Bonding to zirconia using a new surface treatment

Purpose: Selective infiltration etching (SIE) is a newly developed surface treatment used to modify the surface of zirconia-based materials, rendering them ready for bonding to resin cements. The aim of this study was to evaluate the zirconia/resin bond strength and durability using the proposed technique. Materials and Methods: Fifty-four zirconia discs were fabricated and divided into three groups (n = 18) according to their surface treatment: as-sintered surface (control group), airborne-particle abrasion (50-μm aluminum oxide), and SIE group. The zirconia discs were bonded to preaged composite resin discs using a light-polymerized adhesive resin (Panavia F 2.0). The zirconia/resin bond strength was evaluated using microtensile bond strength test (MTBS), and the test was repeated after each of the following intervals of accelerated artificial aging (AA): thermocycling (10,000 cycles between 5 and 55◦C), 4 weeks of water storage (37◦C), and finally 26 weeks of water storage (37◦C). Silver nitrate nanoleakage analysis was used to assess the quality of zirconia/resin interface. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 18, α = 0.05) Results: There were significant differences in theMTBS values between the three test groups at each of the test intervals (p < 0.001). AA resulted in reduction in the bond strength of the as-sintered and the particle-abraded groups (5.9 MPa and 27.4, MPa, respectively). Reduction in the bond strength of these groups was explained by the observed nanoleakage across the zirconia/resin interface. The bond strength of the SIE specimens was stable after completion of AA (51.9 MPa), which also demonstrated a good seal against silver nitrate penetration across the zirconia/resin interface. Conclusion: SIE established a strong, stable, and durable bond to zirconia substrates. Conservative resin-bonded zirconia restorations are now possible using this new technique. The introduction of zirconia-based materials to the dental field broadened the design and application limits of all-ceramic restorations. As a result of the unique mechanical properties of zirconia framework materials, three- or four-unit-fixed partial dentures (FPDs) are no longer the safe limit for the construction of all-ceramic restorations. Combined with CAD/CAM technology, the fabrication of extensive zirconia restorations became a simple and an accurate procedure.1 Chemical bonding is the basic fundamental for minimally invasive dentistry where the retention of the restoration mainly depends on adhesion to the tooth structure instead of retentive features made in the preparation.2 Additionally, it reduces microleakage, tooth sensitivity, and the possibility of recurrent decay.3 Patients have a preference for methods that can spare the reduction of their sound abutment teeth and would welcom