Experimental Research Of Hot Alkaline Solution Etching Treatment On Zirconia/resin Bonding Strength

Objective:Through the study of alkali solution pretreatment on zirconia ceramics surface in vitro, evaluating shear bond strength between zirconia and self adhesive resin.Method :1. The method of making zirconia test pieces:Eighteen yttria stabilized tetragonal zirconia polycrystal ceramic blocks were cut,than dense sintered into10mm×10mm×3mm( ±0.02) blocks, Specimens were polished with Si C abrasive papers(grit # 600, 1000, 1200 and 2000), Specimens were sonicated in deionized water for 15 min and randomly divided into 3 groups, six blocks in each group.2. Groups according to the surface treatment performed on zirconiaA group: Hot alkali solution treatment(n=6) B group: sandblasting(n=6) C group: the control group. Then treated specimens were sonicated in deionized water for 30 min.3. Experimental determination(1) Determination with atomic force microscopeEvery specimens from each group were evaluated under an Atomic force microscope. Images were taken in air, Average surface roughness values were checked for normal and equal distribution(Kolmogorov–Smirnov and Levene’s tests,respectively). The data were analysised by using the statistical software SPSS16.0.Statistical analysis of the Sq was performed by single factor analysis and the Least-significant difference(LSD) method was used for multiple paired comparisons(α=0.01).(2) Determination with shear bond strengthZirconia blocks that were treated with 3 different methods mentioned above were embedded in autopolymerizing resin in order to make specimens 4.0mm in height and 14.0mm in diameter.Two side sticky tape with a central hole 2.0mmin diameter was positioned over the surface of zirconia ceramic to define the bonding area. Then the copper ring(4.0mm in internal diameter and 2.0mm in height) was placed on the sticky tape. The self-adhensive resin cements(Rely XTM Unicem,RU) were injected into the copper ring, and illuminated 40 seconds by LED source. After that,the specimens were stored in distilled water at 37℃ for 24 hours prior to testing. The SBS test was performed using a universal testing machine. Maximum shear load at the point of failure was recorded, and the SBS was calculated. A single observer examined the fractured specimen interface. The data were analysised by using the statistical software SPSS16.0.Statistical analysis of the SBS was performed by single factor analysis and the Least-significant difference(LSD) method was used for multiple paired comparisons(α=0.01).Result:1. Single factor analysis of variance on surface roughness of different zirconia surface treatment,the result shows: significant difference between A group and B group and C group p<0.01. Surface roughness:B group>A group>C group2. Single factor analysis of variance on shear bond strength of different zirconia surface treatment,the result shows: significant difference between A group and B group and C group p<0.01. SBS:B group>A group>C group.Conclusion:1.Under the 180 temperature, 20%Na OH solution treatment can improve the surface roughness of zirconia ceramic, but the sandblasting treatment is more effective then the hot alkali solution treatment.2. Under the 180 temperature, 20%Na OH solution treatment can improve shear bond strength of zirconia ceramic and resin, but the sandblasting treatment is more effective then the hot alkali solution treatment.