Effect of Different Finishing and Polishing Agents on the Surface Roughness of Cast Pure Titanium

PURPOSE: The aim of this study was to evaluate the effect of finishing and polishing agents on surface roughness of cast commercially pure titanium using scanning electron microscope (SEM) analysis. MATERIALS AND METHODS: A standardized square steel die measuring 10 x 10 mm with a thickness of 2 mm was machine cut. An impression of this die was used to create wax patterns for casting. Sixty specimens were cast in commercially pure titanium. These were divided into three groups (A, B, and C) of 20 specimens each. Group A specimens were polished with black, brown, and green rubber discs followed by green polishing compound with buff. Group B specimens were polished with black, brown, and green rubber cones, buffed with yellow polishing cake designed for gold alloy. Group C specimens were polished with silicium carbide cones and buffed with orange polishing cake. Surface roughness of the test specimens was measured in microns with a perthometer. Data were analyzed with ANOVA and Tukey's honest significant difference (HSD) multiple comparison tests among the different groups. Qualitative analysis was done by SEM photomicrographs. RESULTS: Surface roughness values R(a) for Groups A, B, and C were 0.68 microm, 0.78 microm, and 0.27 microm, respectively. SEM photomicrographs and the statistical analysis revealed that the finishing and polishing were better with Group C test specimens with lower surface roughness values compared with groups A and B. Tests showed that Group C was statistically smoother (p< or = 0.01). CONCLUSION: Within the limitations of this study, surface roughness was less on cast CpTi specimens that were finished and polished from the cutters designed specifically for titanium.