3D evaluation and shear bond strength (SBS) for metal and ceramic brackets after three pre-treatment surfaces of lithium disilicate (LD) crowns. Sixty lithium disilicate (LD) crowns were fabricated in laboratory according to manufacturer instruction and then divided into six groups (three groups for metal brackets and three groups for ceramic one). The 1st group for both was treated with round diamond bur, the 2nd one by hydrofluoric acid (HFA) 9.0%, and the 3rd group by laser (Er,Cr:YSGG). All treated surfaces were examined by laser profilometer and scan electron microscope. The Scotchbond Universal Adhesive and Transbond XT were used for bracketing procedure for metal and ceramic bracket (central incisor, 0,022” slot). Universal testing machine was used for shear bond. A crosshead speed of 1 mm/min was used, and the maximum load necessary to deboned the bracket will be recorded. HFA treated surfaces gave a highest SBS for both metal and ceramic brackets, then laser and finally the bur. The lowest roughness parameter Sa (arithmetical mean height) was in bur, both laser and HFA gave no significant differences. The HFA gave a highest Sz (maximum height) and Spc (arithmetic mean peak curvature) value. To increase the shear bond strength, the HFA is one of the best methods for roughness although the laser gave nearby roughness parameters. Ceramic brackets gave higher SBS than metal one with all pre-treatment procedures.
Three-Dimensional Surface Evaluation and Shear Bond Strength of Three Pre-treatment E-max Surfaces for Metal and Ceramic Orthodontic Brackets
