[Bonding interfaces of three kinds of cements and root canal dentin: a scanning electron microscope observation].

Objective: To compare the bonding properties of three kinds of cements by observing the bonding inteffaces of cements and root canal dentin.

Methods: 15 extracted mandibular premolars were divided into 3 groups, and were cemented by Rely X luting, Panavia F and Paracore 5 mL, respectively. Each tooth was sectioned into two parts and the dentin-cement interfaces at the coronal, middle and apical parts of the fiber post were oberved by scanning electron microscope (SEM).

[Effect of porcelain firing cycle on microstructure and corrosion resistance of 4 metal ceramic alloys].

Objective: To determine the effect of porcelain firing cycle on microstructure of 4 metal ceramic alloys, and to analyze the changes of their corrosion resistance in the artificial saliva.

Methods: We simulated the process of firing and repolishing when fabricating porcelain-fused-to-metal restoration in clinic,and then observed the microstructures of Ni-Cr, Ni-Cr-Ti, Co-Cr alloys and high gold alloy by field emission scanning electron microscopy and energy dispersive spectroscopy. The electrochemical corrosion behavior of alloys in artificial saliva was analyzed by polarization curves and corrview 2 corrosion analysis software.