Effect of Polishing Systems on Surface Roughness and Topography of Monolith Zirconia

Abstract

Aim: The aim of this study was to evaluate effectiveness of various polishing agents over surface roughness and topography of monolithic zirconia. Materials and methods: Total 300 high-translucency LAVA PLUS Zirconia specimens (8 mm × 6 mm × 3 mm thickness) were prepared by sectioning blocks in the green stage. Sectioned blocks were sintered at 1450°C. Baseline surface roughness values of unpolished, ground blocks were measured using a profilometer. Samples were categorized into five groups, with each group having 60 samples—group I: White stone at 200,000 rpm with 40 strokes for 60 seconds and water coolant followed by polishing with diamond-impregnated silicone kit at 10,000 rpm with 40 strokes for 60 seconds (two steps); group II: Polishing done using diamond-impregnated silicone (two steps) at 10,000 rpm at 60 strokes for 90 seconds; group III: Polishing done using silicone paper containing silica carbide at 10,000 rpm at 40 strokes for 1 minute; group IV: Polishing done using silicone paper containing diamond at 10,000 rpm using 60 strokes in 90 seconds (two steps); group V: Polishing performed with silicone paper with diamond (two steps) at 8,000 rpm at 60 strokes for 90 seconds. Mean surface roughness (Ra) values were calculated. Collected data were analyzed using the one-way ANOVA and post hoc test using the SPSS software. One specimen per group was subjected to scanning electron microscopic analysis. Results: Mean surface roughness values for all groups were found as 0.8, 0.7, 0.054, 0.002, and 0.01, respectively. No statistically significant difference was observed in polishing agents containing diamond (p = 0.7). Significant difference (p = 0.0) was observed between control groups compared to other groups. On SEM examination, surfaces polished with kits manufactured for Zirconia demonstrated greater smoothness compared to other porcelain polishers. Conclusion: Polishing systems containing diamond particles were found to enhance the surface smoothness and reduce roughness of monolithic zirconia as compared to silica carbide. Polishing systems should be adhered to as per manufacturer due to abrasive particle size appropriateness.