Air abrasion or silicatization – optimal conditioning method for zirconium dioxide prosthetic restorations due to the bonding of ceramic orthodontic brackets

According to the results obtained from the survey of the American Orthodontic Society conducted in 2015, the number of adult patients that requested orthodontic treatment was increased from 14% to 27% between 2010 and 2014. Because of the increased age of the patients, fixed orthodontic treatment is expected to be performed on restored teeth as well. The aim of the present study was to evaluate the bond strength of the ceramic brackets bonded to the zirconium dioxide ceramic surfaces after air abrasion or silicatization as a single method of mechanical conditioning and their combination with the use of a universal primer. In this research, zirconium dioxide CAD CAM blocks were used for the experimental phase. The following conditioning treatments were performed: group 1 - direct bonding of the ceramic brackets, group 2 – air abrasion with 29 μm aluminum oxide (Al 2 O 3 ), group 3 – silicatizaion with 30 μm aluminium oxide coated with silicium dioxide (Al 2 O 3 x SiO 2 ), group 4 - air abrasion combined with universal primer, group 5 – silicatization combined with universal primer. It was observed that the treatment from group 5 achieved the highest average value of shear bond strength SBS (MPa): 30 µm Al 2 O 3 x SiO 2 + universal primer - 9.32±1.29 (95%CI 8.3-10.3) MPa with min/max values of 7.6/11.1 MPa. In group 1, the lowest average value of SBS was established by 0.51±0.12 (95%CI 0.4-0.6) MPa with min/max values of 0.4/0.8 MPa. After evaluation of the obtained results, it was concluded that air abrasion followed by the application of a universal primer can be considered as an adequate method for conditioning the zirconium dioxide ceramic bonding surfaces.