COMPARATIVE EFFECTIVENESS OF DIFFERENT CLEANSING PROTOCOLS ON BONDING OF A SELF-ETCH ADHESIVE TO DENTINCONTAMINATED BY ROOT CANAL SEALER: AN IN-VITRO STUDY

Objectives: To compare the effectiveness of different sealer cleaning methods on bonding of a self-etch adhesive to root canal sealer-contaminated dentine. Methods: Forty-nine extracted molars were divided into seven groups. Dentine surfaces were exposed and contaminated with a thin layer of epoxy resin-based sealer (AH Plus (AHP)) or zinc oxide eugenol-based sealer (Pulp Canal Sealer (PCS)). Three cleaning protocols were examined: dry cotton pellet, 70% ethanol-saturated cotton pellet and a surfactant-based cleaner (ZirClean (ZC), Bisco, US). Uncontaminated dentine served as control. The dentine surfaces were bonded with a two-step self-etch adhesive and restored with resin composite. Bond strength testing was performed using a micro-tensile approach. Results: Tensile bond strength for uncontaminated dentine control was 46.4±7.3 MPa; bond strength decreased significantly for the dry cotton group (29.6±4.2 MPa for AHP, 24.7±4.7 MPa for PCS, p<0.05). Both ethanol and ZC restored bonding performance after cleaning, with no significant difference from the control. Significantly lower mTBS was observed for the ZOE/ethanol subgroup (38.9±5.1 MPa). Conclusions: Zirclean decontaminates root canal sealer-smeared dentine surfaces effectively and restores the bonding performance of a self-etch adhesive to dentine. Clinical significance: The surfactant-based ZirClean Cleaner, originally designed for cleaning zirconia surfaces prior to adhesive bonding, may be used as for cleaning dentine that has been contaminated with unset root canal sealers after root canal treatment to restore the bonding strength of a self-etch adhesive to sealer-contaminated dentine.