Surface Roughness and Microhardness of Monolithic Zirconia under Polishing and Glazing Using CAD/CAM Computer-Aided Design/computer-Aided Manufacturing Technology

Abstract:

AbstractAlthough manufacturers recommend glazing and polishing for CAD/CAM milled restorations, the relative efficacy of either in achieving optimal surface roughness and wear remains ambiguous. This study has been carried out to investigate how polishing and glazing affect the surface characteristics and hardness of milled monolithic zirconia. Thirty cuboid-shaped milled zirconia samples (10 mm length× 10 mm width× 3mm thickness) were cut from a pre-sintered zirconia block (Aconia^®, Besmile Biotechnology Co., Ltd. Chengdu, China). Samples were sintered, cleaned, and divided into two groups according to surface treatment (n = 15). Group P: Polished only, Group PG: Polished and glazed. Each treatment was performed according to the manufacturer’s guidelines. One sample was examined from each group using a Scanning Electron microscope (SEM) to explore the surface morphology. Surface roughness was assessed using a profilometer. Vickers hardness (VHN) was evaluated using a Vickers diamond indenter. All data were calculated, and statistical analysis was performed. There was a significant difference between groups in surface roughness and hardness. The average surface roughness (Ra) value of polished zirconia samples (2.1611 µm) was higher than the Ra value of glazed zirconia samples (1.3273 µm), while the Vickers hardness (VHN) of polished zirconia samples (1.4721) was lower than the VHN of glazed zirconia samples (3.7843). SEM analysis images validated the findings on the surface roughness. The glazing after polishing of monolithic zirconia showed better surface smoothness and higher hardness.

• Periodical: Engineering Headway (Volume 30)
• Pages: 31-41
• DOI: https://doi.org/10.4028/p-UpJTb0
• Online since: January 2026
• Authors: Nour Ibrahem Dawood*, Sahar Naji, Zahraa AL Wahab
• Keywords: CAD/CAM Zirconia, Glazing, Microhardness, Monolithic Zirconia, Surface Roughness

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