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Objective: In this study, to explore different firings of two gold nano-ceramic the ordinary ceramic surface of the metal-ceramic crowns and porcelain cross section structure by scanning electron microscopy (Scanning Electron Microscope, SEM) , and by the destruction test comparison between the compressive strength high strength ceramic crowns and nano - gold porcelain crown strength to provide experimental evidence for the clinical application of the nano- ceramic material . Method: 1 specimen preparation : to create a simulation of the preparation of metal -generation type , generation type , including base and column (equivalent to the preparation of metal crown nuclear part ) , base diameter 30mm, thickness 10mm, metal crown nuclear high precision lathe 6mm occlusal surface diameter 3.9mm, generation type corresponds to making a casing , casing diameter 4.5mm , the top above the crown nuclear 0.3mm in place to ensure that the axial plane and the occlusal surface of the casing and metal crown nuclear maintain a uniform gap of 0.3mm . Substituting type metal preparatory body portion immersed in the wax dipped for 5 seconds after the wax , the wax-type of the pressure shaping Preparation basal crown , conventional embedding, casting , respectively, sculpture and the ordinary porcelain , nano - ceramic , production of uniform thickness ordinary metal-ceramic crowns , ceramic crowns , gold nanoparticles 20 each , a total of 40 . According to the different types of ceramic powder and firings are divided into eight groups of five . AD group as ordinary ceramic group , the firings in turn 4, 6, 8, 10 times . A'-D ' nano-ceramic group , firings with AD group corresponding . Sintering times of each group including opaque Sintering 2 times since Glazed 1 , the rest is the number of the sintered body porcelain . 2 SEM observation of the surface structure of the specimen . 3 compressive strength test : the specimen is located on the generation type is placed on an Instron universal material testing machine , destructive testing , using 5KN value of the force sensor to 1mm/min
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