Compatibility between self-etching adhesive and self-curing resin by addition of anion exchange resin

The aim was to investigate whether anion exchange resin powder in the OH(-) form, added to the amine component of self-cured resin can deprotonize acid groups of a self-etching adhesive and thus eliminate incompatibility caused by amine neutralization.

Shear bond strength (SBS) of a self-cured CorePaste (COP), bonded either with all-in-one adhesive iBond (IBO) or with IBO coated with a self-cured experimental resin (SCR), loaded with 0, 8, 16, or 32 wt% of anion exchange resin powder (AER) in OH- form, were determined on 80 enamel and dentin surfaces each after 24 h water storage. IBO specimens were either light-activated or not. Flexural modulus and strength of the four SCR resins were determined by three-point bending. Data was analyzed by one-way ANOVA and Duncan's post hoc test (p<0.05).

Enamel SBSs of COP on IBO were 20-25 MPa, in combination with SCR (0 up to 32%) >25 MPa for activated or non-activated IBO. COP on IBO produced no bond on dentin, with the non-loaded SCR 5-10 MPa SBS was achieved, and 15 and 21 MPa were measured with the three AER-loaded SCRs on activated and non-activated IBO, respectively. Flexural moduli of SCR with 0 and 8% AER were higher than with 16 and 32%. Flexural strengths were not significantly different.

Addition of anion exchange resin to the amine component of self-cured resin is an effective means of enhancing the bond strength on dentin and to prevent amine neutralization through the acid groups of self-etching primer adhesives.