Replacing glazing with polishing is still controversial in terms of the surface roughness of dental porcelains. This study investigated the polishing performance of a ceramic-polishing rubber wheel (CP-RW), which contains large uniform and rounded silicon carbide particles and small diamond particles, in improving the surface roughness of two feldspathic porcelains for sintering and CAD/CAM milling. Using a confocal laser scanning microscopy, the changes in the surface roughness parameters were evaluated before and after polishing or glazing for three surface treatment groups: SofLex polishing, CP-RW polishing, and Glazing. Regardless of the parameters, all treatments reduced roughness values (repeated measures ANOVA, p<0.05). The roughness values obtained after CP-RW polishing were lower than those obtained after SofLex polishing and glazing (2-way ANOVA, p<0.05). Polishing both ceramics with CP-RW made the surfaces smooth with the lowest roughness values in all parameters. The effect was dependent on the materials used.