Abstract
<title>Abstract</title> <p> <bold>Purpose</bold> To investigate the effects of common clinical surface pretreatments on the surface properties, microhardness, and bacterial adhesion of glazed zirconia ceramics. <bold>Materials and Methods</bold> Glazed zirconia specimens were assigned to 5 groups: control, ground, ground+polished, grit-blasted, and acid-etched. Surface characteristics were evaluated via roughness/contact angle measurement, microscopy, X-ray diffraction, and micro-Vickers hardness test. Streptococcus mutans and human whole-saliva biofilm adhesion were assessed by colony counting, CCK-8 assay, and 16S rDNA sequencing. <bold>Results</bold> Grinding and grit-blasting significantly increased surface roughness, contact angle, and hardness, and induced tetragonal-to-monoclinic phase transformation, which was reversed by polishing. Bacterial adhesion was positively correlated with roughness; polishing reduced bacterial colonization and microbial diversity, while the grinding group had the highest adhesion and species richness. <bold>Conclusion</bold> Surface pretreatments markedly affect the mechanical/surface properties and bacterial adhesion of glazed zirconia. Polishing optimizes clinical performance by reducing roughness and bacterial colonization, whereas grinding and grit-blasting increase roughness and bacterial adhesion. Clinical Significance: This study clarifies that polishing after grinding optimizes surface smoothness and reduces bacterial adhesion on glazed zirconia, helping to lower caries and periodontal risks. It supports standardized surface protocols for durable, safe CAD/CAM restorations. </p>