[The microscopic characteristic of the dentinal tubule obstructed by desensitizer and the effect of desensitizer on the shear strength of resin cements].

Objective: To observe the microscopic characteristic of the dentinal surface and cross section after using dental desensitizer, and evaluate the effect of the dental desensitizer on the shear strength of resin cements.

Methods: To use the dental desensitizer (Gluma, Single Bond 2, BisBlock) individually on the prepared human bicuspid teeth which were extracted for orthopaedics. The microscopic characteristic of the dentinal surface and cross section were observed with scanning electron microscope (SEM).

[Effect of different dental polishing methods on cobalt-chromium casts surface roughness and accuracy].

Purpose: To evaluate the effect of different polishing methods on surface roughness and accuracy of cobalt-chromium castings.

Methods: Five polishing methods were compared: centrifugal barrel polishing, electrical brightening, grinding, grinding+centrifugal barrel polishing and grinding+electrical brightening. 30 specimens (30 mmx 10 mm x l.