An In-vitro Evaluation of Grinding and Polishing on Surface Roughness and Flexural Strength of Monolithic Zirconia

Introduction: For a dentist, it is a matter of concern to restore the original luster or glaze on a Monolithic Zirconia (MZ) restoration after clinical adjustments. For a long time, the gold standard for surface restoration was reglazing; however, with advancements in technology, new polishing kits optimised for zirconia have become available for chairside polishing. Aim: To examine the effects of grinding, reglazing, and polishing techniques on the surface roughness and flexural strength of Materials and Methods: This in-vitro study was conducted in the Department of Prosthodontics at MM College of Dental to December 2019 and 32 specimens of MZ, each measuring 20 mm x 5 mm x 3 mm, were fabricated and divided into four groups, with each group consisting of eight specimens. Group C was considered the Control group. Specimens in Group G were only Ground, specimens in Group GR were Ground and Reglazed, and specimens in Group GP were Ground and Polished using a zirconia polishing kit. All specimens were using a profilometer and a Universal Testing Machine (UTM), respectively. Statistical analysis was performed using Analysis of Pearson's correlation, and other methods using International Results: The surface roughness (Ra) of the control group (C) was 0.4403 mu m, followed by the Polished Group (GP) at 0.656 mu m and the Reglazed Group (GR) at 0.809 mu m. The difference between the polished (GP) and reglazed (GR) groups, was statistically insignificant (p=0.53). There was a statistically significant increase in flexural strength in the reglazed samples (GR) when compared to the polished samples (GP). No significant correlation (p=0.58 and r=-0.1) was found between Conclusion: Chairside polishing can be an effective alternative to reglazing for restoring the surface finish of MZ. Additionally, polishing increases the strength of zirconia after adjustments.