The Outcome of Immediate or Delayed Application of a Single-Step Self-Etch Adhesive to Coronal Dentin Following the Application of Different Endodontic Irrigants

OBJECTIVES The aim of this study was to evaluate the outcome of immediate or delayed bonding of a single-step self-etch adhesive to coronal dentin after the application of different endodontic irrigants. METHODS Thirty five human molars were used. The coronal dentin was irrigated with either 0.9% physiologic saline (NS), 2% Chlorhexidine gluconate (CHX) or 2.5% commercially used sodium hypochlorite (NaOCl). Composite cylinders were bonded with the coronal dentin using the Clearfil S(3) bond, which was applied either immediately or after one week storage time following the irrigation procedures. Shear bond strength testing was performed at a cross-head speed of 0.5 mm/min, and the resin/dentin interface was evaluated using SEM. RESULTS Irrigation with NS, CHX, or NaOCL followed by immediate adhesive application resulted in a reduction in the shear bond strength values recorded and this was statistically significant in comparison with the control group (P<.05). However, delaying the adhesive application resulted in a statistically significant (P<.05) improvement in the shear bond strength recorded in specimens irrigated with NS and CHX only. CONCLUSIONS Delaying the bonding procedures for one week appeared to be beneficial in improving the shear bond strength of Clearfil S(3) bond with coronal dentin especially when NS and CHX were used as endodontic irrigants. NaOCL proved to be an incompatible irrigating solution when used prior to the application of such adhesive.