Influence of enzymatic and chemical degradation on zirconia resin bond strength after different surface treatments

Purpose: To investigate the influence of chemical and enzymatic degradation on the stability of zirconia resin bond strength using micro-shear bond strength test.

Methods: Zirconia discs were airborne particle abraded (SB) or selective infiltration etched (SIE) while no surface treatment served as control. Resin composite (Filtek Z250) micro-discs were bonded to zirconia using self-adhesive universal resin cement (RelyX UniCem). Micro-shear bond strength (μSBS) test was conducted after immersion in the following degrading media: 24 hours and 2 weeks of water storage, and 2 weeks in NaOH, alcohol, or esterase enzyme (n=10).

Results: There was a significant influence of the surface finish (P< 0.001, F=154.5), biodegradation medium (P< 0.001, F=52.9), and their interaction (P< 0.001, F=6.0) on zirconia resin bond strength. In general SIE group revealed the highest μSBS values (8.1 - 34.5 MPa) after degradation in different media, followed by SB group (8.7 - 28.5 MPa), while the control group showed significantly lower bond strength (0.4 - 9 MPa).