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 .
Air-particle abrasion on zirconia ceramic using different protocols: effects on biaxial flexural strength after cyclic loading, phase transformation and surface topography.
This study evaluated the effect of different air-particle abrasion protocol s on the biaxial flexural strength and structural stability of zirconia ceramics . Zirconia ceramic specimens ( ISO 6872 ) ( Lava , 3 M ESPE ) were obtained ( N=336 ) . The specimens ( N=118 , n=20 per group ) were r and omly assigned to one of the air-abrasion protocol s : Gr1 : Control ( as-sintered ) ; Gr2 : 50 µm Al2O3 ( 2.5 bar ) ; Gr3 : 50 µm Al2O3 ( 3.5 bar ) ; Gr4 : 110 µm Al2O3(2.5 bar ) ; Gr5 : 110 µm Al2O3 ( 3.5 bar ) ; Gr6 : 30 µm SiO2 ( 2.5 bar ) ( CoJet ) ; Gr7 : 30 µm SiO2(3.5 bar ) ; Gr8 : 110 µm SiO2 ( 2.5 bar ) ( Rocatec Plus ) ; and Gr9 : 110 µm SiO2 ( 3.5 bar ) ( duration : 20 s , distance : 10 mm ) . While half of the specimens were tested immediately , the other half was subjected to cyclic loading in water ( 100,000 cycles ; 50 N , 4 Hz , 37 ° ° C ) prior to biaxial flexural strength test ( ISO 6872 ) . Phase transformation ( t→m ) , relative amount of transformed monoclinic zirconia ( FM ) , transformed zone depth ( TZD ) and surface roughness were measured . Particle type ( p=0.2746 ) , pressure ( p=0.5084 ) and cyclic loading ( p=0.1610 ) did not influence the flexural strength . Except for the air-abraded group with 110 µm Al2O3 at 3.5 bar , all air-abrasion protocol s increased the biaxial flexural strength ( MPa ) ( Controlnon-aged : 1,030 ± 153 , Controlaged : 1,138 ± 138 ; Experimentalnon-aged : 1,307 ± 184 - 1,554 ± 124 ; Experimentalaged : 1,308 ± 118 - 1,451 ± 135 ) in both non-aged and aged conditions , respectively . Surface roughness ( Ra ) was the highest with 110 µm Al2O3(0.84 µm . FM values ranged from 0 % to 27.21 % , higher value for the Rocatec Plus ( 110 µm SiO2 ) and 110 µm Al2O3 groups at 3.5 bar pressure . TZD ranged between 0 and 1.43 µm , with the highest values for Rocatec Plus and 110 µm Al2O3 groups at 3.5 bar pressure
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 .