Tensile bond strength of metal bracket bonding to glazed ceramic surfaces with different surface conditionings

The objective of this study was to compare the tensile bond strengthof metal brackets bonding to glazed ceramic surfaces using three various surfacetreatments. Forty two glazed ceramic disks were assigned to threegroups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA). Subsequently in first group, ceramic primer and adhesivewere applied, but in second group a bonding agent alone was used. In third group,specimens were treated with 35% phosphoric acid followed by ceramic primerand adhesive application. Brackets were bonded with light cure composites. Thespecimens were stored in distilled water in the room temperature for 24 hours andthermocycled 500 times between 5°C and 55°C. The universal testing machinewas used to test the tensile bond strength and the adhesive remenant index scoresbetween three groups was evaluated. The data were subjected to one-wayANOVA, Tukey and Kruskal-Wallis tests respectively. The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimensshowed tensile strength values significantly different from other groups (P<0.01). In spite of limitations in laboratory studies it may be concluded thatin application of Scotch bond multipurpose plus adhesive, phosphoric acid can beused instead of HFA for bonding brackets to the glazed ceramic restorations withenough tensile bond strength.