Experimental Study Of Zirconium Oxide Surface Bonding Orthodontic Metal Brackets

Objectives In this study, the surfaces of the zirconia chemically were treated differently, and orthodontic brackets were bonded on zirconia ceramic surface with different orthodontic adhesive, then to compare the shear bond strength?SBS? of the orthodontic bracket, the surface of zirconia adhesive residue index?ARI?, and microleakage between resin adhesives and zirconia, to explore zirconia ceramics surface morphology and the microstructure of bonding interface after the chemical treatment, and the bonding mechanism, providing reference for clinical application.Methods Experiment1: 50 zirconia ceramic specimens were treated with sandblasting and phosphate and randomly divided into 5 groups?n = 10?, Group A was the control group, Group B treated by silane coupling agent, Group C by silane coupling agent + SE Bond, Group D by Z-prime^TM plus treating agent and Group E by Z-prime^TM plus + SE Bond. All the specimens were bonded with orthodontic bracket of upper right central incisor using 3M Transbond light-cured resin adhesives. The specimens tested for the SBS after bathing by 37 ? constant water for 24 hours. After removal of brackets, zirconia ceramic surface ARI was counted with a stered microscope and one specimen in each experimental group that was not bonded with the bracket after treating agency treatment was selected and their zirconia ceramic surface microscopic changes were observed with scanning electron microscope. Infrared spectrum analysis of treating agents and zirconia ceramic was carried out. Using SPSS17.0 software package, analysis of variance of SBS in each group and rank sum test of ARI. Experiment2: 144 zirconia ceramic specimens were treated with sandblasting and phosphate and were randomly divided into 6 groups?n = 24? including Group A1 treated with Z-prime^TM plus + Beijing-Tianjin enamel adhesives, Group A2 with SE Bond +Z-prime^TM plus+Beijing-Tianjin enamel bonding agent, Group B 1with Z-prime^TM plus+3M Transbond adhesives, Group B2 with Z-prime^TM plus + SE Bond + 3M Transbond adhesives, Group C1 with Z-prime^TM plus + P60 resin, Group C2 with Z-prime^TM plus + SE Bond + P60 resin. All specimens were bonded with the same bracket of upper right central incisor. 8 specimens of each group were tested for the SBS. After the removal of brackets, zirconia ceramic surface ARI was counted with a stered microscope. then 8 specimens were embedded and cutted,the proportion of different interface morphology to entire bonding interface was observed with scanning electron microscope.Another 8 specimens in each group were dyed with 1% methylene blue for 30 days, then embedded and cutted. Besides, micro-leakage was counted with stered microscope.Using the SPSS17.0 package, analysis of variance for SBS, bonding interface and the micro leakagein each group and rank sum test of ARI.Results Results in Experiment1: 1 The difference in the SBS in each group was significant?P < 0.01?. The SBS in 5 groups ranks as follows: Group E was highest, whereas Group A was lowest. There was no statistically significant difference in SBS between Group A and Group B?P?0.05?, and SBS in group D and group E met clinical needs. 2 ARI: The difference in ARI was significant between different groups?P < 0.01?, and Group E had the highest ARI. 3 After treating zirconia ceramics with treating agent, their surface microscopic changes were observed with the scanning electron microscope: Z-prime^TM plus evenly was embedded into between zirconia crystals, wettability of the silane coupling agent was not good and was not evenly distributed on the surface of zirconia ceramics. However, Z-prime^TM plus in Group B and Group C treated with SE Bond was evenly embedded into between zirconia crystals, and the surface was extremely smooth. Results in Experiment2: 1 SBS: SBS had significant difference between groups?P < 0.01?, and LSD revealed that after comparison between two groups, there was no statistically significant difference in SBS in Group A and Group A1?P?0.05?, the differences between other groups were statistically significant. 2 ARI: The difference in ARI between each group was statistically significant?P < 0.01?. After removing bonding bracket with P60, ARI was highest compared with the other groups?P < 0.05?.3 The degree of the micro leakage: the differences between groups was statistically significant?P < 0.01?, micro leakage was the smallest with 3M Transbond, and the difference in micro leakage in the same resin adhesive group was not statistically significant?P?0.05?.4 Bonding interface was observed with scanning electron microscope: the integrity rate of specimen interface bonded with 3M Transbond, Beijing-Tianjin enamel adhesive and P60 resin had significant difference?P < 0.05?, the integrity rate of specimen interface bonded with 3M Transbond is highest?P < 0.05?, the integrity rate of specimens bonded with the Beijing-Tianjin enamel adhesive and P60 resin was no significant difference?P?0.05?, and the integrity rate was no significantly statistical difference?P?0.05? treated with the same resin adhesive interface.Conclusions 1 Silane coupling agent can not increase the bond strength of orthodontic bracket on zirconia ceramic surface. 2 Z-prime^TM plus can increase the bond strength of the orthodontic bracket on zirconia ceramic surface. Furthermore, if Z-prime^TM plus is used together with SE Bond, it will work more effectively. 3 It is not appropriate to use the Beijing-Tianjin enamel adhesive to bond the orthodontic bracket on zirconia restoration surfaces. 4 SBS is clinically suitable with 3M Transbond resin, which micro leakage is relatively small. 5 SBS with P60 resin the largest,which microleakage is larger.6 The results show that there isn't correlation between the different adhesive SBS and micro leakage.