An in vitro study to compare the surface roughness of glazed and chairside polished dental monolithic zirconia using two polishing systems

AIM: To evaluate the efficiency of two commercially available polishing systems in reducing surface roughness of a monolithic zirconia after clinical adjustment and to compare them to glazed zirconia. SETTING AND DESIGN: In vitro study. MATERIAL AND METHODS: This in vitro study was conducted on 25 discs (10mm in diameter and 2mm in thickness) using monolithic zirconia (Ceramill Zolid). From 25 specimens, 5 specimens were randomly selected as the positive control. The remaining discs were abraded for 15 secs with a red band diamond finishing bur using an air rotor handpiece. Then the specimens were randomly divided into 5 equal groups of 5 specimens each. Group 1: Roughened, unpolished and unglazed. Group 2 (Positive Control): Glazed without prior roughening,Group 3: Roughened and polished with eZr polishing kit, Group 4: Roughened and polished with Optra fine ceramic polishing kit and Group 5: Roughened and glazed. The surface roughness (Ra) values (μm) were measured quantitatively by a surface analyzer. The mean values were compared using one-way ANOVA and Post Hoc Test. One specimen of each group was evaluated qualitatively under a scanning electron microscope(SEM) for surface topography. STATISTICAL ANALYSIS USED: One-way ANOVA and Post Hoc Test. RESULTS: The lowest Ra value was found in Group 4-Roughened and polished with Optrafine ceramic polishing kit (Ra=0.47μm) as compared to Group 3-Roughened and polished with eZr polishing kit (Ra=0.49μm) and Group 5-Roughened and glazed (Ra=0.59μm). There was no stastistically significant difference between two polishing systems. SEM analysis of surfaces polished with Optrafine polishing kit revealed smoother and regular morphology as compared to surfaces polished with eZr polishing kit. CONCLUSION: The Optrafine polishing kit created more smoother and uniform surfaces as compared to surfaces polished with eZr polishing kit both quantitatively and qualitatively. Also, lowest surface roughness values were produced by optrafine ceramic polishing kit on monolithic zirconia as compared to glazed monolithic zirconia after their clinical adjustments.Thus Optrafine ceramic polishing kit can be used as alternative to glazing.