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
welcome