Evaluation of the Effect of Different Glazing Brands on Hardness of Monolithic Zirconia Fabricated By CAD/CAM Technique

Abstract

The purpose of this study was to evaluate the hardness of different glazing brands materials on monolithic Zirconia. Materials and methods: - A CAD/CAM machine (computer aided design- computer aided manufacturing) was used to manufacture 40 specimens from a zirconia block (VITA Zahnfabric YZ®XT Color, 98.4x14mm height). The Vickers hardness test sample dimensions (diameter 10 mm and thickness 2 mm) were separated into 4 groups based on the brands of glazing materials used (VITA AKZENT® Plus, Ivoclar vivadent, GC Initial spectrum, Soprano glaze) powder and fluid. Data are statistically analyzed using statistical package for social science (SPSS), and the (ANOVA) test and Bonferroni test are used to determine whether the statistical hypothesis is true. Results: - For the hardness readings the higher mean value of Vickers hardness test in Zirconia was found in GC group (544.792±25.416) then Ivoclar group (538.622±18.701) while the lower mean of Vickers hardness was found in Vita group (475.800±15.699) followed by Soprano group (467.895±23.298).There was a statistically significant difference between each two groups (VITA, Ivoclar, GC and Soprano) with p-value < 0.05, except between (VITA & Soprano) and (Ivoclar & GC), there no statistically significant association with p-value >0.05 for both. : Zirconia glazed with GC paste (powder, fluid) has higher hardness than samples glazed with Ivoclar paste (powder, fluid) followed by VITA group then Soprano group that has lower hardness. Conclusion: - Zirconia coated with GC paste (powder, fluid) has a higher hardness than samples glazed with Ivoclar, VITA group and Soprano group.