers and changes to the dentine structure/chemistry after sealer placement. METHODOLOGY: Two irrigation protocols - Protocol A using 2% NaOCl used 5 mL/5 min and Protocol B with 2% NaOCl (5 mL/5 min) followed by 17% EDTA (5 mL/3 min) - were used to prepare dentine. The chemical and microstructural changes following irrigation were assessed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy (n = 5) on dentine obtained from the mid-root and coronal parts of extracted human teeth. Four sealers (AH Plus, BioRoot, MTA Fillapex, TotalFill) were characterized by SEM/EDS (n = 3). The ability of the sealers to eradicate intratubular Enterococcus faecalis biofilms was assessed by live/dead dye and confocal laser scanning microscopy to measure the percentage of living cells. The effect of combined irrigation and root filling on dentine was assessed by SEM and EDS analysis (n = 5). Statistical analysis was undertaken using one-way anova and a number of post hoc tests to detect intergroup differences. The F-test was used for comparison of variances in the microbiology testing. RESULTS: The use of NaOCl alone left the smear layer intact, with traces of chlorine remaining on dentine. The use of BioRoot sealer restored the calcium levels of dentine which had been depleted by the irrigation with EDTA. BioRoot exhibited antimicrobial properties against intratubular bacteria even in the presence of smear layer (Protocol A). Smear layer removal improved the bactericidal effect of all sealers and Ca2+ leaching. The use of a chelating agent was important for the intratubular sealer penetration for AH Plus but not the other sealers. CONCLUSION: The removal of smear layer was necessary for penetration of AH Plus into the dentinal tubules. BioRoot was a more effective sealer in reducing the bacterial load in the dentinal tubules than the other materials tested and the presence of smear layer did not affect its activity.

Retreatment Efficacy of Endodontic Bioceramic Sealers: A Review of the Literature / Eficacia del retratamiento de cementos endodónticos biocerámicos: Revisión de Literatura

Abstract The endodontic retreatment is a feasible solution when post-operative apical periodontitis persists or develops. The complete removal of the filling materials is important in order to ensure the unobstructed contact of the intracanal disinfectants with the microbes. As a new generation of bioceramic endodontic sealers has emerged, their removal efficacy from the root canal system during retreatment is a matter of concern among clinicians. The aim of this article is to provide a comprehensive review of the current literature on the retreatability of these novel obturating materials. A significant amount of bioceramic sealer remnants in the root canal walls was observed in all studies. Even though canal cleanliness could not be obtained at an ideal level, the re-establishment of the working length and patency can be considered manageable and comparable to other endodontic sealers.

Resumen El retratamiento endodóntico es una solución factible cuando la periodontitis apical post-operatoria persiste o se desarrolla. La eliminación completa de los materiales obturadores es importante para garantizar el contacto y acción de los desinfectantes e irrigantes endodónticos con los microorganismos persistentes. A medida que ha surgido una nueva generación de selladores endodónticos biocerámicos, su eficacia de eliminación del sistema de conductos radiculares durante el retratamiento es motivo de preocupación entre los profesionales. El objetivo de este artículo es proporcionar una revisión exhaustiva de la literatura actual sobre la influencia o posibles limitantes del uso de este tipo de cementos bioactivos durante el retratamiento endodóntico. Los estudios determinaron una cantidad significativa de restos de selladores biocerámicos en las paredes del conducto radicular. Aunque la limpieza del canal no se pudo obtener a un nivel "ideal", el restablecimiento de la longitud de trabajo y la permeabilidad se puede considerar manejable y comparable a otros selladores endodónticos.