Bond degradation resistance of self adhesive sealer bonded to radicular dentin using an alternative adhesive strategy

Objective: This study was carried out to evaluate the effect of an alternative adhesive strategy; double layering dentin bonding procedure in root canal obturation on the durability of root canal sealing using Resilon/Epiphany dual cure resin composite sealer system. Materials and methods: One hundred and twenty freshly extracted human upper central incisors teeth with straight root canals were used. The crowns were removed at the level of Cemento-Enamel Junction (CEJ). All roots were instrumented with a crowndown technique. The root canals were filled with either single or double layering bonding techniques, aged for 7 days and 3 months, and then sectioned perpendicular to the longitudinal axis of each root into a series of 1.0 mm thick cross-sectional slices. Durability of sealing was tested by both micropush out and nanoleakage tests. For the micropush out test, each root slice was subjected to compressive loading via a computer controlled materials testing machine, while for nanoleakage, the slices were immersed in the tracing solution of ammoniacal silver nitrate for 24 h in complete darkness. Photomicrographs were obtained by Environmental Scanning Electron Microscope. Results: The micropush out bond strength increased significantly with the double layering technique. On the other hand, it was not affected by aging. Only one nanoleakage pattern start to emerge as early as 7 days after sealing and continue after that. Conclusions: The current study supports the concept that double layering bonding strategy might be successfully adapted to endodontics to optimize bond strength of endodontic self-adhesive sealers to radicular dentin and to reduce nanoleakage.