Effects Of Different Surface Treatments On The Shear Bond Strength Between Domestic Translucent Zirconia And Resin Cements:An In Vitro Study

Objective:The purpose of this paper was to investigate the effects of different surface treatments on the immediate and long-term bond strength between the domestic translucent zirconia and resin cements,so as to provide reference for clinical work.Method:The domestic translucent zirconia(TT,Upcera)was chosen as the subject in this study.The specimens of translucent zirconia(10 mm×10 mm×2mm)were fabricated from translucent zirconia blocks,and then were randomly divided into three groups according to the following surface treatments(n=37):polishing(PZ),air-particle abrasion(AZ)and lithium disilicate coating(CZ).Additionally,lithium disilicate glass ceramic(GC)was chosen as positive control,and the specimens of glass ceramic(n=37)(15mm×13mm×2mm)were fabricated from lithium disilicate glass ceramic blanks.The followings were the experimental processes:1.Scanning electron microscope(SEM)was used to show surface morphology.2.Each group was treated with one of the following bonding procedures:(1)Multilink Speed(S),(2)Monobond N+Multilink Speed(NS),(3)Monobond N+60℃ hot air treatment for 60 seconds+Multilink Speed(N60S).There were total of 12 groups,and 12 bonding specimens in each group were stored in distilled water at a temperature of 37℃ for 24 hours and then assigned to two subgroups(n=6/test group):short-term test and thermocycling for 5000.Then,shear bond strength(SBS)was measured and failure mode was recorded.Statistical analysis was performed with two-way ANOVA and Tukey test.(α=0.05)Results:1.The SEM images showed that air-particle abrasion could significantly change the surface morphology of translucent zirconia,resulting in creation of sharp scratches and grooves,and microscopic pores could also be seen on the surface of lithium disilicate coating and lithium disilicate glass ceramic.2.The results of the immediate SBSs showed that,with the application of Monobond N and Multilink Speed,the SBSs of PZ-NS group(9.60±1.38 MPa),AZ-NS group(14.30±1.74 MPa)and CZ-NS group(13.40±2.22 MPa)were respectively higher than PZ-S group(6.91 ± 1.27 MPa),AZ-S group(7.13±1.18 MPa)and CZ-S group(6.28±0.80 MPa)(P<0.05);additionally,the SBSs of PZ-N60S group(11.33±0.60 MPa)and CZ-N60S group(16.50±1.83 MPa)were respectively further improved compared to those of PZ-NS group and CZ-NS group(P<0.05),and there is an increase in the proportion of mixed failure and cohesive failure.With the same bonding program,AZ-NS group,CZ-NS group and GC-NS group showed the higher SBS than PZ-NS group(P<0.05),and there was no statistical difference among the groups(AZ-NS group,CZ-NS group and GC-NS group)(P>0.05),and the failure mode was mainly cohesive failure.With the application of hot air treatment,CZ-N60S group(16.50±1.83 MPa)showed the lower SBS than GC-N60S group(18.36±1.78 MPa),but higher SBS than AZ-N60S group(14.59±1.13 MPa).3.After aging treatment,the results of SBSs showed that,with the same surface treatment,PZ-NS group(7.44±1.92MPa),AZ-NS group(10.25±0.87 MPa)and CZ-NS group(13.75±0.99 MPa)showed significantly higher SBSs than PZ-S group(5.07±1.66 MPa),AZ-S group(7.26±1.28 MPa)and CZ-S group(4.66±0.79 MPa)(p<0.05),and there is an increase of proportion of mixed and cohesive failure;additionally,AZ-N60S group(12.61±0.84 MPa)and CZ-N60S group(14.94±0.77 MPa)showed higher SBSs compared to AZ-NS group and CZ-NS group(P<0.05).With the same bonding procedure,CZ-NS group(13.75±0.99 MPa)showed the highest SBS,similarly to GC-NS group(15.19±1.69 MPa),and there was no statistical difference between the two groups(P>0.05),AZ-NS group showed the lower SBS than CZ-NS group(P<0.05),and PZ-NS group showed the lowest SBS(P<0.05).The difference among groups at level of N60S was the same as level of NS.Conclusion:1.With the use of primer and hot air treatment,Air-particle abrasion or lithium disilicate coating treatment could improve the bonding strength between domestic translucent zirconia and resin cements.2.Lithium disilicate coating treatment combined with Monobond N could achieve stable and long-term bonding strength between domestic translucent zirconia and resin cements..