الفهرس | Only 14 pages are availabe for public view |
Abstract The current study was performed on Cerasmart blocks to evaluate the behaviour of Shear bond strength to different surface treatment of hybrid ceramics bonded with resin cement. Seven cerasmart blocks were used to prepare fifteen specimens with the following dimensions: (14 mm*12mm*1.5mm) using ISOMET 4000 with blade speed of (2150 rpm) and continous water irrigation. After specimen preparation they were assigned to three main groups according to the surface treatment applied. The first group was the control group which include samples with no surface treatment, the second group contain samples which received hydrofluoric acid etching, and the last one included samples which received sandblasting surface treatment. After surface treatments, Bisco silane coupling agent was applied for all specimen. A single layer of silane coupling agent was applied using a microbrush, allowed to dry for 60 seconds and then further gentle dryness was done for 10 seconds using oil/water free compressed air. Each specimen received one resin cylinder of polyethylene tube were positioned over the specimen surface and filled with resin cement, creating resin cylinder having the same dimensions. Resin cement was injected into the irise of polyethylene tube lumen using the supplied auto-mixing tips with intra-radicular tips. After filling the polyethylene tube irises, resin cement was light-cured for 20seconds as recommended by the manufacturer. Polyethylene irises were removed after 24 hours to ensure a complete polymerization of the dual- cured resin cement, in order not to subject the resin cylinders to shear stress, polyethylene irises were sectioned vertically using blade No. (12). Shear test was designed to evaluate the bond strength. Samples were fixed to specially designed sample holder [metal block with central hole for sample housing] secured to the lower fixed compartment of testing machine by tightening screws. Shear test was done by tensile mode of load applied at ceramic-resin interface. The load required for debonding was recorded in Newton. Failure mode analyesis was evaluated. |