Surface Roughness And Colour Stability Of Dental Porcelain Treated With Different Polishing Methods

Background: The study aims to investigate the effect of different polishing methods on the dental porcelain surface roughness and tea extract staining resistance. Methods: A total of 40 disc-shaped dental porcelain of 10mm diameter and 2mm thickness were divided into four groups: Group A (Glaze), untreated control; Group B (Polishing paste), using slow speed green stone bur and followed by diamond polishing paste; Group C (NTI), using NTI CeraGlaze polishing kits; and Group D (Identoflex), using Identoflex Diamond Ceramic Polisher. The specimens were then subjected to a baseline measurement for surface roughness and colour shade using a surface profilometer and digital spectrophotometer, respectively. The glaze layer was removed using a medium-grit diamond rotary bur, followed by 60 seconds polishing according to the assigned method. A second surface roughness measurement ensued. The specimens were then subjected to thermal cycling between 5°C and 55°C for 2000 cycles, followed by 30 days staining in a tea extract solution. A second colour shade measurement ensued. Results: The surface roughness of dental porcelain was highest in the Polishing paste group (p 0.05). In all test groups, the Glaze group shows superiority in colour stability with DE value significantly higher compared to all test group (p < 0.05). Conclusion: Although the mechanical polishing can restore the smoothness of the glazed surface, it cannot restore the ability to resist tea extract staining