Conclusions .
Airborne-particle abrasion and tribo-chemical silica coating are the pre-treatment methods with more evidence in the literature .
Increased adhesion could be expected after physico-chemical conditioning of zirconia .
Surface contamination has a negative effect on adhesion .
There is no evidence to support a universal adhesion protocol
Background .
Reliable bonding between resin composite cements and high strength ceramics is difficult to achieve because of their chemical inertness and lack of silica content that makes etching impossible .
The purpose of this review is to classify and analyze the existing methods and material s suggested to improve the adhesion of zirconia to dental substrate by using composite resins , in order to explore current trends in surface conditioning methods with predictable results .
Methods .
Effect of chemical etching solutions versus air abrasion on the adhesion of self-adhesive resin cement  to IPS e.max ZirCAD with and  without aging.
OBJECTIVES This study evaluated the adhesion of self-adhesive resin cement to zirconia after various surface conditioning methods in non-aged and aged conditions . METHODS Zirconia ( IPS e.max ZirCAD , Ivoclar Vivadent ) and resin composite blocks were obtained and r and omly divided into four groups according to one of the following surface conditioning methods : C : No surface treatment ( Control ) ; AS : Air abrasion ( 50 µm Al2O3 ) at low pressure ( 0.2 MPa ) plus silane ( Monobond Plus , Ivoclar Vivadent ) ; MC : Methylene chloride for 60 min ; CE : Chemical etching solution at 100 ° C for 60  min . Surface roughness ( Ra ) measurements were performed on the control and conditioned zirconia specimens using a profilometer . Each conditioned zirconia block was bonded to its corresponding resin composite block using self-adhesive resin cement ( RelyX Unicem Aplicap , 3 M ESPE ) under a load of 300 g. Half of the groups were tested without aging ; the other half were tested after x6000 thermocycling . Sticks were obtained from bonded specimens and subjected to microtensile bond strength ( MTBS ) testing in a universal testing machine ( 0.5 mm/min ) . Failure types were classified after debonding . Data ( MPa ) were analyzed using two-way ANOVA and Tukey 's tests ( α = 0.05 ) . RESULTS The highest mean Ra value was obtained in Group CE ( 0.52 µm ) , and the lowest in Group C ( 0.25 µm ) . Significantly lower MTBS test results were obtained in Group C , both in non-aged ( 17.4 ± 1.1 MPa ) and aged ( 5.11 ± 0.5 MPa ) conditions than in the other groups ( 34.6 ± 1.5 to 51.2 ± 1.1 MPa ; 28.0 ± 0.9 to 49.5 ± 1.0 MPa in non-aged and aged conditions , respectively ) ( P < 0.05 ) . Group CE presented the highest MTBS test results in both non-aged and aged conditions ( 51.2 ± 1.1 MPa and 49.5 ± 1 MPa , respectively ) ( P < 0.05 ) . Failure types were predominantly adhesive in all groups before and after aging . After aging , less adhesive and more mixed and cohesive failures in cement were observed in Groups AS and CE than in the other groups . CONCLUSION Chemical etching of zirconia may have potential use as a substitute for air abrasion as a surface conditioning method for zirconia
Conclusions .
Airborne-particle abrasion and tribo-chemical silica coating are the pre-treatment methods with more evidence in the literature .
Increased adhesion could be expected after physico-chemical conditioning of zirconia .
Surface contamination has a negative effect on adhesion .
There is no evidence to support a universal adhesion protocol
Background .
Reliable bonding between resin composite cements and high strength ceramics is difficult to achieve because of their chemical inertness and lack of silica content that makes etching impossible .
The purpose of this review is to classify and analyze the existing methods and material s suggested to improve the adhesion of zirconia to dental substrate by using composite resins , in order to explore current trends in surface conditioning methods with predictable results .
Methods .