Studying the Bond Strength of Orthodontic Brackets to Ceramic Materials

Objectives: This study evaluated and compared the effect of different ceramic surface treatments with three primers and a resin bonding agent on the bond strength of metal orthodontic brackets to two different ceramic surfaces.
Methods: Eighty zirconia and lithium disilicate ceramic cubes were divided into five equal groups for each surface treatment application (n=16). The study groups were labelled as follows: No primer - Control (CNT), Transbond XT (TXT), Clearfil Ceramic Primer Plus (CCP), Assure Plus All Surface Bonding Resin (APB), and iBond Ceramic Primer (IBC). The zirconia samples were sandblasted with 50-μm Al₂O₃, while the lithium disilicate samples were subjected to etching with 9.6% hydrofluoric acid, followed by application of a silane coupling agent (Ultradent) before the surface treatments. The metal brackets of APC II Adhesive Coated Appliance System (3M Unitek) were bonded to the primed surfaces and light cured. The SBS was measured by the Instron Universal testing machine. The data was calculated in MPa and analyzed with two-way analysis of variance (ANOVA) and Tukey’s HSD test.
Results: The highest SBS values were achieved with the APB resin group for both ceramic surfaces (p <0.001). Although the second highest bond strength was achieved with the CCP primer group, there was no statistically significant difference among the primer groups of both ceramic surfaces (p >0.001).
Conclusions: Treating the ceramic surfaces with an MDP containing resin bonding material is clearly the best alternative to achieve reliable bonding performance in adherence of orthodontic brackets.