Strength Analysis Of Bonding Metal Brackets To Polished Or Glazed Zirconia Ceramics With Three Adhesives

Objectives:To compare and analyze the effects of three adhesives on the bond strength and durability of metal brackets to polished and glazed zirconia ceramics,and to explore the role of the active ingredients in the universal adhesives on the two zirconia ceramic surfaces for clinical reference.Methods:Sixty polished and sixty glazed zirconia specimens were embedded in self-curing resin,and the pre-bonded surfaces were treated with Al₂O₃ sandblasting+HF acid etching,and one specimen was taken from each group before and after treatment for scanning electron microscopy observation.The zirconia specimens in the polished and glazed groups were randomly divided into three groups,and the specimens were bonded to the maxillary incisal metal brackets by applying the universal adhesives Single Bond Universal,Prime&Bond Universal,the orthodontic pretreatment agent Transbond^TMMIP with the resin composite paste Transbond^TMXT.After 24 hours of 37℃water bath,10 specimens were randomly selected from each group and subjected to 5000thermal cycles.The shear bond strength of the brackets on 120 specimens was tested with a universal testing machine and the adhesive residue index（ARI）on the surface of the zirconia ceramic after debonding was recorded.SPSS 22.0 software was used for data analysis.After one-way ANOVA,multiple comparisons between group means were performed using Tukey’s HSD test;Kruskal-Wallis test was used to analyze the statistical differences of ARI scores among groups.P<0.05 was considered statistically significant.Results:1.In the polished group,the shear bond strength of the brackets and zirconia ceramics in the Single Bond Universal group and Prime&Bond Universal group was significantly higher than that in the Transbond^TMMIP group（P<0.05）,and the bond strength of Transbond^TMMIP group did not meet the clinical requirements.There was no significant difference in the shear bond strength of each group before and after thermocycling（P>0.05）.2.In the glazing group,the shear Bond strength of the three adhesives was higher than the minimum standard after water bath at 37℃for 24 h,and the Single Bond Universal group was the highest.After thermocycling,the mean value of SBS in Prime&Bond Universal group and Transbond^TMMIP group decreased significantly（P<0.05）,Transbond^TMMIP group<Prime&Bond universal group<Single Bond Universal group（P<0.05）.3.In the polished and glazed groups,the ARI scores of Transbond^TM MIP group were mainly 0,which were generally lower than those of Single Bond Universal group and Prime&Bond Universal group（P<0.05）.And there was no statistical difference between Single Bond Universal group and Prime&Bond Universal group（P>0.05）.There was no statistical difference before and after thermocycling（P>0.05）.4.Scanning electron microscopy showed that there were slight cutting marks on the surface of polished zirconia,and the glazed zirconia surface was smooth.Sandblasting and acid etching resulted in increased porosity and roughness on the surface of zirconia,and glazed zirconia was rougher than polished zirconia.Conclusion:1.Transbond^TMMIP+Transbond^TMXT,the light-curing adhesives commonly used in orthodontic practice,cannot bond the brackets firmly to the surface of zirconia ceramic.2.Both Universal adhesives showed higher shear Bond strength in the polished and glazed groups,and Single Bond Universal exhibited better anti-aging performance.3.The universal adhesive group had a higher ARI score after debonding,but still maintained the integrity of the zirconia ceramic.4.Universal adhesives have advantages in optimizing orthodontic bonding efficiency and simplifying clinical procedures.