Study On The Interface Between Yttria-stabilized Zirconia And The Corresponding Veneering Ceramic

ObjectiveTo investigate the bonding properties and interface characterization of a 3Y-TZP framework fired on with 4 different veneering ceramics for zirconia; To evaluate the effect of different surface treatments on the bond strength between composite resin and 3Y-TZP core material.Methods4 different commercial veneering ceramics for zirconia(VITA VM9,SHOFU VINTAGE ZR,IPS e.max Ceram,Cercon ceram Kiss) were sintered on 3Y-TZP rectanglars(15mm×5mm×5mm) according to the manufacturers'instructions for shear bond strength test, a metal-ceramic system(Ni-Cr alloy,VITA VMK95) was fabricated in the same type as a control group.Two bilayerd specimens(3Y-TZP/VM9,Ni-Cr/VMK95) were prepared for SEM and EDS.Sixty 3Y-TZP blocks were fabricated and randomly assigned to six groups,then five surface treatments were performed:acid etching with 8%hydrofluoric acid(H),airborne-particle abrasion(A),silica coating(S),H+S;A+S,no treatment(N) as a control group.Then,composite resin were bonded onto the 3Y-TZP rectanglars.After 24 h at 37℃distilled water storage,all 3Y-TZP/resin specimens were subjected to a shear load until fracture occurred. SEM was used to inspect the surface characterization of 3Y-TZP after different trentments.ResultsThe mean values in MPa±SD of shear bond strength test were(18.83±1.77)MPa for 3Y-TZP/VITA VM9, (23.83±7.05) for 3Y-TZP/SHOFU VINTAGE ZR,(17.87±2.30) for 3Y-TZP/IPS e.max Ceram,(22.26±7.45) MPa for 3Y-TZP/Cercon ceram Kiss, (20.55±5.13)MPa for Ni-Cr alloy/VITA VMK95,there is no statistically significant between all-ceramic groups and the control group(P>0.05);The failure modes in all-ceramic groups showed predominately adhesive at the interface;SEM showed the 3Y-TZP/VITA VM9 contacted tightly at the interface,while EDS detected Si element diffused into 3Y-TZP material.The mean values in MPa±SD of shear bond strength test for group A(33.45±3.46)MPa and AS(36.95±2.93)MPa were statistically higher than other groups(P<0.01);No significant differences were detected in N(20.60±3.14)MPa,H(21.91±3.05)MPa,S(22.81±2.48)MPa and HS (23.08±3.51)MPa groups(P>0.05); And there was no statistically significant between silica coating groups and no-silica coating groups under the same treatment(P>0.05).SEM showed that acid etching with 8%hydrofluoric acid had no effect on 3Y-TZP surface structure,but the 3Y-TZP surface could be modified significantly by airborne-particle abrasion.ConclusionsThe result indicated that 3Y-TZP had a good interface compatibility with 4 commercial veneering ceramics,as a dental framework material,it can satisfy the clinical requairments; Si element was detected in 3Y-TZP interface nearby;Airborne-particle abrasion was the most effective surface treatment in terms of bond strength increase; Acid etching with 8%hydrofluoric acid and silica coating had a poor influence on the bond strength between 3Y-TZP and repaired composite resin.