Abstract: PURPOSE: To compare the effect of different treating agents on the shear bond strength (SBS) between zirconia and orthodontic brackets. METHODS: Fifty zirconia specimens were randomly divided into 5 groups(n=10), and treated with sandblasted and 37% phosphoric acid.Group A was control sample without any treatment; Group B was treated with silane coupling agent; Group C was treated with silane coupling agent and SE Bond; Group D were treated with Z-PrimeTM Plus; Group E were treated with Z-PrimeTM Plus+SE Bond. The upper incisor brackets were bonded to each specimen using 3M Transbond light-cured resin adhesive. Each specimen was put into 37℃ water, and SBS tests were performed after 24 hours. Then statistical analysis was carried out regarding to the adhesive residual index(ARI) of the zirconia oxide surface after removing the brackets. The surface of zirconia in each group was scanned with scanning electron microscope after surface treatment, and the surface morphology changes were observed, infrared spectra analysis was conducted on zirconia and treating agents. SPSS 17.0 software package was utilized for statistical analysis. RESULTS: The mean SBS in each group was as follows: group A (3.12±0.84) MPa; group B (1.92±0.83) MPa; group C (5.26±0.80) MPa; group D (6.54±0.98) MPa; group E (9.47±2.11) MPa. Significant difference existed between each group (P<0.05), group A and B had lower ARI, while ARI in group E was highest. Group D and E achieved effective bond strength. CONCLUSIONS: Using Z-PrimeTM Plus can achieve effective bond strength, which is lower than Z-PrimeTM Plus combined with SE Bond. It's suggested to use Z-PrimeTM Plus combined with SE Bond to achieve higher SBS for orthodontic treatment.

Key words: Zirconia, Z-PrimeTM Plus, SBS, ARI